Abstract

Several investigations show that flowers are a preferable food source for the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). A study was initiated to see how population growth of a E occidentalis population on greenhouse grown chrysanthemum was affected by flower growth and development. The hypothesis was that the relative reproduction rate of thrips was not constant over time but increased when flowers were available. Plants of the chrysanthemum pot plant cultivar 'Lompoc' were infested with female western flower thrips and grown at three different temperatures. The results showed that thrips growth and development was stimulated by an increased temperature, and that the increase was not correlated with the effect of temperature on chrysanthemum flower development. Since there was no significant difference between thrips grown on plants with or without flowers, the original hypothesis could not be supported. The results indicated further that the relative reproduction rate increased over time. A growth equation with an exponentially increasing relative reproduction rate fitted the data better (R-2-values from 0.529 to 0.826) than a traditional exponential equation (R2-values from 0.434 to 0.728). It was proposed that intrinsic factors within the population, such as population density, the probability of finding a mating partner, and the switching from parthenogenesis to sexual reproduction, were the cause for the increasing relative reproduction rate during early population growth

Published in

European Journal of Horticultural Science
2007, volume: 72, number: 6, pages: 248-254
Publisher: EUGEN ULMER GMBH CO

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