Treesearch

Life history information has been collected for pear thrips in orchard habitats in California and British Columbia (Cameron & Treherne 1918, Bailey 1944). However such information is not available for this insect in a northern hardwood forest ecosystem in the eastern United States. Research is currently underway at the University of Vermont to determine the pear thrips life cycle in Vermont sugarbushes. These data are urgently needed to assist researchers and forest managers in their efforts to develop methods to effectively manage this pest. Results from 1988-89 are presented here to...

Techniques are described for the sampling and extraction of microarthropods from soil and the potential of these methods to extract the larval stages of the pear thrips, Taeniothrips inconsequens (Uzel), from soil cores taken in sugar maple stands. Also described is a design for an emergence trap that could be used to estimate adult thrips populations as they move from the forest floor into the tree canopy.

Slash pine flower thrips typically destroy about 24% of the flowers (cones) present in slash pine seed orchards. The seasonal distribution and abundance of slash pine flower thrips are being investigated and methods for sampling field populations of the insect are being evaluated for potential use in integrated pest management strategies. The efficacies of several sampling methods, including Berlese funnel extractions of host plant materials, suction apparatus, scouting, flight traps, and soil emergence samplers are reported.

In 1975, Illinois experienced an exceptionally mild winter, followed by a warm spring. This sequence of climatic events resulted in a massive outbreak of the soybean thrips, Sericothrips variabilis (Beach), along with large numbers of the flower thrips, Frankliniella tritici (Fitch). The outbreak covered an area of over 600 thousand hectares (1.5 million acres) of soybean and was particularly heavy in the southern third of the state. In areas where thrips densities were particularly high early in the season, entire fields of young soybean seedlings began to die, causing panic within the...

No one knows what caused the 1988 outbreak of pear thrips, Taeniothrips inconsequens (Uzel), in sugar maple, Acer saccharum Marsh., in the northeastern United States. As an entomologist and ecologist who knows even less about this insect than most of the authors of this volume, I cannot presume to understand the causes of this event any better than anyone else does. This essay will of necessity be highly speculative.

The chemical ecology of the Thysanoptera is identified with a variety of natural products discharged in anal droplets during confrontations with adversaries. These exudates are fortified with defensive allomones that may function as repellents, contact irritants, or in some cases, fumigants. Thrips synthesize a large diversity of allomonal products that include hydrocarbons, acids, esters, aromatic compounds, and monoterpenes. Most of the exudates contain mixtures of natural products whose defensive efficacies may reflect synergistic interactions of selected compounds. That the anal...

Thrips are increasingly recognized as potentially serious pests in a number of different agricultural, ornamental and sylvan commodities worldwide as indicated by the papers presented at this conference. The small size of thrips, their large numbers, capacity for flight and wind dispersal, wide host ranges, poorly understood life histories and probable potential for pesticide resistance exacerbate the timely development of control strategies.

The aim of this paper is to amplify some of the general points made in my introductory paper on the order Thysanoptera (Lewis 1990, this proceedings), with particular reference to feeding, flight and dispersal. These aspects of thrips behaviour are clearly of great relevance to the spread and effects of infestations of Taeniothrips inconsequens in New England, and although most of the work described has concentrated on another species, Limothrips cerealium (Haliday) (Lewis 1973, Chisholm & Lewis 1984) much of the information is probably applicable to terebrantian species of similar...

The systematics of the Thysanoptera, and several economic species in the United States and Canada (North America) are discussed briefly. Morphological characters to distinguish the six families in North America and the following economic species, pear thrips (Taeniothrips inconsequens (Uzel)), basswood thrips (Thrips calcaratus Uzel), western flower thrips (Frankliniella occidentalis (Pergande)), flower thrips (Frankliniella tritici (Fitch)), tobacco thrips (Frankliniella fusca (Hinds)), and onion thrips (Thrips tabaci Lindeman) are discussed.

Most participants of this symposium will be concerned with understanding thrips ecology primarily in order to develop practical and effective control strategies. Questions dealing with historical aspects (evolution) may seem of only isolated "theoretical" interest with little significance for everyday pragmatic concerns. Evolutionary theory is widely presented, however, as a cornerstone of modern biology and this position implies that evolutionary considerations can and do provide a direct input into our understanding of both ecosystems and individual organisms. Most evolutionary perspectiv...