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A role of some volatile compounds produced by plant tissues may be as defensive molecules against various pests, including arthropods. Volatile six-carbon compounds derived in plant tissue from polyunsaturated fatty acids via lipoxygenase/hydroperoxide lyase reduced tobacco aphid fecundity at certain concentrations when added to headspace vapor to which aphids were exposed. Both C6 aldehydes and alcohols were effective, with the alcohols having greater activity. (Z)-3-Hexenyl acetate at levels in the headspace similar to those of the alcohols and aldehydes did not reduce aphid fecundity. A 6-hr exposure period to the C6 aldehydes and alcohols was needed for maximum effect on the aphids feeding on tobacco leaves. Analysis of the direct versus indirect effects of these compounds indicates that the volatile aldehydes had both direct effects on aphid fecundity and indirect effects due to induced changes in the leaves upon which the aphids were feeding, while only indirect effects were observed for the alcohols. Tomato leaves have the capacity to produce volatile compounds at levels that impact aphid population increase, with the volatiles produced from crushed leaves having a much larger effect. The C6 aldehydes and alcohols may be components of the fecundity reduction seen with tomato volatiles; however, volatile terpenes showed no effect. These results can be of significance for the genetic alteration of plants for improved aphid resistance.

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The effect of atmospheric methyl jasmonate on the oxylipin pathway was investigated in leaves of tobacco (Nicotiana tabacum L.), cucumber (Cucumis sativa L.), and Arabidopsis thaliana (L.). Differential sensitivities of test plants to methyl jasmonate were observed. Thus, different concentrations of methyl jasmonate were required for induction of changes in the oxylipin pathway. Arabidopsis was the least and cucumber the most sensitive to methyl jasmonate. Methyl jasmonate induced the accumulation of lipoxygenase protein and a corresponding increase in extractable lipoxygenase activity. Atmospheric methyl jasmonate additionally induced hydroperoxide lyase activity and the enhanced production of severa1 volatile six-carbon products. It is interesting that lipid hydroperoxidase activity, which is a measure of hydroperoxide lyase plus allene oxide synthase plus possibly other lipid hydroperoxidemetabolizing activities, was not changed by methyl jasmonate treatment. Methyl jasmonate selectively altered the activity of certain enzymes of the oxylipin pathway (lipoxygenase and hydroperoxide lyase) and increased the potential of leaves for greatly enhanced six-carbon-volatile production.MJ and JA are thought to be involved in numerous aspects of plant biochemistry. These include wound-induced defense (Farmer and Ryan, 1992;Pena-Cortes et al., 1993) Both JA and MJ are derived from linolenic acid via the oxylipin pathway (Vick and Zimmerman, 1984; Song and Brash, 19911, and there has been speculation that they may fulfill a biochemical and regulatory signaling role in plants '

Increased threat of mosquito-borne disease coupled with decreased tolerance of nuisance mosquitoes has opened a market for pest management professionals to offer mosquito control services for homeowners. A pest management professional applied bifenthrin (0.08%) and lambda-cyhalothrin (0.1%) at their maximum label concentrations as barrier treatments. We tested treatments residual efficacy in reducing adult mosquito populations and compared these chemicals against a water control at 24 residential properties (eight replications by three treatments). Mosquito populations were measured on each property by using five methods: CO2-baited Centers for Disease Control (CDC) light traps (without a light), human landing rates, CDC gravid traps, ovitraps, and sweep nets. Populations were monitored weekly for 2 wk before treatment and 8 wk posttreatment. Additionally, to confirm residual efficacy of each insecticide, a randomly treated leaf underwent a no-choice bioassay with laboratory-reared Aedes albopictus (Skuse). Trap collections were dominantly Aedes albopictus and Culex pipiens L. Both insecticidal treatments significantly reduced Aedes spp. lambda-Cyhalothrin- and bifenthrin-treated sites had 89.5 and 85.1% fewer Ae. albopictus bites than the untreated control, respectively. Ae. albopictus bioassay results showed significant residual efficacy for both insecticides up to 6 wk posttreatment. There were no significant differences between properties treated with the two insecticides. In contrast, Culex spp. were not reduced by either insecticidal treatment. Our study indicated that barrier sprays applied to low-lying vegetation do not properly target adult daytime resting sites for Culex mosquitoes but that they can reduce Aedes mosquitoes. Perhaps by treating upper tree canopies Culex spp. abundance may be reduced.

Increased threat of mosquito-borne disease coupled with decreased tolerance of nuisance mosquitoes has opened a market for pest management professionals to offer mosquito control services for homeowners. A pest management professional applied bifenthrin (0.08%) and lambda-cyhalothrin (0.1%) at their maximum label concentrations as barrier treatments. We tested treatments residual efficacy in reducing adult mosquito populations and compared these chemicals against a water control at 24 residential properties (eight replications by three treatments). Mosquito populations were measured on each property by using five methods: CO2-baited Centers for Disease Control (CDC) light traps (without a light), human landing rates, CDC gravid traps, ovitraps, and sweep nets. Populations were monitored weekly for 2 wk before treatment and 8 wk posttreatment. Additionally, to confirm residual efficacy of each insecticide, a randomly treated leaf underwent a no-choice bioassay with laboratory-reared Aedes albopictus (Skuse). Trap collections were dominantly Aedes albopictus and Culex pipiens L. Both insecticidal treatments significantly reduced Aedes spp. lambda-Cyhalothrin- and bifenthrin-treated sites had 89.5 and 85.1% fewer Ae. albopictus bites than the untreated control, respectively. Ae. albopictus bioassay results showed significant residual efficacy for both insecticides up to 6 wk posttreatment. There were no significant differences between properties treated with the two insecticides. In contrast, Culex spp. were not reduced by either insecticidal treatment. Our study indicated that barrier sprays applied to low-lying vegetation do not properly target adult daytime resting sites for Culex mosquitoes but that they can reduce Aedes mosquitoes. Perhaps by treating upper tree canopies Culex spp. abundance may be reduced.

Two species of phlebotomine sand flies, Lutzomyia shannoni (Dyar) and Lutzomyia vexator (Coquillett), are reported for the first time from Kentucky and Ohio. L. vexator also is reported for the first time from Tennessee. These insects were found in a northeasterly band extending from southwestern Kentucky to southwestern Ohio. Both species were consistently captured from mid-July through September in 2006 and 2007 by using CO2-baited Center for Disease Control light traps. Weekly sampling revealed that these flies are more abundant in the southern part of this band than in the northern part, but increasing densities throughout this new range indicate that the flies are currently expanding their range. Although both species have been reported further north along the Atlantic coast, and L. vexator along the Pacific coast, neither of them had been reported this far north along the Mississippi Valley. Previous reports established L. shannoni as far north as west central Tennessee and L. vexator in a similar spatial pattern in the eastern part of its range, extending as far north as northern Alabama. Whether the new records reported herein represent a northerly expansion of the geographic range of these species or are reflective of sampling changes is inconclusive. However, the former scenario could presage an increased prevalence of the diseases associated with this group of insects.