A field trial to assess damage by Bactericera cockerelli to early potatoes at Pukekohe

An early season potato trial at Pukekohe assessed the damage caused by Bactericera cockerelli, tomato-potato psyllid (TPP), and investigated the need for insecticide treatment. Four treatments were used: insecticide drench at planting; insecticide drench and weekly foliar sprays; insecticide drench and threshold-based foliar sprays; and no insecticides. TPP and associated insects in the trial were monitored weekly using yellow sticky traps and sampling plants from mid-October until mid-December 2011. TPP adult catches remained very low, reaching 1.5 per trap per week in December, and egg and nymphal infestations were absent or very low. Other exotic psyllid species dominated trap catches in December. The predator, Micromus tasmaniae (brown lacewing) was the most common insect, present throughout the trial, peaking at a combined total of 6.6 eggs and adults per plant. No damage was caused by TPP in any treatments indicating that insecticides may not be required to produce healthy 'early crop' potatoes at Pukekohe.