Detection and Evolution of Resistance to the Pyrethroid Cypermethrin in <I>Helicoverpa zea</I> (Lepidoptera: Noctuidae) Populations in Texas

Abstract

The bollworm, Helicoverpa zea (Boddie), is a key pest of cotton in Texas. Bollworm populations are widely controlled with pyrethroid insecticides in cotton and exposed to pyrethroids in other major crops such as grain sorghum, corn, and soybeans. A statewide program that evaluated cypermethrin resistance in male bollworm populations using an adult vial test was conducted from 2003 to 2006 in the major cotton production regions of Texas. Estimated parameters from the most susceptible field population currently available (Burleson County, September 2005) were used to calculate resistance ratios and their statistical significance. Populations from several counties had statistically significant (P < or = 0.05) resistance ratios for the LC(50), indicating that bollworm-resistant populations are widespread in Texas. The highest resistance ratios for the LC(50) were observed for populations in Burleson County in 2000 and 2003, Nueces County in 2004, and Williamson and Uvalde Counties in 2005. These findings explain the observed pyrethroid control failures in various counties in Texas. Based on the assumption that resistance is caused by a single gene, the Hardy-Weinberg equilibrium formula was used for estimation of frequencies for the putative resistant allele (q) using 3 and 10 microg/vial as discriminatory dosages for susceptible and heterozygote resistant insects, respectively. The influence of migration on local levels of resistance was estimated by analysis of wind trajectories, which partially clarifies the rapid evolution of resistance to cypermethrin in bollworm populations. This approach could be used in evaluating resistance evolution in other migratory pests.

Resistance to Pyrethroid Insecticides in <I>Helicoverpa zea</I> (Lepidoptera: Noctuidae) in Indiana and Illinois

“…The reasons are unclear. Pyrethroid resistance has been reported in H. zea populations from the southern United States (Pietrantonio et al 2007;Hopkins & Pietrantonio 2009Helicoverpa zea (Boddie, and in the Midwest (Jacobson et al 2009)"plainCitation":" (Jacobson et al 2009. There is no published evidence of resistance in New York.…”

The Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) voltage-gated sodium channel and mutations associated with pyrethroid resistance in field-collected adult males

“…Resistant moths were obtained through the Texas Bollworm Resistance Monitoring Program (Pietrantonio et al, 2007) and were exposed to different residual concentrations of cypermethrin in 20 ml scintillation vials using the adult vial test (Plapp et al, 1987).…”

“…HM022883) exon d is shown and represents cDNA identified from a resistant specimen that contained a mutation homologous to I951V (*) of para, potentially an RNA-editing event associated with resistance to pyrethroid insecticides. populations of H. zea (Pietrantonio et al, 2007). The ability of these heterozygous resistant individuals to survive this 10 mg per vial dosage requires us to change the assumptions that have previously been made for resistance monitoring, at least for the target-site insensitivity mechanism.…”

“…Resistance to pyrethroids was first detected in H. zea in the early 1990s (Stadelbacher et al, 1990;Hsu and Yu, 1991), and presently, high levels of resistance are detected yearly in the US Cotton Belt (Pietrantonio et al, 2007;Hopkins and Pietrantonio, 2010). In insects, target-site resistance to pyrethroids is due to polymorphisms in the sodium channel gene that affect pyrethroid binding and/or the gating kinetics of the channel.…”

Lethal and sublethal effects of cypermethrin and methoxyfenozide on the larvae ofRachiplusia nu(Guenee) (Lepidoptera: Noctuidae)

“…In this way, IPM promotes the use of more selective insecticides to reduce the impact on natural enemies, thereby promoting the natural control of pests by conservation of their natural enemies (predators, parasitoids, and entomopathogens), as well as other beneficial organisms (pollinators) present in the crops. Pyrethroids are currently among the major insecticides used against Lepidoptera and other pests (Pietrantonio et al 2007) due to their broad spectrum and cost-effectiveness. Cypermethrin belongs to this insecticide group, which acts on the central nervous system, altering the axonic sodium channels and allowing excessive ion entrance, causing abnormal nervous activity and eventually paralysis (Stenersen 2004 (Pietrantonio et al 2007).…”