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
EVALUATION OF ECOFRIENDLY TECHNIQUES FOR THE MANAGEMENT OF STEM BORERS, Chilo partellus (Swinhoe) AND Sesamia inferens (Walker) IN MAIZE
(Acharya N G Ranga Agricultural University, Guntur, 2019) ANIL KUMAR, K; MADHUMATHI, T
Investigations on the effect of organic amendments at high and normal densities of maize on the incidence of stem borer, influence of morphological and biochemical plant characters of maize on the stem borer incidence, evaluation of organics and botanicals in the management of stem borer were conducted at College Farm and Department of Entomology, Agricultural College, Bapatla and a roving survey was conducted in Guntur and Krishna districts of Andhra Pradesh to ascertain the occurrence of maize stem borers. All these experiments were conducted for four consecutive seasons i.e., on kharif 2017-18, rabi 2017-18, kharif 2018-19 and rabi 2018-19 on Chilo partellus Swinhoe (in kharif) and Sesamia inferens Walker (in rabi) The two plant densities (main plots) of maize tested were on par with each other with regard to the stem borer infestation and organic amendments (sub plots) significantly differed from others with lowest per cent leaf infestation (12.23%), dead hearts (1.48%), stem tunneling (2.66%), number of exit holes (0.45), number of larvae (0.31) and number of pupae (0.18) observed in untreated control and highest leaf infestation (22.91%), dead hearts (5.36%), stem tunneling (16%), number of exit holes (1.55), number of larvae (1.00) and number of pupae (0.74) in RDF treatment against C. partellus during kharif 2017-18 & 18-19. Similarly during rabi the same trend was followed with lowest per cent leaf infestation (16.0%), dead hearts (3.25%), stem tunneling (8.52%), number of exit holes (0.93), number of larvae (0.63) and number of pupae (0.28) observed in untreated control and highest leaf infestation (29.54%), dead hearts (7.32%), stem tunneling (17.47%), number of exit holes (2.16), number of larvae (1.36) and number of pupae (0.75) in RDF treatment against S. inferens. However all the organic amendments alone treated plots are on par with untreated control having lower infestation levels and yields while organic manures + 75% RDF treated plots are almost on par with RDF treated plots in terms of infestation levels and yield of maize. xxii Correlations of morphological plant characters with stem borer incidence revealed that some of morphological characters have correlation with the stem borer infestation and showed significance in both normal plant density and high plant density of maize. During kharif 2017-18 & 2018-19 the morphological plant characters like number of nodes, plant height, cob height, leaf length and leaf width recorded nonsignificant positive correlation with leaf infestation and dead hearts by C. partellus. Significant positive correlations with leaf infestation and dead heart damage were observed with cob length, internodal length, stem diameter, 100 grain weight and dry matter. However, significant negative correlation was observed between leaf infestation, dead heart and trichome density. Similar results were also observed with high density planting. During rabi 2017-18 & 2018-19, the morphological plant characters like cob height, leaf length, leaf width recorded non-significant positive correlations while, number of nodes, plant height, cob length, internodal length, stem diameter, 100 grain weight recorded significant positive correlation with S. inferens leaf infestation and dead heart damage whereas, trichome density recorded significant negative correlation. At high density, the morphological characters like number of nodes, plant height, cob height, leaf length, leaf width, total dry matter of the plant, cob length recorded nonsignificant correlation with S. inferens leaf infestation and dead heart damage whereas 100 grain weight, internodal length and stem diameter showed significant correlation with both leaf infestation and dead heart damage. During kharif 2017-18 & 2018-19, at 45 days after sowing (normal plant density), the biochemical plant characters like nitrogen, carbohydrate and protein recorded significant correlation with leaf infestation of C.partellus while, phenols recorded non-significant negative correlation. Similar correlation results were observed at 75 days after sowing. During rabi 2017-18 & 2018-19, at 45 days after sowing (normal plant density), the biochemical plant characters like nitrogen, carbohydrate and protein recorded significant correlation with leaf infestation of S. inferens while, phenols recorded non-significant negative correlation. Similar correlation results were observed at 75 days after sowing. Survey conducted during kharif 2017-18 and 2018-19 revealed that in Guntur district, the least infestation of maize by C. partellus in terms of per cent leaf infestation (12.37%), dead heart percentage (8.64%), stem tunneling length (1.83), no. of larvae (0.32), no. of pupae (0.17) and no. of exit holes (0.33) was observed in Narasaraopet mandal. The highest per cent leaf infestation (23.39%), with high dead heart percentage (21.56%) recorded in Pedanandipadu mandal while, Ponnur recorded highest tunneling length (3.6) and found more no. of larvae (0.49), no. of pupae (0.29) and no. of exit holes (0.58) compared to other mandals surveyed. In Krishna district, Veerullapadu mandal recorded the least infestation of maize by C. partellus in terms of per cent leaf infestation (10.25%), dead heart percentage (6.67%), stem tunneling length (1.87) and found less no. of larvae (0.24), no. of pupae (0.11) and no. of exit holes (0.23) and Musunuru mandal recorded the highest per cent leaf infestation (22.66%), dead heart percentage (20.16%), tunnel length (3.00) and found more no. of larvae (0.42), no. of pupae (0.22) and no. of exit holes (0.48) compared to other mandals surveyed during kharif 2017-18 and 2018-19. More number of spiders and coccinellids were recorded in Pedanandipadu mandal (2.96 & 7.09) and xxiii least in Narsaraopet mandal (1.58 & 3.82) of Guntur district and in Krishna district more number of spiders and coccinellids were recorded in Musunuru mandal (3.53 & 7.33) and least in Veerullapadu mandal (1.40 & 3.68). During rabi 2017-18 and 2018-19, Narasaraopet mandal recorded the least infestation of maize by S. inferens in terms of per cent leaf infestation (18.28%), dead heart percentage (15.16%), stem tunneling length (2.66) and found less no. of larvae (0.39), no. of pupae (0.22) and Battiprolu mandal recorded the least no. of exit holes (0.38). However, Ponnur mandal recorded the highest per cent leaf infestation (28.05%) with stem tunneling length (5.71), Battiprolu mandal recorded highest dead heart percentage (22.66%) and no. of pupae (0.34), Pedanandipadu mandal recorded more no. of larvae (0.63), and no. of exit holes (0.48) compared to other mandals surveyed in Guntur district. In Krishna district, Veerullapadu mandal recorded the least infestation of maize by S. inferens in terms of per cent leaf infestation (15.33), dead heart percentage (12.97), stem tunneling length (2.10) and found less no. of larvae (0.24), no. of pupae (0.18) and no. of exit holes (0.17) and Mylavaram mandal recorded the highest per cent leaf infestation (24.28), dead heart percentage (21.26) and musunuru mandal recorded highest tunnel length (3.81) and G. Konduru found more no. of larvae (0.51), Mylavaram mandal recorded more no. of pupae (0.33) and no. of exit holes (0.57). More number of spiders and coccinellids were recorded in Battiprolu mandal (2.42); Ponnuru mandal (4.74) and least in Narsaraopet mandal (1.39), Battiprolu (3.54) in Guntur district and more number of spiders recorded in Mylavaram mandal (2.69), coccinellids in Musunuru mandal (7.12) and least in Veerullapadu mandal (1.18; 2.58). During kharif 2017-18 and 2018-19 carbofuran 3G@ 12.5 kg ha-1 recorded 47.7 per cent mean reduction of leaf infestation of maize by C. partellus over untreated control (UTC), lowest per cent dead hearts (2.28%) followed by NSKE (5%) which recorded 35.2 per cent mean reduction of leaf infestation over UTC with 4.33% dead hearts. However, UTC recorded highest dead hearts (8.52%) by C. partellus. Similarly, during rabi 2017-18 and 2018-19 carbofuran 3G @ 12.5 kg ha-1 found to be the best over other treatments and recorded 45 per cent mean reduction of leaf infestation of maize by S. inferens over UTC, lowest per cent dead hearts (7.05%) followed by NSKE (5%) which recorded 33.7 per cent mean reduction of leaf infestation over UTC with 8.00% dead hearts. However UTC recorded highest dead hearts (13.96%). The data of stem tunneling, exit holes, larvae of C. partellus and S. inferens also followed the same trend. The results of benefit to cost ratio inferred NSKE (5%) as the best treatment in reducing the C.partellus infestation and increasing of yields with 3.89 in kharif and 2.99 in rabi. It was followed by carbofuran 3G @ 12.5 kg ha-1 with 2.53 in kharif and 2.35 in rabi. All other botanicals and organics tested proved to be ineffective and showed very low benefit to cost ratios. The pooled data (four seasons) pertaining to effect of botanicals and organics on natural enemies showed highest number of spiders in UTC (1.15), NSKE (5%) (1.10) and cow urine (10%) (1.06) and lowest number of spiders found in carbofuran 3G@ 12.5 kg ha-1 (0.38) and panchagavya (3%) (0.51). Similarly, highest number of coccinellids were recorded in UTC (1.38), NSKE (5%) (1.34) and cow urine (10%) (1.25) and lowest in carbofuran 3G@ 12.5 kg ha-1 (0.49) and panchagavya (3%) (0.61)
Open Access
MOLECULAR AND BIOCHEMICAL VARIABILITY OF CERTAIN BRINJAL GENOTYPES AGAINST SHOOT AND FRUIT BORER Leucinodes orbonalis (GUENEE) (LEPIDOPTERA: PYRALIDAE
(ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) CHINNABBAI, CHETTUBATHINA; DAYAKAR, S
The present investigations on “Molecular and biochemical variability of certain brinjal genotypes against shoot and fruit borer Leucinodes orbonalis (Guenee) (Lepidoptera: Pyralidae)” were carried out at college of Horticulture, Venkataramannagudem during both Rabi and Kharif seasons of 2016-17 and 2017-18, 2017-18 and 2018-19. Studies on screening of genotypes against shoot and fruit borer revealed that none of the genotypes showed complete resistance to shoot and fruit borer. Significantly lowest shoot infestation (9.01 %), as well as fruit infestation (12.73 %) were recorded with IC 136061.The highest infestation of shoot (34.99 %) and fruit (46.77 %) was recorded on Dommeru Local.The shoot infestation on remaining genotypes ranged from 11.34 % to 30.96 % and while the same for was 15.39 % to 43.79 %. Based on per cent fruit infestation genotypes fourteen genotypes viz., IC 136061 (12.73%), IC 136148 (15.39%), IC 135912 (16.08%), IC 136299 (16.14%), IC 136041(16.23%), IC 136296 (16.94%), IC 154517 (17.18%), A.Nidhi (17.18%), IC 203589 (17.23%), IC 213564 (17.46%), S.Pratibh (17.54%), IC 137751(19.06%), IC 144525 (19.42%) and IC 136231(19.89%) were categorized as moderately resistant due to low level of fruit infestation (11-20 %). In the remaining genotypes, twenty four were categorized as tolerant (20.00 to 30.00 % fruit infestation), twenty as susceptible (30.00 to 40.00 % fruit infestation) and five genotypes as highly susceptible (above 40.00 % fruit infestation). Genotype IC 136061 recorded highest fruit yield (1.484 kg plant-1) whereas VR 02 recorded lowest fruit yield (0.211 kg plant-1). The fruit yield in the remaining genotypes was ranged from 0.279 to 1.089 kg plant-1. IC 136148 (1.089 kg plant-1), A.Nidhi (1.070 kg plant-1) and IC 135912 (1.051 kg plant-1) were the other promising moderately resistant genotypes with low per cent shoot and fruit infestation and higher yield. xix The influence of physicomorphic and biochemical factors of shoot and fruit on the infestation of shoot and fruit borer revealed that per cent shoot infestation showed positive and highly significant correlation with shoot thickness (r = 0.9403), significantly high negative correlation with trichomes on leaf lamina (r = - 0.9755), significantly high negative correlation with trichomes on shoot (r = - 0.9484), non significant correlation with plant height (r = 0.1899), number of branches (r = 0.2395) and plant spread (r = 0.0557). The per cent fruit infestation showed positive correlation with fruit length (r = 0.9403), fruit diameter (r = 0.9755), pedicel length (r = 0.0009), number of branches (r = 0.1921), plant spread (r = 0.0379) while a significant and negative correlation with calyx length (r = - 0.3298). The per cent shoot infestation showed negative and highly significant correlation with phenol content in shoot (r = - 0.9587), highly significant and negative correlation with peroxidase content in shoot(r = - 0.9645), highly significant and negative correlation with PAL content in shoot (r = - 0.9692). Highly significant and positive correlation was observed between phenol content of shoot with peroxidase (r = 9937) and PAL (r = 0.9776). Peroxidase and PAL also showed highly significant and positive correlation (r = 0.9911). The per cent fruit infestation showed negative and highly significant correlation with phenol content in fruit (r = - 0.9717), highly significant and negative correlation with peroxidase content in fruit (r = - 0. 9586), highly significant and negative correlation with PAL content in fruit (r = - 0.9719). Significant and highly positive correlation was observed between phenol content of fruit with peroxidise (r = 0.9628) and PAL (r = 0.9758). Peroxidase and PAL also showed highly significant and positive correlation (r = 0.9643). The highest PIC was recorded in the SSR marker 133 (0.5911), while it was found to be lowest for the marker 120 (0.3504). SSR marker 139 recorded the highest heterozygosity of 0.5801 while the lowest in 133 (0.2217). All the genotypes under the present investigation were found to have unique allelic profiles with SSR loci.The ten selected SSR primers amplified alleles across the 60 genotypes and 3 checks with varying degrees of polymorphism. High level of polymorphism was observed with as many as 3 alleles per locus with 131,133 and 134 primers. The high level of polymorphism obtained with SSRs in the present study is consistent with their known characteristics that they were more variable and revealed greater diversity. The similarity index based on 10 SSR markers ranged from 0.200 to 1.000 Out of the seven modules evaluated against shoot and fruit borer, M1(moderately resistant genotype) found effective by recording low mean shoot infestation (11.76%), fruit infestation (15.05%) and was significantly superior over other modules. M7 (farmers practice) was the next best performer with 14.28% and 19.51% of shoot and fruit infestation respectively and was followed by M6 (17.69%, 31.34%), M5 (20.61% and 36.33%), M4 (23.24% and 39.75%), M3 (25.82% and 43.55%) and M2 (29.23%, 50.45%). In overall mean fruit infestation on weight basis also M1 showed significant superiority in performance over other modules. xx In terms of marketable fruit yield, M7 (farmers’ practice) effective as it recorded significantly highest marketable fruit yield (31692.27 kg ha-1) followed by M1 (31315.20 kg ha-1), M6 (25603.20 kg ha-1), M5 (23654.40 kg ha-1), M4 (19159.47 kg ha-1), M3 (17808.00 kg ha-1) and M2 (15052.80 kg ha-1). Observations on yield and cost economics of different IPM modules revealed that module M7 showed superiority over other modules in terms of yield ( 31692.27 kg ha-1), cost of production (Rs. 121750.00 ha-1) and gross returns (Rs.380307.20 ha-1). Module M1 produced 31315.20 kg ha-1 fruit yield, incurred low production cost (Rs.93137.00 ha-1) with gross returns of Rs. 375782.40 ha-1. The highest B: C ratio of 4.03:1 was registered with M1 and next best was M7 with 3.38:1. From the above investigation conducted for two years, it was concluded that selection of a moderately resistant variety and adoption of IPM methods are more effective in the management of shoot and fruit borer and was economically profitable.
Open Access
MANAGEMENT OF SPOTTED STEM BORER, Chilo partellus (Swinhoe) THROUGH ECOLOGICAL ENGINEERING IN MAIZE
(Acharya N G Ranga Agricultural University, Guntur, 2019) RAVI KUMAR, V; MADHUMATHI, T
Experiments were conducted at Agricultural college farm, Bapatla during kharif and rabi 2017-18 and 2018-19 with objectives to identify suitable leguminous intercrops and gramineous trap crops in maize for the management of Chilo partellus (Swinhoe). Among the leguminous intercrops evaluated, maize-cowpea intercropping system supported with higher number of coccinellid beetles (0.93 /plant) and spiders (1.02/plant) than maize sole crop, which recorded 0.53 coccinellid beetles and 0.71 spiders /plant. These natural enemies suppressed C. partellus damage in maize that resulted in reduced foliage damage (15.18%), dead hearts (4.79%) and larval density (0.81/plant) when compared to maize sole crop i.e., 26.80 per cent, 8.80 per cent and 1.48 per plant, respectively. Results indicated that maize-green gram and maize-black gram intercropping systems were the next best treatments in suppressing C. partellus incidence. Influence of cowpea intercropping on C. partellus incidence in maize was clearly reflected on grain yield. Maize-cowpea intercropping system produced higher grain yield (5643 kg/ha) over maize sole crop (4553 kg/ha). Studies pertaining to evaluation of suitable gramineous trap crops for the management of C. partellus revealed the glory of napier grass. Maize trap cropped with napier grass treatment recorded with least foliage damage (9.62%), dead hearts (1.99%) and larval density (0.35larave/plant) found significantly superior to maize xiv sole crop which had shown highest foliage damage (29.30%), dead hearts (8.83%) and larval density (1.14 larvae/plant). Yield parameters clearly indicated the influence of napier grass in suppressing C. partellus incidence by showing highest grain yield of 5813 kg/ha compared to maize sole crop that recorded 4585 kg/ha. Sorghum and sudan grass were found to be next best trap crops while bajra was ineffective in managing C. partellus. Ovipositional studies revealed the effectiveness of napier grass as a trap crop against C. partellus. Results from dual-choice tests indicated that female moths of C. partellus preferred to oviposit on napier grass instead of maize. Significantly higher number of egg batches (4.5/plant) and total number of eggs (354.6/plant) were laid on napier grass than maize (2.3 egg batches/plant and 148 eggs). Larval survival and development studies indicated the greater mortality of C. partellus larvae occurred within five days on napier grass. None of the C. partellus larvae survived upto pupation in napier grass while 38.80 per cent larvae pupated in case of maize. Integration of different pest management approaches for the management C. partellus revealed that cultural+biological+chemical method of treatment reduced foliage damage (8.19%), dead hearts (2.40%) and larval density (0.38/plant) over untreated control. The per cent stem tunnelling was least (2.70) in case of cultural+biological+chemical method of treatment where as untreated maize crop recorded highest tunnelling length (9.21). Cultural method alone was on par with cultural+biological+chemical method in suppressing C. prtellus incidence which indicated its importance in integrated pest management practice. Highest grain yield (6096 kg/ha) was observed in cultural+biological+chemical method of treatment than remaining combinations of pest management and least grain yield in untreated control (4596 kg/ha). Higher net profits were observed in cultural method (Rs 23015/-), cultural+biological method (Rs 21619/-) and cultural+biological+ chemical method (RS 21429/-). The incremental benefit cost ratio was higher in cultural method (6.67) followed by cultural+biological (3.84), cultural+chemical (3.65) and cultural+biological+chemical method (2.70).
Open Access
INSECTICIDE INDUCED RESURGENCE OF RICE BROWN PLANTHOPPER, Nilaparvata lugens (Stal) (Hemiptera:Delphacidae) AND MANAGEMENT WITH CERTAIN INSECTICIDES
(Acharya N G Ranga Agricultural University, Guntur, 2019) ANAND KUMAR, A. D. V. S. L. P.; RAMA RAO, C.V.
Indiscriminate use of insecticides is leading to resurgence of insect pests in various crops. Rice brown planthopper management has become very difficult due to its ability to develop resurgence to different insecticides regularly used by the farmers. Keeping this in view studies were initiated to find out the insecticides causing resurgence and their effect on biology of brown planthopper and also reasons for resurgence. Studies were also conducted to find out the effective insecticide rotations for management of BPH during kharif and rabi 2017-18. Information generated on insecticide usage pattern adopted by the rice growers revealed that calendar based sprays irrespective of pest and disease incidence, use of non-recommended synthetic pyrethroids for controlling insect pests, application of insecticides at higher doses than the recommended level, mixing more than one pesticide (cock tails) to control insect pests and diseases simultaneously and defective spraying etc. are some of the practices followed by the rice growers contributing to the resurgence of brown planthopper infesting rice. Brown planthopper had two peaks with first peak during 41st SMW (i. e., second week of October 2016) followed by second peak during 43rd SMW (i. e., fourth week of October 2016) during kharif 2016. During rabi 2016-17, the activity of BPH was found initially low during 7th SMW (February 12-18) and gradually increased during successive standard weeks (8th-14th SMW) and reached the highest number during 14th SMW (i.e., first week of April). The incidence of WBPH attained peak initially during 38th SMW (September 17-23) and later during third week of October (42nd SMW) during kharif 2016, while in rabi 2016-17 first WBPH was noticed during 7th SMW (February 12-18) and population increased gradually during successive weeks and attained peak number during 13th SMW (March 26-April 1). Brown planthopper had significant negative relationship with morning relative humidity of current week and sunshine hours of two weeks earlier but positive correlation with evening relative humidity two weeks earlier in kharif 2016. Maximum and minimum temperatures (current week, one week and two weeks xviii earlier) and evening relative humidity two weeks earlier in rabi had significantly positive impact on population of BPH. White backed planthopper had significant negative relation with morning relative humidity of current week during kharif 2016. None of the abiotic factors has showed significant relationship with activity of WBPH during rabi 2016-17. Field population of both BPH and WBPH had a positive relationship with light trap catches of planthoppers. The field populations of BPH and WBPH are in the proportion of 69.00 per cent and 31.00 per cent, respectively during kharif 2016 and 98.00 per cent and 2.00 per cent, respectively during rabi 2016-17. Among fourteen insecticides screened in field during kharif and rabi 2016-17 for induction of resurgence in BPH, seven insecticides viz., chlorpyriphos, profenophos, deltamethrin, cypermethrin, bifenthrin, lambda cyhalothrin and imidacloprid significantly increased the population of N. lugens over untreated check and consequently resulted in higher resurgence, whereas the remaining i.e., acephate, monocrotophos, cartap hydrochloride, fipronil, chlorantraniliprole, buprofezin and pymetrozine can be used judiciously, with periodic monitoring for development of resistance and induction of resurgence. The resurgence inducing mechanism of seven identified insecticides was studied in detail in green house experiments. The results revealed that out of seven insecticides applied at two doses (half of the recommended field dose and recommended field dose), four insecticides viz., cypermethrin, deltamethrin, bifenthrin and lambda cyhalothrin significantly enhanced the reproductive rate (153.67 to 227.67 nymphs / 2 females) of N. lugens and consequently resulted in higher resurgence ratio (1.17 to 1.74 folds). Increase in feeding index (144.33 mm2 to 496.00 mm2 honey dew area), growth index (6.35 % to 7.11 %) and sex ratio in favour of females (1.39 to 1.84 females per 1 male) were the additional factors contributing to the resurgence in the population of the brown planthopper caused by the application of synthetic pyrethroids. While chlorpyriphos, profenophos and imidacloprid resulted in brown planthopper resurgence through changes in the nutritional quality of the host plant that may favour the phytophagus herbivores as indicated by the increased feeding indices (135.33 mm2 to 326.33 mm2 honey dew area). The results obtained from both field and green house experiments in the present investigation revealed that insecticide induced resurgence in the populations of brown planthopper is due to the direct stimulatory effect on the reproductive potential of the insect, indirect effect through favourable changes in the nutritional quality of rice plant and selective destruction of natural enemies. Field experiments carried out during kharif and rabi 2017-18 revealed that fipronil (1000 ml ha-1) followed by pymetrozine (300 g ha-1), buprofezin (800 ml ha-1) followed by pymetrozine (300 g ha-1) and acephate (750 g ha-1) followed by pymetrozine (300 g ha-1) were the most effective insecticide rotations in the management of brown planthopper and recorded higher grain yields. With regard to cost benefit ratio, insecticide rotations, acephate (750 g ha-1) followed by pymetrozine (300 g ha-1) and fipronil (1000 g ha-1) followed by pymetrozine (300 g ha-1) had the highest cost benefit ratio of 1: 6.01 and 1: 6.03, respectively. Buprofezin (800 ml ha-1) followed by pymetrozine (300 g ha-1) and fipronil (1000 ml ha-1) followed by dinotefuran (250 g ha-1) are the next best rotations with cost benefit ratioof 1: 5.87 and 1: 5.07, respectively.
Open Access
IMPACT OF ELEVATED CO2 AND TEMPERATURE ON TRITROPHIC INTERACTIONS OF Zea mays (L.), Rhopalosiphum maidis (F.) AND Menochilus sexmaculatus (Fab.)
(ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) MOUNICA, DUVVANA; KRISHNAYYA, P.V.
Studies on ‘Impact of elevated CO2 and temperature on tritrophic interactions of Zea mays (L.), Rhopalosiphum maidis (F.) and Menochilus sexmaculatus (Fab.)’ were conducted during 2016-2018 at ICAR - Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad, Telangana. The growth and development of three successive generations of R. maidis on maize grown under elevated and ambient concentrations of CO2 (550 and 380 ppm ± 25 ppm, respectively) at six constant temperatures of 20, 25, 27, 30, 33 and 35 ± 1oC were studied. Under eCO2 conditions across the temperatures the concentrations of nitrogen (4.97-7.30%), amino acids (14.01-17.40%) and proteins (6.39-11.03%) were lower compared to that at aCO2 conditions but the concentrations of carbon (1.08-1.63%), C: N (6.96-9.26%), tannins (5.196.13%), total soluble sugars (TSS) (2.47-6.81%), starch (3.67-5.63%), carbohydrates (3.08-6.93%) and total polyphenols (12.86-16.95%) were higher under eCO2 conditions compared to that at aCO2 conditions. Elevated CO2 and temperature significantly extended the duration of reproductive time (19.96-23.32 days) with highest fecundity (83.20-87.68 nymphs per female) whereas the development time (6.60-7.16 days) and total life cycle (26.96-29.92 days) were declined compared to that at aCO2 and temperatures in R. maidis across the three generations. The first instar nymphal weight was significantly increased with temperature in the range of 20oC to 27oC (3.67-3.85 µg day-1) but significantly declined at 30oC to 35oC (1.87-2.78 µg day-1) under eCO2 compared to aCO2 conditions across the three generations. xx Mean relative growth rate of R. maidis was significantly increased with temperature in the range of 20oC to 35oC (0.269 to 0.464 µg µg-1 day-1) under eCO2 compared to that of aCO2 conditions across the three generations. The durations of different stages and life table parameters of R. maidis were studied under the two levels of CO2 conditions at 20, 25, 27, 30, 33 and 35°C temperatures. The durations of first (3.00 to 1.00 days), second (1.92 to 1.00 days), third (1.08 to 1.00 days), fourth nymphal instar (1.00 day), adult (23.1 to 1.20 days) and total developmental periods (29.84 to 5.36 days) decreased from 20 to 35°C temperature under eCO2 conditions compared over aCO2 conditions. Intrinsic rate of increase (rm), finite rate of increase (λ), net reproductive rate (Ro), gross reproductive rate (GRR) and mean generation time (T) of R. maidis increased significantly with temperatures ranging from 20-27°C and declined with further increase in temperature and were found to have nonlinear relationship with temperature. Reduction of ‘T’ was observed from maximum of 17.29 days at 20°C to minimum 5.57 days at 35°C. The future pest status based on Providing Regional Climates for Impacts Studies (PRECIS) A1B model showed increased rm and λ with varied Ro and reduced T of R. maidis at 6 maize growing regions of India. The durations of different growth stages of M. sexmaculatus were studied under the two levels of CO2 conditions at 20, 25, 27, 30, 33 and 35°C temperatures. The durations of egg (5.92-2.00 days), first (3.92 to 1.04 days), second (4.08 to 1.92 days), third (2.92 to 1.00 days), fourth instar (4.84 to 2.04 day), adult longevity (56.84 to 32.91 days) and total developmental periods (71.84 to 36.68 days) decreased from 20 to 35°C temperature under eCO2 conditions compared to aCO2 conditions. The adult predation efficiency of M. sexmaculatus (2982.84 day-1) was increased under eCO2 and temperatures. The impact of eCO2 and temperatures on maize plant height (1.22-3.20 m), number of leaves (6.20-14.60 no. per plant), total leaf area (153.66-196.33 cm2), specific leaf weight (0.084-0.104 g cm-2), total biomass (322.61-675.6 g) and energy value (24.14-28.55 KJ g-1) were increased compared to that of aCO2 and temperatures where as leaf water content (74.67-64.55%) was decreased compared to that aCO2 and temperatures. Significantly decreased nitrogen, amino acids and proteins leading to extended nymphal duration, highest MRGR and fecundity of aphids while increased carbon, carbon to nitrogen (C: N) (modify the feeding behaviour), total soluble sugars (cues in sieve element location), starch and carbohydrates enhanced the nutritional quality of maize foliage and increased growth and development of R. maidis was observed under eCO2 and temperatures. Increased tannins and total polyphenols in maize foliage showed antifeedance and indigestibility to R. maidis grown under eCO2 and temperatures.
Open Access
RELATIVE ABUNDANCE OF STEM BORER SPECIES INFESTING RICE AND MANAGEMENT OF RICE YELLOW STEM BORER, Scirpophaga incertulas (WALKER) (CRAMBIDAE: LEPIDOPTERA)
(ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) SUDHA RANI, DANETI; CHIRANJEEVI, Ch
The studies on relative abundance of stem borer species infesting rice and management of rice yellow stem borer, Scirpophaga incertulas (Walker) (Crambidae : Lepidoptera) were carried out at farmers fields of Krishna district and at Agricultural Research Station, Garikapadu, Krishna district, Andhra Pradesh for four consecutive seasons viz., kharif 2016, rabi 2016-17, kharif 2017 and rabi 2017-18. A total of 215 rice germplasm lines from IIRR, Hyderabad were screened for resistance/ susceptibility against rice yellow stem borer, S. incertulas in augmented block design for two seasons i.e., kharif, 2016 and kharif, 2017. Only seven entries exhibited moderate resistance/ resistance with regards to both dead hearts and white ears symptoms and these seven promising genotypes (IC No. 381538, 450535, 463380, 464140, 464186, 574807 and 578388) were selected for further biochemical analysis. The analysis revealed that rice genotypes with low sugars, low free amino acids and high total phenols, proteins, proline and silica content conferred resistance to rice yellow stem borer and these genotypes can be utlilised in the breeding programme to develop resistant varieties against S. incertulas. Survey was conducted to assess the relative abundance and distribution of various stem borer species and predators in rice ecosystem through stratified random sampling procedure. The survey was carried out for four consecutive seasons i.e., kharif 2016, rabi 2016-17, kharif 2017 and rabi 2017-18 in ten mandals of Krishna district. The results inferred that yellow stem borer was the predominant stem borer species in rice ecosystem of Krishna district with 82.0 and 78.88 per cent abundance during kharif and rabi seasons, respectively. Next to yellow stem borer, pink stem borer was more abundant than white stem borer and dark headed stem borer during kharif season, whereas white stem borer was more dominant compared to pink stem borer and dark xx headed stem borer in rabi season. The predatory fauna prevalent in rice ecosystem of Krishna district exhibited uniform distribution throughout the crop season. The cluster analysis indicated a relationship between stem borer species abundance and predatory guild prevalence in rice ecosystem of Krishna district and the highest species divergence was witnessed in Jaggayapeta mandal (20.88%) followed by Penuganchiprolu mandal (17.58%) whereas, in Mopidevi mandal the least divergence (0.01%) was noticed. The influence of various planting methods viz., manual transplantation (random), manual transplantation (straight row), direct seeding, drum seeder and machine transplantation (8 row) on incidence of rice yellow stem borer was assessed for four consecutive seasons (kharif 2016, rabi 2016-17, kharif 2017 and rabi 2017-18). The cumulative mean incidence of yellow stem borer in ascending order among various planting methods was machine planting (3.80 & 3.41% DH; 3.65 & 4.55% WE) > straight row planting (4.99 & 4.29% DH; 5.93 & 7.08% WE) > random planting (9.84 & 10.66% DH; 9.62 &13.25%WE) > drum seeded (15.31 & 14.31% DH; 17.12 &15.11 %WE) > direct sown (12.28 & 10.93% DH; 18.38 &19.52%WE) during kharif and rabi seasons, respectively. The efficacy of five pest management modules against rice yellow stem borer were evaluated for four successive seasons viz., kharif 2016, rabi 2016-17, kharif 2017 and rabi 2017-18 and it was evident from the pooled mean data that among various modules, the least per cent dead heart and white ears were registered in IPM module (2.68 & 2.56% DH; 2.79 & 2.31% WE), farmers practice (2.31 & 2.32% DH; 3.92 & 4.77%WE) and chemical based module (2.90 & 4.24% DH; 5.59 & 5.18% WE) and were statistically on par with each other as against highest incidence in non chemical (13.78 & 13.7% DH; 18.24 & 17.94% WE) and non chemical + bio rational (11.40 & 9.88% DH; 13.09 & 11.25% WE ) based modules. However, the average highest C: B ratio (1: 2.75 & 1: 2.49) and net profits (Rs. 151587 ha-1 & Rs. 150115 ha-1) were realized with IPM based management module in both kharif and rabi seasons, respectively.
Open Access
IDENTIFICATION OF RESISTANT SOURCES FOR BPH, Nilaparvata lugens (Stål) AND MOLECULAR CHARACTERIZATION OF DIFFERENT BPH POPULATIONS
(Acharya N G Ranga Agricultural University, Guntur, 2019) SHILPAKALA, V; VENKATESWARLU, N.C.
The present investigation was undertaken with an aim to identify the resistant sources of brown planthopper, Nilaparvata lugens (Stål) among 1110 ENRRD (Establishment of Rice Resource Database) germplasm lines. Resistance mechanism Studies were carried out on the selected resistant lines. In another study efforts were made to identify the biochemical basis of resistance in the identified sources. Attempts were also made to validate the BPH resistant genes in the identified resistant lines. Standard Seed box screening was conducted during 2016-17 for 1110 germplasm lines in two replications. Among 1110 rice germplasm tested, 3 were categorized as highly resistant, 24 as resistant, 19 as moderately resistant, 192 as moderately susceptible, 509 as susceptible and rest of other 363 genotypes were highly susceptible to BPH. Honeydew excreted by the third instar nymphs and one day old adults was significantly lowest in the germplasm accessions IC 343394, IC 577624 and IC 377527 indicating antixenosis mechanism. The studies on probing marks revealed that resistant entries, IC 464944 and IC 377527 was least preferred by BPH nymphs for settling, received more number of probing marks The results indicate that the IC 377527, IC 343457 and IC 300168 possess non-preference / antixenosis mechanism of resistance and are not preferred by BPH either for shelter or feeding. The studies on nymphal growth and development, % macroptery and sex ratio, indicate that survival of BPH nymphs was significantly low on resistant entries compared to moderately resistant and susceptible entries. On resistant entries viz., IC 577624, IC 450041 and IC 343394 nymphal survival was very low i.e. 31.11, 35.56 and 37.78 per cent respectively, whereas resistant and susceptible checks viz., Ptb 33 and TN1 recorded 39.6 and 93.3 per cent nymphal survival respectively. Brachypterous females were higher than macropterous females in all the entries including susceptible check, TN1. However, on resistant entry, IC 377051 and IC 343392, macropterous females were higher than brachypterous females. Macropterous males were more than brachypterous males in all the entries except IC IC 300167 and IC 300202. Growth index of BPH was low on the resistant entries xvi compared to susceptible entries 2.48 - 9.49 indicating unsuitability of the cultivar for growth and development of BPH The studies on nymphal growth and development, % macroptery and sex ratio in the BPH on resistant and susceptible ENRRD entries indicate the presence of antibiosis mechanism of resistance in the resistant entries IC 343394, IC 450041 and IC 343392 where nymphal survival was reduced, nymphal duration was prolonged and growth index was low. The biology of BPH was adversely affected on the resistant entries, but not in case of susceptible entries. Tolerance studies revealed that resistant entries, IC 343457, IC 343394 and IC 319799 required more days to wilt, 36.67, 34.33 and 33.67 days, respectively and was on par with the resistant check, Ptb 33 (35.67 days) and susceptible check TN1 wilted in 12.33 days. The correlation studies of damage score with the parameters revealed that damage score and honeydew area of both nymphs and adults are positively correlated and highly significant. Days to wilt exhibited as highly significant negative correlation with BPH reaction. BPH infestation on most of the resistant cultures and resistant check Ptb 33 resulted in an increase in the phenolic content in the infested plant. Significantly highest phenolic content (45.37 mg g-1 tissue) was observed in infested IC 300202 compared to all test cultures including resistant check Ptb 33. The total sugar content was significantly highest in the uninfested susceptible check TN1 compared to the resistant and moderately resistant cultures. Upon infestation of BPH there was a decrease in total reducing sugars in all the plants. However, when infested IC 343457 (7.55) showed slight decrease in sugars which was on par with Ptb 33 (9.57). The high quantity of amino acid was present in IC 343457 (4.36) and IC 449821 (4.47), IC 545441 (3.99) & IC 343394 (3.17) which was on par with resistant check PTB 33 (2.85) and which is significantly different from susceptible check TN1 (1.97). In the infested paddy cultures, there was an increase in the amino acid content in all the resistant cultures including the checks (20.72% to 76.86%). Highest per cent of increase observed in IC 300168 (76.86) which is more than PTB 33, least per cent of increase in amino acids was recorded in IC 545441 (20.72) i.e., more than TN1 (17.92). In general the total N content in the infested cultures decreased over healthy plants in most of the rice cultures and it varied with the culture. Decrease in the N content was highest in the susceptible variety TN1 (38.3%). In the resistant Ptb 33 decrease in the N content was marginal (10.13%).The P and K contents of the selected rice germplasm accessions were also estimated. Potash content was more or less same in all the selected rice germplasm accessions tested before infestation. However, some increase after infestation was observed in the resistant cultures and resistant check Ptb 33, but not in susceptible TN1. Molecular profiling by using 17 SSR markers for detecting 9 Bph genes revealed the presence of Bph6 gene in IC 300167 and Bph18 gene in IC 301181, IC 319799, IC 450041 IC 343392, IC 343457 and IC 449821. The markers RM28004 of Bph1 gene, RM589 of Bph3 gene, RM313 of Bph7 gene, RM8213 & RM5953 of Bph17 gene, RM435 & RM540 of Bph20 gene and RM8072 of Bph32 gene were failed to show polymorphism between resistant and susceptible checks. However, new alleles were reported in some entries, these new alleles might be source for BPH resistance in these lines. The number of alleles per marker ranged from 1 to 10 with an average of 3.94 alleles indicating the presence of average allelic diversity. The PIC values of 17 SSR markers used in our study varied from 0 (RM5953) to 0.84 (RM586) with an average of 0.46. While, The overall He values ranged from 0 (RM5953) to 0.86 (RM586) with an average of 0.53. The 24 genotypes categorized into four major xvii clusters at 30% level of genetic similarity. Most of the resistant genotypes were grouped under major cluster III. Cluster I consist of only Mudgo, cluster II comprised of resistant donor, TN1 and BPT 5204. Cluster III includes Sampada, IC 300168, IC 343394 and IC 450041. Major Cluster IV included 4 rice genotypes, IC 377051, IC 49821, IC 343457 and IC 577624. Study was conducted to study the variability of BPH populations by collecting BPH insects from different places of India like West Godavari (Maruteru, AP), Nellore (AP), Nalgonda (Kampasagar, TS), Toofran (Medak Dist., TS), Bargarh (Orissa), Gangavathi (Karnataka), Raipur (Chattisgarh) and IIRR Glasshouse. Phenotypic studies were performed on thirty different gene differentials with Reference TN1 as susceptible check. Among all the populations Gangavathi population was observed as highly virulent and least virulent was Bargarh. Average damage scores on gene differentials by all BPH populations were as follows: Gangavathi (DS 7.98), Glasshouse (DS 7.28), West Godavari (DS 7.24), Nellore (DS 7.13), Raipur (DS 6.8), Nalgonda (DS 6.76), Toofran (DS 6.51) and Bargarh (DS 5.06). Based on average scores of gene differentials when screened with all the eight populations RP 2068 (DS 2.56) and ARC 10550 (DS 4.85) were proved to be resistant The clustering analysis of eight Brown planthopper populations collected from different regions of India was done using damage score revealed the presence of three groups. Group 1 consists of three populations viz., Bargarh population (Orissa), Toofran (Medak Dist., TS) and Raipur (Chattisgarh). But Raipur (Chattisgarh) population outgrouped from other two populations. Group- 2 is comprised of two sub groups viz., Gangavathi (Karnataka) & West Godavari (Maruteru, AP) as one and IIRR glasshouse population as another sub group. Group 3 includes Nalgonda (Kampasagar, TS) and Nellore (AP) populations. In order to study the genetic variability eight Brown planthopper populations collected from different regions of India. Six SSR markers from each linkage chromosome of bph were selected and run to check the polymorphism. When cluster analysis using genotypic data was done, eight populations were grouped into three clusters. Group 1 consists of four populations i.e., IIRR glasshouse population, Bargarh population (Orissa), Raipur (Chattisgarh) and Gangavathi (Karnataka). Group 2 consists of three populations viz., Nalgonda (Kampasagar, TS), Nellore (AP) and west Godavari (Maruteru, AP), Toofran (Medak Dist, TS) BPH population alone grouped into one (Group 3) with the similarity of 0.35. When both genotypic and phenotypic grouping is compared Nalgonda & Nellore populations, Raipur & Bargarh populations, Gangavathi & Glasshouse populations were found to be similar whereas West Godavari and Toofran are differing in grouping phenotypically and genotypically.
Open Access
STUDIES ON INSECTICIDE RESIDUES IN PADDY GROWN IN SOUTHERN AGRO-CLIMATIC ZONE OF ANDHRA PRADESH
(Acharya N G Ranga Agricultural University, Guntur, 2019) PEDDA VENKATA REDDY, L; KOTESWARA RAO, S.R.
The present investigations on “Studies on insecticide residues in paddy grown in Southern Agro-climatic zone of Andhra Pradesh” were carried out in Department of Entomology, Pesticide Residue Laboratory, Institute of Frontier Technology (IFT), Regional Agricultural Research Station (RARS), Tirupati and college farm, S. V. Agricultural College, Tirupati during rabi seasons of 2016-17 and 2017-18. The results of the field survey which was conducted at paddy growing farmers fields of Southern Agro-climatic zone (Chittoor, S P S Nellore and Y S R Kadapa districts) of Andhra Pradesh on pesticide usage pattern during rabi, 2016-17 and 2017-18 revealed that, most of the rice growing farmers were males with an age group ranging between 40-50 years leading nuclear family and without any education (illiterates). A higher seed rate of 25-30 kg acre-1 and the adoption of seed treatment with fungicides were followed by majority of farmers. During the crop growing stages, most of the farmers applied higher dosages of fertilisers and to control the weeds preferred manual weed control. Among the insect pests and diseases, the yellow stem borer and blast caused damage in all the farmers (100.00%) fields. During tillering, panicle initiation, milky and grain formation stages of the paddy crop, all the farmers (100.00%) applied insecticides and fungicides. Most of the farmers used insecticides belonging to organophosphates, followed by fungicides and herbicides during the crop growing season. Before application of pesticides most of them preferred to contact pesticide dealers for pesticide recommendations and used approximate quantity of pesticides while preparing spray solutions. Most of the farmers used power sprayer for spraying during the morning or evening hours by wearing shirts with full sleeves. After the application of pesticides at weekly interval, the majority of the farmers threw the empty bottles in trash. The detection of insecticide residues in milky and harvested grains of Southern Agro-climatic zone of Andhra Pradesh during rabi, 2016-17 and 2017-18 revealed that, in milky grains, more insecticide residues of organophosphates followed by anthranilic diamides and neonicotinoids were observed. In the harvested grains and straw samples, very less number of samples were detected with residues belonging to antharanilic diamides. Chlorantraniliprole 18.5 SC proved as the most effective insecticide with the lowest Dead Hearts (DHs) (9.50%) and White Ear Heads (WEHs) (4.22%) where as cartap hydrochloride 50 SP proved as least effective with 14.80 percentage of DHs and 13.84 percentage WEHs against paddy Yellow Stem Borer (YSB), Scirpophaga incertulas (Walker) damage. The efficacy of ten insecticides against Cnaphalocrosis medinalis (Guenee) during rabi, 2016-17 and 2017-18 revealed that, all the tested insecticides had significantly affected the larvae of C. medinalis and reduced the leaf damage over untreated control. Chlorantraniliprole 18.5 SC proved as the most effective insecticide with the 4.95 percentage of paddy leaf damage and the least effective was cartap hydrochloride 4 G (7.39%) against paddy leaf folder damage. The influence of test insecticides against S. incertulas and C. medinalis on paddy grain yield showed that, all the treatments showed significantly higher yields over control (42.56 q ha-1). The highest yield was recorded in the chlorantraniliprole 18.5 SC (58.19 q ha-1) treated plots and the lowest was recorded in cartap hydrochloride 50 SP (47.33 q ha-1) treated plots. The dissipation pattern of the certain insecticides in paddy leaf, grain and straw samples at different interval of time after second insecticidal application in both the seasons viz., rabi, 2016-17 and 2017-18, revealed that, all the insecticides showed some residues for particular interval of time in leaf samples, while the residues of BDL (Below Detectable Level) were observed in grains 30 days after application and in straw samples of paddy 60 days after application. The carbofuran and cartap hydrochloride 4G insecticide residues increased in paddy leaves from zero to one day after second insecticidal application and later dissipated following pseudo-first order kinetics and reached to BDL after 21 days. The insecticidal residues viz., acephate, cartap hydrochloride, chlorantraniliprole, chlorpyrifos, dichlorvos, flubendiamide, monocrotophos and profenofos followed the first order kinetics in their dissipation behaviour and individually reached to BDL at 14, 7, 14, 14, 10, 10, 45 and 30 days after second insecticidal application.
Open Access
STUDIES ON IDENTIFICATION OF NEW SOURCES OF RESISTANCE AGAINST GALL MIDGE, Orseolia oryzae, IN RICE
(Acharya N G Ranga Agricultural University, Guntur, 2019) HARATHI, P.N.; RAJA SEKHAR, P
The present work on “Studies on identification of new sources of resistance against gall midge, Orseolia oryzae in rice” was carried out at Agricultural Research Station, Nellore, ANGRAU and Agricultural Research Station, Ragolu, ANGRAU during 2015-17. A total of 105 accessions were used to evaluate resistance against O. oryzae. The resistant check, Kavya (5.00%) recorded lowest per cent plant damage followed by RGL-1 (6.50) during kharif, 2015 at ARS Nellore at 50 DAT. From the results of the field experiments (2015-17) at ARS, Ragolu, it was evident that the genotypes RGL 7002 (7.37%), RGL 7003 (7.19%), RGL 7009 (5.83%) and RGL 7010 (6.35%) recorded less than 10 per cent plant damage and were considered for genotyping. The selected entries were phenotyped under laboratory conditions and the genotypes showed neither positive nor negative hypersensitive reaction in the genotypes RGL 1, RGL 7002, RGL 7003, RGL 7009 and RGL 7010. The selected entries were studied for the presence of reported gene specific SSR markers, it was found that RGL 7003 has the alleles for the genes Gm1 and Gm8. The entry, RGL 1 amplified with Gm8 gene and RGL 7002 with Gm1. All these three entries can be used as potential donors in breeding trials. xvi Studies were also carried to find out the existence of gall midge biotype at Nellore by screening of differentials (17) supplied by IIRR, Hyderabad. Conclusive results could not be drawn from the data recorded at ARS, Nellore regarding the identification of the biotype, due to the low pest incidence at the site of experimentation. However, the data recorded based on the reaction pattern at Salmanpuram of Nellore district, revealed that the biotype identified might be biotype VI with no damage in Kavya, W 1263 and ARC 6605 of group I, ARC 5984, Madhuri L9 and BG-380-2 of group II, Aganni and B 95-1 of group IV and the per cent similarity index value of Nellore biotype was 70.1 per cent. The gall midge population at ARS, Nellore was heterogeneous. The population was less virulent on the differential W1263 and more virulent on Purple (susceptible check), followed by Aganni and RP 2068-18-3-5. Studies on the genetic diversity of gall midge population across Andhra Pradesh and Telangana revealed that gall midge population in Chittoor showed a closer genetic relation with the gall midge population from Nellore with a similarity coefficient of 0.75 while, the populations from Warangal was placed in second cluster through the dendrogram based on UPGMA. The population from Jagtial was placed in separate cluster indicating that it is distantly related to the gall midge populations in other two clusters.

Acharya N G Ranga Agricultural University, Guntur

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