Naturally occurring predators of <i>Bactericera cockerelli</i> in potatoes

Abstract

In recent intensive sampling of insecticidefree potatoes at Pukekohe several insect predators and spiders have been found in association with the new pest Bactericera cockerelli tomatopotato psyllid (TPP) Micromus tasmaniae (brown lacewing) Melanostoma fasciatum (small hover fly) Coccinella undecimpunctata (11spotted ladybird) and sheet web spiders (Linyphiidae) were collected from potatoes at Pukekohe Research Station and reared in the laboratory to assess their potential as predators against TPP nymphs Individual predators were presented every 24 h to a maximum of 10 TPP nymphs of different instars ranging from 2nd to 4th instar depending on the size of the predator All predator species fed on TPP nymphs and all predatory life stages were capable of consuming more than five nymphs per day Ongoing studies with these species show that all predatory life stages of all predatory species feed on all life stages of TPP Together with separate data on predator incidence these results suggest that naturally occurring predators are likely to be important biological control agents of TPP particularly early in the season when TPP infestations are low