Colonization of Weeds and Lettuce by Thrips (Thysanoptera: Thripidae)

Abstract

Colonization of lettuce and five common weed species by thrips was studied in lettuce fields at Kula, Hawaii. Frankliniella occidentalis (Pergande), a vector of tomato spotted wilt virus, was the most abundant thrips species (82.4%of total) of the twelve species collected. Nonflowering lettuce, Lactuca sativa var. longifolia Lam., was less attractive to thrips than flowering plants of the weed species. Among weeds in flower, Verbesina enceliaides (Cav.) Benth & Hook. ex Gray, Malva parviflora L., and Amaranthus hybridus (L.) Rob. were most attractive to thrips. However, among nonflowering stages, V, encelioides attracted the fewest thrips and only A. hybridus and M. parviflora were more attractive than lettuce. For each weed species, flowering individuals attracted more thrips than plants with flowers removed.