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Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 9 Number 11 (2020) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2020.911.281 Management of Sucking Pest, Jassid (Amrasca devastans) and Thrips (Thrips palmi) on Lady’s Finger (Abelmoschus esculentus L.) by using Safe Insecticides Sunil Kumar Ghosh* Department of Agricultural Entomology, B.C.K.V-Agricultural University, Kalyani, Nadia, West Bengal, 741235, India *Corresponding author ABSTRACT Keywords Dinotefuran, Fipronil, Imidacloprid, Persistency, Coccinellid Article Info Accepted: 17 October 2020 Available Online: 10 November 2020 Lady’s finger Abelmoschus esculentus (L.) Moench is an annual kharif vegetable crop belongs to the family Malvaceae. This crop is cultivated in various parts of tropical and sub-tropical areas of the world. In West Bengal, India it is cultivated in a commercial scale but its pest complex is very high which limit its production. Contribution jassid (Amrasca devastans) and thrips (Thrips palmi) as sucking pest in this case is of great importance. Three doses of dinotefuron 20 SG (@ 20, 30 and 40 a.i. g /ha) two doses of imidacloprid 70 WG(@ 21 and 24.5 a.i. g /ha) and two doses of fipronil 5% SC ( @ 25 and 37.5 a.i. g /ha) were applied to control jassid and thrips. From overall observation it was revealed that Dinotefuron 20 SG @ 40 g a.i./ha, Fipronil 5% SC @ 37.5 g a.i./ha and imidacloprod 70 WG @ 24.5 g a.i/ha provided best suppression of jassid (90.29 %, 89.34 % and 78.42 % jassid population suppression respectively) and thrips (96.55 %, 96.01 % and 85.37 % thrips population suppression respectively). They are also safe insecticides to cocconellid predators. These insecticides may be recommended for farmers use to control sucking pest. Introduction Lady’s finger Abelmoschus esculentus (L.) Moench is an annual kharif vegetable crop belongs to the family Malvaceae and grown in various parts of tropical and sub-tropical areas of the world. In the sub-Himalayan region of north east India lady’sfingers is cultivated at a commercial scale but insect pest damage constitutes a limiting factor in successful production (Ghosh, 2013; Ghosh, et al., 2013). Lady’s finger is infested by a large number of sucking pest viz. jassid, thrips, mites, whitefly aphid etc. Contribution of jassid and thrips in this case is of great importance. Both nymphs and adults suck the sap from tender crop canopy, resulting in shriveling of leaves, retarded shoot development and finally the leaves fall-off, yield reduced significantly. Ghosh and senapati (2003) reported that hopper/jassid population (4.63/leaf) was very high during April-May and positively correlated with temperature gradient, relative humidity and rainfall. Thrips population 2340 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 touched the peak during the third week of September (10.2/ 3 leaves) (Saini et al., 2017). Peak population of thrips (12.58 thrips/three leaves) was recorded in 18th standard week (Priyadarshini et al., 2017). Subba and Ghosh (2016) reported that maximum level of thrips population on tomato was observed during 6th to 20th standard week. Ghosh et al., (2005) reported that thrips population showed significant positive correlation (p=0.05) with temperature, relative humidity, and rainfall on eggplant. Laskar and Ghosh (2005) reported that thrips population ranged from 6.9-16.17 per leaf in untreated chilli field. Ghosh et al., (2007) reported that lady bird beetle / coccinellid beetle Menochilus sexmaculatus was an important predator of aphid and jassid and its feeding activity was found throughout the year. Coccinellid beetle Coccinella septempunctata as the generalized predatory agent has gained great scientific interest for biological control in West Bengal, India (Ghosh, 1999; Chakraborty and Ghosh, 2010). For the effective control of jassid, thrips in vegetable field farmers usually use a lot of pesticides chemicals indiscriminately and frequently (Ghosh, 1999). Ghosh et al., (2009) reported that imidacloprid was found most effective (91.15 % control) against aphid three days after treatment. Mandal et al., (2016) reported that imidaclorprid was found most effective against thrips on som plant providing 75.18% suppression. Most of the conventional chemicals are broad spectrum, persistent in nature and having long residual action. Ghosh and Chakraborty (2012) reported that pest control by using biocontrol agent is an important component of Integrated Pest Management and organic farming. So, there is need of search of bio- control agent in specific time that can break the resistance and become eco-friendly. Das et al., (2010) and Ghosh et at. (2012) reported that a rapid degradation of persistency was observed in Imidacloprid which had a greater importance as fruits and vegetables are consumed after little cooking. Subba et al., (2015) reported that acetamiprid was very effective against jassid recording more than 80% control. Imidacloprid was the most effective in providing more than 80% aphid suppression followed by azadirachtin (Ghosh et al., 2016). Most of the Conventional chemicals are broad spectrum, persistent in nature and having long residual action (Subba et al, 2017; Nayar, et.al., 1992). The objective of the study was to formulate suitable management of sucking pests of lady’s finger with the use of some new safe molecules and less harmful to beneficial insects and environment. Materials and Methods Period and location of the study The studies were done at A-B Block Farm of Bidhan Chandra Krishi Viswavidyalaya located at Kalyani, West Bengal, India during the year 2018-2019. The geographical position of the areas are 23° N latitude, 89° E longitude and 9.75 meter above mean sea level (Thakoor et al., 2020). The soil was gangetic alluvial soil (Entisol) with sandy clay loam texture, neutral in reaction with moderate in fertility (Priyadarsini et al., 2019). The soil type of the experimental field was sandy loam with PH range 5.75 to 6.5 and climate of this zone is subtropical humid having short winter spell during December – January (Bala et al., 2015; Karmakar et al., 2017). The experimental plot was situated on upland with good irrigation and drainage facility. The soil has good water holding capacity. 2341 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 Treatment details Treatment details are as follows: Dose Dose g or ml. a.i. / ha (g or ml/ha) --T1: UTC 20 100 T2: Dinotefuron 20 SG 30 150 T3: Dinotefuron 20 SG 40 200 T4: Dinotefuron 20 SG 21 30 T5: Imidacloprid 70WG 24.5 35 T6: Imidacloprod 70 WG 25 500.0 T7: Fipronil 5% SC 37.5 750.0 T8: Fipronil 5% SC Treatment Lay out of the experiment Season of experiment : Kharif-2018 Variety of lady’s finger: Samrat Date of sowing : 12.07.2018 Plot size : 5m X 5m Spacing : P-P X R-R = 5 cm X 20 cm Fertilizers : N: P: K @ 100:60:60 Design of experiment : Randomized Block Design (RBD) Number of replications : Three Number of spraying : Two Application date : First spray: 10.08.2018 and second spray: 25.08.2018 Application method : ASPEE Knapsack Sprayer with hollow cone nozzle Harvesting : Multiple picking Methodology for bio-efficacy recording against pests data The data of target pests were recorded from randomly selected five plants in each plot. Observations of total number of jassid and thrips on lady’s finger were recorded from five top young leaves of each plant per plot and converted to number of insect pest/leaf. First count was taken one day before first Spray fluid used 500 500 500 500 500 500 500 500 spray and post treatment counts were recorded on 3, 7, 10 and 14 days after each spray. All the observations were recorded with the help of a hand lens (10X). The population of natural enemies (coccinellid) was also recorded from 5 randomly selected plants on 10 days after each spray. Reduction of insect population in different treatments over control was used as an indicator of insecticidal efficacy which was calculated from the following formula (Abbott, 1925): Po − Pc Pt = ----------------------- ×100 100 − Pc Where, Pt = Corrected mortality, Po = Observed mortality and Pc = Control mortality. Data were analyzed by using INDO-STATsoftware for analysis of variance following randomized block design (RBD) treatment means were separated by applying CD Test (critical difference) at 5 % level of significance. Results and Discussion Three doses of dinotefuron 20 SG (@ 20, 30 and 40 a.i. g /ha) two doses of imidacloprid 2342 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 70 WG(@ 21 and 24.5 a.i. g /ha) and two doses of fipronil 5% SC (@ 25 and 37.5 a.i. g /ha) were sprayed to work out their efficacy against jassid and thrips. One treatment of untreated control was taken for observing natural infestation of target pests. Two round spraying has been done where first round was initiated during second week of July and subsequent spraying has been done at 15 days interval. The data on the result has been presented in table 1-4 and the natural enemy population has been presented in table-5. Efficacy evaluation of insecticides against jassid (A. devastans) Data presented in Table 1 and 2 revealed that, all the insecticide treatments significantly reduced the infestation of jassid as compared to untreated control (5.06-7.62 jassid/leaf). From the two round spray it was revealed that dinotefuron 20 SG @ 40 g a.i./ha provided best suppression of jassid population (first spray 92.59 % and second spray 87.99 % with a mean of 90.29 % suppression) closely followed by fipronil 5% SC @ 37.5 g a.i./ha (first spray 92.65 % and second spray 86.03 % with a mean of 89.34 % suppression) and imidacloprod 70 WG @ 24.5 g a.i/ha (first spray 84.29 % and second spray 72.55 % with a mean of 78.42 % suppression). Three days after first spraying lowest population was recorded in Dinotefuron 20 SG @ 40 g a.i./ha treated plot (0.34 jassid/L) closely followed by fipronil 5% SC @ 37.5 g a.i./ha (0.36 jassid/L) and imidacloprod 70 WG @ 24.5 g a.i/ha (0.78 jassid/L). There were no significant differences among these three treatments. Similar trend was followed 7 days, 10 days and 14 days after first spraying. Three days after second spraying lowest population was recorded in dinotefuron 20 SG @ 40 g a.i./ha treated plot (0.12 jassid/L) closely followed by Fipronil 5% SC @ 37.5 g a.i./ha (0.13 jassid/L) and imidacloprod 70 WG @ 24.5 g a.i/ha (0.45 jassid/L). There were no significant differences among these three treatments. Similar trend was followed 7 days after second spraying. Ten days after second spraying lowest population was recorded in dinotefuron 20 SG @ 40 g a.i./ha treated plot (0.78 jassid/L) closely followed by fipronil 5% SC @ 37.5 g a.i./ha (0.79 jassid/L). There were no significant differences between these two treatments. Similar trend was followed 14 days after second spraying. Efficacy evaluation of insecticides against thrips (Thrips palmi) Data presented in Table 3 and 4 revealed that, all the insecticide treatments significantly reduced the infestation of thrips as compared to untreated control (5.46-8.33 thrips/leaf). From the two round spray it is revealed that dinotefuron 20 SG @ 40 g a.i./ha provided best suppression of thrips population (first spray 96.32 % and second spray 96.78 % with a mean of 96.55 % suppression) closely followed by fipronil 5% SC @ 37.5 g a.i./ha (first spray 96.17 % and second spray 95.86 % with a mean of 96.01 % suppression) and imidacloprod 70 WG @ 24.5 g a.i/ha (first spray 88.96 % and second spray 81.78 % with a mean of 85.37 % suppression). Three days after first spraying lowest population was recorded in Dinotefuron 20 SG @ 40 g a.i./ha treated plot (0.04 thrips/L) closely followed by fipronil 5% SC @ 37.5 g a.i./ha (0.06 thrips/L) and imidacloprod 70 WG @ 24.5 g a.i/ha (0.57 thrips/L). There were no significant differences among these three treatments. 2343 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 Table.1 Effect of insecticides on the population abundance of jassid in lady’s finger, Kharif-2018 (1st spray) Treatments Dose/ha Pretreatment Count (jassid/L) 3 DAS 7DAS 10 DAS 14 DAS 4.12 4.78 5.34 6.54 6.98 (2.54) (2.70) (2.82) (3.07) (3.15) 4.23 2.67 2.98 3.23 3.67 (2.57) (2.14) (2.24) (2.31) (2.43) 4.33 1.01 1.23 1.76 2.02 (2.59) (1.51) (1.62) (1.84) (1.93) 4.34 0.34 0.45 0.78 1.03 (2.59) (1.09) (1.18) (1.39) (1.52) 4.65 1.25 1.45 1.87 2.01 (2.67) (1.63) (1.71) (1.88) (1.93) 4.56 0.78 0.98 1.45 1.68 (2.65) (1.39) (1.50) (1.71) (1.81) 4.54 1.04 1.22 1.78 2.09 (2.64) (1.53) (1.61) (1.84) (1.96) 4.65 0.36 0.48 0.79 1.05 (2.66) (1.10) (1.19) (1.39) (1.52) S Em (±) -- 0.16 0.17 0.22 0.21 -- C.D (p<0.05) NS 0.51 0.54 0.68 0.66 -- T1: UTC (g.or ml a.i.) Formulatio n (g or ml) -- -- 20 T2: Dinotefuron 20 SG 30 T3: Dinotefuron 20 SG 40 T4: Dinotefuron 20 SG 21 T5: Imidacloprid 70WG T6: Imidacloprod 70 WG 24.5 25 T7: Fipronil 5% SC 37.5 T8: Fipronil 5% SC 100 150 200 30 35 500 750 Mean no. of jassid/leaf Post mean % reduction over control 5.06 0.00 2.83 45.62 1.12 78.96 0.40 92.59 1.35 76.38 0.88 84.29 1.13 79.73 0.42 92.65 st 1 Spray Figures in parentheses indicate √X+0.5 transformed value, L=leaf, DAS: Days after spraying 2344 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 Table.2 Effect of insecticides on the population abundance of jassid in lady’s finger, Kharif-2018 (2nd spray) Treatments Dose/ha Pretreatment Count (jassid/L 3 DAS 7 DAS 10 DAS 14 DAS 4.12 7.34 7.89 8.34 8.79 (2.54) (3.22) (3.32) (3.40) (3.47) 4.23 1.12 1.45 1.87 2.03 (2.57) (1.57) (1.71) (1.88) (1.93) 4.33 0.78 1.11 1.32 1.97 (2.59) (1.39) (1.56) (1.66) (1.91) 4.34 0.12 0.15 0.28 0.43 (2.59) (0.86) (0.90) (1.04) (1.17) 4.65 1.03 1.13 1.78 2.01 (2.67) (1.52) (1.57) (1.84) (1.93) 4.56 0.45 0.67 0.98 1.32 (2.65) (1.18) (1.33) (1.50) (1.66) 4.54 0.83 1.15 1.43 1.98 (2.64) (1.42) (1.58) (1.71) (1.92) 4.65 0.13 0.19 0.30 0.45 (2.66) (0.86) (0.94) (1.05) (1.17) S Em (±) -- 0.15 0.17 0.16 0.18 -- C.D (p<0.05) NS 0.46 0.53 0.51 0.56 -- T1: UTC (g.or ml a.i.) Formulat ion (g or ml) -- -- 20 T2: Dinotefuron 20 SG 30 T3: Dinotefuron 20 SG 40 T4: Dinotefuron 20 SG 21 T5: Imidacloprid 70WG T6: Imidacloprod 70 WG 24.5 25 T7: Fipronil 5% SC 37.5 T8: Fipronil 5% SC 100 150 200 30 35 500 750 Mean no. of jassid/leaf Post mean % reduction over control 7.62 0.00 1.29 67.91 0.95 57.12 0.14 87.99 1.08 50.75 0.56 72.55 0.99 56.58 0.16 86.03 nd 2 Spray Figures in parentheses indicate √X+0.5 transformed value, L=leaf, DAS: Days after spraying 2345 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 Table.3 Effect of insecticides on the population abundance of thrips in lady’s finger, Kharif-2018 (1st spray) Treatments Dose/ha Pretreatment Count (thrips/L) 3 DAS 7 DAS 10 DAS 14 DAS 3.79 5.03 5.88 7.25 7.67 (2.46) (2.75) (2.94) (3.20) (3.28) 3.91 2.66 3.23 3.53 3.95 (2.49) (2.14) (2.31) (2.39) (2.50) 4.02 0.80 1.26 1.88 2.09 (2.52) (1.40) (1.63) (1.88) (1.96) 4.03 0.04 0.39 0.78 0.98 (2.52) (0.72) (1.13) (1.39) (1.50) 4.38 1.07 1.51 2.00 2.08 (2.60) (1.54) (1.74) (1.93) (1.95) 4.28 0.57 0.79 1.23 1.92 (2.58) (1.26) (1.40) (1.62) (1.90) 4.26 0.83 1.25 1.90 2.17 (2.57) (1.42) (1.63) (1.89) (1.98) 4.38 0.06 0.42 0.79 1.00 (2.59) (0.75) (1.15) (1.39) (1.50) -- 0.19 0.15 0.17 0.22 -- NS 0.54 0.43 C.D (p<0.05) Figures in parentheses indicate √X+0.5 transformed value, L=leaf, DAS: Days after spraying 0.47 0.62 -- T1: UTC (g.or ml a.i.) Formulati on (g or ml) -- -- 20 T2: Dinotefuron 20 SG 30 T3: Dinotefuron 20 SG 40 T4: Dinotefuron 20 SG 21 T5: Imidacloprid 70WG T6: Imidacloprod 70 WG 24.5 25 T7: Fipronil 5% SC 37.5 T8: Fipronil 5% SC S Em (±) 100 150 200 30 35 500 750 Mean no. of thrips/leaf Post mean % reduction over control 5.46 0.00 2.95 47.74 1.03 82.25 0.21 96.32 1.29 79.62 0.68 88.96 1.04 83.05 0.24 96.17 st 1 Spray 2346 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 Table.4 Effect of insecticides on the population abundance of thrips in lady’sfinger, Kharif-2018 (2nd spray) Treatments Dose/ha Pretreatment Count (thrips/L) 3 DAS 7 DAS 10 DAS 14 DAS 3.79 7.91 8.75 9.28 9.70 (2.46) (3.32) (3.47) (3.56) (3.62) 3.91 1.56 1.87 2.00 2.45 (2.49) (1.76) (1.88) (1.93) (2.08) 4.02 0.54 0.89 1.12 1.54 (2.52) (1.24) (1.45) (1.57) (1.75) 4.03 0.02 0.05 0.21 0.30 (2.52) (0.65) (0.73) (0.97) (1.06) 4.38 0.45 0.78 1.32 1.78 (2.60) (1.18) (1.39) (1.66) (1.84) 4.28 0.34 0.42 0.57 0.89 (2.58) (1.09) (1.16) (1.26) (1.45) 4.26 0.59 0.96 1.19 1.62 (2.57) (1.28) (1.49) (1.60) (1.78) 4.38 0.03 0.06 0.24 0.33 (2.59) (0.67) (0.74) (0.99) (1.07) -- 0.15 0.20 0.16 0.18 -- NS 0.43 0.38 C.D (p<0.05) Figures in parentheses indicate √X+0.5 transformed value, L=leaf, DAS: Days after spraying 0.45 0.51 -- T1: UTC (g.or ml a.i.) Formulat ion (g or ml) -- -- 20 T2: Dinotefuron 20 SG 30 T3: Dinotefuron 20 SG 40 T4: Dinotefuron 20 SG 21 T5: Imidacloprid 70WG T6: Imidacloprod 70 WG 24.5 25 T7: Fipronil 5% SC 37.5 T8: Fipronil 5% SC S Em (±) 100 150 200 30 35 500 750 Mean no. of thrips/leaf Post mean % reduction over control 8.33 0.00 1.72 60.03 0.71 68.57 0.03 96.78 0.62 72.78 0.38 81.78 0.78 67.12 0.05 95.86 nd 2 Spray 2347 Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 Table.5 Effect of insecticides on the population abundance of predator in lady’s finger Kharif-2018 Treatments Dose/ha (g.or ml a.i.) Formulation (g or ml) Pre-treatment Count Coccinellids Coccinellids (Number/plant) 10DAS (1st spray) 10 DAS (2nd spray) Mean of 1st and 2nd spray 4.53 4.76 4.98 4.87 (2.64) (2.69) (2.74) 4.34 4.33 4.31 (2.59) (2.59) (2.59) 4.34 4.32 4.12 (2.59) (2.59) (2.54) 5.00 4.64 4.32 (2.75) (2.66) (2.59) 4.32 4.28 4.13 (2.59) (2.54) (2.54) 4.23 4.22 4.18 (2.57) (2.57) (2.48) 4.65 4.12 4.34 (2.67) (2.54) (2.59) 4.21 4.15 4.15 (2.55) (2.53) (2.53) NS NS NS (Number/p) -- T1: UTC 20 T2: Dinotefuron 20 SG 30 T3: Dinotefuron 20 SG 40 T4: Dinotefuron 20 SG 21 T5: Imidacloprid 70WG 24.5 T6: Imidacloprod 70 WG 25 T7: Fipronil 5% SC 37.5 T8: Fipronil 5% SC -100 150 200 30 35 500 750 C.D (p<0.05) Figures in parentheses indicate √X+0.5 transformed value, P=plant, DAS: Days after spraying 2348 4.32 4.22 4.48 4.20 4.20 4.23 4.15 -- Int.J.Curr.Microbiol.App.Sci (2020) 9(11): 2340-2352 Similar trend was followed 7 days and 10 days after first spraying. Fourteen days after first spraying lowest population was recorded in dinotefuron 20 SG @ 40 g a.i./ha treated plot (0.98 thrips/L) closely followed by fipronil 5% SC @ 37.5 g a.i./ha (1.00 thrips/L). There were no significant differences between these two treatments. But these two treatment were significant different from imidacloprid treatment. Three days after second spraying lowest population was recorded in dinotefuron 20 SG @ 40 g a.i./ha treated plot (0.02 thrip/L) closely followed by Fipronil 5% SC @ 37.5 g a.i./ha (0.03 thrips/L) and imidacloprod 70 WG @ 24.5 g a.i/ha (0.34 thrips/L). There were no significant differences among these three treatments. Similar trend was followed 7 days and 10 days after second spraying. Fourteen days after second spraying lowest population was recorded in dinotefuron 20 SG @ 40 g a.i./ha treated plot (0.30 thrips/L) closely followed by fipronil 5% SC @ 37.5 g a.i./ha (0.33thrips/L). There were no significant differences between these two treatments. But these two treatment were significant different from imidacloprid treatment. Effect of insecticides on natural enemies of lady’s finger ecosystem During the period of study, natural enemy fauna were found included several species of coccinellid beetles and their grubs (Coccinella transversalis, C. septempunctata, Cheilomenes sexmaculata and Micraspis discolor), larvae of syrphid fly, chrysopids (Chrysoperla spp.) and spiders. Among these only coccinellids were observed frequently, whereas, the population of others were scanty. The data on coccinellid on the crop before and after treatment with different chemicals show that, none of the insecticidal treatments significantly reduced the population of coccinellid natural enemies than the untreated control (Table 5). From overall observation it was found that Dinotefuron 20 SG @ 40 g a.i./ha, Fipronil 5% SC @ 37.5 g a.i./ha and imidacloprod 70 WG @ 24.5 g a.i/ha provided best suppression of jassid and thrips population. There were no significant differences among these treatments. These findings were supported by some research works. Thakoor Pavan et al., (2019) reported that maximum tomato sucking pest population reduction was found in the imidacloprid. Ghosh (2013) reported that Imidacloprid 17.8 SL resulted in the best suppression of sucking hopper population (91.89 %). Ghosh and Chakraborty (2015) reported that imidacloprid was found the most effective treatment for controlling lady’sfinger jassids, followed by the microbial insecticide spinosad. Ghosh (2020) reported that lower percent reduction of jassid was observed in the plots treated with fipronil 5% SC than imidacloprid. Priyadarshini et al., (2017) reported that imidacloprid 17.8% SL @ 50 a. i. g/ha and 37.5 a.i. g/ha and recorded maximum reduction of thrips on chilli recording 96.13% and 94.96% respectively at one day after spray. Das et al., (2010) reported that a rapid degradation of persistency was observed in Imidacloprid which had a greater importance as fruits and vegetables are consumed after little cooking. Acharya et al., (2002) reported that the efficacy of new molecules like imidacloprid, abamectin were safer to lady bird beetles. These supported the present findings. Acknowledgements This study was carried out with the support of the Director of research and Department of Agricultural Entomology, BCKV; I thank the Department, and those who have contributed to it. 2349