Impacts of Cruciferous Extracts on the Parasitism Efficiency of Diadegma Insulare; a Hymenopterous Parasitoid of the Diamondback Moth

Herbivore's attack stimulates chemical production in the plants; that communicates with natural enemies (chemical communication) and urges them for help (i.e. cry-for-help phenomenon). Such chemicals play an important role to attract the parasitoids and increase the chances of host pests' encounter. Current studies were performed to observe the extracts' efficacy in order to attract the parasitoid (i.e. Diadegma insulare) and thereby increase the likelihood of encounter with the host pest (i.e. Plutella xylostella). Cruciferous cultivars' extracts were developed and applied with artificial release of parasitoids under semi-field conditions. Findings revealed that extracts had the potential to enhance the parasitism efficiency of D. insulare against P. xylostella. However, non-significant impacts of the extracts were observed concerning the offspring sex ratio and adult longevities of the parasitoid. Cruciferous extracts of cauliflower and cabbage cultivars (i.e. White marble and Asha, respectively) with relatively high nitrogen and phosphorus; and low potassium contents were identified as the potential ones to be applied for enhancing the parasitism efficiency of D. insulare in cruciferous cultivars.