Acharya N G Ranga Agricultural University, Guntur

The Andhra Pradesh Agricultural University (APAU) was established on 12th June 1964 at Hyderabad. The University was formally inaugurated on 20th March 1965 by Late Shri. Lal Bahadur Shastri, the then Hon`ble Prime Minister of India. Another significant milestone was the inauguration of the building programme of the university by Late Smt. Indira Gandhi,the then Hon`ble Prime Minister of India on 23rd June 1966. The University was renamed as Acharya N. G. Ranga Agricultural University on 7th November 1996 in honour and memory of an outstanding parliamentarian Acharya Nayukulu Gogineni Ranga, who rendered remarkable selfless service for the cause of farmers and is regarded as an outstanding educationist, kisan leader and freedom fighter. HISTORICAL MILESTONE Acharya N. G. Ranga Agricultural University (ANGRAU) was established under the name of Andhra Pradesh Agricultural University (APAU) on the 12th of June 1964 through the APAU Act 1963. Later, it was renamed as Acharya N. G. Ranga Agricultural University on the 7th of November, 1996 in honour and memory of the noted Parliamentarian and Kisan Leader, Acharya N. G. Ranga. At the verge of completion of Golden Jubilee Year of the ANGRAU, it has given birth to a new State Agricultural University namely Prof. Jayashankar Telangana State Agricultural University with the bifurcation of the state of Andhra Pradesh as per the Andhra Pradesh Reorganization Act 2014. The ANGRAU at LAM, Guntur is serving the students and the farmers of 13 districts of new State of Andhra Pradesh with renewed interest and dedication. Genesis of ANGRAU in service of the farmers 1926: The Royal Commission emphasized the need for a strong research base for agricultural development in the country... 1949: The Radhakrishnan Commission (1949) on University Education led to the establishment of Rural Universities for the overall development of agriculture and rural life in the country... 1955: First Joint Indo-American Team studied the status and future needs of agricultural education in the country... 1960: Second Joint Indo-American Team (1960) headed by Dr. M. S. Randhawa, the then Vice-President of Indian Council of Agricultural Research recommended specifically the establishment of Farm Universities and spelt out the basic objectives of these Universities as Institutional Autonomy, inclusion of Agriculture, Veterinary / Animal Husbandry and Home Science, Integration of Teaching, Research and Extension... 1963: The Andhra Pradesh Agricultural University (APAU) Act enacted... June 12th 1964: Andhra Pradesh Agricultural University (APAU) was established at Hyderabad with Shri. O. Pulla Reddi, I.C.S. (Retired) was the first founder Vice-Chancellor of the University... June 1964: Re-affilitation of Colleges of Agriculture and Veterinary Science, Hyderabad (estt. in 1961, affiliated to Osmania University), Agricultural College, Bapatla (estt. in 1945, affiliated to Andhra University), Sri Venkateswara Agricultural College, Tirupati and Andhra Veterinary College, Tirupati (estt. in 1961, affiliated to Sri Venkateswara University)... 20th March 1965: Formal inauguration of APAU by Late Shri. Lal Bahadur Shastri, the then Hon`ble Prime Minister of India... 1964-66: The report of the Second National Education Commission headed by Dr. D.S. Kothari, Chairman of the University Grants Commission stressed the need for establishing at least one Agricultural University in each Indian State... 23, June 1966: Inauguration of the Administrative building of the university by Late Smt. Indira Gandhi, the then Hon`ble Prime Minister of India... July, 1966: Transfer of 41 Agricultural Research Stations, functioning under the Department of Agriculture... May, 1967: Transfer of Four Research Stations of the Animal Husbandry Department... 7th November 1996: Renaming of University as Acharya N. G. Ranga Agricultural University in honour and memory of an outstanding parliamentarian Acharya Nayukulu Gogineni Ranga... 15th July 2005: Establishment of Sri Venkateswara Veterinary University (SVVU) bifurcating ANGRAU by Act 18 of 2005... 26th June 2007: Establishment of Andhra Pradesh Horticultural University (APHU) bifurcating ANGRAU by the Act 30 of 2007... 2nd June 2014 As per the Andhra Pradesh Reorganization Act 2014, ANGRAU is now... serving the students and the farmers of 13 districts of new State of Andhra Pradesh with renewed interest and dedication...

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Open Access
STUDIES ON IDENTIFICATION OF SOURCES, MECHANISMS OF RESISTANCE TO INSECT VECTOR AND HOST VECTOR RELATIONSHIP OF SESAME PHYLLODY
(Acharya n G Ranga Agricultural University, 2024-04-15) KALAPUREDDY REVATHI; Dr. K.V. HARI PRASAD
A field experiment entitled “Studies on identification of sources, mechanisms of resistance to insect vector and host vector relationship of sesame phyllody” was conducted at dry land farm, S.V. Agricultural College, Tirupati; Department of Entomology, S.V. Agricultural College, Tirupati and Institute of Frontier Technology (IFT), RARS, Tirupati during two consecutive years i.e., 2019-20 and 2020-21. Hundred and seven sesame genotypes were screened to identify the resistant source against phyllody. The pooled results of 2019-20 and 2020-21 on leafhopper population in different sesame genotypes indicated that the mean leafhopper population was 1.08, 1.01, 1.11 and 1.02 leafhoppers/plant during kharif, 2019; late rabi, 2019 20; kharif, 2020 and late rabi, 2020-21, respectively. The leafhopper population was found to be statistically non-significant; however, the overall pooled results on leafhopper population for two consecutive years were found to be statistically significant. The mean per cent phyllody incidence was in the range of 6.25 to 86.90 per cent during kharif, 2019; 2.09 to 56.73 during late rabi, 2019-20; 9.77 to 92.61 per cent during kharif, 2020 and 6.25 to 68.42 during late rabi, 2020-21. The cumulative results on mean phyllody incidence during kharif, 2019 and kharif, 2020 indicated that out of 107 genotypes screened for resistance against phyllody, one genotype (IC 203871) was found resistant, three genotypes (EC 377002-2, YLM 141 and IC 204132) as moderately resistant, seven genotypes as tolerant, 13 genotypes as moderately susceptible, 25 genotypes as susceptible and 58 genotypes were found as highly susceptible to phyllody with an average of 49.80 per cent phyllody incidence; while, pooled results during late rabi, 2019-20 and late rabi, 2020-21 revealed four genotypes to be resistant, 28 genotypes as moderately resistant, 31 genotypes as tolerant, 19 genotypes as moderately susceptible, 22 genotypes as susceptible and three genotypes as highly susceptible to phyllody with 28.45 per cent mean disease incidence. xvi moderately susceptible, 22 genotypes as susceptible and three genotypes as highly susceptible to phyllody with 28.45 per cent mean disease incidence. Studies on biophysical characters of resistance revealed that trichome density and leaf thickness were negatively correlated with mean leafhopper population and per cent phyllody incidence, while, leaf area was positively correlated with mean leafhopper population and per cent phyllody incidence. Studies on biochemical characters of resistance revealed that phenols and chlorophyll content were negatively correlated with mean leafhopper population and per cent phyllody incidence, while, proteins, amino acids and total reducing sugars were positively correlated with mean leafhopper population and per cent phyllody incidence. The studies on transmission of phytoplasma clearly indicated that there was no mechanical transmission of phytoplasma into healthy plants, while, the per cent phyllody transmission by leafhopper, Orosius albicinctus was in the range of 13.3 to 93.3 per cent with a mean of 54.67 per cent. The results from the transmission studies with leafhopper, Hishimonus phycitis revealed that the leafhopper could not be able to disseminate phytoplasma (zero per cent transmission rate) from infected sesame plants to healthy seedlings. The potential insect vector identified in successful transmission of phytoplasma was confirmed taxonomically with the help of keys and by dissection of male genitalia. LCO-HCO primers were used to amplify part of mitochondrial cytochrome oxidase subunit I (COI) gene for further confirmation of insect at molecular level. Results on BLAST analysis of obtained DNA sequence showed 96.85 per cent resemblance with existing sequences of Orosius albicinctus available in Genbank, NCBI. The findings on per cent identity matrix of mitochondrial gene sequence of test insect, O. albicinctus indicated that it showed highest per cent similarity of 96.62 with O. albicinctus (Accession no: MK690286.1, MT621035.1 and LN8790006.1). The sequence was submitted in GenBank, NCBI with accession number OL818327. Investigation on management of sesame leafhoppers with newer insecticides during two seasons i.e., kharif, 2019 and kharif, 2020 revealed that pymetrozine 50 WG @ 0.6 g l-1 was found to be most superior and effective by recording the highest per cent reduction of leafhopper population over control (90.58%), followed by dimethoate 30 EC @ 2.0 ml l-1 (79.71%) and thiamethoxam 20 WG @ 0.2 g l-1 (78.01%). The insecticidal treatments dimethoate and thiamethoxam were at par with each other. The next effective treatments in the descending order of their efficacies were dinotefuran, diafenthiuron, flonicamid and thiacloprid with 73.84, 70.51, 64.52 and 64.15 per cent reduction over control, respectively. The lowest per cent reduction over control was observed in plots treated with spinosad and spiromesifen showing 55.78 and 50.31 per cent reduction over control, respectively and was found least effective in reducing leafhopper population. Pymetrozine treated plots recorded highest yield of 527 and 472 kg ha-1 during kharif, 2019 and kharif, 2020, respectively.
Open Access
STUDIES ON BIO-SYSTEMATICS, POPULATION DYNAMICS AND MANAGEMENT OF MANGO LEAFHOPPERS
(Acharya N G Ranga Agricultural University, 2024-04-12) SIRASANI JAMMI PRASANTHI; Dr. M. S. V. CHALAM
The present experiment titled “Studies on Bio-systematics, Population Dynamics and Management of Mango Leafhoppers” was conducted for two consecutive years viz., 2019-20 and 2020-21 at S. V. Agricultural College, Tirupati. An extensive survey was conducted in major mango growing regions of 48 mandals of Rayalaseema zone, Andhra Pradesh to determine the species diversity of leafhoppers. The collected leafhoppers were segregated into males and females of different groups and were identified as three different species viz., Idioscopus nitidulus (Walker), Idioscopus nagpurensis (Pruthi) and Amritodus atkinsoni (Lethierry) (Cicadellidae: Hemiptera) based on external morphology and characters of male genitalia. Among the three species identified, I. nitidulus was the most abundant species followed by A. atkinsoni and both the species were collected from all the four districts viz., Kurnool, Kadapa, Chittoor and Anantapur surveyed during both the years, whereas I. nagpurensis was collected from Chittoor district only. Diagnostic key along with the characters of male genitalia for the identification of leafhoppers in mango ecosystems of Rayalseema zone was provided. The total DNA was extracted from the legs of taxonomically confirmed species of mango leafhoppers and the mitochondrial Cytochrome Oxidase subunit-I (mtCO-I) gene was amplified. The final aligned sequences of mtCO-I gene of three mango leafhopper species viz., A. atkinsoni, I. nagpurensis and I. nitidulus were 636, 658 and 658 bp in size respectively. MtCO-I sequences of I. nitidulus, I. nagpurensis and A. atkinsoni showed a maximum similarity of 93.92, 98.63 and 95.75 per cent with Indian populations of same species retrieved from NCBI database, respectively. Phylogenetic tree revealed two main clusters of subfamilies viz., Typhlocybinae (Amrasca splendens) and Idiocerinae. The main cluster of Idiocerinae was further diverged into three subclusters where xix each represented A. atkinsoni, I. nitidulus and I. nagpurensis, respectively. Each sequence of identified leafhoppers diverged separately within the sub clusters indicating genetic variations between the populations of Andhra Pradesh and from other parts of India along with China and Pakistan. Mitogenomes of mango leafhoppers were A-T rich with 41.2, 15.6, 28.3 and 14.9 per cent of thymine, cytosine, adenine and guanine, respectively. Studies regarding the influence of weather parameters on the incidence of leafhoppers were carried out from 31st SW, 2019 to 30th SW, 2021. Overall average number of leafhoppers present per sticky trap, twig and panicle ranged from 0.00 to 26.79 during the first year of study. Initially, very low number of leafhoppers (0.01 to 3.36 leafhoppers) was recorded till 38th SW and later the population increased gradually reaching a peak of 16.13 leafhoppers during the emergence of new flush of shoots and leaves in 46th SW. A second peak in the population was observed during the emergence of panicles recording 26.79 leafhoppers in the 16th SW which later declined with the flower drop. During the second year of experiment, mean number of leafhoppers ranged from 0.00 to 31.09. Though a very low initial population ranging from 0.00 to 2.20 leafhoppers was recorded, population increased during vegetative stage reaching a peak of 17.01 leafhoppers in 44th SW after which the population took a decreasing trend. A second peak of 31.09 leafhoppers was recorded in the reproductive stage during 12th SW followed by a decrease in the population reaching a minimum of 0.03 leafhoppers during the last week of experiment i.e., 25th SW, 2021. During 2019-20, the incidence of leafhoppers revealed a significant positive correlation with evaporation (r = 0.600) and sunshine hours (r = 0.646), a non-significant positive correlation with maximum temperature (r = 0.134), whereas a negative correlation with minimum temperature (r = -0.259), mean relative humidity (r = -0.404), rainfall (r = -0.508) and rainy days (r = -0.527) and the relationship was significant except for minimum temperature. During 2020-21, incidence of leafhoppers was positively correlated to the maximum temperature (r = 0.330), evaporation (r = 0.530) and sunshine hours (r = 0.531), whereas it was negatively correlated to minimum temperature (r = -0.284), relative humidity (r = -0.559), rainfall (r = -0.465) and rainy days (r = -0.511) and the result was significant. Multiple regression analysis revealed that 60 and 56 per cent of leafhopper population was under the influence of weather parameters during 2019-20 and 2020-21, respectively. A field trial was conducted at farmer’s orchard, Tirupati to screen four popular cultivars of mango viz., Baneshan, Bangalora, Neelum and Cherukurasam against leafhoppers during flowering period of 2020 and 2021. Significantly lower population of 12.58 leafhoppers per panicle was recorded in the cultivar, Bangalora followed by Cherukurasam (18.78 leafhoppers panicle-1) and Baneshan (20.80 leafhoppers panicle-1). Whereas, significantly higher incidence i.e., 27.23 leafhoppers per panicle was recorded in the cultivar, Neelum. Healthy and infested leaves and panicles of all the four test varieties were analysed for the concentration of total phenols, total proteins, free amino acids, xx total sugars, reducing sugars and non-reducing sugars. Significantly lower concentrations of phenols (2011.0 & 1757.0 µg g-1), total sugars (7475.0 &11581.0 µg g-1) and non-reducing sugars (2100.0 & 2063.0 µg g-1) and higher concentrations of proteins (2018.0 and 5512.0 µg g-1), free amino acids (1430.0 & 2318.0 µg g-1) and reducing sugars (5264.0 & 9409.0 µg g-1) were recorded in the healthy leaves and panicles of the cultivar, Neelum, respectively. Significantly higher levels of phenols (3146.0 & 2676.0 µg g-1), total sugars (92.06.0 & 14974.0 µg g-1) and non-reducing sugars (5197.0 & 7530.0 µg g-1) and lower levels of proteins (1019.0 & 4361.0 µg g-1), free amino acids (502.0 & 1254.0 µg g -1) and reducing sugars (3735.0 & 7048.0 µg g-1) were recorded in the healthy leaves and panicles of the cultivar, Bangalora, respectively. Infested leaves and panicles of all the four test varieties recorded significantly lower concentration of total sugars, reducing sugars, non-reducing sugars and proteins and higher concentrations of phenols and free amino acids when compared to the healthy leaves and panicles. Significantly maximum increase of phenols (47 & 56 %) and free amino acids (59 % each) and maximum reduction in the levels of proteins (48 & 63 %), total sugars (56 & 60 %), reducing sugars (61 & 63 %) and non-reducing sugars (45 % each) was recorded in both the infested leaves and panicles of Neelum over healthy leaves and panicles, respectively. Bangalora recorded significantly minimum increase of phenols (9 & 15 %) and free amino acids (25 % each) and minimum reduction in the levels of proteins (28 & 31 %), total sugars (22 & 29 %), reducing sugars (37 & 30 %) and non-reducing sugars (11 & 28 %) in both leaves and panicles over healthy leaves and panicles, respectively. Correlation studies between the incidence of leafhoppers on panicles and biochemical components of all the four test cultivars revealed a significant positive correlation with reducing sugars (r = 0.988) and free amino acids (r = 0.958), whereas a non-significant positive correlation with proteins (r = 0.834). Incidence of leafhoppers was negatively correlated to the level of total phenols (r = -0.972), total sugars (r = -0.931), and non-reducing sugars (r = -0.983). The negative correlation between incidence of leafhoppers and total sugars was non-significant, whereas it was significant with phenols and non reducing sugars. Studies on evaluation of efficacies of certain newer insecticides against mango leafhoppers were carried out on the variety, Bangalora at farmer’s orchard, Tirupati during the flowering season of 2020 and 2021. Among nine insecticides evaluated, imidacloprid (40 %) + ethiprole (40 %) 80 WG @ 0.6 g l-1 recorded significantly maximum per cent reduction (95.68 %) of leafhoppers over untreated control and was at par with thiamethoxam (12.6 %) + lambda cyhalothrin (9.5 %) 247 ZC @ 1.0 ml l-1 (94.88 %). The next best treatment was buprofezin (15 %) + acephate (35 %) WP @ 2.5 g l-1 (92.54 %) followed by pymetrozine 50 WG @ 0.6 g l-1 (84.81 %), imidacloprid 17.8 SL @ 0.3 ml l-1 (77.45 %) and lambda cyhalothrin 5 EC @ 2.0 ml l-1 (73.65 %). The next effective treatment in the descending order of efficacy was flonicamid 50 WG @ 0.4 g l-1 (69.83 %) which was at par with dinotefuran 20 SG @ 0.3 g l-1 (68.10 %). A minimum of 53.85 per cent reduction of leafhoppers was recorded with spinosad 480 SC @ 0.3 ml l-1
Open Access
STUDIES ON SEASONAL OCCURRENCE OF INSECT PESTS VIS-À-VIS USE OF PESTICIDES IN RICE ECOSYSTEM OF GUNTUR DISTRICT OF ANDHRA PRADESH
(Acharya N G Ranga Agricultural University, 2023-12-02) VALLURI JHANSI HIMA VARSHA; CHERUKURI SREENIVASA RAO
The studies were carried out on occurrence of insect pests, insecticide usage pattern and pesticide residues in Guntur District of Andhra Pradesh during rabi 2020-21 in NSJ Canal area and kharif 2021-22 in Krishna Western Delta in 45 and 90 farmers fields, respectively. The farm gate and market rice samples were analyzed at ISO/IEC 17025:2017 accredited Pesticide Formulation and Residue Analytical Centre (PFRAC) of National Institute of Plant Health Management. Seasonal occurrence of insect pests during rabi 2020-21 in NSJ Canal area revealed that rice leaf folder, yellow stem borer, brown planthopper, white backed planthopper, armyworm and gall midge incidence was found in the entire crop growth period among which leaf folder, yellow stem borer incidence was more evident and the pest incidence was always below the ETL. The incidence of all insect pests was below ETL due to application of 345 pesticides in 177 applications / sprayings, with an average of 4.32 sprayings / applications per farmer, and 8.41 pesticides in each field during the crop season. The commonly used pesticides in the area were acephate, flubendiamide and propineb, out of a total of 34 pesticide formulations (17 insecticides; 12 fungicides; 4 herbicides and one bio chemical product) used by the farmers. The farmers of the area majorly used (92.75%) recommended pesticides, but 45.94 per cent of the pesticide applications at higher doses. Seasonal occurrence of insect pests during kharif 2021-22 in KWD area revealed that leaf folder, yellow stem borer, brown planthopper, rice hispa and rice leafhopper incidence was found but always below the ETL except for BPH where the pest has crossed ETLs in very few fields in one week. The incidence of insect pests was below ETL, due to application of 703 pesticides in 280 applications / sprayings, with an average of 3.45 sprayings per farmer, and use of 8.67 pesticides. xxvi The commonly used pesticides in the area are bispyribac sodium, fenoxaprop-p-ethyl and metsulfuron methyl + chlorimuron ethyl, all herbicides, because the farmers in this area follow direct seeding of rice. Among insecticides, and fungicides, pymetrozine and hexaconazole, respectively, were highly used. A total of 50 pesticide formulations (25 insecticides; 20 fungicides; one bactericide; three herbicides and one unregistered product i.e., bio chemical pesticide) are used in the area. The majority of the pesticide applications (92.32 %) with recommended pesticides, and applied (57.01 %) with recommended doses. A comprehensive study on general awareness and knowledge of farmers on pesticide use and handling reveals that majority of the farmers in the study areas were unaware about the recommended pesticides in rice, pesticide classification based on toxicity, pesticide residues in food, rejection of the food exports due to pesticide residues, use of personal protection equipment, and disposal of empty containers. A significant relation was found between the educational qualification of farmers and awareness on first aid practices and toxicity classification. However, it was recorded that majority of them in both areas were using recommended pesticides in rice as per the suggestions of pesticide dealers / officials of department, as majority of the farmers contact retail pesticide shop dealers (82.22 % in NSJ Canal area and 66.3 % in KWD area). The farm-gate rice (de-husked brown) samples from ZBNF farmers and polished rice samples from market were free from pesticide residues, due to non application of pesticides in ZBNF farms and may be removal of pesticide residues due to processing in polished rice samples. About 28.8 % of farm-gate rice (de-husked brown) samples from NSJ canal area were detected with pesticide residues, but all with recommended pesticides only. However, the use of higher dosages of pesticides (94.44 % applications of propiconazole; 37.5 % applications of hexaconazole) in the area led to occurrence of pesticide residues above FSSAI MRL in 10 % samples with propiconazole, 4 % samples with hexaconazole and 4 % samples with buprofezin residues above FSSAI MRLs. About 25.5 % of farm-gate rice (de-husked brown) samples from NSJ canal area were detected with pesticide residues, but all with recommended pesticides only. However, the use of higher dosages of pesticides (100 % applications of quinalphos; 42.85 % applications of thiamethoxam) in the area led to occurrence of pesticide residues above FSSAI MRL in 9 % samples, where quinalphos and thiamethoxam residues were above MRLs. Risk assessment was conducted taking Highest Residue (HR) into consideration for each pesticide in rice and it was revealed that the hazard quotients (HQ) for individual pesticides and the hazard index (HI) which is cumulative of all the detected pesticides from all the samples were less than unity i.e., HQ and HI < 1, indicating that food is safe for consumption. The comprehensive studies on pest and pesticide management in two major rice areas in Guntur district reveals that the insect pests were under control due to continuous use of pesticides, principally the recommended pesticides as per CIBRC, but sprayed at higher doses incase of insecticides and fungicides. The awareness on safe handling and reading the labels found to be lacking among farmers in both areas. Residue analysis for rice collected from study area farmers indicate that about 10 % samples are with residues above FSSAI MRLs, and residues can be managed through simple mitigation advisories such as avoiding use of higher doses through extension networks.
Open Access
STUDIES ON FIELD SCREENING OF OKRA VARIETIES AND MANAGEMENT OF OKRA FRUIT AND SHOOT BORER, Earias vittella (Lepidoptera: Noctuidae)
(Acharya N G Ranga Agricultural University, 2023-12-02) ANKIREDDY JAWAHAR REDDY; D.V. SAI RAM KUMAR
Earias vittella commonly known as spotted bollworm or okra fruit and shoot borer is a major pest of the economically important crops, viz., cotton and okra. Since the introduction of Bt cotton, the insecticidal usage was drastically reduced for the management of E. vittella in cotton, at the same time there are many reports on increased infestation of E. vittella in okra crop, so this study mainly focused to find out the resistant genotypes, role of biophysical and biochemical characters of genotypes to impart the resistance against E. vittella, management of E. vittella with biopesticides under field conditions and finally genetic diversity studies among the E. vittella populations collected from different geographic locations of Andhra Pradesh, India. Observations on incidence of E. vittella were recorded at weekly interval corresponding to rabi 2020-2021, kharif and rabi 2021-2022. Twenty four okra genotypes were screened against E. vittella, the minimum shoot infestation was recorded in Abelmoschus tetraphyllus var. tetraphyllus (5.64%) and 1685 (6.04%) which is at par with IC-0117024 (6.72%) and IC-0112502 (6.96%). The highest infestation recorded in genotypes, A. Abhay (18.96%) which is statistically at par with IC-0601181(18.29%), IC-0039139 (18.72%) and IC-0602982 (17.55%). Similarly, xix pooled mean data on fruit infestation indicted that the per cent fruit infestation varied from 9.04 to 33.57 per cent. The minimum fruit infestation was recorded in Abelmoschus tetraphyllus var. tetraphyllus (9.04%) and IC-0112502 (13.80%) which is at par with 1685 (14.74%) and IC-0117024 (15.46%). The highest infestation recorded in genotypes, A. Abhay (33.57%) which is statistically at par with IC-0601181 (33.00%), IC-0039139 (32.34%), IC-0042491 (31.66%), IC-0602982 (31.46%), IC-0022283 (31.34%), IC-0117319 (29.56%), IC-0601181 (29.30%), IC-0601433 (29.16%). Categorization of okra genotypes on the basis of pooled mean shoot infestation data of three seasons i.e., rabi 2020-2021, kharif and rabi 2021-2022 indicated that none of the genotypes were neither immune nor resistant to E. vittella. But eleven genotypes viz., Abelmoschus tetraphyllus var. tetraphyllus (5.65%), 1685 (6.04%), IC-0117024 (6.72%), IC-0112502 (6.96%), IC-0112196 (9.20%), IC-0117331 (10.07%), IC-0117343 (11.16%), IC-0117028 (12.37%), IC-0116967 (12.61%), IC-0601433 (12.89%), IC-0112499 (13.43%), IC-0116966 (14.18%), IC-0022283 (14.75%), IC-0057733 (13.24%) and IC-0601182 (14.67%) were found to be moderately resistant. However nine genotypes viz., IC-0042491 (15.31%), IC-0039140 (16.87%), IC-0601411 (16.12%), IC-0117319 (16.78%), A. Anamika (15.68%), IC-0602982 (17.55%), IC-0601181 (18.29%), IC-0039139 (18.72%) and A. Abhay (18.96%) were found as moderately susceptible genotypes. Categorization of okra genotypes on the basis of of cumulative mean fruit infestation data of three seasons i.e., rabi 2020-2021, kharif and rabi 2021-2022 indicated none of the genotype recorded immune as well as resistant response to E. vittella, but three genotypes viz., Abelmoschus tetraphyllus var. tetraphyllus (9.04%), IC-0112502 (13.80%) and 1685 (14.74%) were found as moderately resistant against E. vittella. Eleven genotypes viz., IC-0117024, IC-0117343, IC-0117331, IC-0112196, IC-0057733, IC-0116966, IC-0116967, IC-0601182, IC-0112499, IC-0117028 and IC-0117319 recorded mean fruit infestation of 15.46, 18.40, 19.02, 20.11, 24.78, 26.34, 27.48, 29.30, 26.79, 26.36 and 29.56 per cent fruit infestation on number basis respectively, were found as moderately susceptible. While, rest of the genotypes viz., IC-0022283 (31.34%), A. Abhay (33.57%), IC-0601181 (33.00%), IC-0602982 (31.46%), IC-0039139 (32.34%), A. Anamika (31.87%), IC-0601411 (32.10%), IC-0042491 (31.66%) and IC-0039140 (30.63%) were found susceptible. Among the physico-morphic characters viz., trichome density has negative significant correlation with per cent fruit infestation (-0.717, -0.744 & -0.743) during all the seasons. However fruit angle and fruit length showed negative correlation with -0.409, -0.402, -0.474 and -0.307, -0.395, -0.341 against per cent fruit infestation) during all the seasons. While strongly negative significant correlation (-0.929, -0.953 & -0.941) was found with fruit yield per plant against per cent fruit infestation during all the three seasons. However biochemical characteristics viz., nitrogen and protein per cent of fruits have positive significant correlation with per cent fruit infestation 0.539, 0.451, 0.785 and 0.541, 0.456, 0.782 during all the three seasons. While potassium content of fruits has significant negative correlation against per cent fruit infestation by E. vittella (-0.567, -0.487 & -0.608). However total chlorophyll showed strongly significant xx positive correlation with 0.873, 0.705 and 0.790 against per cent fruit infestation by E. vittella. Positive significant correlation was found with ascorbic acid (0.437, 0.527 & 0.539), while strongly negative significant correlation was found with phenol (-0.881, -0.550 & -0.735) against per cent fruit infestation by E. vittella. Anthocyanin showed non significant negative correlation (-0.354, -0.147 & -0.254) against per cent fruit infestation by E. vittella during all the three seasons. All the native Bt isolate treatments recorded more than 50% per cent mortality in the laboratory evaluation against E. vittella by fruit dip method. The highest mortality was recorded with native Bt isolate 493 (90.00%) and the lowest mortality was recorded with isolate 49 treated larvae (60.00%). The median lethal concentration (LC50) ranged from 1.947x107 to 5.246x1010 CFU ml-1. The lowest LC50 value was recorded with HD 1 strain and the highest LC50 was recorded with isolate 49. The fastest lethal action against E. vittella larva was shown by reference strain HD1 (106.99 hpi) and the highest LT50 was recorded by isolate 52 (141.82 hpi). A field experiment was conducted with 13 treatments including seven native Bt isolate treatments viz., HD1, 49, 51, 52, 55, 16 and 493 along with commercial Bt treatment (Dipel), three Entomopathogenic fungal treatments viz., M.anisopliae, B. bassiana, M. rileyi, one chemical check viz., Chlorantraniliprole and untreated control. Cumulative efficacy of three sprays during rabi 2020-2021 indicated that Chlorantraniliprole 18.5% SC @ 0.27 ml l-1 was found superior with lowest mean fruit infestation (7.69%) and it was on par with M. rileyi (1x108 CFU g-1) @ 5 g l-1 (9.50%), Isolate 493 (1x1010 CFU g-1) @ 3 g l-1 (9.64%) and M. anisopliae (1x108 CFU g-1) @ 5 g l-1 (9.76%). However Isolate 55 (1x1010 CFU g-1) @ 3 g l-1 , Isolate 51 (1x1010 CFU g-1) @ 3 g l-1, Isolate 49 (1x1010 CFU g-1) @ 3 g l-1 and B. bassiana (1x108 CFU g-1) @ 5 g l-1 were least effective treatments with 12.29, 12.93, 13.29 and 12.47 per cent respectively, which were on par with each other. The cumulative efficacy of different treatments tested for the management E. vittella on okra during kharif 2021-2022 revealed that all the treatments were found effective over untreated control (20.08%). Among the treatments, Chlorantraniliprole 18.5% SC @ 0.27 ml l-1 was found superior with lowest mean fruit infestation (8.05%) and it was on par with M. rileyi (1x108 CFU g-1) @ 5 g l-1 (9.70%), Isolate 493 (1x1010 CFU g-1) @ 3 g l-1 (9.17%), M. anisopliae (1x108 CFU g-1) @ 5 g l-1 (9.90%) and Isolate 16 (1x1010 CFU g-1) @ 3 g l-1 (9.87%). However Isolate 52 (1x1010 CFU g-1) @ 3 g l-1, Isolate 49 (1x1010 CFU g-1) @ 3 g l-1, Isolate 55 (1x1010 CFU g-1) @ 3 g l-1, Isolate 51 (1x1010 CFU g-1) @ 3 g l-1, and B. bassiana (1x108 CFU g-1) @ 5 g l-1 were least effective treatments with 11.89, 12.78, 13.40, 13.53 and 13.95 per cent respectively, which were on par with each other. During rabi 2021-2022 all the treatments were found effective over untreated control (23.82%). Among the treatments, Chlorantraniliprole 18.5% SC @ 0.27 ml l-1 was found significantly superior over all the other treatments with lowest mean fruit infestation 6.73 per cent. While, Dipel ES (5x109 CFU ml-1) @ 3 ml l-1 emerged as next best treatment with 9.48 per cent which is on par with M. rileyi (1x108 CFU g-1) @ 5 g l-1 (9.88%), Isolate 493 (1x1010 CFU g-1) @ 3 g l-1 (9.81%), M. anisopliae (1x108 CFU g- xxi 1) @ 5 g l-1 (10.17%) and Isolate 16 (1x1010 CFU g-1) @ 3 g l-1(11.03%). However Isolate 55 (1x1010 CFU g-1) @ 3 g l-1, Isolate 49 (1x1010 CFU g-1) @ 3 g l-1, Isolate 52 (1x1010 CFU g-1) @ 3 g l-1, Isolate 51 (1x1010 CFU g-1) @ 3 g l-1, and B. bassiana (1x108 CFU g-1) @ 5 g l-1 were least effective treatments with 12.75, 12.95, 11.24, 12.31 and 12.07 per cent respectively, which were on par with each other. Genetic diversity among the E. vittella populations (39 locations) was studied by using RAPD primers. A total of eight RAPD primers were used to detect the polymorphism among the populations. Among the eight RAPD primers tested, OPA-09, OPA-11, OPA-12 and OPK-14 resulted in 100 per cent polymorphism with PIC value of 0.842. A dendrogram was constructed using similarity matrix, which showed four major clusters. A lone cluster contained the larval population from Yemmiganur which is considered as uni subcluster among all subclusters. The differences in the banding patterns with the RAPD primers revealed that polymorphism existed within the populations, which might be due to variations in single nucleotide resulting in variation in restriction sites. To obtain species specific primers for easy identification of E. vittella, among the RAPD primers used for genetic diversity studies, OPA-09 and OPA 10 were selected for development of SCAR markers. Using the OPA 10 primer which produced a unique DNA amplicon of 391 bp was specifically amplified in all 39 larval populations. Subsequently sequencing confirmed that actual size of these amplicons were 370 bp. Based on this sequence, several pairs of PCR primers were designed and screened. Among them the primer pair EV-OPA10F/EV-OPA10R, was shown to be able to specifically amplify a 375 bp amplicon in all the 39 larval populations. Another SCAR marker was developed using OPA 09 primer, which was EV-OPA09F/EV-OPA09R, amplified 220 bp amplicon in all the 39 larval populations. Therefore, these primer pairs were designated as the SCAR marker for easy identification of E. vittella. The specific mt COI primer was used in the current study enabled successful amplification of most collected specimens, which were sequenced bidirectional and then submitted in NCBI website for accession numbers. Generated sequences of present study showed 97 to 99 per cent similarity with data base sequences. A phylogenetic tree was constructed using neighbor joining (NJ, ML) method depicted cohesive clustering of the identified sequences of E. vittella. Tajima’s D statistic revealed the existence of low genetic polymorphism among the 35 mt COI sequences of E. vittella populations.
Open Access
STUDIES ON MANAGEMENT OF PULSE BEETLE, Callosobruchus maculatus (Fab.) (COLEOPTERA: CHRYSOMELIDAE) ON STORED CHICKPEA (Cicer arietinum L.) WITH NOVEL TECHNIQUES
(Acharya N G Ranga Agricultural University, 2023-12-02) PANATHULA CHAITHANYA; T. MADHUMATHI
The present investigation entitled “Studies on management of pulse beetle, Callosobruchus maculatus (Fab.) (Coleoptera: Chrysomelidae) on stored chickpea (Cicer arietinum L.) with novel techniques” was carried out in the laboratory of Department of Entomology, Agricultural College, Bapatla during 2020-21 and 2021-22. A total of twenty chickpea genotypes were screened against C. maculatus through no-choice and free-choice test. The data were recorded on number of eggs laid, adult emergence, mean developmental period, growth index, per cent grain damage by count and weight, per cent weight loss, number of exit holes on grains. The chickpea genotypes were categorized based on mean and standard deviation of different parameters studied through free-choice test as less susceptible (NBeG 452, NBeG 1129, ICC 86111, NBeG 49 and NBeG 776), moderately susceptible (NBeG 3, NBeG 47, JG 11, NBeG 699, NBeG 779, NBeG 857, NBeG 1137, NBeG 1174, NBeG 119, NBeG 810, KAK 2 and Vihar) and highly susceptible (NBeG 440, NBeG 789 and NBeG 833). Certain physical parameters and biochemical constituents of chickpea genotypes also influenced their relative susceptibility to C. maculatus. The less susceptible genotypes were desi type, small to medium sized grains with wrinkled surface nature. NBeG 452 and NBeG 1129 were found with high phenol content (119.06 and 115.71 mg CAE 100 g-1), tannin content (5.46 and 4.94 mg TAE g-1) and low total soluble sugars (55.94 and 59.98%), protein content (20.16 and 18.67%), medium test weight (24.73 and 25.27 g) and high seed coat thickness (0.173 and 0.207 mm); ICC 86111 with less test weight (17.27 g) recorded low number of eggs (24.33, 25.33 and 25.67) and adult emergence (19.67, 19.00 and 20.67) per 100 grains, low growth index (2.89, 2.73 and 2.90), lesser grain damage (17.75, 18.18 and 19.89%), low weight loss (4.86, 4.35 and 3.78%) and minimum number of exit holes per ten grains (2.67, 2.67 and 3.00) and less susceptible genotype, NBeG 49 was xviii found with high phenol content (118.91 mg CAE 100 g-1) and tannin content (5.15 mg TAE g-1), NBeG 776 with more seed coat thickness (0.210 mm) and less total soluble sugars (60.11%). Whereas highly susceptible genotypes were kabuli type, medium to bold sized grains with smooth surface nature, apart from these, NBeG 440 and NBeG 789 were found with less phenol content (84.48 and 74.25 mg CAE 100 g-1), tannin content (2.75 and 2.23 mg TAE g-1), more total soluble sugars (75.36 and 73.65%), medium test weight (31.33 and 35.67 g), less seed coat thickness (0.060 and 0.103 mm) and NBeG 833 with more test weight (44.60 g), low seed coat thickness (0.093 mm), more total soluble sugars (72.53%) and low tannin content (3.06 mg TAE g-1). Bioassay studies through jute cloth disc impregnation method revealed the lowest LC50 (0.00006%), LC75 (0.0002%) and LC90 (0.0006% and 0.0008%) values for emamectin benzoate and chlorfenapyr at 72 HAT and found relatively more toxic as compared to malathion (233.33, 191.00; 156.50 and 117.38 times, respectively) and deltamethrin (41.67, 83.00; 151.50 and 113.63 times, respectively). Permethrin @ 0.14% was found to be most effective against C. maculatus with highest average toxicity (62.38%) and with high PT index (11228.57) and recording relatively minimum population build-up of C. maculatus and per cent grain damage and weight loss of chickpea grains up to 150 DAT. However, among the novel insecticides, spinosad @ 0.1% was found to be effective with an average toxicity of 39.05 per cent against C. maculatus with 5857.14 PT index. The microwave radiation treatment of pre infested chickpea grains at 900-Watt power level with 30 s exposure time was found to be effective with less number of adult emergence of C. maculatus per 100 grains (6.67) with prolonged mean development period (30.01 days), low per cent adult emergence (17.32%), growth index (0.58) and number of exit holes per ten g grains (6.00). The microwave treatment, 720 W 30 s was found to be optimum in controlling growth and development of pulse beetle with 15.67 number of adults emerged per 100 g sample and 0.64 growth index along with maintenance of viability and germination above 80 per cent, followed by treatment at 540 W 30 s found to be effective in maintaining the viability and germination percentages above 90 per cent with 22.33 number of adults per 100 g sample and 0.69 growth index. Among the immature stages of C. maculatus, pupa was found to be resistant to microwave radiation with respect to highest range of per cent adult emergence of C. maculatus from the irradiated chickpea samples containing pupal stages (0.00 to 79.33%) followed by late larval (0.00 to 74.67%), early larval (0.00 to 72.00%), and egg stage (0.00 to 69.33%) at 900 W 90 s to 180 W 30 s, respectively. Chickpea grains stored in super bags recorded zero number of adult beetles of C. maculatus, zero grain damage by count and weight, zero weight loss, no moisture change, and above 90 per cent viability and germination of chickpea grains up to six months storage period followed by triple layer plastic bags and found to be most effective when compared to other types of bags tested.
Open Access
EVALUATION OF PHEROMONE BLENDS AND BIORATIONAL INSECTICIDES FOR THE MANAGEMENT OF Spodoptera frugiperda (J. E. Smith) (Lepidoptera : Noctuidae) IN MAIZE
(Acharya N G Ranga Agricultural University, 2023-12-01) NARAM RAJASEKHAR; N.V.V.S. DURGA PRASAD
Studies on ‘Evaluation of Pheromone Blends and Biorational Insecticides for the Management of Spodoptera frugiperda (J. E. Smith) (Lepidoptera : Noctuidae) in Maize’ were conducted at Regional Agricultural Research Station (RARS), Lam, Guntur during four seasons i.e., kharif 2019, rabi 2019-20, kharif 2020 and rabi 2020-21 with an aim to study the survey on the incidence of S. frugiperda in Guntur, Krishna and Prakasam districts of Andhra Pradesh, evaluation of pheromone blends against fall armyworm, assessment of damage potentials of fall armyworm at different crop growth stages and evaluation of bio-rational insecticides against fall armyworm. Highest per cent leaf damage was observed in Prakasam district with 21.91per cent during kharif 2019 and lowest per cent (6.87%) of leaf damage was observed in Guntur district during rabi 2020-21. Among three crop growth stages reproductive stage recorded highest per cent leaf damage of 24.29 per cent during kharif 2019 and lowest per cent leaf damage of 3.47 per cent was recorded in reproductive stage during during rabi 2020-21. Study on evaluation of pheromone blends against S. frugiperda in maize during kharif 2019 and 2020 demonstrated that among the seven different pheromone blends, Z9-14Ac:Z11-16Ac:Z7-12Ac (85.5:12.5:2) pheromone blend was found to be most effective blend which attracted highest number of moths at 98 DAS (50.00 moths/trap/week) and lowest number of moth catches at 49 DAS (7.17 moths/trap/week). Z9-14Ac:Z11-16Ac (99.4:0.6) blend was next best effective blend which attracted more number of moths at 98 DAS (39.67 moths/trap/week) and least number of moth catches was observed at 49 DAS (1.83 moths/trap/week). Z9-14Ac:Z11-16Ac (87:12.5:0.5) pheromone blend attracted more number of moths (15.33 moths/trap/week) at 77 DAS and lowest at 7 DAS (1.00 moths/trap/week). Whereas, Z9-14Ac:Z11-16Ac:Z7-12Ac (10:1:0.1) and Z9-14Ac:Z11-16Ac:Z7-12Ac xvii (10:1.5:0.1) attracted more number of moths (8.50 and 5.84 moths/trap/week) at 63 and 35 DAS respectively. Similar results were obtained during rabi 2019-20 and 2020-21 also. Assessment of damage potentials of S. frugiperda at different crop growth stages during kharif 2019, 2020 and rabi 2019-20, 2020-21 indicate that completely protected plot was recorded with 8.08 to 14.73 per cent leaf damage with 0.50 to 1.30 damage scale and achieved 68.24 to 70.45 q ha-1 yield. Completely unprotected plot recorded 100 per cent leaf damage at 42 DAS with 9.00 damage scale and achieved 10.97 to 13.66 q ha-1 yield. Completely protected plot recorded 57.27 and 56.79 q ha-1 incremental yield compared to unprotected plot in kharif and rabi seasons respectively with 9.02 and 6.07 per cent yield loss. In 60 days protected plot recorded 49.12 and 50.28 q ha-1 incremental yield and 18.34 and 16.30 per cent yield loss respectively compared to unprotected plot. In 40 days protected plot with management practices up to 42 DAS, 29.69 and 31.87 q ha-1 incremental yield was noted as compared to unprotected plot, with 45.79 and 49.30 per cent yield loss respectively. Whereas, unprotected plot had received 10.97 and 13.66 q ha-1 incremental yield with 85.38 and 81.79 per cent yield loss compared to fully protected plot. Among the seven treatments tested, the lowest per cent of leaf damage was observed in spinosad 45% SC treatment by 21.50 per cent (0.06 larvae/plant) at 3 DAT, which is statistically on par with emamectin benzoate 5% SG (23.39% and 0.09 larvae/plant) and novaluron 10% EC (28.79% and 0.11 larvae/plant). The remaining treatments i.e azadirachtin 1500 ppm, NSKE 5%, Bacillus thuringiensis (Berliner) and Metarhizium rileyi (Farlow) had recorded 43.30, 45.73, 49.38, 50.98 per cent leaf damage and 0.25, 0.30, 0.36, 0.48 larvae/plant respectively. Similar trend was observed at 7 and 10 DAT. Similar trend of per cent leaf damage and larval population was also observed in rabi 2019-20 and 2020-21. During rabi season M. rileyi was performed better compared to B. thuringiensis. Spinosad 45% SC (92.41%) and emamectin benzoate 5% SG (89.96%) were found effective in reducing the larval population over control, they were followed by novaluron 10% EC (85.46%). Lowest per cent population reduction over control was observed in B. thuringiensis (55.19%) and M. rileyi (43.98%) treatments and were statistically at par with one another. Similar trend was observed at 7 and 10 DAT. Similar trend of per cent population reduction over control was observed in rabi 2019-20 and 2020-21 also, but in rabi season M. rileyi was performed better compared to B. thuringiensis. Regarding yields highest kernel yields of 67.50 and 76.40 q ha-1 was obtained from plots treated with spinosad 45% SC in kharif and rabi seasons respectively. Emamectin benzoate 5% SG and novaluron 10% EC which were on par with spinosad 45% SC recorded the yields of 65.04, 73.77 and 59.70, 69.38 q ha-1 respectively. Azadirachtin 1500 ppm, NSKE 5%, B. thuringiensis and M. rileyi were on par and recorded the yields of 50.33, 47.11, 36.71, 30.70 and 62.18, 55.63, 45.19, 49.20 q ha-1 respectively in kharif and rabi seasons. Control plot recorded lowest yields of 27.65 and 35.24 q ha-1 in kharif and rabi seasons respectively.
Open Access
MOLECULAR CHARACTERIZATION OF BEET ARMYWORM, Spodoptera exigua (Hubner) AND DEVELOPMENT OF FORECAST MODEL FOR POD BORERS IN CHICKPEA
(Acharya N G Ranga Agricultural University, 2023-12-01) NARAVA RAMANA; D.V. SAI RAM KUMAR
The present study entitled “Molecular Characterization of Beet Armyworm, Spodoptera exigua and Development of Forecast Model for Pod Borers in Chickpea” was carried out during 2019-20 and 2020- 21. The objectives are; to assess the varietal and temporal factors on the incidence of pod borer, H. armigera and beet armyworm, Spodoptera exigua, development of weather based forecast model for pod borer, phylogeographic characterization of S. exigua with reference to mt COX 1 gene, In vivo characterization of Ryanodine receptors and evaluation of chlorantranilliprole induced mitochondrial dysfunction and metabolic changes in S. exigua. The experiments were conducted under field and laboratory conditions at International Crops Research Institute for Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad. Telangana, India. Ten Chickpea genotypes were sown at monthly interval during first week of September, October and November. Among the different sowing regimes tested, November sown crop was found to be optimal and right time for sowing of the chickpea genotype to evade the pod borer and beet armyworm incidence. The borer population fluctuated with the change in dates of sowing. Pod borer population was higher in the early sown crop (September) and with delayed dates of sowing in October and November, population decreased, further H. armigera peak larval population coincided with the flowering and pod formation stages, whereas S. exigua incidence was restricted to early vegetative stages of the crop growth. There were significant differences in percent pod damage across genotypes ranging from 10.50 to 40.66 per cent. Minimum pod damage was observed in ICCV 10 and maximum pod damage was observed in ICC 3137. To provide a more efficient and accurate information on timely application of insecticides, this research was aimed to develop a forecast model to predict population dynamics of pod borer using Autoregressive Integrated Moving Average (ARIMA), xxiv Artificial Neural Networks (ANN), ARIMAX and NNARX models. Several ARIMA (p, d, q) (P, D, Q) and ANN models were developed using the historical trap catch data. ARIMA model (1,0,1), (1,0,2) with minimal BIC, RMSE, MAPE, MAE and MASE values and higher R2 value (0.53) was selected as the best ARIMA fit model, and neural networks (7-30-1) was found to be the best fit to predict the catches of male moths of pod borer from September 2021 to August 2023. Similarly, ARIMAX and NNARX models were developed by including weather variables. ARIMAX model (2,0,0) with maximum temperature and rainfall as external variables was selected as the best ARIMAX fit. The neural network (10-32-1) was found to be the best fit to predict the catches of male moths of pod borer from September, 2021 to August, 2023. A comparative analysis performed between the ARIMA and ANN, shows that the ANN based models were best suited for effective pest prediction. The Phylogeographic studies based COX-1 and EF-1 gene sequences revealed that genes of the studied populations were separated into 2 major clades with a total of 31 COX-1 and 27 EF-1 alpha haplotypes. The FST values indicated low genetic difference between the population groups and within the groups, 14-18% genetic variation was observed. There are no gene flow and conversion tracts between the populations of four southern India. Our molecular studies on In vivo characterization of S. exigua Ryanodine receptors revealed the presence of target site mutations I4743M, Insertion of QLRHRLLATQS, YLKWISHNTPG, stop codon formation and several other mutations (replacements of P-X, T-A, Q-L, K-D, S-N, E-A, A-V, E-K, K-T, Y-H I-M, L-X, Deletion of APSALSQVDLSQ, Q and IEI (Numbered according to SeRyR, AFC36359.1) and are important for formation of the calcium channel pore formation and may alter the putative diamide insecticide binding sites in insect RyRs, thus these mutations conferring resistance in the field populations of S. exigua. Studies on chlorantranilliprole induced effects on mitochondrial function and metabolic changes revealed that chlorantranilliprole impeded the mitochondrial respiratory functions (Mitochondrial complex I- V) and induced lipid peroxidation, H2O2 content and LDH leak in a time and dose-dependent manner, further altered the level of antioxidant enzymes, gut proteases, trypsin, chymotrypsin and aminopeptidase leading to oxidative stress in cells, resulting in deleterious effects on the growth of S. exigua larvae, along with the neurotoxic effects.
Open Access
IDENTIFICATION AND MOLECULAR CHARACTERIZATION OF THRIPS COMPLEX TRANSMITTING THE Groundnut bud necrosis virus IN BLACKGRAM AND THEIR MANAGEMENT
(Acharya N G Ranga Agricultural University, 2023-12-01) LELLA RAJASEKHAR; T. MADHUMATHI
Thrips species were collected from 35 major blackgram cultivating areas in Andhra Pradesh. Based on the morphological identification, major species of thrips species on black gram in Andhra Pradesh state was Thrips palmi (63.12), Megalurothrips usitatus (30.05) and Scirtothrips dorsalis (6.83). Out of thirty five locations surveyed, no record of S. dorsalis was observed in 19 mandals and highest mean per cent of S. dorsalis i.e., 52.38 was recorded in Mentada mandal of Vizianagaram district. In Chittoor district Megalurothrips typicus (Bagnall), Ayyaria chaetophora (Karny), Phibalothrips peringueyi (Faure) and some Tubuliferan thrips were also observed in meager number. Molecular characterization of thrips samples revealed that T. palmi produced an amplicon size of 570 bp with ITS2 marker, M. usitatus with mtCOI marker at 655 bp and S. dorsalis amplified with mtCOIII marker at 713 bp. This study contributed a total of 21 gene sequences (seven samples for each thrips species ) to NCBI website Tajimas d statistic revealed the existence of low genetic polymorphism among the, ITS2 sequences of T. palmi, COI sequences of M. usitatus, COIII sequences of S. dorsalis. The thrips population was observed in the field approximately after 14 DAS during rabi 2019-2020 where as during kharif 2020-2021 in third week of August (21 DAS) Highly fluctuating thrips population incidence was noticed during the kharif season as population has increased gradually and reached peak at 35 DAS with 17.35 mean number of thrips per plant and after 35 DAS, thrips population started declining to 5.2 and 4.6, 4.55, 3.33 (thrips per plant) at 42, 49, 56, 63 DAS respectively. At 70 DAS slight increase in thrips population was noticed i.e. 7.1 thrips per plant during first week of October (40th SMW). Similarly thrips population was observed initially at 21 DAS during fourth week of December i.e. during 52nd SMW with 2.15 mean number of thrips per plant and reached peak at 63 DAS during second week of xxiii February i.e. during 6th SMW (Standard meteorological week) with 10.10 mean number of thrips per plant. The thrips population started declining towards maturity and lowest incidence was recorded at 77 DAS during fourth week of February i.e. during 8th SMW with 1.10 mean number of thrips per plant during rabi 2020-21. Overall view of GBNV incidence in blackgram in the present study revealed that the per cent disease incidence was more during kharif 2020-2021 (26.05 %) compared to rabi 2019-2020 (25.90 %) and rabi 2020-2021 (10.22 %). During rabi 2019-20, rabi 2020- 2021 the number of thrips per plant showed a highly significant positive correlation with maximum temperature i.e. 0.74, 0.726 respectively where as during kharif 2020-2021 positive correlation with out any significance i.e. 0.151 was observed. Similarly minimum temperature (0.75, 0.55), mean temperature (0.819, 0.435) showed highly significant positive correlation during rabi 2019-20, rabi 2020- 2021 respectively where as during kharif 2020-2021 positive correlation with out any significance i.e. 0.158, 0.172 was observed with number of thrips per plant. Rainfall showed non significant negative correlation with thrips population i.e. -0.256, -0.289, -0.319 during rabi 2019-20 and kharif 2020-2021, rabi 2020-2021 respectively. Number of rainy days (-0.156, -0.319) showed non significant negative correlation during rabi 2019-20 and rabi 2020-2021, respectively where as significant negative correlation -0.657 was observed during kharif 2020-2021. Wind speed (0.802) showed highly significant and positive correlation with thrips population was observed during rabi 2019-20. But during kharif 2020-2021, rabi 2020-2021 wind speed showed non significant negative correlation i.e. -0.346, -0.463 respectively. The number of thrips per plant showed a highly significant positive correlation with per cent disease incidence (0.889) where as mean number of thrips per square meter showed non significant positive correlation with disease incidence (0.57) during rabi 2019-2020 whereas the number of thrips per plant (0.279), mean number of thrips per square meter (0.179) showed a positive correlation with per cent disease incidence during kharif 2020-2021. Similarly during rabi 2020-2021, the number of thrips per plant (0.466) and mean number of thrips per square meter (0.508) showed a non significant positive correlation with per cent disease incidence. Multiple linear regression equation showed that all the weather variables together could influence the incidence of thrips by 77.0 (R2 = 0.77), 70.0 (R2 = 0.70) per cent, 83.0 (R2 = 0.83) per cent during rabi 2019-2020; kharif 2020-2021; rabi 2020-2021 respectively whereas weather variables together contributed to the incidence of bud necrosis disease incidence by 95.0 (R2 = 0.95) per cent, 94.0 (R2 = 0.94) per cent, 92.0 (R2 = 0.92) per cent during rabi 2019-2020; kharif 2020-2021; rabi 2020-2021 respectively. Out of the two species tested for transmission of GBNV, only T. palmi could able to transmit the GBNV from diseased to healthy plants where in the inoculated plants exhibited symptoms viz. chlorotic local lesions. Whereas M. usitatus failed to transmit the virus and the inoculated plants remained healthy. Hence Thrips palmi was identified as vector of Groundnut bud necrosis virus in blackgram. A minimum of 2 h acquisition access period (48 IAP), 4 h inoculation access period (24 h AAP) was required to transmit the bud necrosis disease in case of first instar larvae of T. palmi and a minimum of 2 larvae were required to transmit the bud necrosis disease xxiv at 24 AAP, 48 h IAP; 48 AAP, 48 h IAP. A minimum of 2 h acquisition access period (with 48 h IAP), 8 h inoculation access period (24 h AAP) was observed in case of second instar larvae and a minimum of 10 larvae required to transmit the disease at 24 AAP and 48 h IAP, and 2 larvae required to transmit the disease at 48 AAP and 48 h IAP. There was no disease transmission was observed at 30 min, 1 h, 2 h, 4 h, 6 h, and 8 h of acquisition access period and inoculation access periods in case of adults. Surprisingly a minimum of 24 h AAP (48 h IAP), 24 h IAP (24 h AAP) was observed with 8.33 per cent of disease transmission and there is no further increase of disease with increasing AAP (48 h IAP) and IAP (24 h AAP). A minimum of 10 adults were required to transmit the disease at 24 h AAP, 48 h IAP; 48 AAP and 48 h IAP. Among the all evaluated insecticides imidacloprid 70 WG seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 followed by thiamethoxam seed treatment + fipronil 5 SC spray @ 50 g a.i were proved best in reducing the thrips population with highest blackgram grain yield i.e. 1414 kg ha-1 with incremental cost benefit ratio 1:4.80 followed by thiamethoxam 70 WS seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 (1:4.47) during rabi 2019-2020. Similarly imidacloprid 70 WG seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 recorded least bud necrosis disease incidence among the all other tested insecticides. During Kharif 2020-2021, highest per cent population reduction over untreated control was found in treatment imidacloprid 70 WG seed treatment + spinosad 45 SC spray @ 72 g a.i ha-1 (86.67 per cent) followed by imidacloprid 70 WG seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1(86.62). Whereas among the treatments tested, imidacloprid 70 WG seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 recorded highest grain yield i.e. 1372 kg ha-1 with incremental cost benefit ratio 1:3.73 followed by thiamethoxam 70 WS seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 (1:2.93). Similarly, among the tested treatments imidacloprid 70 WG seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 recorded least mean bud necrosis disease incidence in blackgram i.e. 5.19 per cent and it was at par with thiamethoxam 70 WS seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 (5.64 per cent), imidacloprid 70 WG seed treatment + flonicamid 50 WG spray @ 75 g a.i ha-1 (5.94 per cent) thiamethoxam 70 WS seed treatment + spinosad 45 SC spray @ 72 g a.i ha-1(6.13 per cent), thiamethoxam 70 WS seed treatment + flonicamid 50 WG spray @ 75 g a.i ha-1 (6.39 per cent), imidacloprid 70 WG seed treatment + spinosad 45 SC spray @ 72 g a.i ha-1 (6.64 per cent) during kharif 2020-2021. During rabi 2020-2021, thiamethoxam 70 WS seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1, imidacloprid 70 WG seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1, imidacloprid 70 WG seed treatment + spinosad 45 SC spray @ 72 g a.i ha-1 proved best in reducing the thrips population. Thiamethoxam 70 WS seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 recorded least mean disease incidence. Among the treatments imidacloprid 70 WG seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 recorded highest grain yield i.e. 1439 kg ha-1 with incremental cost benefit ratio 1:4.45 followed by thiamethoxam 70 WS seed treatment + fipronil 5 SC spray @ 50 g a.i ha-1 (1:3.97).
Open Access
INTERACTIVE EFFECTS OF ELEVATED CARBON DIOXIDE AND TEMPERATURE ON HELICOVERPA ARMIGERA HUB. AND SPODOPTERA LITURA FAB. ON BT COTTON
(Acharya N G Ranga Agricultural University, 2023-11-30) D. V. SRAVAN KUMAR; Ch. CHIRANJEEVI
The present investigations titled „Interactive effects of elevated Carbon dioxide and Temperature on Helicoverpa armigera Hub. and Spodoptera litura Fab. on Bt cotton‟ of Department of entomology, Agricultural college, Bapatla, Acharya N. G. Ranga Agricultural university (ANGRAU) were conducted during 2018-2020 at ICAR - Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad, Telangana. The two test insects, H. armigera and S. litura are major polyphagous cotton pests, causing heavy yield losses. In the context of global warming, largely driven by elevated carbon dioxide (eCO2) and elevated temperatures (eTemp), understanding the future status of these pests is an important task. Hence, growth, development and feeding indices of H. armigera and S. litura for three successive generations on cotton and also the biochemical constituents of cotton foliage and the larvae were elaborately studied under ambient carbon dioxide (aCO2: 380 ± 25 ppm) and elevated carbon dioxide (eCO2: 550 ± 25 ppm), at five temperatures (28, 29, 31, 33 and 35 ± 1°C). Growth parameters in test insects, H. armigera and S. litura, viz., food ingestion, larval weight and larval excretion increased under eCO2 (550 ppm) + eTemp (35 °C) whereas, pupal weight and fecundity decreased. Food ingestion capacity of the larvae increased significantly in every next generation, thus indicating greater adaptation of the test insects to climate change with advancement of generations. Notably, larval and pupal weights in the three successive generations were relatively higher for S. litura, probably due to good food ingestion. The durations of larvae, pre-pupae and pupae increased significantly under eCO2 + eTemp. The major reproductive parameter fecundity decreased under eCO2 + eTemp. In Bt cotton, mean fecundity of H. armigera under eCO2 was reduced by 7.29, 9.03, 9.58, 9.93 and 6.39 % in fiber comparison to 1.90, 3.54, 5.18, 1.62 and 1.53 % in S. litura. xx Among feeding indices of both the test insects, with increase in CO2 and temperature, Approximate Digestibility (AD) and Relative Consumption Rate (RCR) increased whereas Efficiency of Conversion of Ingested food (ECI), Efficiency of Conversion of Digested food (ECD) and Relative Growth Rate (RGR) decreased. In Bt cotton, under eCO2, the mean decrease of RGR of H. armigera was higher by 14.79, 9.80, 10.36, 7.11 and 7.81 % compared to 11.50, 13.08, 14.39, 13.65 and 13.75 % in S. litura compared to that of aCO2. At elevated conditions, H. armigera has higher ECI in Bt cotton and high RGR in both non-Bt and Bt cotton, compared to S. litura. It implies that H. armigera could be a potential key pest in future climate stress scenarios even in Bt cotton. The biochemical constituents of non-Bt and Bt cotton were down regulated by eCO2 + eTemp i.e., nitrogen, proteins, Cry1Ac and Cry2Ab toxin contents were reduced, there by the future cotton production may challenged by these polyphagous insect pests under stressed environmental conditions. Commensurate with the decline in leaf Bt endotoxins, the larval mortality of both the test insects also reduced. Among the biochemical components in test insects, carbohydrate content in H. armigera increased at elevated conditions, whereas the protein content in H. armigera and S. litura decreased. Succinctly, anticipated eCO2 necessitates the test insects to attain more nitrogen from the under nutritious foliage by huge consumption as evident from the enchanced foliage ingestion and AD and RCR. Apart from the other growth and feeding indices, higher foliage consumption itself is a major threat of future crop production. Further, increased larval and pupal durations may play a key role in gaining biomass and sufficient energy for transforming into adults with improved fitness. Besides, they could adapt to changing climate as evident from the higher values of all the parameters in the third generation under eCO2 +eTemp. Another intriguing issue is the decrease in Bt toxin production in Bt cotton leaves under eCO2 +eTemp, thus cotton crop can become more vulnerable for these pests, especially for H. armigera.

Acharya N G Ranga Agricultural University, Guntur

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