Professor/Extension Specialist University of Arizona Yuma, Arizona
The diamondback moth, Plutella xylostella, is an important pest of cole crops in Arizona which is a major producer of cole crops in the United States. From 2017-2020, field studies in in the Yuma, Arizona evaluated pheromone-baited traps for monitoring and determining the seasonal establishment of P. xylostella on commercial brassica crops. In general, Areawide trapping provided a consistent description of seasonal DBM movement and establishment, particularly at the beginning of the fall growing season. Areawide trapping showed distinct differences in seasonal P .xylostella moth captures where populations in Yuma were absent during the summer months but reappeared each fall. Data strongly support the hypothesis that Plutella xylostella disappear in the summer in the absence of brassica hosts, only to reappear in September via transplantintroductions or migration on wind currents. In terms of IPM, pheromone trapping should only serve as a monitoring tool for detecting adult movement into newly established fields and not a replacement for scouting fields for eggs and larvae. Trap captures in fields where transplants originate from California should be used to alert growers to intensify field scouting and be cautious which insecticides are used for control if needed.
