Western flower thrips, Frankliniella occidentalis (Pergande), are one of the most-destructive insect pests of greenhouse-grown horticultural crops worldwide due to the direct and indirect damage they cause to plants. Western flower thrips induce direct damage by feeding on leaves and flowers and also cause indirect damage by vectoring certain tospoviruses including Impatiens necrotic spot and Tomato spotted wilt viruses. As a result, the threshold for this insect pest is near zero. Consequently, the primary means of suppressing populations of western flower thrips in greenhouse production systems is the application of insecticides. In general, insecticides are inexpensive, easy to apply, and relatively effective. However, the selection pressure placed on western flower thrips populations due to intensive applications of insecticides has resulted in severe problems associated with the development of resistance. Therefore, in order to avoid the prospect of insecticide resistance developing in western flower thrip populations, greenhouse producers must implement a multitude of plant protection strategies including scouting, insecticide rotations, insecticide mixtures, and the use of alternative insecticides (e.g., entomopathogenic fungi and insect growth regulators) with broad-spectrum modes of action.

Western flower thrips, Frankliniella occidentalis (Pergande), is an economically important pest of greenhouse production systems, and entomopathogenic fungi may be used to suppress populations of the western flower thrips. The objectives of our study were (a) to evaluate the efficacy of products containing three different entomopathogenic fungi (Beauveria bassiana [BotaniGard^®], Isaria fumosoroseus [NoFly^™], and Metarhizium anisopliae [Met52^®]) against western flower thrips larvae and adults and (b) to assess effectiveness of combinations of entomopathogenic fungi and the insect growth regulator azadirachtin against western flower thrips larvae. In two laboratory bioassays western flower thrips larvae and adults were exposed to the three entomopathogenic fungi at two label rates (maximum and minimum), and two product shelf-life conditions (unexpired and expired). Bioassay 1 involved a 120-h incubation period; bioassay 2 entailed a 216-h incubation period. A third bioassay evaluated any synergistic effects of combining the entomopathogenic fungi with azadirachtin on western flower thrips larvae. Results indicated that (a) by 120 h of incubation, adult western flower thrips were more susceptible than larvae to maximum rates of unexpired B. bassiana and I. fumosoroseus; (b) unexpired products of B. bassiana and I. fumosoroseus had higher percentages of adult western flower thrips mortality than expired products at the maximum label rate; and (c) azadirachtin combined with unexpired M. anisopliae at the maximum label rate resulted in greater mortality of western flower thrips larvae than B. bassiana and I. fumosoroseus. However, there was no evidence of any enhanced efficacy when combining azadirachtin with B. bassiana or I. fumosoroseus.

The microclimate within western cotton (Gossypium spp.) seems favorable for the western tarnished plant bug (Lygus hesperus Knight) (Hemiptera: Miridae), provided adequate soil moisture is available. Diminishing water supplies and increasing costs in the West will likely change irrigation practices and induce at least periodically unfavorable conditions for L. hesperus. Knowledge of L. hesperus thermal ecology has been limited to constant temperatures for which relevance to variable temperature environments is unknown. Eggs of L. hesperus were reared under low (mean = 15°C), medium (mean = 22°C), or high (mean = 29°C) constant (±<0.5°C) or diurnally fluctuating (±8°C) temperatures. Developmental time and survival were similar between constant and variable regimes at the medium temperature. In contrast, variable low temperatures hastened egg development and increased survival, whereas variable high temperatures delayed development and reduced survival compared with constant regimes. Within the studied temperature range, the relationship between temperature and egg developmental rate was linear for constant temperatures, but a quadratic term was needed to describe this relationship under variable temperatures. Under medium variable temperatures, egg hatch was disproportionately high during the warmest period of the day (1300–1900 h) compared with the constant regime. Differences between regimes were less pronounced at high temperatures, except for the conspicuous absence of hatch between 1300 and 1900 h in the variable regime when temperatures were always >32°C. These results indicate the limited utility of constant temperature data for understanding L. hesperus thermal ecology and provide baseline information to better plan and interpret applied studies of L. hesperus thermal ecology.

The fruit fly Drosophila melanogaster (Meigen) (Diptera: Drosophilidae) is often used in various biological, molecular, and toxicological studies. Sodium tetraborate, a boron compound, was added to the artificial diet of developing D. melanogaster to determine its effects on adult longevity and fecundity. Insects reared from first instars to adults on diets containing 10, 30, 150, 300, or 400 mg/liter sodium tetraborate showed that the highest concentration (400 mg/liter) significantly reduced female longevity (31.65 ± 4.02 [mean ± SD] d for the controls versus 1.87 ± 0.30 d for 400 mg/liter) and male longevity (32.80 ± 1.96 d for controls versus 3.57 ± 0.42 d for 400 mg/liter). Females from the control diet produced 9.46 ± 0.57 (mean ± SD) eggs per female, whereas those fed on a diet containing 300 mg/liter produced only 1.92 ± 0.30 eggs per females. These results expand our knowledge of the impact of sodium tetraborate on various insects and indicate that boron compounds should be further investigated to ascertain their potential as an alternative control tactic for pest insects.

Culex pipiens pallens Coquillet can spread various mosquito-borne infectious diseases. This study identifies the overwintering sites and physiological condition of Cx. pipiens during hibernation in Shandong Province of P.R. China. Results show that female adult Cx. pipiens overwinter in habitats characterized by warm temperature, high humidity, and calm winds. Cellars yielded the highest densities, followed by air-raid shelters, caliducts, sewers, mountain caves, wells, stone caverns, etc. The adult density among overwintering sites differed significantly (F = 45.88, P < 0.01). Larvae and pupae were not captured after late December. In early winter, multiparous and bloodsucking mosquitoes accounted for a large proportion of the observed populations. However, their numbers gradually decreased as winter progressed, mainly due to their relatively high death rate in winter. Most mosquitoes overwinter in a state of diapause, and females have usually mated. Collections in midwinter showed that of those collected, 99.8% were in diapause and 100% had mated. Overwintering mosquitoes suffered few deaths under natural conditions and, upon emerging from overwintering diapause, could take blood meals and oviposit. The time taken for oviposition by mosquitoes emerging from diapause was longer than that observed with females continuously reared in the laboratory; however, there was no significant difference in the numbers of eggs (F = 0.571, P = 0.467) oviposited.