Laboratory Methodology for Screening of Cruciferous Host for Egg Laying Preference of Diamondback Moth, Plutella xylostella (L.)

Background: Diamondback moth (DBM), Plutella xylostella (L.), significantly damages Cole crops worldwide, causing major yield losses and management costs. Efficient control measures, including host plant resistance are imperative. While molecular methods offer insights into resistance mechanisms, conventional screening methods remain advantageous. Here, we present a novel laboratory-based oviposition preference screening method for DBM, significantly shortening screening time in resistance breeding. Methods: We studied DBM’s oviposition preferences among cruciferous hosts and plant tissues. Extract was prepared from leaves and heads of dark green and light green cabbage varieties, as well as cauliflower. Aluminum egg-laying sheets were treated with these extracts and introduced into mating boxes with insects. Egg-laying was monitored over seven days, with the number of eggs recorded daily. Result: DBM adults preferred light green cabbage for egg laying (1238±10.54 eggs), with no significant difference between leaf and head tissues. Dark green cabbage was the second choice (514.5±15.78 eggs), while cauliflower was the least preferred (217±37.2 eggs). Interestingly, DBM exhibited varying preferences between leaf and head tissues, with cauliflower heads being favored over leaves. Additionally, we observed distinct day-wise egg laying trends, providing insights into DBM’s oviposition behavior over time. This study demonstrates the efficiency of lab-based screening in identifying resistant crop varieties, aiding sustainable pest management and crop production and highlights the importance of considering host plant selection and tissue specificity in screening of genotype for resistance breeding programs.