Debashis Roy and Pijush K Sarkar

Transcription

1 2017; 5(2): EISSN: ISSN: JEZS 2017; 5(2): JEZS Received: Accepted: Debashis Roy Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, in: , West Bengal, India ijush K Sarkar Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, in: , West Bengal, India Evaluation of pest management packages for their performance against major insect pests and predatory fauna of Okra in Gangetic alluvial plain of West Bengal Debashis Roy and ijush K Sarkar Abstract The present investigation was carried out to study the fieldeffectiveness of different pest management modules (M1: biointensive, M2: farmers conventional package of practice, M3: proposed IM compatible biorational module and M4: adaptable package of practice) against major insect pests of okra and their impact on prevailing natural enemies and crop yield during spring summer season of 2015 and 2016 (FebruaryMay). Mean percent reduction of leafhopper population over untreated control was highest in Module3 (59.33%) followed by Module4 (42.84%) while, in case of whitefly, Module3 recorded lowest number of nymphs and adults (2.01/ leaf) followed by Module2. Module3 registered lowest mean population of Helicoverpa armigera (0.17 larvae/ plant) along with lowest mean fruit damage (3.22%) and highest yield (13.69 t/ ha). Highest mean number of Coccinellids and spiders were encountered in Module3 (0.32 and 0.31 per plant respectively) also which can be an excellent option for sustainable management of major insect pests of okra. Keywords: Okra fruit borer complex, leafhopper, whitefly, biorational module, IM, predators, economic yield Correspondence Debashis Roy Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, in: , West Bengal, India 1. Introduction Okra (Abelmoschus esculentus (L.) Moench), frequently known as lady s finger or bhendi belonging to family Malvaceae, is an important summer season vegetable crop [1]. In India, it is commonly grown in Maharashtra, Gujarat, Karnataka, Tamil Nadu, Haryana, unjab, Uttar radesh, Bihar, West Bengal and Orissa. West Bengal is the leading state in okra production sharing 18.4% of the total national production [2]. est incidence in okra is very high as that of cotton due to similar botanical family. As high as 72 species of insects have been recorded to attack okra [3] of which, the sucking pests like leafhopper (Amrasca biguttula biguttula Ishida), whitefly (Bemisia tabaci Gennadius), fruit borers viz., Earias vittella (Fabricius), Earias insulana (Boisd) and Helicoverpa armigera (Hubner) are known to cause severe damage to the crop [4]. [5] documented that in India losses in okra due to leafhopper (Amrasca biguttula biguttula) and fruit borer (Earias vittella) were 5052 and 4974 per cent, respectively. Moreover, it has also been reported that the fruit borer complex alone is responsible to cause economic damage to the extent of to per cent in okra [6]. [7] reported that the foliage feeder Sylepta derogata culminates a huge economic loss in okra by hampering photosynthetic activities of the plant. But, the injudicious use of conventional synthetic molecules to manage these pests is fraught with the tribulations of resistance, resurgence, secondary infestation, toxicity to beneficial organisms, residues in food beyond the tolerance limits posing unwarranted health hazards to the consumers [8]. Indiscriminate use of these pesticides leads to undesirable load of their residues in marketable vegetables [9]. However, in view of the changing scenario in pest appearances and cropping pattern, application of botanicals along with identification of biorational molecules having novel target sites with better insecticidal properties, low mammalian toxicity and safe to natural enemies is essential. Keeping these in view, the present investigation was attempted to evaluate different package of practices with special reference to pest management modules against different insect pests of okra and their impacts on prevailing natural enemies under okra agroecosystem in Gangetic alluvial plain of West Bengal. ~ 831 ~

2 2. Materials and Methods 2.1 Experimental site The experiment was conducted at the Students Instructional Farm, Jaguli under Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal during the springsummer season of year 2015 and The geographical details of the site are N latitude, E longitude and 9.75 meter above mean sea level (MSL). The climate of the area is subhumid tropical climate with average annual rainfall mm. The soil of the experimental site was moderate in fertility, sandy loam in texture with good water holding capacity while, ph is slightly acidic i.e. 6.5 in nature. WAS), lambda cyhalothrin 5 EC (Syngenta, 0.75 ml/l (10 WAS). 2.8 Untreated control No plant protection measures have been provided in untreated control plots. 2.9 Target insects ests: Leafhopper (Amrasca biguttula biguttula Ishida), whitefly (Bemisia tabaci Gennadius), fruit borers viz., Earias vittella (Fabricius) and Helicoverpa armigera (Hubner), leaf roller (Sylepta derogata Fabricius). 2.2 Growing of Okra Okra crop cv. Shakti (a very common and popular cultivar used by the farmers of West Bengal due to its susceptibility against major insect pests but tolerance against Yellow Vein Mosaic Virus) was sown at 1 st week of March during both the consecutive years in 20 different plots of 3 4 m 2 area with 60 cm 30 cm spacing. Fertilizers were 80:50:50 kg/ha of NK in the form of urea, single super phosphate and muriate of potash in all the plots followed by recommended horticultural practices. 2.3 Treatment details The combinations of treatments were considered as different modules where the whole experiment was arranged in a completely randomized block design (RBD) with five treatments including untreated control and replicated four times each. 2.4 Module I (Biointensive practices) Application of neem cake at final land preparation and 3 week after sowing 240 kg/ha, neem oil 0.3% (Afield Crop Care, 2.5 ml/l (6 WAS), Bacillus thuringiensis (Valent Biosciences Corporation, 2 g/l (8 WAS), karanja oil (Ozone Biotech, 2 ml/l (10 WAS). 2.5 Module II (Conventional farmers practices) Acephate 75 S (Rallis India Limited, 0.75 g/l (3 WAS), thiamethoxam 25 WG (Syngenta, 0.3 g/l (5 WAS), chlorpyrifos + cypermethrin 16% + 5% EC (Crop Life Science Limited, 1 ml/l (6 WAS), flubendiamide SC (Bayer Crop Science, 0.3 ml/l (8 WAS), chlorpyrifos + cypermethrin 16% + 5% 1 ml/l (10 WAS). 2.6 Module III (roposed package of practices) Neem cake at final land 240 kg/ha, flonicamid 50 WG (United hosphorus Limited, 0.4 g/l (3 WAS), neemazol TS 5% (E.I.D. arry India Limited, 2 ml/l (4 WAS), dinotefuran 20 SG (Indofil Industries Limited, 0.3 g/l (5 WAS), flubendiamide ml/l (6 WAS), chlorfluazuron 5.4 EC (Ishihara Sangyo Kaisha Limited, 1 ml/l (8 WAS), emamectin benzoate 5 SG (Syngenta, 0.5 g/l (10 WAS). 2.7 Module IV (Adaptable practices) Imidacloprid 17.8 SL (Bayer Crop Science, 0.3 ml/l (3 WAS), neemazol TS 2 ml/l (4 WAS), acetamiprid 20 S (Rallis India Limited, 0.3 g/l (5 WAS), methomyl 40 S (Duont, 1 ml/l (6 WAS), indoxacarb 14.5 SC (Duont, 0.75 ml/l (8 ~ 832 ~ 2.10 redators Coccinellids or ladybird beetles (Coccinella septempunctata, Coccinella transversalis, Cheilomenes sexmaculata, Micraspis discolor) and spider complex (Oxyopes sp. and Argiope sp.) Recording of Data Observations were made on the number of leafhopper (no. of nymphs and adults/ leaf), whitefly (no. of nymphs and adults/ leaf), shoot and fruit borer (no. of bored shoots/ plant), leaf roller (no. of larvae/ plant), gram pod borer (no. of larvae/ plant) and natural enemies (no. of motile stages/ plant) from ten randomly selected plants in each treatment. From each selected plant three leaves i.e., from top, middle and lower canopy were considered as different tiers for taking observation. Total number and weight of fruits as well as healthy and infested by borer complex was recorded in each picking to calculate damage percentage. The observations were made at weekly interval from four week after sowing (WAS) and nine such observations were taken throughout the crop season Yield and Economics At each picking, the weight of fruits was recorded on net plot basis which was computed to hectare basis and then subjected to statistical analysis. Gross returns were calculated by multiplying total yield with the average market price of the produce. Cost of cultivation and cost of treatment imposition were deducted from the gross returns, to find out net returns followed by incremental cost benefit ratio. er cent increase in yield over control against different treatments was also worked out Statistical Interpretation The percent reduction in pest population in different treatments over untreated control was assessed through the formula given by Henderson and Tilton (1955) [10]. Where, T a = opulation in treated plants after treatment; C b = opulation in treated plants before treatment; T b = opulation in control plots after treatment; C a = opulation in control plots before treatment. The data on the pest population and yield were subjected to analysis of variance following RBD using SSS (version 18.0: Inc., Chicago, IL, USA) software after making necessary transformation (squire root transformation and/or angular transformation) wherever required. The critical difference (CD) was also calculated by multiplying student s

3 t value with standard error of mean to judge the significance (5% level of significance) of any one treatment over untreated control. 3. Results and Discussion Observation at different weeks after sowing (WAS) was considered on the mean population of nymphs and adults of leaf hopper (Amrasca biguttula biguttula) per leaf as an attempt to assess the impact of different modules against this pest. The result of the present investigation during 2015 and 2016 (Table 1) recorded significant high mean leaf hopper population in Module1(4.31/ leaf) where the infestation was at par with Module2 (4.14/ leaf). Interestingly, the infestation was significantly low in Module4 (mean 3.95/ leaf), however, it was lowest in Module3 (2.81/ leaf). Mean percent reduction of leaf hopper population over untreated control was highest in Module3 (59.33%) followed by Module4 (42.84%) found statistically at par with Module2 (40.09%). The findings of [11] are in parity with the findings of present author, where they found that flonicamid followed by dinotefuran proved very much effective to manage jassid infestation in Bt cotton. [8] also acknowledged that soil application of neem cake at final land preparation followed by spray application of different chemicals effectively managed jassid population in okra which fully supports the present findings. The effect of different modules on the population of whitefly at different DAS has been presented in table 2. At 4 WAS, the population varied between / leaf in upper canopy, / leaf in middle canopy and / leaf in lower canopy and among all the modules, Module3 was found to be the superior. At 8 WAS, lowest population (3.78/ leaf) was recorded in Module3 and Module4 whereas, highest population was in Module2 followed by Module1 and were statistically at par. In case of mean population of whitefly, Module3 recorded the lowest number (2.01/ leaf) followed by Module2 (2.79); whereas, Module1 recorded highest population in all observations indicating the least effective module. Findings of the present investigation are in conformity with the findings of [12] who have confirmed the superiority of novel systemic molecule flonicamid over conventional insecticides against whitefly of cotton. [13] found that neem oil registered more than 60% mortality of whitefly in okra, proved statistically at par with imidacloprid. The impacts of different modules on percent shoot damage of okra by Earias vittella has been depicted in Table 3 where the result clearly indicated that percent shoot infestation significantly differed among the modules. Module2 registered highest mean percent shoot damage (3.53%) after untreated control followed by Module1 (3.09%) which was statistically at par with Module4 (2.78%). Module3 registered lowest mean percent shoot infestation by E. vittella (1.55%) with highest mean percent reduction (76.12%) over untreated control. Field bioeffectiveness of flubendiamide against okra shoot and fruit borer was evaluated by [14] who confirmed that all the dosages of flubendiamide found very much effective over conventional synthetic molecules; fully supports the present investigation. Findings of [15] are also in parity with the findings of the present authors. The effect of different modules on the population of gram pod borer, Helicoverpa armigera infesting okra was investigated during 2015 and 2016 where it is clear that the larval population of H. armigera/ plant was differed significantly among all the modules (Table 4). In Module3 lowest mean population was recorded (0.17 larvae/ plant) and found statistically at par with Module4 (0.18 larvae/ plant) and Module2 (0.19 larvae/ plant). Module3 was found to have highest mean percent reduction of larval population over untreated control (59.52%) found to be the most effective module against H. armigera. Efficacy of emamectin benzoate against H. armigera in okra and chlorfluazuron against the same pest in chickpea were evaluated by [16 and 17] respectively where their findings fully support the findings of present investigation. Data presented in Table 5 indicated the percent fruit damage by fruit borer complex recorded in different modules on okra during 2015 and Module1 registered highest mean percent fruit infestation to the tune of 8.21% (ranged between %) found statistically at par with Module2 (mean fruit infestation of 7.79%). Module3 registered the lowest mean percent fruit infestation of 3.22% (ranged between %) with 83.07% reduction of fruit damage over untreated control followed by Module4 with 5.94% mean fruit infestation and 68.77% reduction over control respectively. The effect of different modules against leaf roller, Sylepta derogata was assessed during a couple of years of 2015 and 2016 which is shown in Table 6. It appears that the population of leaf roller at different week intervals i.e. 5 and 7 was less in Module2 (0.08 and 0.08 larvae/ plant respectively) and were at par with Module3 in all the observations (0.09 and 0.09 larvae/ plant respectively. But the mean data on larval density in descending order was Module1 > Module4 > Module2 > Module3. The observations draw their support from the findings of [18 and 19] where methomyl and other insecticides alone or in combination effectively managed leaf roller population in okra crop. Among non synthetic insecticides, Bt and neem seed extracts also found to be effective against leaf roller in okra [20]. Relative effects of different pest management modules on the prevailing predatory fauna in okra ecosystem is shown in Table 7 where it was found that Coccinellids and spiders population were least in Module2 ( and per plant respectively), whereas, Module1 registered highest population ( and per plant respectively) found statistically at par with Module3. But, highest mean number of Coccinellids and spiders were encountered in Module3 (0.32 and 0.31 per plant respectively) followed by Module1 (0.20 and 0.24 per plant respectively) found statistically at par with Module4 (0.17 and 0.16 per plant respectively). [14] confirmed the negligible nontarget toxicity of flubendiamide against prevailing predatory fauna in okra ecosystem. Moreover, safety evaluation of novel insecticides used in proposed module against different natural enemy population was investigated by [15] and corroborates the present findings. Data presented in Table 8 indicated the yield of okra recorded in different modules during 2015 and Highest yield of tender marketable fruit was encountered in Module3 (13.69 t/ ha) followed by Module4 (10.13 t/ ha) while, Module1 (8.86 t/ ha) found statistically at par with Module2. Incremental cost: benefit ratio was highest in case of Module3 (1: 4.77) followed by Module4 (1: 3.06). The findings of [21] lends further support to the findings of the present author who has also recorded the combination of neem and insecticidal module as most effective in increasing yield of okra and higher benefit : cost ratio. ~ 833 ~

4 Table 1: erformance of different modules against cotton jassid, Amrasca biguttula biguttula infesting okra during springsummer season of 2015 and 2016 (pooled data). Number of jassids (nymph and adult) per leaf 4 WAS 5 WAS 6 WAS 7 WAS 8 WAS 9 WAS 10 WAS 11 WAS 12 WAS UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC Overall mean reduction over (37.84)# (39.28) (50.38) (40.88) MODULE (2.09)* (1.74) (1.00) (2.27) (1.76) (1.15) (2.59) (1.75) (1.34) (2.94) (2.23) (1.60) (3.35) (2.28) (1.78) (2.99) (2.06) (1.58) (3.53) (2.43) (1.41) (2.35) (2.38) (0.63) (1.56) (0.91) (0.00) (2.08) MODULE (2.20) (1.39) (1.29) (2.93) (2.15) (1.61) (2.35) (1.38) (1.06) (2.63) (1.58) (1.17) (3.27) (2.10) (1.32) (3.31) (2.73) (1.82) (3.08) (1.83) (0.93) (2.78) (1.79) (0.79) (1.80) (1.08) (0.17) (2.04) MODULE (1.95) (1.63) (0.96) (3.47) (2.40) (1.52) (2.16) (1.61) (0.85) (2.22) (1.37) (0.81) (2.48) (1.75) (1.53) (1.98) (1.52) (0.48) (2.47) (1.84) (1.06) (1.51) (1.06) (0.00) (0.96) (0.58) (0.00) (1.68) MODULE (2.17) (1.66) (1.34) (3.48) (2.93) (1.51) (2.27) (1.43) (0.79) (2.85) (1.92) (1.29) (3.22) (1.90) (1.10) (2.98) (1.69) (0.85) (3.18) (1.84) (1.02) (2.23) (1.58) (0.79) (1.58) (0.52) (0.00) (1.99) (2.47) (1.62) (1.21) (3.18) (2.41) (1.95) (4.31) (2.68) (1.51) (4.50) (2.24) (1.67) (4.67) (2.85) (1.32) (4.25) (3.21) (1.95) (4.03) (2.05) (1.24) (2.87) (1.15) (0.48) (2.06) (0.84) (0.17) (2.63) S.Em± NS NS 1.23 CD (0.05) NS NS 2.08 Abbreviations: WAS = Weeks After Sowing; = Untreated Control; UC = Upper Canopy; MC = Middle Canopy; LC = Lower Canopy. *Data in these parentheses are n transformed values; #Data in these parentheses is sin 1 transformed values. Table 2: erformance of different modules against whitefly, Bemisia tabaci infesting okra during springsummer season of 2015 and 2016 (pooled data). Number of whitefly (nymph and adult) per leaf 4 WAS 5 WAS 6 WAS 7 WAS 8 WAS 9 WAS 10 WAS 11 WAS 12 WAS UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC UC MC LC Overall mean reduction over (25.55)# (34.82) (45.83) (29.92) MODULE (1.75)* (1.55) (1.06) (3.34) (2.61) (1.68) (3.03) (2.20) (1.37) (2.96) (2.14) (0.99) (2.86) (1.94) (1.05) (2.10) (1.76) (0.88) (2.38) (1.38) (0.69) (1.44) (1.13) (0.52) (0.52) (0.27) (0.00) (1.84) MODULE (1.67) (1.63) (0.76) (3.41) (2.18) (1.49) (2.38) (1.95) (0.96) (2.56) (1.85) (0.95) (2.67) (1.64) (1.10) (2.20) (1.71) (0.73) (2.13) (1.55) (0.45) (1.37) (0.77) (0.17) (0.36) (0.48) (0.17) (1.67) MODULE (1.68) (1.38) (0.48) (2.81) (1.67) (1.05) (2.64) (1.79) (0.55) (1.84) (1.45) (0.27) (2.66) (1.90) (0.82) (1.68) (0.63) (0.00) (1.59) (1.14) (0.00) (1.48) (0.57) (0.00) (0.69) (0.41) (0.00) (1.42) MODULE (1.71) (1.45) (0.99) (3.52) (3.01) (1.63) (2.87) (2.14) (1.28) (2.38) (1.61) (0.91) (2.50) (1.85) (1.28) (1.80) (1.39) (0.61) (2.14) (1.53) (0.78) (1.70) (1.14) (0.57) (1.17) (0.32) (0.00) (1.76) (1.75) (1.53) (1.06) (3.33) (2.56) (1.70) (3.40) (2.66) (1.85) (3.48) (2.65) (1.06) (2.98) (2.03) (1.14) (2.68) (2.09) (0.89) (1.97) (1.85) (0.89) (2.18) (1.02) (0.77) (1.00) (0.48) (0.27) (2.04) S.Em± NS NS NS NS NS 0.26 CD (0.05) NS NS NS NS NS 1.54 Abbreviations: WAS = Weeks After Sowing; = Untreated Control; UC = Upper Canopy; MC = Middle Canopy; LC = Lower Canopy. *Data in these parentheses are n transformed values; #Data in these parentheses is sin 1 transformed values. Table 3: erformance of different modules against percent shoots damage by Earias vitella in okra during springsummer season of 2015 and 2016 (pooled data). MODULE 1 MODULE 2 MODULE 3 ercent shoot damage by E. vitella 4 WAS 5 WAS 6 WAS 7 WAS 8 WAS 9 WAS 10 WAS 11 WAS 12 WAS Overall mean reduction over (0.00)* (0.00) (7.47) (14.03) (12.76) (16.43) (11.62) (8.88) (5.56) (10.12) (46.37) (0.00) (0.00) (5.16) (18.32) (13.17) (17.77) (7.60) (10.69) (6.75) (10.83) (42.48) (0.00) (0.00) (6.75) (13.17) (6.10) (9.65) (5.91) (7.04) (5.38) (7.15) (60.75) ~ 834 ~

5 MODULE (0.00) (0.00) (5.74) (18.44) (8.63) (10.88) (7.60) (11.98) (8.39) (9.60) (49.12) (0.00) (3.19) (9.44) (20.71) (18.56) (19.49) (17.52) (17.59) (10.78) (14.76) S.Em± 0.00 NS CD (0.05) 0.00 NS Abbreviations: WAS = Weeks After Sowing; = Untreated Control. * Data in these parentheses is sin 1 transformed values. Table 4: erformance of different modules against larval population of Helicoverpa armigera in okra during springsummer season of 2015 and 2016 (pooled data). Larval population of Helicoverpa armigera per plant 4 WAS 5 WAS 6 WAS 7 WAS 8 WAS 9 WAS 10 WAS 11 WAS 12 WAS Overall mean reduction over MODULE (0.00)* (0.00) (0.44) (0.88) (0.74) (0.83) (0.44) (0.30) (0.00) (0.52) (36.70)# MODULE (0.00) (0.00) (0.00) (0.77) (0.71) (0.76) (0.00) (0.00) (0.00) (0.44) (47.73) MODULE (0.00) (0.00) (0.25) (0.90) (0.60) (0.45) (0.30) (0.00) (0.00) (0.41) (50.49) MODULE (0.00) (0.00) (0.00) (0.78) (0.62) (0.76) (0.28) (0.00) (0.00) (0.42) (49.11) (0.00) (0.00) (0.66) (1.04) (0.87) (0.98) (0.69) (0.20) (0.00) (0.65) S.Em± NS NS CD (0.05) NS NS Abbreviations: WAS = Weeks After Sowing; = Untreated Control. *Data in these parentheses are n transformed values; #Data in these parentheses is sin 1 transformed values. Table 5: erformance of different modules against percent fruit damage in okra by fruit borer complex (Earias vitella and Helicoverpa armigera) during springsummer season of 2015 and 2016 (pooled data). 1 st 2 nd 3 rd 4 th 5 th 6 th 7 th 8 th ercent fruit damage by fruit borer complex (E. vitella and H. armigera) Rounds of picking at every alternate day 9 th 10 th 11 th 12 th MODULE (16.49)# (30.56) (26.10) (17.40) (18.85) (16.58) (13.03) (18.11) (19.31) (18.72) (18.49) (19.23) (15.49) (12.22) (9.94) (11.98) (14.62) (15.01) (16.10) (11.17) (11.24) (14.33) (17.73) (16.65) MODULE (14.77) (27.74) (27.84) (17.41) (22.12) (10.24) (15.63) (16.91) (15.79) (18.15) (15.88) (21.13) (17.20) (9.15) (7.56) (13.05) (15.05) (10.02) (13.28) (13.92) (16.16) (18.79) (11.43) (16.21) MODULE (11.81) (16.57) (16.85) (13.01) (16.35) (8.87) (7.62) (8.01) (7.71) (10.94) (11.14) (9.49) (10.21) (9.08) (8.41) (0.40) (10.69) (8.57) (10.01) (10.27) (10.72) (11.55) (11.62) (10.34) MODULE (18.30) (21.62) (18.34) (16.94) (18.29) (8.82) (8.33) (13.13) (13.32) (12.04) (13.05) (19.36) (12.36) (10.59) (11.14) (13.10) (15.49) (8.35) (11.51) (11.73) (14.68) (17.57) (19.80) (14.11) (17.20) (35.77) (34.69) (31.11) (28.90) (22.10) (20.77) (22.47) (26.44) (22.91) (28.14) (24.88) (23.33) (22.20) (32.04) (29.25) (24.85) (21.46) (26.73) (21.51) (25.22) (24.91) (29.89) (25.86) S.Em± CD (0.05) Abbreviations: = icking; = Untreated control; #Data in these parentheses is sin 1 transformed values. 13 th 14 th 15 th 16 th 17 th 18 th 19 th 20 th 21 st 22 nd 23 rd fruit damage reduction of fruit damage over control (48.93) (50.21) (65.70) (56.03) ~ 835 ~

6 Table 6: erformance of different modules against cotton leaf roller, Sylepta derogata infesting okra during springsummer season of 2015 and 2016 (pooled data). Larval population of S. derogata per plant 4 WAS 5 WAS 6 WAS 7 WAS 8 WAS 9 WAS 10 WAS 11 WAS 12 WAS Overall mean reduction over MODULE (0.30)* (0.37) (0.33) (0.40) (0.17) (0.28) (0.28) (0.00) (0.00) (0.28) (48.19)# MODULE (0.00) (0.28) (0.28) (0.28) (0.30) (0.00) (0.00) (0.00) (0.00) (0.22) (58.19) MODULE (0.17) (0.30) (0.17) (0.30) (0.20) (0.00) (0.00) (0.00) (0.00) (0.17) (65.90) MODULE (0.22) (0.45) (0.20) (0.37) (0.25) (0.28) (0.00) (0.00) (0.00) (0.25) (54.74) (0.40) (0.50) (0.59) (0.53) (0.59) (0.40) (0.30) (0.00) (0.00) (0.42) S.Em± NS NS NS NS CD (0.05) NS NS NS NS Abbreviations: WAS = Weeks After Sowing; = Untreated Control. *Data in these parentheses are n transformed values; #Data in these parentheses is sin 1 transformed values. Table 7: Impact of different modules on the prevalence of predatory fauna in okra ecosystem during springsummer season of 2015 and 2016 (pooled data). Number of predators (motile stages) per plant 4 WAS 5 WAS 6 WAS 7 WAS 8 WAS 9 WAS 10 WAS 11 WAS 12 WAS Overall mean a b a b a b a b a b a b a b a b a b a b MODULE (0.28)* (0.30) (0.37) (0.51) (0.36) (0.40) (0.49) (0.45) (0.48) (0.63) (0.49) (0.48) (0.48) (0.55) (0.50) (0.60) (0.53) (0.46) (0.45) (0.49) MODULE (0.20) (0.17) (0.39) (0.30) (0.28) (0.28) (0.44) (0.37) (0.33) (0.39) (0.28) (0.33) (0.38) (0.33) (0.33) (0.32) (0.33) (0.39) (0.33) (0.33) MODULE (0.39) (0.46) (0.42) (0.39) (0.44) (0.44) (0.74) (0.56) (0.60) (0.71) (0.71) (0.73) (0.44) (0.42) (0.59) (0.66) (0.60) (0.54) (0.57) (0.56) MODULE (0.37) (0.30) (0.37) (0.42) (0.37) (0.42) (0.55) (0.48) (0.45) (0.32) (0.45) (0.49) (0.32) (0.33) (0.44) (0.48) (0.39) (0.32) (0.41) (0.40) (0.53) (0.53) (0.70) (0.67) (0.79) (0.63) (0.76) (0.66) (0.89) (0.76) (0.92) (0.81) (0.83) (0.78) (0.78) (0.81) (0.74) (0.71) (0.78) (0.71) S.Em± CD (0.05) Abbreviations: a = Coccinellid predators; b = Spider complex; WAS = Weeks After Sowing; = Untreated Control. *Data in these parentheses is n transformed values. Table 8: Yield of tender marketable fruits and economics employed under different modules of okra during springsummer season of 2015 and 2016 (pooled data). Mean yield of tender Gross Return Total cost of cultivation including Net Return Net profit over untreated Incremental marketable fruit (tonnes/ ha) (Rs./ ha) chemicals, labour charges (Rs./ ha) (Rs./ ha) control (Rs./ ha) Cost: Benefit Ratio MODULE : 1.68 MODULE : 1.76 MODULE : 4.77 MODULE : S.Em± 0.19 CD (0.05) 1.20 Cost of tender marketable fruit = Rs per kg Labour charges Rs per man per day; Spray charges Rs per sprayer per day. ~ 836 ~

7 4. Conclusion The present study concluded that the new generation biorational molecules having novel target sites in association with botanicals like neem as foliar application as well as organic manure can be adapted by the okra growers. And this particular proposed pest management module can be incorporated under the umbrella of IM for sustainable management of major insect pests of okra from entomological, ecotoxicological and economic point of view in near future. 5. Acknowledgements Authors are grateful to Directorate of Farms, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal for allotting the field in order to conduct the concerned research. 6. References 1. Bairwa DK, Kanwat M, Kumawat KC. Effect of dates of sowing on the incidence of jassids, whiteflies and shoot and fruit borer of okra. Annals of Agricultural Research. 2005; 26: Anonymous. Indian Horticultural Data Base, 2013, National Horticulture Board, Ministry of Agriculture, Govt. of India. 2013, Rao NS, Rajendran R. Joint action potential of neem with other plant extracts against the leafhopper, Amrasca devastans (Distant) on okra. est Management and Economic Zoology. 2002; 10: Mandal SK, Sattar A, Gupta SC. opulation dynamics of Earias vittella Fab. in okra as influenced by weather parameters in north Bihar. Journal of Agrometeorology. 2006; 8: Dhandapani N, Shelkar UR, Murugan M. Biointensive pest management (BIM) in major vegetable crops: an Indian perspective. Food, Agriculture and Environment. 2003; 2: areek L, Bhargava MC. Estimation of avoidable losses in vegetables caused by borers under semi arid condition of Rajasthan. Insect Environment. 2003; 9: Ogbalu OK, Bob Manuel RB, Gbarakoro T. The role of Sylepta derogata [Lepidoptera: yralidae] in the abscission and defoliation of okra flowers, seeds and pods in monocrop gardens in ort Harcourt, Nigeria. IOSR Journal of harmacy and Biological Science. 2015; 10: Mandal SK, Sah SB, Gupta SC. Neembased integrated management approaches for insectpests of okra (Abelmoschus esculentus L. Moench). International Journal of Agricultural Science. 2006; 2: Kumar B, Madan VK, Kumar R, Kathpal TS. Monitoring of seasonal vegetables for pesticide residues. Earth and Environmental Science. 2002; 74: Henderson CF, Tilton EW. Tests with acaricides against the brown wheat mite. Journal of Economic Entomology. 1955; 48: Ghelani MK, Kabaria BB, Chhodavadia SK. Field efficacy of various insecticides against major sucking pests of Bt cotton. Journal of Biopesticides. 2014; 7: Gaurkhede AS, Bhalkare SK, Sadawarte AK, Undirwade DB. Bioefficacy of new chemistry molecules against sucking pests of Bt transgenic cotton. International Journal of lant rotection. 2015; 8: Ghosh SK, Mandal T, Chakraborty K. Efficacy of chemical insecticides and Neem Oil against whitefly (Bemisia tabaci Genn.) infesting ladysfinger (Abelmoschus esculentus L.). International Journal of Bioresource and Stress Management. 2013; 4: Katti, Surpur S. Field bio efficacy of flubendiamide 480 SC against okra fruit and shoot borer, Earias vittella (Fab.) during Rabi season, International Journal of lant rotection. 2015; 8: Devi LL, Ghule TM, Senapati AK, Chatterjee ML. Comparative efficacy of some biorational insecticides for management of shoot and fruit borer (Earies vittella Fab.) on okra. Indian Journal of Applied Research. 2014; 4: Govindan K, Gunasekaran K, Veeramani K, Kuttalam S. Field and laboratory evaluation of biological compatibility of Emamectin benzoate 5 SG with agrochemicals against okra fruit borer (Helicoverpa armigera Hubner). International Journal of lant and Animal Science. 2013; 1: Khatri I, Shaikh AA, Sultana R, Wagan MS, Ahmed Z. Effect of some insect growth regulators against gram pod borer Helicoverpa armigera (Hb.) on chickpea Cicer arietinum (L.) under laboratory conditions. akistan Journal of Zoology. 2015; 46: Chakraborty S, ahari AK. Studies on the control of important pests of okra by Lannate 40 S. esticide Research Journal. 2002; 14: Misra H, Dash DD, Mahapatra D. Efficacy of some insecticides against okra fruit borer, Earias spp. and leafroller, Sylepta derogata Fab. Annals of lant rotection Science. 2002; 10: Obeng OD, Sackey J. Field evaluation of nonsynthetic insecticides for the management of insect pests of okra Abelmoschus esculentus (L.) Moench in Ghana. Sinet Ethiopian Journal of Science. 2003; 26: Jakhar BL. Development of integrated pest management (IM) modules against insect pests of okra in Gujarat. estology. 2014; 38:5863. ~ 837 ~