Green vegetable bug on macadamia nuts - a sustainable pest management system.

Abstract

Green Vegetable Bug, Nezara viridula (GVB) was first recorded in New Zealand in 1944 and early reports state that it was a severe pest of vegetable crops, tamarillos and peaches in Northland (Cameron, 1989). GVB populations declined following the introduction of the egg parasitoid Trissolcus basalis to New Zealand in 1949. However, GVB has is now been designated as a key pest of macadamias (Figure 1) having a serious impact on the economic viability of macadamia growing in New Zealand. Adults cause damage by piercing the husk and shell of the nut and injecting digestive fluid into the kernel. This can cause premature fruit drop or sunken lesions on mature nuts making them rancid, as well as providing entry points for pathogens (Figure 2). Damage by GVB to more than 10% of nuts in a season can make harvesting and processing nuts uneconomic. The damage is not detectable until after processing as there are no external marks on the nuts.