Damage assessment of Helopeltis schoutedeni Reuter [Hemiptera: Miridae] on selection cashew accessions in the field.

Abstract

The bug, Helopeltis schoutedeni Reuter sucks the sap from the shoots, inflorescence, developing nuts and apples of cashew, thereby causing considerable crop loss. Due to the far-reaching consequences associated with the application of pesticides for controlling pests, this study aimed at exploring the option of evaluating for resistance among cashew accessions, which is cost effective and environment–friendly. Field study was conducted on eight cashew accessions comprising 40 stands each during the flowering/fruiting and post-flowering seasons. Data was collected on the total number of twigs and total number of infested twigs by the bug from the base to girth at breast height of 1.2m. Young and mature cashew plants raised from Brazilian Jumbo nut- size were the least damaged with infestation levels of 9.01% and 8.9%% respectively during the flowering/fruiting period, while during the post-fruiting season, infestation levels of 22.02% and 4.37% were observed on young and mature cashew plants raised from Jumbo nut-size respectively. Mature cashew stands raised from Indian medium and Indian small nut-sizes were often the most susceptible with infestation levels of 44.64% and 40.83% respectively during the flowering/fruiting period. Attack was more severe during the flowering/fruiting period which might be due to the abundance of food sources through flushing. While this field evaluation is on-going, further studies will be conducted to ascertain the mechanisms of resistance.