29. To study the effect of natural enemy Trichogramma chilonis (Ishii) against spotted bollworm (Earias Vittella F.) on okra

Abstract

The present study was conducted at the Pussia Goth near Tandojam during the year 2016, to study the effect of natural enemy Trichogramma chilonis (Ishii.) against spotted bollworm (Earias Vittella Fabricius) on okra. Observations on spotted bollworm population were recorded at once per week. Pre-treatment observation was recorded one day before release and post-treatment observation was recorded three and five days after release. The reduction percentage was also calculated. The maximum population of spotted bollworm recorded in 6^th week was (17.66±1.72) and minimum population in 10^th week was (14.33±0.29) in control plot during 1^st to 10^th weeks duration, respectively. The natural enemies were released at the interval of 10 days. However, the population in treated plot after 3 days of (T. chilonis) releases the maximum population of spotted bollworm was recorded in 2^nd week (8.89±1.24) and minimum population in 10^th week (6.19±0.29) during 1^st to 10^thweek duration, respectively. Peak level of spotted bollworm was observed during 1^st and 2^nd weeks afterward the spotted bollworm population was declined in a linear sequence from 3^rd to 10^th weeks. Similarly, after 5 days (T. chilonis) releases, the maximum population of spotted bollworm was recorded in 1^st week (10.16±1.33) and minimum population in 10^th week (8.00±0.41) during 1^st to 10^th week duration, respectively. Peak level of spotted bollworm was observed during 1^st and 2^nd weeks afterward the spotted bollworm population was declined in a linear sequence from 3^rd to 10^th weeks. Moreover, the results showed that spotted bollworm populations were considerably declined in treated plots due to the presence of T. chilonis as compare to control plot.

Keywords: Biological agent; Okra; Population; Spotted bollworm

http://dx.doi.org/10.19045/bspab.2018.70081