Occurrence of the Western Flower Thrips, Frankliniella occidentalis, and potential predators on host plants in near-orchard habitats of Washington and Oregon (Thysanoptera: Thripidae)

One hundred thirty species of native and introduced plants growing in uncultivated land adjacent to apple and pear orchards of central Washington and northern Oregon were sampled for the presence of the western flower thrips (WFT) Frankliniella occidentalis (Pergande, 1895) and potential thrips predators. Plants were sampled primarily while in flower. Flowering hosts for WFT were available from late-March to late-October. Adult WFT occurred on 119 plant species and presumed WFT larvae were present on 108 of 119 species. Maximum observed WFT density on several plant species exceeded 100 individuals (adults and larvae) per gram dry weight of plant material. The most abundant predator was Orius tristicolor (White, 1879) (Heteroptera: Anthocoridae). It was collected on 64 plant species, all of which were hosts for WFT. The second most abundant predators were spiders (Araneae). Small spider immatures (first and second instars) of several species were common on certain host plants, and are likely to feed on WFT

Influence of Trap Colour on the Capture of Codling Moth (Lepidoptera: Tortricidae), Honeybees, and Non-target Flies

Studies were conducted to evaluate the influence of trap colour on the captures of honeybees, Apis mellifera L., codling moth, Cydia pomonella L., and non target muscoid flies in sticky delta traps. Traps varied widely in their spectral reflectance. The unpainted white and the painted white and cream traps had the highest reflectance. The painted green trap had the lowest total reflectance. The green, orange, and red traps had low reflectance at wavelengths < 560 nm. Red and green painted traps consistently caught the fewest honeybees, while the unpainted white trap caught the most. Red painted traps caught the greatest number of flies. Significantly more codling moths were caught in green and orange versus the unpainted white traps. In a later experiment, painted green traps caught more codling moths than unpainted white traps

Spatial patterns of western flower thrips (Thysanoptera: Thripidae) in apple orchards and associated fruit damage

Western flower thrips, Frankliniella occidentalis (Pergande), is an economic pest of apples in orchards of North America. Western flower thrips causes damage (“pansy spot”) to apples by its egglaying activities during the bloom and immediate post—bloom periods. Difficulties in monitoring this pest and incomplete understanding of its biology during the bloom period have complicated control efforts in apple orchards. Densities of western flower thrips were monitored in seven (2003) or eight (2004) apple orchards at each of four bloom stages; in each orchard, thrips counts in blossom clusters were estimated at four to six distances into the orchard from an orchard edge that abutted native sagebrush-steppe habitat. We hypothesized that numbers of thrips in blossoms would decline with increasing distance along transects into orchards if the native habitat acted as a source of thrips. Thrips numbers in blossom clusters peaked at full bloom and petal fall. Densities showed a linear drop with increasing distance into the orchard, which we interpreted as evidence that the native habitat adjacent to each orchard did indeed act as a source of thrips moving into the orchards. Pansy spot incidence declined with increasing distance into the orchard. The major drop in damage occurred between the border row trees and samples taken at the adjacent distance (nine m away), suggesting that border rows adjacent to native habitats should be monitored with particular care. Regression analyses showed that damage and thrips density were positively correlated, albeit with substantial levels of unexplained variation in levels of damage

Absence of photoperiod effects on mating and ovarian maturation by three haplotypes of potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae)

We examined the effects of photoperiod on reproductive diapause of three haplotypes of potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae), collected from three geographic locations: south Texas (Central haplotype), California (Western haplotype), and Washington State (Northwestern haplotype). Psyllids were reared from egg hatch to adult eclosion under short- and long-day conditions, to determine whether short-days led to a lack of mating, delays in ovarian development, and accumulation of fat by female psyllids. Our expectation was that a reproductive response to short-days would be more likely to be exhibited by psyllids of the northern-latitude haplotype (Northwestern) than psyllids of the other two haplotypes. We also examined whether this species exhibited a photoperiod-controlled polymorphism in body size, as observed in other psyllid species, by comparing six body and wing measures of psyllids reared under short- and long-day conditions. Virtually 100% of females of each haplotype exhibited both egg maturation and mating at both long- and short-day conditions, providing no evidence that this species exhibits a photoperiod-induced reproductive diapause. Fat was present in most psyllids, although with higher probability of presence in short-day females than long-day females. Phortoperiod had no effect on body size. We found differences among haplotypes in body size, with psyllids from Washington State (Northwestern haplotype) having larger wings and longer tibiae than psyllids of the two southern populations. Our photoperiod results, combined with overwintering observations for this species and for other Triozidae, prompted us to hypothesize that potato psyllid -- at least in the Pacific Northwest growing region -- overwinters in a temperature-controlled quiescence rather than in a true diapause

Observations on the bionomics of the bee Andrena (Tylandrena) erythrogaster Ashmead (Hymenoptera: Andrenidae) with notes on A. (Micrandrena) personata Robertson and A. (Holandrena c. cressonii Robertson

Bibliography: p. 18

Nesting biology of the bee Melissodes (Eumelissodes) microsticta Cockerell in Washington State (Hymenoptera: Apidae)

Volume: 76Start Page: 184End Page: 19

Patterns of Resource Utilization by Spring Bees Visiting Salix With Emphasis on Use of Pollen by Bees in the Genus Andrena (Hymenoptera: Apoidea) (Competition, Resource Partitioning)

172 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.The resource utilization patterns of native vernal bees visiting Salix (willows) were studied at a site in Champaign Co., east central Illinois during 1982-84. Hourly sweep collections of insects visiting willows and several other important pollen/nectar sources were made throughout the active seasons of the most important spring bees (late April through late June). More than 20,000 bees in over 100 species were captured. A majority were identified to species in the field and returned to the local population. The rest were processed in the laboratory. Four species of Salix were present at the study site and all were visited by bees, the most important of which were members of the large, holarctic genus Andrena and several genera in the family Halictidae. Salix rigida, S. amygdaloides, and S. nigra bloomed sequentially starting in late April and ending in late May. Each bloomed for 10-20 days with little overlap during peak bloom of temporally adjacent species. The fourth species, S. interior, had an extremely long flowering period. Beginning near the end of April and extending into July, it overlapped the other three.Three abundant bees in the genus Andrena that are specialists (oligoleges) on Salix pollen were found to differ in seasonal phenology. Differences in daily activity periods were present but probably less important ecologically. The three oligoleges, however, showed similar preferences for concurrently blooming willows as pollen sources. Although S. rigida was used primarily as a nectar source, being the first to bloom and rare at the site, S. amygdaloides and S. nigra in turn, were preferred as pollen sources over the concurrently flowering S. interior by all three. During June, when S. interior was the only willow in flower, it was visited for pollen by the oligoleges. Many non-specialist bees (polyleges) visited the willows and showed similar pollen preferences to the oligoleges. They did not, however, use S. interior as a pollen source during June, visiting it primarily for nectar. Pollen preferences may be related to certain characteristics of the catkins and flowering phenologies of the male willows that appear to make them more attractive pollen sources.The foraging behavior of the three Salix oligoleges on S. interior is described and evidence presented indicating that bees are important pollinators of the dioecious willows.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD