The western grape leafhopper (Erythroneura elegantula Osborn) and the Virginia creeper leafhopper (Erythroneura ziczac Walsh) are the two leafhopper pests frequently observed in Washington State vineyards. Organic viticulturists have difficulties controlling these leafhopper pests, and outbreaks can result in economic loss. We vineyard-tested the efficacy of several candidate bioinsecticides and conventional insecticides against the western grape leafhopper and the Virginia creeper leafhopper. This study included the initial testing of several alternative candidate insecticides for leafhopper control. Controlled laboratory bioassays also were completed, and the 50% and 90% lethal concentrations were calculated for the nonsystemic insecticides tested. Of the bioinsecticides tested, pyrethrum (Pyganic^TM, Valent Bioscience Corporation, Libertyville, IL) was the only product that provided effective control of leafhoppers in both the vineyard and laboratory components of this study. In vineyard efficacy tests all the conventional insecticides applied significantly (P < 0.05) reduced leafhopper abundance compared to untreated controls. Flupyridifurone (Sivanto^TM, Bayer AG, Leverkusen, Germany) was the most efficacious of the conventional insecticides tested and the only insecticide that provided 100% mortality in the vineyard. We demonstrated that organic viticulturists could apply pyrethrum to control outbreaks of the Virginia creeper leafhopper. We also demonstrated that there are several effective conventional insecticides that can be added to vineyard integrated pest management programs in Washington State.

The citrus mealybug, Planococcus citri (Risso), is a major pest of greenhouse-grown horticultural crops. Systemic insecticides are often used by greenhouse producers in an attempt to prevent infestations or suppress citrus mealybug populations. However, minimal information is available on the efficacy of systemic insecticides against citrus mealybug populations when applied as a granule or water-soluble drench to the growing medium. We determined the efficacy of curative and preventative applications of six commercially available systemic insecticides against the citrus mealybug on coleus (Solenostemon scutellarioides [L.] Codd) plants. The systemic insecticides tested were imidacloprid, dinotefuran, thiamethoxam, azadirachtin, cyantraniliprole, and spirotetramat. The curative applications of dinotefuran, imidacloprid, and thiamethoxam resulted in citrus mealybug mortality that never exceeded 35%. Preventative applications of dinotefuran, imidacloprid, and thiamethoxam yielded only 50% citrus mealybug mortality. Azadirachtin, cyantraniliprole, dinotefuran, imidacloprid, spirotetramat, and thiamethoxam applied preventatively yielded mortality levels that never exceeded 22%. Even at 4× the label rate, none of the systemic insecticides provided >61% mortality of citrus mealybugs. We concluded that the systemic insecticides evaluated in these four experiments failed to provide sufficient control or suppression (≥80% mortality) of citrus mealybug populations on coleus plants under the parameters of our study.

The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a pest that causes direct damage to host plants and also vectors plant viruses. Chemical insecticides are not always effective management tools because this insect has developed resistance to a wide range of insecticides. An essential oil from citronella (Cymbopogon nardus L.) leaves was assessed in studies of contact-toxicity, repellency, and ovipositional deterrence against B. tabaci. Mortality of B. tabaci exposed to the essential oil increased with the concentration of the essential oil with the greatest mortality observed at the highest concentration (6.66 μL/L air) tested (survival was reduced 94.3% in comparison to control treatments). The median lethal concentration was 1.028 μL/L air. Furthermore, the essential oil was highly repellent against B. tabaci in a dual-choice bioassay, and it significantly deterred females from laying eggs on essential oil-treated chili (Capsicum annuum L.) leaves as compared to control leaves. Chemical analysis of the oil was characterized by high levels of oxygenated monoterpenes (56.28%).

Aposematic traits such as bright contrasting coloration and gregarious feeding are often signals to predators that a potential prey is unpalatable. Larvae of Ceratomia catalpae (Boisduval) (Lepidoptera: Sphingidae), the catalpa sphinx, show aposematic traits and sequester catalpol, a secondary compound from their host plant Catalpa spp. (Bignoniaceae). Catalpol sequestration by other caterpillar species has been shown to deter both invertebrate and vertebrate predators, but the palatability of C. catalpae has not been explicitly tested. Choice tests were performed with spiders (Hogna carolinensis Walckenaer, Araneae: Lycosidae) and predatory hemipterans (Podisus maculiventris [Say], Hemiptera: Pentatomidae). These tests showed that predators naïve to both C. catalpae and the alternate prey Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) and Manduca sexta (L.) (Lepidoptera: Sphingidae) preferred the alternate species, and that P. maculiventris that were exposed previously to T. ni also preferred T. ni. In nonchoice tests, P. maculiventris grew significantly more slowly upon C. catalpae compared to M. sexta. These results suggest that C. catalpae, like other caterpillars that sequester catalpol, is less palatable to invertebrate predators compared to nonsequestering caterpillar species.

Exotic lace bugs (Hemiptera: Tingidae) have previously been evaluated for potential biocontrol of pervasive, exotic Chinese privet, Ligustrum sinense Lour. This study was conducted to determine if a native lace bug, Leptoypha mutica Say, could utilize Chinese privet and to determine the lace bug's preferred host plant. A no-choice test determined the lace bug's acceptance and utilization of three plant hosts: fringe tree (Chionanthus virginicus L.), swamp privet (Foresteria acuminata Michx), and Chinese privet, based on frass production, oviposition, and survival of lace bugs. Choice tests in the laboratory and the field evaluated lace bug preference among swamp privet, Chinese privet, and green ash (Fraxinus pennsylvanica Marsh). All plant hosts supported the lace bugs in laboratory assays, but fewer eggs were produced on Chinese privet. Green ash was the most preferred while Chinese and swamp privet were equally preferred. These laboratory results were consistent with a field choice test and field observations. Chinese privet is a suitable host for Le. mutica, but not an optimal host, suggesting that host switching to Li. sinense by this lace bug is unlikely.

The native lace bug, Leptoypha mutica Say (Hemiptera: Tingidae), has demonstrated potential as an insect biological control agent of invasive Chinese privet (Ligustrum sinense Lour). To better evaluate its potential to establish on a new host, developmental biology on Chinese privet was studied at temperatures of 20°C, 24°C, 28°C, and 32°C. The complete duration of development of L. mutica from egg deposition through five instars on this previously unreported host ranged from 24.4 to 57.1 d. Estimated threshold temperatures and calculated thermal unit requirements for egg development were 11.0°C and 211.9 degree-days (DD); for nymphal development, 9.9°C and 326.8 DD; and for complete development, 10.5°C and 527.4 DD. Results of this study indicate that L. mutica will oviposit and can develop successfully on Chinese privet over a range of temperatures suggesting the potential for multiple generations to occur in a single season.

The corn wireworm, Melanotus communis Gyllenhal, is a serious pest of several agricultural crops including corn (Zea mays L.). Numerous studies have been reported on wireworm control at crop planting including the use of seed treatments. However, there are no published reports on the efficacy of corn seed treatments for wireworm control. The objective of this study was to determine efficacy and mode of action of various corn seed treatments against M. communis. Wireworms (larvae) were collected by digging under sugarcane stools in Florida. Testing was conducted in plastic buckets which contained soil, insecticide-treated seeds, and six wireworms per bucket. Buckets were held at 24°C for 1 mo and then plant growth and insect survival were measured. Wireworms were also held an additional month to measure possible delayed mortality. Treatments with insecticides or the fungicide Maxim Quattro (Syngenta Crop Protection, Inc., Greensboro, NC), or both, in various combinations and rates, all had greater emergence and significantly greater plant vigor, height, and weight than did controls. However, many wireworms were also alive, active, and completing development in all treatments after 2 mo. These data are consistent with the growing recognition that in many cases plant protection from wireworms may be obtained through nonlethal means.

Sugarcane (Saccharum spp.) is an important field crop grown in southern Florida. White grubs (Scarabaeidae) and wireworms (Elateridae) historically and currently are important soil insect pests of the crop. Twenty sugarcane fields on muck soil (Histosols) were sampled for soil insect pests during 2015 and 2016. No new unknown soil insect pests were found. The recently established sugarcane root weevil, Diaprepes abbreviatus (L.), was rarely found in samples. Interestingly, the once very important grub pest, Tomarus subtropicus (Blatchley) was not detected. And, last, fewer wireworms and especially grubs were found in shallow muck fields than deep muck fields.

Beta-glucosidases play an important role in the hydrolysis of cellulose and are among the cellulases in termites responsible for cellulose degradation and regulation of gene expression. A cDNA encoding putative β-glucosidase (CfBGIa) from the Formosan subterranean termite, Coptotermes formosanus Shiraki, was successfully cloned. The full-length of the cDNA of CfBGIa was 2,195 base pairs (bp) with an open reading frame of 1,500 bp that encoded for a 499–amino acid protein. Excluding a putative signal peptide of the first 21 amino acid residues, the 478-residue mature CfBGIa has a calculated molecular mass of 54.49 kDa. Sequence assessment and phylogenetic analysis suggested that CfBGIa belongs to β-glucosidase cluster I (BG-I group) encoding digestive enzymes. Homology modeling shows a classical (β/α)₈ barrel structure of glycosyl hydrolase family 1 including two catalytic residues, Glu193 and Glu402. Quantitative PCR analysis in different temperatures revealed a similar expression pattern between CfBGIa and Co. formosanus clone Glu1B β-glucosidase mRNA. Both genes were induced in low (4°C) and high (38°C) temperatures. CfBGIa may prove to be a supplement to the cellulase system to improve the cellulose digestion in the termite, and these results might contribute to mining novel cellulases for cellulosic conversion.