BACKGROUND Fumigants like phosphine, methyl bromide and sulfuryl fluoride are highly effective for the control of structural, storage and agricultural arthropod pests. Unfortunately, many of these synthetic compounds are highly toxic to people, many pests have developed resistance to these compounds and methyl bromide, the 'gold standard' for fumigants, was de-registered because of its contribution to depletion of the stratospheric ozone layer. Alternative fumigant chemistry is needed. RESULTS Several plant species produce n-aliphatic methyl ketones to prevent plant herbivory. To examine the use of methyl ketones as a fumigant, structure-mortality studies were conducted using the red imported fire ant, Solenopsis invicta Buren, as a model. A new easy-to-use, inexpensive and disposable bioassay system was developed for this study. The LC50 values for heptanone, octanone, nonanone and undecanone were 4.27, 5.11, 5.26 and 8.21 µg/cm3 of ambient air, respectively. Although heptanone, octanone and nonanone were more effective than undecanone, subsequent research was conducted with 2-undecanone because this compound already has US Environmental Protection Agency (EPA) registration as a biopesticide. In dose-response field studies, 12.4 mL of undecanone injected into mounds was the lowest application rate that produced no ant activity in the mound with no re-establishment of ants. Reagent grade undecanone was more cost-effective than methyl bromide for fire ants, adult German cockroaches and tobacco budworm eggs, but slightly more expensive for adult flour beetles. CONCLUSION The naturally occurring methyl ketone undecanone has the potential to be an alternative to current fumigants for a variety of pest applications. © 2017 Society of Chemical Industry.

Studies were conducted to evaluate the potential of changes in caterpillar behavior on resistance to protein toxins like that from Bt expressed in transgenic cotton. Evidence is provided that there are natural variations of feeding rates in caterpillars, that reductions in Bt susceptibility in caterpillars can be correlated with an increased feeding rate, that a laboratory strain of the tobacco budworm resistant to Bt has an increased feeding rate, and that temperature increases which increases the feeding rate reduces caterpillar susceptibility to Bt toxin. First studies are reported on the microbiome of the tobacco budworm where temperature effects on Bt susceptibility could not be explained by changes in the bacteria microbiome. Potential mechanisms for resistance to protein toxins expressed in cotton are discussed, a mechanism by which feeding rate could affect toxin susceptibility is provided, and a rationale explained on how this same mechanism could affect other large molecular weight, biological polymers like dsRNA.

The adoption of Bt transgenic cotton has practically eliminated lepidopteran pests from this crop and has produced a secondary pest problem, with pierce-sucking insects such as the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae). The future of cotton genetic pest management is threatened by these insects and their development of resistance to chemical insecticides. Lygus lineolaris is also a pest of more than 100 other crops. The development of transcriptome data for this insect should be transformative in essentially all aspects of research on plant bug biology and the development of control strategies. The first 454 tarnished plant bug whole body (WB) and gut (G) transcriptomes were constructed (half plate for each). A total of 116163527 bases were obtained, representing 262555 WB and 229919 G reads (SRA048217) of which 232058 (SRS280903) and 168069 (SRS280894) reads, respectively, were available for assembly. The average read length was 233.1 and 208.5bp for WB and G, respectively. The whole body and gut reads were assembled together (WB-G) to produce the most complete transcriptome possible from our sequencing effort and resulted in 6970 contigs with an average length of 393bp. The gut transcriptome alone was assembled into 3549 contigs with an average length of 349bp. The smallest contig was 55bp and the largest was 3466bp, and there were 62484 sequences that could not be assembled (singletons) among both transcriptomes. Overall transcriptome analysis was organized according to the Gene Ontology consortium, enzyme commission, and InerPro using the Blast2GO (R) program. We further characterized metabolic systems and messages associated with development.

Proof of concept was demonstrated for a practical, off-the-shelf bioassay to monitor for tobacco budworm resistance to pyramided Bt cotton using plant filtrates. The bioassay was based on a previously described feeding disruption test using hydrateable artificial diet containing a blue indicator dye, a diagnostic dose of insecticide and novel assay architecture. Using neonate larvae from a Bt-susceptible, laboratory reared tobacco budworm strain, a diagnostic dose for Bollgard II and WideStrike cotton was obtained that limited neonate blue fecal production to 0-2 pellets in 24 h (Bt-resistant larvae produced >2 fecal pellets). The bioassay was tested with three different field populations of tobacco budworm collected from tobacco in central North Carolina (USA) and shown to accurately diagnose susceptibility to Bt. The diagnostic doses were also successfully evaluated with two Bt-resistant, laboratory reared tobacco budworm strains. Shelf life studies showed the assay could be stored for at least 6 months at room temperature (longer storage times were not studied). The application of the bioassay as an easy to use monitoring tool is discussed. (C) 2011 Elsevier Ltd. All rights reserved.

BACKGROUND:The codling moth, Cydia pomonella (L.), is one of the most important pests of apple worldwide. Use of insecticides for management of this insect has been extensive and has resulted in resistance development. There are a number of different bioassay methods to monitor for codling moth resistance; however, many are not applicable to new insecticides and most are time consuming. A novel 16-well plasticware bioassay plate containing lyophilized diet was developed for rapid resistance monitoring of codling moth.RESULTS:The contact insecticides acetamiprid and azinphosmethyl were significantly more toxic to neonates than to fourth instars. However, there was no significant difference in LC(50) values between neonates and fourth instars to the ingestion insecticides chlorantraniliprole, methoxyfenozide, novaluron and spinetoram. Field colonies of codling moth were significantly more resistant to methoxyfenozide than susceptible populations. A diagnostic dose of 20 µg mL(-1) (LC(99) ) was established to monitor for codling moth resistance to methoxyfenozide.CONCLUSIONS:The results presented here demonstrate that a novel and rapid bioassay can be used to monitor for codling moth resistance to methoxyfenozide. The bioassay method is relevant to both ingestion and contact insecticides, but a single diagnostic dose, regardless of larval age, is only relevant to ingestion insecticides. Age-dependent diagnostic doses are likely necessary for contact insecticides.

Separate transcriptomes were constructed by pyrosequencing on the GS-FLX sequencer (Roche), for the whole body and digestive system of the adult Tarnished plant bug, Lygus lineolaris, collected from the field in North Carolina, USA. Each cDNA library from the two samples examined were sequence on one-half plates each. The total ouput from the two reads was 116, 635, 527 bps of data. The whole body library produced 292,714 reads which were assembled using the GS Assembler ver. 1.1.02.15 (Roche) with default parameters into 5,529 contiguous sequences (contigs). The digestive system library produced 229,919 reads which was assembled into 3,549 contigs. Contigs were putatively identified using the Tera-BLASTX algorithm with DeCypher (TimeLogic) against Genbank nr and est databases that were downloaded on June 2008. The contigs obtained from the tarnished plant bug gut transcriptome were analyzed using the blast2go program (www.blast2go.org). Blast2go also blasted the contigs using its blastx function and performed the gene ontologies. The analysis of the results from the whole bug and gut transcroptomes are in its infancy. However, the gut library has some obvious messages that should be of interest to plant, genetic pest management.