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Open Access
Interaction of Beauveria bassiana (Bals.) Vuill. with Leptocorisa oratorius Fab. (Hemiptera: Alydidae) with special reference to chitinase
(2021) Das,Karishma; Das, Purnima
Rice earhead bug, Leptocorisa oratorius Fab. and Leptocorisa acuta Thun. (Hemiptera: Alydidae) are the most important sucking pests of rice. The insect cause significant yield losses to the rice crop in the field condition. Therefore, the present investigation was carried out with a view to study the seasonal incidence of L. oratorius in relation to the meteorological parameters, their damage potential, biology, pathogenicity of Beauveria bassiana (Bals.) Vuill. against different stages of L. oratorius and to characterize the B. bassiana-chitinase that secreted during insect fungus interaction. To study the seasonal incidence of L. oratorius, an experiment was conducted at Instructional Cum Research (ICR) Farm, Assam Agricultural University, Jorhat during Ahu, 2018 & 2019 and Sali (Kharif), 2018 & 2019. During Ahu, 2018 & 2019, the population of L. oratorius was first appeared on 2nd week of May i.e. 20th standard meteorological week (SMW) with an average of 0.33 and 0.30 adult per hill, respectively. The population was gradually increased with a peak of 2.66 and 1.56 adult per hill on 24th SMW (2nd & 3rd week of June), respectively. During Sali (Kharif) 2018 & 2019, the population of L. oratorius was first appeared on 41st standard (SMW) with an average of 0.30 and 0.36 adult per hill, respectively. The population was found to be highest at 1st week of November i.e. 44th SMW with an average of 1.20 and 1.13 adult per hill, respectively. The correlation studies between incidences of L. oratorius with meteorological parameters showed non significant correlation with all the meteorological parameters during Ahu, 2018 and Sali (Kharif), 2018 and 2019. However, during Ahu 2019, it showed significant positive correlation with maximum (r = 0.802) & minimum (r = 0.711) temperature and BSSH (r = 0.631) whereas, significant negative correlation with morning (r = -0.849) & evening (r = -0.750) relative humidity and non significant negative correlation with rainfall (r = -0.255). Multiple regression analysis during Ahu 2019, revealed that only morning relative humidity determined the incidence of L. oratorius in concert with R2 =0.721 (72.10%) and adjusted R2= 0.691 (69.10 %). The „best fit model‟ Y= 12.82531-0.13115*Mor. RH (%) expressed the magnitude of the relationship. The percent grain infestation due to rice earhead bug were recorded as 39.34 and 37.11 during Ahu, 2018 & 2019 and 35.43 & 36.28 during Sali (Kharif), 2018 & 2019, respectively. The biology of L. oratorius and L. acuta were studied under laboratory condition. The preoviposition and oviposition period of L. oratorius were found to be 12.00±7.17 and 11.60±4.35 days whereas, 7.40±3.50 and 10.20±5.71 days were recorded incase of L. acuta, respectively. A gravid female of L. oratorius laid on an average 99.20±22.01 number of eggs during her life span whereas, 76.80±21.79 number of eggs was laid by L. acuta. The incubation period of L. oratorius and L. acuta were 5.80±1.09 and 5.00±1.00 days, respectively. Both the species have five nymphal instars. The duration of each instar of L. oratorius were 3.80±0.84, 2.20±0.45, 3.60±0.89, 6.80±0.84 and 4.80±0.84 days whereas, 4.40±1.14, 4.80±1.09, 3.40±1.14, 3.80±1.48 and 6.00±1.22 days incase of L. acuta. The total nymphal period and total developmental period of L. oratorius were found to be 21.20±1.09 and 27.00±1.58 days whereas, 22.40±1.14 and 27.40±2.02 days were found incase of L. acuta, respectively. Adult male of L. oratorius lived for 28.60±2.40 days and female lived for 57.60±7.06 days. The longevity of both male and female of L. acuta were 28.40±5.81 and 51.80±6.37 days, respectively. The morphometric study of L. oratorius revealed that the average length of eggs, first, second, third, fourth and fifth instar were 1.02±0.06, 1.49±0.06, 2.82±0.05, 5.05±0.06, 10.61±0.09 and 14.03±0.15 mm whereas, width were found as 0.75±0.05, 0.28±0.04, 0.40±0.05, 0.48±0.05, 1.07±0.07 and 1.39±0.06 mm, respectively. The female L. oratorius was slightly shorter than the male and measured 17.08±0.16 mm in length and 1.98±0.09 mm in width while the male bug was slightly longer than female measured 18.01±0.16 mm in length and 2.11±0.11 mm in width. In case of L. acuta the average length of eggs, first, second, third, fourth and fifth instar were recorded to be 1.27±0.04, 1.39±0.05, 2.41±0.08, 3.75±0.07, 5.46±0.11 and 6.68±0.12 mm whereas, width were found to be 0.52±0.03, 0.55±0.07, 0.59±0.05, 1.38±0.08, 1.75±0.05 and 2.29±0.04 mm, respectively. The average length and width of male bug were 10.23±0.12 and 2.31±0.04 mm whereas, female bug were 9.85±0.12 and 2.39±0.44 mm, respectively. The head length and width of L. oratorius varied as 2.35±0.07 and 0.82±0.07 mm whereas, incase of L. acuta 1.29±0.02 and 0.53±0.02 mm, respectively. Likewise thorax length, thorax width, abdomen length, abdomen width, distance between two compound eyes, length of compound eyes, width of compound eyes, antennal length, stylet length, fore wing length, fore wing width, hind wing length, hind wing width, fore leg length, middle leg length and hind leg length of L. oratorius were also measured as 3.16±0.15, 2.05±0.07, 12.65±0.13, 2.23±0.14, 1.03±0.13, 0.89±0.10, 0.73±0.08, 14.74±0.12, 5.60±0.05, 12.20±0.19, 2.00±0.14, 8.51±0.16, 2.02±0.09, 9.07±0.25, 9.85±0.27 and 14.22±0.20 mm whereas, 1.60±0.02, 1.94±0.04, 6.00±0.07, 2.61±0.05, 1.8±0.08, 0.41±0.03, 0.29±0.02, 5.20±0.04, 4.85±0.06, 6.38±0.07, 1.87±0.08, 4.64±0.07, 1.79±0.05, 3.43±0.16, 4.11±0.21 and 5.37±0.16 mm were found incase of L. acuta, respectively. The pathogenicity test of B. bassiana against different stages of L. oratorius was carried out under laboratory condition and found to be effective against all the stages of this pest. The B. bassiana treated eggs showed 72.00±3.74 percent egg hatchability as compared to the untreated control (100±0.00). The mean percent mortality of first, second, third, fourth, fifth instar and adult were recorded as 84.00, 80.00, 66.00, 70.00 and 62.00 and 58.00, respectively at 9 days after treatment (DAT). However, significant differences (P ≤ 0.05) were found among the mean percent mortality of nymphal and adult stages at different DAT. Infection process of B. bassiana in insects is mainly triggered by the chitinase which is secreted during insect fungus interaction. Therefore, an experiment was conducted in the Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat during the period 2016-2021 to optimize the growing condition of B. bassiana for chitinase production, reaction condition for chitinase activity assay and to purify the enzyme. For the production of B. bassiana-chitinase, different growth parameters viz., growth period, media composition (peptone concentrations, colloidal chitin concentrations and ferrous sulphate concentrations), media-pH and growth temperature were optimized. Along with the different growth parameters, reaction parameters viz., temperature and pH were also optimized for the estimation of B. bassiana–chitinase activity. The optimum incubation time required for chitinase production by B. bassiana was found to be 5 days, peptone concentration as 0.07%, colloidal chitin concentration as 0.4% and ferrous sulphate (FeSO4.7H2O) concentration as 0.015%, media pH as 5.0 and growth temperature as 28°C, whereas, for B. bassianachitinase activity the optimum reaction temperature and reaction pH were found to be 37°C and 5.0, respectively. Chitinase was purified by ammonium sulphate precipitation method by using different salt fractions, 55%, 65%, 75%, 85% and 95%. Chitinase activity and protein were estimated in crude enzyme as well as in its different salt fractions after proper dialysis. From the estimated chitinase activity and protein, the specific activity, fold purification and yield were calculated. Among the different fractions, with 75% ammonium salt saturation showed the best result as it purified the enzyme to the maximum fold of 2.68 with a yield of 14.34% and specific activity of 2.60 U/mg. The purity of the enzyme was examined by SDS-PAGE and determined the molecular weight at the highest purified fraction i.e. 75% ammonium salt saturation. The molecular weight of purified chitinase was estimated to be around 60 kDa.
Open Access
DIVERSITY, HABITAT OF MAJOR MONKEY SPECIES AND THEIR CROP LOSS ASSESSMENT IN AGRO-ECOSYSTEM
(2022) Chakraborty, Debjyoti; Borah, R. K.
The study on “Diversity, habitat of major monkey species and their crop loss assessment in agro-ecosystem” was conducted at Upper Brahmaputra Valley Zone (Golaghat), Hills zone (Karbi anlong) and North Bank Plain Zone (North Lakhimpur) of Assam in the year 2019-21. Population status, habit, habitat, food and feeding behavior of prevalent monkey species were calculated from the Jorhat district in different cropping seasons and the damage caused by the macaques in rice and homestead gardens were calculated. The various population distribution, group size and composition was calculated through transact method in all the locations of the zones comprising all the crop season. During the survey period, the highest number of Rhesus monkeys among all the three locations was recorded at Kakoti gaon of Golaghat district (UBVZ) with 306 monkeys while Sarthe Rongphar gaon, Karbi anlong (Hills zone) recorded the lowest macaque population of 48. During 2019, a total of 151 individuals were encountered in five groups. The largest group (36 individuals) was recorded in Meleng and the smallest group (20 individuals) in Gondhia Gaon. Furthermore, five groups of 159 individuals were found in 2020. Meleng had the largest group of 49 individuals while Madhupur had the smallest (15 individuals). The average overall adult sex ratio of male: to female was 1:2.33 (1 male to 2.33 female) in 2019. On the contrary, proportions of sexes in Rhesus macaques were found to be one male to three females during 2020. During the behavior study period (January 2020-November 2021), scan sampling yielded a total of 9545 scan records. In this study it was found that 24.87% of their total annual time spends on feeding purposes, followed by movement (21.35%), resting (20.09%), grooming (17.72%), playing (14.30%) and calling (1.65%). There were found to be significant differences in time spent in feeding, movement, resting and social activities among the age-sex group. The adult male was found to be spent more time feeding (21.73%) than resting (18.26%) while adult females spent more time resting (25.17%) than feeding (21.80%). Feeding is a major activity and runs throughout the year, but there was found to be variation in feeding during different months of the year i.e. total feeding was not equal in all the months of the year. It was found to be maximum in April 2021 (8.80%), May 2021 (8.47%), March 2021 (8.38%); minimum were in December 2020 (5.35%), October 2020 (5.52%) and November 2021(5.73%). Feeding was found to be highest in April and lowest in December. In this study, 27 plant species representing 13 genera belonging to 19 families were exploited by the study group as natural food. In light of this questionnaire survey, the majority of the respondents (92%) agreed that the damage to crops caused by monkeys was severe. Potato was the most raided crop (30%), paddy (27%), maize (20%), vegetables (18%) and fruits (5%), respectively. Crop raiding was reported by 92 percent of respondents, although the level of crop-raiding was discovered to be different in different places. Crop raiding was found to be highest in Kakoti Gaon (78%), followed by Guwal gaon, which had the least crop raiding (22%).
Open Access
POPULATION DYNAMICS AND CROP LOSS ASSESSMENT OF MAJOR INSECT PESTS OF CUCUMBER (Cucumis sativus)
(2022) Balaga Mohan Ganesh; Saikia, D.K.
Cucumber (Cucumis sativus L.2n = 14) is one of the widely cultivated summer vegetable crops from the gourd family of Cucurbitaceae which is native to India. The climatic conditions of northeast India especially Assam are highly conducive for reproduction of insects, and this region has been considered to be a biodiversity hotspot. Moreover, this region has huge potential for the production of vegetable crops especially cucurbits, but insect pests like fruit flies, pumpkin beetle and sucking pests are major limiting factors for successful cultivation of cucurbits like cucumber etc. Therefore, understanding population fluctuation in the field in relation to losses caused by insect pests are a function of their population dynamics which needs to be thoroughly studied. In view of above factors, an investigation on “Population Dynamics and Crop Loss Assessment of Major Insect Pests of Cucumber (Cucumis sativus)” was carried out at Horticultural Farm and RNA laboratory of Agricultural Biotechnology, Assam Agricultural University, Jorhat. The results showed that during 2019 -2021 summer season, the red pumpkin beetle first appeared on 24th April 2019 and 7th May 2020 with initial population of 4.51 and 2.23 beetles per plant, respectively. However, maximum beetle populations were recorded on 8thMay 2019 and 3rd July 2020 with 6.15 and 6.52 beetles per plant, respectively. Similarly, during 2019-2021, the fruit infestation by fruit fly was recorded first time on 13th June, 2019 and 26th June ,2020 with per cent fruit infestation of 10.24 per cent and 10.75 per cent, respectively. However, highest level of fruit infestation by fruit fly was observed on 25th July, 2019 and 8th August 2020 with 46.86 and 41.3 per cent fruit infestation, respectively. The data on relative abundance of different insects of cucumber during 2019-2021 revealed that the relative abundance of fruit fly species, Bactrocera dorsalis (62.27%) was the highest followed by B. tau (15.68%), B. cucurbitae (10.73%), Dacus longicornis (2.47%), Coccinella transversalis (2.45%), Aulacophora foveicollis (2.20%), Micrapsis discolor (1.56%), A. frontalis (1.16%), and Coccinella septumapunctata (1.08%). During 2019 and 2020, the Simpson-Index diversity showed highest value for fruit fly (0.97 and 0.94) followed by predacious coccinellid beetles (0.67 and 0.71) and red pumpkin beetle (0.55 and 0.64), respectively. Whereas, Shannon-Wiener index diversity (H’) during 2019 and 2020 observed highest in fruit fly (1.65 and 1.85) followed by predacious coccinellid beetles (1.15 and 1.05) and pumpkin beetle (0.68 and 0.85), respectively. The results of yield loss studies during 2019-2020 revealed that the per cent fruit infestation was highest in untreated control plot (30.73%) compared to treated plot (26.8%) with fruit yield of 1223.91 kg/ha and 2311.83 kg/ha, respectively. The yield loss in untreated plot was recorded as 1087.91 kg/ha with 47.05 per cent avoidable loss in yield. Whereas, per cent yield increase over control during 2019-2021 (summer season) was observed as 88.88 per cent. However, economic injury level (EIL) of fruit fly with respect to cucumber was determined as 15.27 and 10.40 per cent with per cent fruit loss of 0.743 and 0.745 during 2019 and 2020, respectively. The optimal phylogenetic tree of 10 fruit fly specimens collected from different locations grouped into two clusters (Cluster A and Cluster B) of two specimens out groups namely B. rubigina and D. longicornis with branch length of 0.0724. In cluster-A, highest genetic distance of 0.047 was recorded between B. rubigina and B. dorsalis. Similarly, in cluster-B the highest genetic distance of 0.0682 was recorded between D. longicornis, B.tau and B.cucurbitae collected from different locations.
Open Access
ECOFRIENDLY MANAGEMENT OF Lepidiota mansueta BURMEISTER (COLEOPTERA: SCARABAEIDAE) IN POTATO
(AAU, Jorhat, 2021) Sravani, Dumala; Bhattacharyya, Badal
Laboratory and field experiments were carried out at Soil Arthropod Pest Laboratory, Department of Entomology, Assam Agricultural University, Jorhat and in the farmer’s field at Maharichuk, Majuli, Assam to study ecofriendly management of Lepidiota mansueta Burmeister (Coleoptera: Scarabaeidae) in potato during 2019-21. Efforts were also made to test the pathogenicity of different entomopathogens and to know their effects on haemocytes in L. mansueta as well to evaluate some newer insecticides against the grubs. While studying the pathogenicity of different entomopathogens for their virulence against third instar L. mansueta grubs, Beauveria bassiana (formulation: KR855715) recorded highest mortality (76%) of grubs followed by 72 per cent mortality in B. brongniartii (formulation: BbUASB16) and 70.67 per cent in Bacillus thuringiensis (formulation: Bio-Bt) at 30 days after treatment (DAT). The Metarhizium anisopliae based formulation (Bio-Meta) registered the highest LT50 value (23.05 days) (FL 19.24-30.33) whereas the lowest LT50 value was 12.15 days (FL 11.15-13.11) in case of B. bassiana (KR855715). Five different haemocytes were identified based on differences in size, shape, morphology and dye-staining properties of cell and nucleus and were functionally categorized as Prohaemocytes (PRs), Plasmatocytes (PLs), Granulocytes (GRs), Spherulocytes (SPs) and Oenocytes (OEs). The Total Haemocyte Count (THC) and the population of PRs, GRs, PLs, OEs and SPs were affected in response to B. bassiana (KR855715). The application of B. bassiana (KR855715) in addition to abnormal haemocyte counts also caused great abnormalities to the haemocytes by distortion of the plasma membrane, cytoplasmic extension, rupturing of cell wall, oozing out of cell contents, degranulation of the cells, vacuolation, enlargement of cells and abnormal staining of the haemocytes. Immunologically activated haemocytes in L. mansueta showed significant cellular immune responses such as phagocytosis, encapsulation and nodulation in response to B. bassiana (KR855715). The toxicity of 10 numbers of insecticides against L. mansueta grubs was assessed by following both film method and soil incorporation method under laboratory conditions. In case of film method, chlorpyriphos 20 EC @ 2.0 ml/L, quinalphos 25 EC @ 2.0 ml/L and clothianidin 50 WDG @ 1.0 g/L were found highly effective among all the insecticides tested as the above three insecticides registered cent per cent mortality of grubs after 96 hours of application. Chlorantraniliprole 18.5 SC @ 0.5 ml//L and imidacloprid 17.8 SL @ 1.0 ml/L showed 93.33 and 86.67 per cent grub mortality, respectively. The lethal effect of quinalphos was observed quickly in 19.60 hours (FL 12.72-25.87), followed by chlorpyriphos in 20.43 hours (FL 14.67-25.88) and clothianidin in 28.10 hours (FL 19.08-37.50). However, the highest LT50 was recorded at 95.98 hours (FL 69.52-180.87) in case of fipronil 5 SC @ 1.0 ml/L. Experimental findings as regards to soil incorporation method revealed that amongst all the insecticidal treatments, chlorpyriphos 20 EC @ 2.0 ml/L (46.67, 66.67 and 83.33%), quinalphos 25 EC @ 2.0 ml/L (43.33, 58.33 and 78.57%), clothianidin 50 WDG @ 1.0 g/L (36.67, 47.22 and 69.05%) and chlorantraniliprole 18.5 SC @ 0.5 ml/L (30, 44.44 and 66.67%) were significantly superior over other insecticidal treatments in recording maximum grub mortality after 24, 48 and 72 hours of exposure, respectively. The highest LT50 of 98.73 hours (FL 80.79-137.80) was recorded in fipronil 5 SC @ 1.0 ml/L and the lowest LT50 value was 27.19 hours (FL 23.32-30.49) in case of chlorpyriphos 20 EC @ 2.0 ml/L. Six different ecofriendly managment modules were evaluated against L. mansueta grubs in potato crop. All the tested modules viz., Module-I (with only pre sowing treatment of mustard oil cake @ 150 kg/ha + wood ash @ 150 kg/ha + Panchagavya @ 3%), Module-II [pre sowing treatment plus soil drenching with neem oil @ 5 ml/L after 1st & 2nd earthing up (25 & 60 DAS)], Module-III [pre sowing treatment plus soil drenching with jatropha oil @ 5 ml/L after 1st & 2nd earthing up (25 & 60 DAS)], Module-IV [pre sowing treatment plus soil drenching with pongamia oil @ 5 ml/L after 1st & 2nd earthing up (25 & 60 DAS)], Module-V [pre sowing treatment plus soil drenching with castor oil @ 5 ml/L after 1st & 2nd earthing up (25 & 60 DAS)] and Module-VI [pre sowing treatment plus application of M. anisopliae @ 10 g/m2 after 1st & 2nd earthing up (25 & 60 DAS)] were found to be significantly superior in reducing L. mansueta grub infestation as compared to the untreated control. Out of all modules, Module-VI was found to be significantly superior and recorded the lowest tuber damage on weight (11.32%) and number (14.07%) basis which was at par with Module-III which registered 11.82 and 14.78 per cent tuber damage on weight and number basis, respectively. Module-VI also registered highest tuber yield (122.71 q/ha) which was at par with Module-III (121.50 q/ha). The maximum benefit cost ratio (2.86) was recorded in Module-VI followed by Module-III (2.80) and Module-II (2.57).
Open Access
Diversity of whitefly species and their vector status in vegetable ecosystem
(AAU, Jorhat, 2021) Gayon, Junmoni; Saikia, Dilip Kumar
Bemisia tabaci (Hemiptera : Aleurodidae) is one of the limiting factors of vegetable crop production system across the world. B. tabaci consist of 24 morphologically indistinguishable species and also plays an important role in transmission of more than 111 plant viruses. In the present investigation, survey was conducted to screen and collect B. tabaci adult and immature stages from 6 different locations covering 3 agro- ecological zone of Assam during 2019 and 2020. Altogether 10 samples were collected from 3 different agroclimatic zones, which were brought to the Biocontrol Laboratory, Department of Entomology, Assam Agricultural University, Jorhat for molecular and morphological analysis. Both the laboratory and grow-out experiments to investigate the vector status were conducted, during 2019-20. The molecular study of the B. tabaci samples collected from different agro-climatic zones was conducted at Department of Plant Pathology, AAU, Jorhat during the year 2020. The samples of B. tabaci were examined for 11 numbers of morphometric characteristics in the case of female, while 10 characters in male. The result on morphometric study revealed that the females were bigger in size than of males. The sample UBZ2 collected from Pulibor, Jorhat showed outgrows in terms of measurement than that of rests. The cluster analysis divided the B. tabaci samples into 2 numbers of clusters on the basis of location and morphometric traits. Cluster 1 comprises the samples NBZ1, NBZ2, CBZ1 and CBZ2; while cluster 2 comprises UBZ1 and UBZ2 sample. The principal component analysis of adult B. tabaci revealed that the morphometrical characters of male and female could be divided into 6 principal component and principal component 1 (PC1) accounts for maximum variability of data. The molecular characterization of B. tabaci collected from different agro-climatic zones using primer based PCR method proves the presence of two different genetic groups. During the experimentation, the mtCOI segment of DNA was amplified at 754bp and 816bp position to determine the genetic variation in B. tabaci. The phylogenetic analysis revealed that the collected B. tabaci samples could be grouped into Asia-II 1 and Asia-II 5; where sample CBZ2 belong to Asia-II 1 and others viz., NBZ1, NBZ2, CBZ1, CBZ2 and UBZ1 belong to Asia-II 5. Phylogenetic tree was constructed using Bayesian method and compared the sequence similarity with the sequence available in the NCBI and found 99-96% similarity. The study on seasonal abundance of B. tabaci was conducted in chilli during 2019 and 2020, which revealed that the population of B. tabaci starts appearing on chilli plants from first standard meteorological week (SMW) (i.e. 1st week of January’2019) with a population density of 1.75±0.15 insects /leaf during 2019. The population gives a major peak at 41st SMW (i.e. 2nd week of October) with a number as high as 90 adults per leaf. In the year 2020, the population of B. tabaci started to increase from 4th SMW with a population of 8 insects/leaf and reached the peak of 72 adults/leaf during 41st SMW at a maximum temperature of 32.9oC, minimum temperature of 24.3oC, morning humidity of 96%, evening humidity of 70% and rainfall 10%. The correlation study revealed that none of the abiotic factors except morning relative humidity significantly correlated with the whitefly population during both the year 2019 and in 2020. The study on the biology of B. tabaci on chilli and brinjal plant shows variability in duration accross different developmental stages. The duration of egg, I instar, II instar, III instar and IV instar was 4.20±0.75-10.20±1.17, 1.60±0.49- 5.20±0.75, 3.20±0.40- 5.20±0.75, 3.00±0.63- 5.60±0.49 and 4.80±0.75-7.00±0.00 days, respectively in chilli; while it was recorded to be 3.00±0.00-9.20±0.40, 1.20±0.40-7.00±0.63, 2.40±0.49-5.40±0.49, 2.60±0.49-5.80±0.40 and 4.00±0.63-6.80±0.40 days in brinjal, respectively. The longevity range of adult female and male in chilli was 2.80±0.75-14.00±0.89 and 1.60±0.49-12.40±0.49 days, respectively; while 4.40±0.49-16.40±0.49 and 2.20±0.40-13.80±0.75 days, respectively in brinjal. Moreover, a total of 10 different natural enemies were also recorded to attack different developmental stages of B. tabaci during the course of inve`stigation from Jorhat district of Assam. The study on transmission status of begomovirus revealed that the B. tabaci can acquire the disease with 1 hr feeding on infected plants with 100% of disease acquisition within 24 hrs. In an inoculation study conducted on chilli plants revealed that an inoculation access period of 1 hr was sufficient to produce disease symptoms in 4 numbers of plants out of total nine with 44.44% disease occurrence. The rate of transmission and number of infected plants was found increases with increase in inoculation time and 100% infection and transmission was found reached at 24 hrs of inoculation feeding period.
Open Access
NUTRITIONAL PROFILING OF SOME EDIBLE ORTHOPTERAN INSECTS
(AAU, Jorhat, 2021) Bhattacharjee, Snigdha; Bhattacharyya, Badal
Laboratory experiments were carried out to assess the nutritive value of four edible orthopteran insect species viz., field cricket (Brachytrupes portentosus), mole cricket (Gryllotalpa africana), rice grasshopper (Oxya sp.) and cone headed grasshopper (Ruspolia nitidula) based on their proximate & elemental content, amino & fatty acid profiles, antioxidant & anti-nutritional properties as well as their microbial aspects in the Soil Arthropod Pests Laboratory, Department of Entomology; Post Graduate Laboratory, Department of Biochemistry & Agricultural Chemistry and Soil Biodiversity- Biofertilizers Laboratory, Department of Soil Science, Assam Agricultural University, Jorhat during 2017-2020. Proximate analysis of all the four edible insect species revealed that the moisture content ranged from 2.559-7.537 per cent. Perusal of data showed that the highest mean percentage of moisture content was recorded in B. portentosus (7.537%) whereas R. nitidula registered the least moisture content (2.559%) which makes the insect powder preferably suitable to be preserved for a reasonable period of time without the risk of any microbial deterioration. The carbohydrate content of the studied species varied widely and ranged from 5.138-24.219 per cent where the maximum (24.219%) was registered in Oxya sp. and the lowest (5.138%) was recorded in B. portentosus. Appreciable amount of crude protein content was estimated in all the studied species which ranged from 45.892-69.591 per cent. The highest (69.591%) crude protein was registered in Oxya sp. and it was found to be significantly superior over rest of the species. The protein content recorded in G. africana, B. portentosus and R. nitidula were 67.884, 53.096 and 45.892 per cent, respectively. Crude fat content registered in the studied species varied significantly and was ranged from 8.478-37.619 per cent. The highest (37.619%) crude fat content was recorded in R. nitidula followed by B. portentosus (25.347%) and Oxya sp. (10.773%) whereas G. africana recorded the lowest (8.478%) amount of crude fat content. The crude fibre content varied from 2.899-9.138 per cent and Oxya sp. registered significantly high amount of crude fibre (9.138%) content followed by B. portentosus (8.409%) and G. africana (7.553%). The highest (5.958%) ash content was recorded in B. portentosus which showed statistical parity with G. africana (5.686%) whereas the lowest (1.642%) was recorded in case of R. nitidula. While analyzing the energy content (kcal/100g) of all the four species, the maximum energy content (573.371) was estimated in R. nitidula followed by Oxya sp. (472.197) and B. portentosus (461.059) whereas, G. africana recorded the lowest energy content of 374.330 kcal/100g. 6 Altogether 8 minerals as elemental composition were estimated in all the studied species. The mineral analysis indicated that the concentration of macro elements viz., K and Ca were significantly higher (58.868 & 29.765, mg/100g, respectively) in B. portentosus except for Na and Mg (35.694 & 20.319 mg/100g) whereas the lowest amount (49.573, 8.188, 17.105 and 29.549 mg/100g, respectively) was recorded in R. nitidula. Considerable amount of four micro elements were also recorded in all the studied species. The Fe content estimated in the studied species ranged from 12.231- 53.280 mg/100g where G. africana registered the highest Fe content (53.280 mg/100g) which was significantly superior over rest of the species. Zn content (mg/100g) was estimated to be the highest (15.423) in G. africana which showed statistical parity with B. portentosus (15.295) whereas significantly superior over Oxya sp. (12.950) and R. nitidula (7.848). Mn and Cu content of all the species were found comparatively in trace amounts which ranged from 0.866-6.579 mg/100g and 0.566-3.348 mg/100g, respectively. Perusal of data as regards to the amino acid composition of all the four edible species indicated the availability of 18 common amino acids, out of which 8 were essential. Among all the amino acids quantified, glutamic acid was found to be the most abundant (7.87-5.14%) in all the four species. Alanine, leucine, aspartic acid and valine were the other amino acids available in appreciable amount with values ranging from 7.21-4.86, 5.11-3.89, 4.78-3.47 and 4.18-2.83 per cent, respectively. The percentage of savory amino acids (i.e. glutamate & aspartic acid) was estimated to be highest in B. portentosus (7.87 & 4.78%) followed by Oxya sp. (7.69 & 4.62%) and G. africana (7.28 & 3.85%), respectively. In case of sweet amino acids (i.e. alanine & glycine), the highest amount was recorded in Oxya sp. (7.70 & 3.93%) followed by B. portentosus (7.21 & 3.42%) and G. africana (5.90 & 3.26%), respectively. Relatively trace amount (0.69-1.14 and 0.10-0.25%) of total sulphur containing amino acids (methionine and cysteine) were quantified in all studied edible insects, respectively. The total fatty acid analysis of all the four species revealed that the highest (13.22, 25.31 and 2.47%) amount of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) were recorded in R. nitidula followed by B. portentosus (9.61% SFA, 10.56 % MUFA and 8.13 % PUFA) and G. africana (5.45 % SFA, 7.18 % MUFA and 4.82 % PUFA). Quantification of the fatty acid profile revealed that palmitic acid was the most predominant fatty acid in all the studied species and was recorded to be highest in R. nitidula (11.35%) followed by B. portentosus (7.14%) and G. africana (3.60%) whereas the least (1.55%) amount was recorded in Oxya sp. The findings also revealed the presence of one essential omega 6 7 fatty acid i.e. linoleic acid (1.65%) in Oxya sp. The rest of the fatty acids were recorded in relatively trace amounts in all the studied insect species. The rest of the fatty acids were recorded in trace amount in all the studied insect species. As antioxidants, phenol and flavonoid contents of all the studied edible insect species was estimated and the data found to be varied from 1.062-4.467 mg catechol equivalent/g and 2.412-4.470 mg quercetin equivalent/g, respectively. Oxya sp. registered the highest (4.467 mg catechol equivalent/g) phenol content and was found to be significantly superior over rest of the species. The highest flavonoid content (4.470 mg quercetin equivalent/g) was also registered in Oxya sp. followed by B. portentosus (3.071 mg quercetin equivalent/g) and G. africana (2.799 mg quercetin equivalent/g). Tannin, phytic acid and oxalic acid contents were also estimated as antinutritional factors and were recorded within the permissible limit (250-500 mg/100g). The concentration of phytic acid and tannin were ranged from 26.620-122.427 mg/100g and 97.823-210.500 mg tannic acid equivalent/100g, respectively. The oxalic acid recorded in case of B. portentosus, G. africana, Oxya sp. and R. nitidula were 3.542, 2.910, 3.530 and 3.795 mg/100g, respectively. Investigations on the microbial aspects of insect powders revealed that the Total Viable Counts (TVC) were higher in the samples stored under ambient temperature (9.06-9.29 log cfu/g) as compared to the samples stored under refrigerated temperature (7.33-7.66 log cfu/g). Perusal of data showed that the obtained values exceeded the guideline values for minced meat (i.e. between 5.7-6.7 log cfu/g), however, microbial enumerations of powdered insect samples after 15 days of storage showed that all the samples were free of any yeast and mould contaminations. Biochemical test kits further confirmed the absence of two common food borne pathogens i.e. Escherichia coli and Salmonella sp. in all the studied insect samples.
Open Access
Toxicity of some insecticides against Helicoverpa armigera (Hubner) in tomato (Lycopersicon esculentum Mill.)
(AAU, Jorhat, 2021) Mili, Phunu; Devee, Anjumoni
The research work on ‘Toxicity of some insecticides against Helicoverpa armigera (Hubner) in Tomato (Lycopersicon esculentum Mill.)’ was carried out in the laboratory and field during 2017-2018 and 2018-2019. The laboratory studieswere done in the Toxicology Laboratory, Department of Entomology. Field studies were conducted in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat. In resistance studies the field collected population of Nagaon, Darrang and Jorhat population of H. armigera showed low level of resistance to very high resistance to deltamethrin(Decis 2.8% EC) imidacloprid(Admire 70% WG), chlorantraniliprole(Coragen 18.5% SC) emamectin benzoate (Pocket 5% SG) and thiamethoxam(Eco-Champ 25% WG) upto fourth generation when reared on artificial diet. Resistance Ratio (RR), showed a range of 111.5-288.9 fold, 32.87-75.40 fold, 24.92-34.73 fold, 89.72-128.66 fold and 95-183.3 fold deltamethrin, imidacloprid, chlorantraniliprole, emamectin benzoate and thiamethoxam, respectively for the H. armigera population collected from Nagaon. The population collected from Darrang showed a Resistance Ratio (RR) of 103.13-190.30 fold,28.84-60.90 fold, 24.1-33.46 fold,24.1-116 fold, 102.15-203.50 fold for deltamethrin, imidacloprid, chlorantraniliprole,emamectin benzoate and thiamethoxam, respectively. While, for Jorhat population the range of Resistance Ratio (RR) were 106.29-236.92 fold, 23.02-63.14 fold, 10.07-34.34 fold, 10.07-88.83 fold and 98.38-168.4 foldfor deltamethrin, imidacloprid, chlorantraniliprole,emamectin benzoate and thiamethoxam, respectively.The field population collected Nagaon district population showed very high resistance to deltamethrin, emamectin benzoateand thiamethoxam (RF: >100), high resistance to imidacloprid (RF: 31-100) and moderate resistance to chlorantraniliprole (RF: 11-30). In case of population collected from Darrang district, deltamethrin and thiamethoxam registered very high resistance, emamectinbenzoate and imidacloprid showed high resistance and moderate resistance observed onchlorantraniliprole. However, the field collected population of Jorhat showed low resistance to chlorantraniliprole (RF: 2-10), moderate to emamectinbenzoate (RF:11-30), high resistance to Imidacloprid and very high resistance to deltamethrin and thiamethoxam (RF:>100). At all three places it was observed that H. armigeraalready developed very high resistance todeltamethrin and thiamethoxam. Bio efficacy studies, all the 6 treatments viz.,deltamethrin @ 15 g a.i./ha,imidacloprid @ 20 g a.i./ha,chlorantraniliprole @ 10 g a.i./ha, emamectin benzoate @ 11g a.i./ha and thiamethoxam @ 26 g a.i./ha were found to be significantly superior over control (untreated). The highest population reduction was observed with the treatment of chlorantraniliprole @ 10 g a.i./ha at one (55.47%), three (75.47%), seven (85.18%), ten day (87.26%) and fifteen (87.07%) days after spraying during 2017-18 and 2018-19 whereas lowest atdeltamethrin @ 15 g a.i./ha (35.74%, 49.43%, 58.58%, 63.20% and 64.25%, respectively). However, in control, population was increased by 1.97%, 4.03%, 8.52%, 10.76% and 13.90% at 1, 3, 7, 10 and 15 days after spraying. The highest mean yield was obtained fromchlorantraniliprole @ 10 g a.i./ha (0.22 q/ha) followed byemamectin benzoate @ 11g a.i./ha(0.21 q/ha),thiamethoxam @ 26 g a.i./ha (0.20 q/ha),imidacloprid @ 20 g a.i./ha (0.19 q/ha) and deltamethrin @ 15 g a.i./ha (0.15 q/ha). The lowest yield was obtained at control (0.12 q/ha). All the treatments gave significantly higher yield over control. Chlorantraniliprole @ 10 g a.i./ha registered highest cost: benefit ratio (1 : 5.01) and successfully reduced the aphid population.The LC50values of deltamethrin, imidacloprid, chlorantraniliprole, emamectin benzoate and thiamethoxam to susceptible laboratory reared AAU collected H.armigera were 0.0063, 0.0042, 0.0035, 0.0038 and 0.0039 per cent after 24 hrs and0.0046, 0.0016, 0.0011, 0.0015, 0.0014 per cent after 48 hrs respectively. The residual toxicity of chlorantraniliprole @ 10 g a.i./ha in tomato to 7 days old larva of H. armigera was highest (85.00% and 87.50% mortality) at 24 and 48 hrs exposure period when treated terminal shoots and fruits were fed after one day of spraying while deltamethrin @ 15 g a.i./ha treated terminal shoots and fruits caused lowest larval mortality (45.00% and 50.00%). The highest PT and RPT values were observed at chlorantraniliprole @ 10 g a.i./ha (1050 and 2.18 respectively) followed by emamectin benzoate @ 11 g a.i./ha (990 and 2.06), thiamethoxam @ 26 g a.i./ha (937.50 and 1.95), imidacloprid @ 20 g a.i./ha (810 and 1.68) and deltamethrin @ 15 g a.i./ha (480 and 1.00).Considering the results ofbio efficacy, relative and residual toxicity, fruit borer population reduction, yield, cost-benefit ratio, application ofchlorantraniliprole @ 10 g a.i./ha can be suggested for field application for management of H. armigerapopulation or can be incorporated in IPM of H. armigera. Moreover, these new chemicals chlorantraniliprole @ 10 g a.i./ha, emamectin benzoate @ 11 g a.i./ha and thiamethoxam @ 26 g a.i./ha can be used in rotation or combination for resistance management.
Open Access
TOXICOLOGICAL STUDIES OF CERTAIN INSECTCIDES ON BRINJAL SHOOT AND FRUIT BORER, Leucinodes orbonalis (Guenee) (PYRAUSTIDAE: LEPIDOPTERA)
(AAU, Jorhat, 2021-10) Thokchom, Sushmita; Devee, A.
Brinjal (Solanum melongena L.) is a Solanaceous, most dominant vegetable crop grown throughout the world. Brinjal contains some essential biochemical and minerals like vitamins, calcium, protein and phosphorus. The present experiment on ‘Toxicological studies of certain insecticides on Brinjal Shoot and Fruit Borer, Leucinodes orbonalis (Guenee) (Pyraustidae: Lepidoptera)’ was carried out to evaluate the bioefficacy, relative toxicity and residual effect of five commonly used insecticides on brinjal against Leuicinodes orbonalis (Guenee). The insecticides were chlorantraniliprole 18.5 SC (Coragen), thiamethoxam 25 WG (Actara) and lambda cyhalothrin 4.9 CS (Karate), Dimethoate 30 EC (Tafgor) and Malathion 50 EC (Cythion). Among all the insecticides chlorantraniliprole 18.5 SC (Coragen) was found to be the most toxic showing LC50 0.031% at 24 hours and 0.010% at 48 hours. The study of bio-efficacy showed that chlorantraniliprole 18.5 SC @40 ga.i/ha was found to be the most effective insecticide for controlling infested shoot and infested fruit, quality parameters and yield of the fruit. Chlorantraniliprole 18.50 SC @ 40 g a.i/ha recorded least number of infested shoot with 0.25 number and 90.56 per cent reduction of infested shoot and also minimum number of infested fruit with 0.20 number and reduction of (91.30%) at 10 DAS during Kharif, 2019. Similar results were also observed during Rabi, 2018 in case of number of infested fruit and infested shoot. The lowest number of infested shoot was registered in chlorantraniliprole 18.50 SC @ 40 g a.i/ha which recorded 0.35 number and 87.27 percent reduction of infested shoot which was significantly lower than the other insecticides after 10 DAS. The highest reduction of infested fruits (89.36%) was also observed in chlorantraniliprole 18.50 SC @ 40 g a.i/ha with 0.25 number. The fruit length for both Rabi, 2018 and Kharif, 2019 was found to be significantly highest in plot treated with chlorantraniliprole 18.50 SC @ 40 g a.i/ha showing (17.75±0.45 cm and 17.50± 0.21 cm). In both rabi 2018 and kharif 2019 season, fruit diameter was observed (2.75±0.32 cm and 2.87±0.40 cm) in chlorantraniliprole 18.50 SC @ 40 ga.i/ha and the mean fruit diameter was found to be non-significant within the insecticidal treatments. The mean fruit weight for both rabi, 2018 and kharif, 2019 was found to be highest in plot treated with chlorantraniliprole 18.50 SC @ 40 g a.i/ha which recorded (16.00±0.24 gm and 16.25±0.40 gm). The yield obtained (q/ha) during the rabi, 2018 and kharif, 2019 was highest in chlorantraniliprole 18.50 SC @ 40 g a.i/ha which differed significantly from other treatments which recorded 40.33 q/ha and 40.13 q/ha respectively. Among the treatments, the highest benefit was obtained from the treatment of chlorantraniliprole 18.50 SC @ 40 g a.i/ha with a cost- benefit ratio of 1: 5.63 during 2018-2019. The study of succession showed that six insect pests were observed during different stages of the crop along with fifteen natural enemies in brinjal ecosystem from October, 2018 to July, 2019. The highest per cent relative abundance was observed in case of aphid (27.70%) followed by shoot and fruit borer (22.22%). Among the natural enemies, the order coleoptera is the most dominant order which recorded (57%) followed by araneae (29%) and the highest relative abundance per cent was observed in both Brumoides saturalis and Micraspis discolor (17.06%) followed by Cheilomenus sexmaculatus and Coccinella transversalis (13.65%). Residual analysis of three insecticides on brinjal was evaluated viz., chlorantraniliprole, thiamethoxam and lambda cyhalothrin. For quantification of chlorantraniliprole, the detection at 225 nm gave satisfactory chromatograms with a retention factor of 5.3 min. Similarly, for quantification of thiamethoxam and lambda cyhalothrin, the detection was found at 230 nm which was similar with a retention factor of 4.5 min and the later 4.3 min. The mean percent recoveries of chlorantraniliprole, thiamethoxam and lambda cyhalothrin at the spiked level of 0.10, 0.25, 0.50 and 1.00 mg/kg were found to be in the range of (83.67% to 96.67%) for chlorantraniliprole, (86.33% to 94.00%) for thiamethoxam and (81.67% to 98.00%) for lambda cyhalothrin. Thiamethoxam residues were found to be maximum which is 0.78 mg/kg collected at 0 day (1hr after spraying) after the first application of thiamethoxam @50 g a.i/ha. After 9 days, it became to 100 per cent which shows no detection of residue. The residues of thiamethoxam washed with normal water were found to be 0.43 mg/kg. It became 100 per cent after 9 days of thiamethoxam washed with normal water. Likewise, the residues of thiamethoxam treated with warm (2%) brine solution was found to be 0.35 mg/kg which is less as compared to thiamethoxam application and thiamethoxam sample washed with normal water after 0 day (1hr after spraying). The maximum residues of chlorantraniliprole were appeared to be 0.51 mg/kg in brinjal sample collected at 0 day (1hr after spraying) after first application of chlorantraniliprole @40 g a. i./ ha. After 9 days, it became to 100 per cent. The residues of chlorantraniliprole washed with normal water at 0 day (1hr after application) was found to be 0.46 mg/kg. No detection of residues was observed after 9 days of treatment. Additionally, the maximum residue was observed to be 0.33 mg/kg at 0 day (1 hr after spraying) in the brinjal sample treated with warm (2%) brine solution. After 7 days, it rises to 100 per cent which shows that there is no residue of chlorantraniliprole. The residues in brinjal sample at 0 day (1 hr after spraying) after first application of lambda cyhalothrin @ 15 g a.i/ha were observed to be 0.31 mg/kg. Finally, it attained to 100 per cent after 9 days. The residues of lambda cyhalothrin washed with normal water at 0 day (1hr after application) was found to be 0.23 mg/kg which has reached to the below determination limit of 0.01 mg/kg which dissipated after 7 days and reached 100 per cent. The (2%) brine solution helped in the removal of pesticide residues in brinjal sample. The residue was found to be 0.20 mg/kg at 0 day (1 hr after spraying). After 7 days, the residue was not traceable which has reached to the below determination limit of 0.01 mg/kg which attained 100 per cent. Half-life (T1/2) of chlorantraniliprole sample was found to be 1.51 days when applied @ 40 g a.i/ ha. For chlorantraniliprole sample washed with normal water, the half-life (T1/2) was shown to be 1.43 days. Half-life (T1/2) of chlorantraniliprole sample treated with 2% brine solution was found to be 1.30 days. Half-life (T1/2) of thiamethoxam sample was observed to be 1.84 days when applied @ 50 g a.i/ha. Whereas half-life (T1/2) of thiamethoxam sample washed with normal water was noticed to be 1.40 days. For thiamethoxam sample treated with (2%) brine solution the half-life (T1/2) was observed to be 1.30 days. Half-life (T1/2) of lambda cyhalothrin sample was seen to be 1.48 days when applied @ 15 g a.i/ha. Additionally, half- life (T1/2) of lambda cyhalothrin sample washed with normal water was found to be 1.06 days. For lambda cyhalothrin sample treated with (2%) brine solution the half-life (T1/2) was observed to be 1.02 days. Tsi (Safety interval) of chlorantraniliprole sample was found to be 6.18 days when applied @40 g a.i/ ha. For chlorantraniliprole sample washed with normal water, the Tsi was shown to be 5.80 days. Tsi of chlorantraniliprole sample treated with (2%) brine solution was found to be 5.29 days. Tsi of thiamethoxam sample was observed to be 1.33 days when applied @ 50 g a.i/ha. Whereas Tsi of thiamethoxam sample washed with normal water was noticed to be 1.01 days. For thiamethoxam sample treated with (2%) brine solution the Tsi was observed to be 0.94 days. Tsi of lambda cyhalothrin sample was seen to be 1.91 days when applied @ 15 g a.i/ha. Additionally, Tsi of lambda cyhalothrin sample washed with normal water was found to be 1.37 days. For lambda cyhalothrin sample treated with (2%) brine solution the Tsi was observed to be 1.32 days. Based on yield, reduction of infested shoots and fruits number, residues, dissipation pattern, half-life, waiting period and MRL (0.03 mg/kg) and (0.2 mg/kg) of chlorantraniliprole 18.50 SC @ 40 g a.i/ha or lambda cyhalothrin 4.9 CS @ 15 g a.i/ha can be suggested as sufficient treatment to optimize the yield of brinjal without harming the consumers.
Open Access
DEVELOPMENT OF INTEGRATED PEST MANAGEMENT MODULES AGAINST INSECT PESTS OF BHUT JOLOKIA (Capsicum chinense Jacq.)
(2019-09) Bora, Sasanka Sekhar; Saikia, D. K.
Experiments were carried out under field conditions at the Experimental Farm, Department of Horticulture as well as in the Department of Entomology and Department of Plant Pathology, Assam Agricultural University, Jorhat during 2017-18 and 2018-19 to study the major sucking and chewing pests of Bhut Jolokia causing substantial losses in fruit yield. At present, IPM has been attaining immense importance in the agricultural scenario of India and abroad. Therefore, evaluation of sustainable IPM modules was felt very much necessary in Bhut Jolokia. The result revealed that altogether twenty three numbers of insect pests were associated with the crop and among them aphid (Aphis gossypii Glover/Myzus persicae Sulzar), Whitefly (Bemisia tabaci Gennadius), thrips (Scirtothrips dorsalis Hood), yellow mite [Polyphagotarsonemus latus (Banks)], Cutworm (Agrotis ipsilon Hufuagel) and fruit fly [Bactrocera dorsalis (Hendel)] were considered as the key pests of Bhut Jolokia. Highest incidence of major pests was obtained in the 1st fortnight of April during 2018 as against 2nd fortnight of April during 2019, respectively. A new invasive pest, spiraling whitefly (Aleyrodicus dispersus Russel, Aleyrudidae:Hemiptera) was also reported for the first time in Bhut Jolokia from Assam. Five IPM modules were evaluated against insect pests of Bhut Jolokia, of which module I comprised of recommended dose of fertilizer and farm yard manure+ application of microbial consortium + growth promoter viz., Tricontanol + weeding at 30, 60 and 90 Days after transplanting (DAT) + imidacloprid 17.8 SL 0.4 ml per lt @ 40 days interval was found to be the most effective module in respect of B: C ratio (3.02: 1) followed by module III (Vermicompost 1.25t/ha+ neem cake 500 kg/ha + application of microbial consortium + black polythene mulching + garlic extract @ 10% at 20 and 70 DAT +NSKE 5% at 35 and 100 DAT + installation of sticky trap @ 25 traps /ha) where the B:C ratio was 2.96 with maximum yield of 740.74 gm per plant with next higher yield of 712.13 gm per plant in module I. Hence, module III in comparison to module I seems to be quite promising strategy as it did not require any insecticidal interference keeping natural enemies and ecosystem undisturbed. Out of eight cultivars collected cv. Assam 1 (King) contributed maximum yield of 719.85 gm per plant followed by Assam 4 with 626.67 gm per plant with minimum susceptibility towards pests and diseases. Correlation studies between sucking pests and phenotypic characters indicated that only number of leaves and leaf area index had negative significant impact while other parameters viz., plant height and branches showed no effect. Result of different shade level, 75 per cent shade showed highest plant height and leaf area index of 90.01 cm and 1.81 as against open condition where it was only 53.18 cm and 1.46. The number of leaves and branches of Assam 1 cultivar were to be highest 220.51 cm and 8.75 in open condition, while they were 80.75 cm and 5.13 in 75 per cent shade level. Likewise, for flowering, 116.75 days required in case of 75 per cent shade level, whereas it was only 93.25 days in case of open condition. Similarly, fruit numbers also reduced in case of 75 per cent shade level which was only 27.0 while 92.13 was in case of open condition. Yield per plant was also around 718.13 gm per plant in open condition, whereas it was only 223.63 gm per plant in 75 per cent shade level. The major sucking pests and coccinellid predator population found to be in higher side in open condition also. In 75 per cent shaded area the pooled infestation of aphid, whitefly, thrips and mite was 0.62, 0.35, 0.26 and 0.54 numbers per three leaves whereas, it was 1.69, 1.58, 1.25 and 2.58 numbers per three leaves in open condition. Predatory spider population found highest with 0.34 numbers per plant while coccinellid population was lowest with 0.15 numbers per plant at 75 per cent shade level. But coccinellid population was highest with 0.40 numbers per plant in open condition while 0.18 numbers per plant spider also found at open condition, respectively. RT PCR method confirmed the presence of Cucumber mosaic virus (CMV) on whole seed and seed coat, which indicates that CMV transmitted through seed.

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