McGregor, Robert R.

Components of search effort were determined for adult females of Orius tristicolor (White) (Hemiptera: Anthocoridae) on bean, Phaseolus vulgaris L., leaves with either western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) or twospotted spider mites, Tetranychus urticae (Koch) (Acari: Tetranychidae) as prey. In the absence of prey, females of O. tristicolor allocated significantly more search time to leaves damaged by western flower thrips than to leaves damaged by twospotted spider mites, artificially damaged leaves or undamaged leaves. In the presence of prey, search time increased with increasing amounts of leaf damage for both prey species, but was not affected by prey species. Amounts of leaf damage or type of prey did not affect giving‐up‐time. The proportion of predators that successfully located thrips increased with increasing amounts of thrips damage on leaves. Females of O. tristicolor appeared to follow some simple, behavioural rules‐of‐thumb for allocation of search effort. The presence and type of damage determined the initial effort allocated to searching a leaf. Subsequent effort was determined by successful capture of prey, regardless of species. The implications of these results for application of Orius spp. for biological control are discussed. [ABSTRACT FROM AUTHOR]

The effects of water stress (produced by water deprivation and prey feeding) on plant feeding were investigated in the omnivorous predator Dicyphus hesperus Knight (Hemiptera: Miridae). The objective was to determine if prey feeding aggravated water deficits and thus increased plant feeding. We measured plant feeding in a factorial experiment where female D. hesperus were prepared for experiments by providing or withholding water and/or prey for 24 h. We then evaluated the amount of plant feeding on Nicotiana tabacum seedlings by the direct observation of insects at three different densities of the prey, Ephestia kuehniella eggs. The amount of plant feeding, as measured by frequency of plant feeding bouts and time spent plant feeding during observation, was significantly greater for water-deprived individuals than for those that had been provided with water. Individuals that had been provided with prey fed on plants at a significantly higher frequency than prey-deprived individuals at two of the prey densities used in the experiment. These results support the hypothesis that plant feeding in zoophytophagous Hemiptera facilitates prey feeding by providing water that is essential for predation. [ABSTRACT FROM AUTHOR]

Dicyphus hesperus Knight (Heteroptera: Miridae) is an omnivorous predator used to control pests of greenhouse vegetables. Plant preferences and life history traits were studied using nine plant species: Lycopersicon esculentum Mill. (Solanaceae), Capsicum annuum L. (Solanaceae), Verbascum thapsus L. (Scrophulariaceae), Nepeta cataria L. (Lamiaceae), Stachys albotomentosa (Lamiaceae), Nicotiana tabacum L. (Solanaceae), Vicia sativa L. (Fabaceae), Zea mays L. (Gramineae), and Chrysanthemum coronarium L. (Asteraceae). Plants were selected from among potential target crops, natural hosts, plants used for mass rearing, and plants on which D. hesperus has not been reported. Plant preference was measured by multi-choice host plant selection and oviposition assays. Development and reproduction were measured on each of the plant species on both a plant diet alone and on a plant diet supplemented with Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs. Dicyphus hesperus females and nymphs expressed a preference for some plants over others. Plant preference ranged from low preference plants, such as Z. mays, V. sativa, C. coronarium, and C. annuum, to high preference plants such as V. thapsus, N. tabacum, and S. albotomentosa. When E. kuehniella eggs were supplied, there were few differences in the development time and fecundity of D. hesperus among plants, with the exception of corn and broad bean, where fecundity was lower. On a plant diet alone, nymphs were able to complete their development on V. thapsus, C. annuum, and N. cataria. However, mortality and development time were much lower on V. thapsus than on C. annuum and N. cataria. On most of the plant species D. hesperus did not lay any eggs when fed on a plant diet alone. On V. thapsus, females laid a few eggs and lived longer than when fed on prey. Dicyphus hesperus females tended to prefer host plants on which nymph survival without prey was greatest. [ABSTRACT FROM AUTHOR]

Responses of female Dicyphus hesperus Knight (Heteroptera: Miridae) to the odours of plants and prey were tested in the laboratory using a Y-tube olfactometer. Females were attracted to the odour of tomato leaves infested with nymphs of the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae), compared to uninfested leaves. No such attraction occurred to tomato leaves infested with two-spotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae). When females were simultaneously presented with the odours of whitefly and mite-infested leaves, no preference for either odour was recorded. Similarly, females were attracted to the odour of pepper leaves infested with green peach aphids [Myzus persicae (Sulzer) (Homoptera: Aphididae)] compared to uninfested leaves, but were not attracted to the odour of pepper leaves infested with eggs of cabbage loopers, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae). When aphid-infested and looper-egg-infested pepper leaves were presented simultaneously, no preference for either odour was detected. The results are discussed as they relate to the evolution of infochemical use in generalist omnivorous predators. [ABSTRACT FROM AUTHOR]

Book Description "Biological control programmes in Canada 2001-2012": This volume (71 chapters), the fifth in a series documenting biological control programmes in Canada, presents new information on specific insect, weed or plant diseases, some of which are updates of on-going studies on historical biological control projects while other chapters report on biological control efforts for new emerging invasive alien species. In each case, information is presented in a consistent and logical manner, starting with the pest status in Canada, followed by a comprehensive background on previous studies, review of the use of biological control in these programmes, and an evaluation of the biological control efforts and future needs in research or implementation activities. A total of 64 chapters is dedicated to biological control case studies over the past 11 years - 36 on insect pests of agricultural importance and forestry or ornamental pests; 18 on the control of weeds for crops, rangeland, pastures or aquatic areas; and 10 on the biological control of plant disease causal agents. This book is intended for researchers and students in biological control, pest management, ecology and risk assessment. Chapter 14 "Bactericera cockerelli (Sulc), tomato/potato psyllid (Hemiptera: Triozidae)": This chapter describes the pest status and biological control (parasitoids, predators and pathogens) of B. cockerelli [Trioza cockerelli] (tomato/potato psyllid) in Canada.

The eggs of seven species of locally occurring coccinellids were reared at constant temperatures. The survival of eggs to hatching, rate, and thermal requirements for hatching were determined. The results were used to evaluate the importance of thermal adaptation of coccinellids in selecting them as biological control agents and in determining the relative species composition of locally occurring faunas of coccinellids.

Behaviour of locally occurring adult females of seven species of coccinellids was assessed on wooden dowel and paper models that mimicked branching patterns and arrangements of leaf attachments to stems. Ambient temperature and hunger of the beetles were controlled. The movements up or down the main branch of the branch models when contacted from a side branch, duration of searching, and method of leaving leaf models were recorded for 20 beetles of each species.Each species responded to the seven models with different frequencies of behaviours that reflected species-specific modifications of the taxes that lead coccinellids to the tops and terminal parts of plants. Some beetles consistently modified the pattern of responses on die models that was displayed by die species as a whole. The individual modifications could be selected for. The differences in frequencies of behaviours were judged to be sufficient to result in differences in the efficiency with which plants with different architectures were searched.

Cumulative temperature requirements and development thresholds were determined for two populations of Dicyphus hesperus Knight, 1943 to compare their suitability for use in biological control in greenhouse vegetable crops. The populations were from near Summerland, British Columbia, Canada (49°36′N, 119°40′W, at 334 m elevation) and from near Woody, California, United States of America (35°42′N, 118°50′W, at 500 m elevation). Eggs of the California (CA) population had a higher cumulative temperature requirement for hatch than those of the British Columbia (BC) population. Males of the CA population had a slightly lower cumulative temperature requirement for development from hatch to adult than males of the BC population. The populations did not differ with respect to development thresholds. Males of the CA population experienced higher mortality during development at 35 °C than BC males or females of either population. Males and females of both populations developing at 35 °C were significantly smaller than those developing at more moderate temperatures. The differences between populations with respect to development were biologically trivial. With respect to the effects of temperature on development time under greenhouse conditions, the two populations appear to be equally suitable for use in greenhouses.