Experiments on management of major pests of cotton with biocontrol agents in India

Abstract

Results of field experiments revealed that three releases of biocontrol agents viz., Tricbogramma chilonis (1,00O,OOO/ha/release) and Brinckocbrysa scelestes (50,0OO/ha/release) on 90, 105 and 120 days after sowing could effectively check the population of Heliotbis armigera and Bemisia tabaci which was equal to that of insecticides. Two applications of nuclear polyhedrosis virus of Spodoptera litura at 250 larval equivalents (LE)/ha with adjuvants could effectively control S. litura larval population and damage. The seed cotton yield could also be increased in biocontrol plots which was equal to that of insecticide treated plots.I . T~-~chogrammu cbilonis (Ishii.) at 1,000,000 parasitoids/hdrelease, 2. Bririckocl~rysa ( C h r y s o p~) scelestes (Banks) grubs at 50,000/ha/rclcase, 3 . Spodopteru litura NPV at 250 LE with adjuvants crude sugar, 2.50 kg + cotton seed kernal powder (CSKP) 0.3 kg/ha. U.S.

Trichogramma egg parasitism of Helicoverpa armigera on short‐duration pigeonpea intercultured with sorghum

“…Although the estimate of the number of adult Trichogramma generated by each plot of sorghum would be an overestimate due to predation, hyperparasitism and other losses of eggs, it provides some indication of the positive effect that sorghum may have on Trichogramma populations in the field. Field releases of Trichogramma against H. armigera in inundative biological control programmes use densities in the region of 40 000-1 000 000 per ha (Yadav et al, 1985;Famosa & Alba, 1988;Dhandapani et aL, 1992). From the results of this study it appears that densities of this magnitude can be generated by plots of sorghum without the need of artificial augmentation.…”

Estimation of Groundwater Recharge in Limestone Aquifer using an Improved Soil Moisture Balance Method: A Case Study in Jaffna District

“…However, the highest cost benefit ratio of 1:2.80 was recorded in Endosulfan 35 EC treatment (Table 8). In a column, means followed by same letter(s) are not significantly different by DMRT (P=0.05) Sangwan (1972) and Dhandapani et al, (1992) reported that the utilization of biocontrol agents increased the seed cotton yield with highest cost benefit ratio. It is in confirmation with the present findings.…”

Field Evaluation of Biocontrol Agents for the Management of Major Insect Pests of Coleus

“…*Mean of three replications; DAP: Days after planting; Each release/spray at monthly interval starting from 30 days after planting; C.c. : Chrysoperla carnea; T. c.: Trichogramma chilonis; B. b.: Beauveria bassiana; B. t.: Bacillus thuringiensis Figures in parentheses are square root transformed values In a column, means followed by same letter(s) are not significantly different by DMRT (P=0.05)pest but sequential release/spray of bio-control agents was useful to manage various insect pests which occurred in various growth stages of crop, as well demonstrated byDhandapani et al(1991),Murali Baskaran et al (2000) andBalakrishnan et al (2005) on cotton andKalyanasundaram et al (1991) on groundnut in which release of either C. carnea or T. chilonis, followed by spraying of NPV was reported to be effective against pests of cotton and groundnut rather than using them individually.…”