PERFORMANCE OFTRICHOGRAMMA EVANESCENSFOR ECO-FRIENDLY MANAGEMENT OF LEPIDOPTEROUS INSECT PESTS OF CABBAGE

Abstract

A field experiment was conducted in the experimental farm of Sher-e-Bangla Agricultural University, Bangladesh during the period from October 2011 to March 2012 to evaluate the performance of Trichogramma evanescens for eco-friendly management of Lepidopterous insect pests of cabbage. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications and nine treatments viz. T1 (Tricho Paper Card @ 0.20 g/plot at 5 days interval), T2 (Tricho Paper Card @ 0.30 g/plot at 5 days interval), T3 (Tricho Paper Card @ 0.40 g/plot at 5 days interval), T4 (Tricho Paper Card @ 0.50 g/plot at 5 days interval), T5 (Tricho Paper Card @ 0.20 g/plot at 10 days interval), T6 (Tricho Paper Card @ 0.30 g/plot at10 days interval), T7 (Tricho Paper Card @ 0.40 g/plot at 10 days interval), T8 (Tricho Paper Card @ 0.50 g/plot at10 days interval) and T9 (untreated Control). It was observed that T4 treatment performed best in managing lepidopterous insect pests of cabbage based on the lowest % leaf infestation (27.70), lowest number of holes /leaf of a plant (3.30), lowest number of larva (3.50), lowest (%) leaf area damage (1.20), lowest % head infestation by number (10.50) and highest % infestation reduction over control on all parameters at vegetative stage of plant. Again, the lowest leaf infestation intensity (7.40%), lowest number of holes / infested head (13.00), lowest number of larva / infested head (1.30), lowest % infestation of head by number (3.30), lowest % head infestation by weight (1.70) were achieved at harvesting stage from the same treatment (T4) whereas the highest values of all these parameters was achieved from untreated Control treatment (T9) . The yield contributing characters provided best performance in yield which found in T4 where yield was increased (105 %) over control giving maximum yield 93.70 ton/ha. Form the study it was found that there is a strong negative relationship between leaf infestation intensity and single head weight and between leaf infestation intensity and yield (t/ha). It also observed that there is a strong positive relationship between number of larvae and leaf infestation intensity, between number of larvae and leaf area damage of cabbage and between number of larvae/infested head and numbers of holes/infested head.