Subsampling plants to monitor tomatopotato psyllid (<i>Bactericera cockerelli</i>) and associated insect predators in potato crops

Abstract

Subsampling of potato plants was assessed as a practical tool for monitoring Bactericera cockerelli tomatopotato psyllid (TPP) and other key pests and their predators at Pukekohe The total numbers of the key insect species and all their life stages on (1) the bottom leaf; (2) a middle leaf (the bottom leaf on the top half of the stem); (3) the bottom half of the stem; and (4) the top half of the stem were compared with numbers on the whole stem Assessing the top half of the stem was the most reliable subsampling method for the three main insects sampled while assessing a middle leaf also gave a reliable estimate for two out of the three insects A crop scouting protocol for monitoring TPP infestations based on sampling 100 middle leaves off 50 randomly selected plants in a crop is now recommended by the potato industry in New Zealand