INFLUENCE OF SUGAR MAPLE HEALTH ON FECUNDITY OF PEAR THRIPS IN MASSACHUSETTS

Abstract

AbstractWidespread defoliation of sugar maple stands due to pear thrips, Taeniothrips inconsequens (Uzel), feeding occurred in Massachusetts in 1987 and 1988. To assess the role of tree health as a possible cause of these outbreaks, an experiment was conducted in sugar maple stands in Massachusetts in 1990. Sleeve cages were placed on mature sugar maples and stocked with adult female pear thrips to determine the relation between root starch reserves (an index of tree health) and thrips fecundity. The experiment was run at four sites, assessing both root starch levels and thrips fecundity on individual trees. Each stand showed a range from high to low starch values and trees at each end of the root starch index spectrum were selected for use in the experiment at each site. Analysis of data showed no differences between sites, apart from those linked to starch levels, and found thrips fecundity to be positively correlated with higher starch reserves. The results of this experiment do not support the original hypothesis that declining tree health was a causal factor in pear thrips outbreaks on sugar maple in Massachusetts.