The Use of F2 Screening for Detection of Resistance to Emamectin Benzoate, Chlorantraniliprole, and Indoxacarb in Australian Populations of Helicoverpa armigera (Lepidoptera: Noctuidae)

Abstract

The ability to effectively detect changes in susceptibility to insecticides is an integral component of resistance management strategies and is highly dependent upon precision of methods deployed. Between 2013 and 2016, F2 screens were performed for detection of resistance alleles in Helicoverpa armigera (Hübner) to emamectin benzoate, chlorantraniliprole, and indoxacarb in major cropping regions of eastern Australia. Resistance to emamectin benzoate was not detected. There were low but detectable levels of survival at discriminating concentrations of chlorantraniliprole and indoxacarb. Alleles conferring an advantage to chlorantraniliprole were present at a frequency of 0.0027 (95% CI 0.0012-0.0064; n = 1,817). Alleles conferring an advantage to indoxacarb were present at a frequency of 0.027 (95% CI 0.020-0.035; n = 1,863). Complementation tests for allelism in six of seven positive indoxacarb tests indicated that resistance was due to alleles present at the same locus. The majority (88%) of lines that tested positive for indoxacarb resistance deviated from a model of recessive inheritance. Pheromone-caught male moths contributed significantly greater numbers of F2 lines compared with moths derived from field-collected eggs or larvae. There was no difference in the detectability of indoxacarb resistance in F2 lines from pheromone-caught moths compared with moths derived from immature stages collected from the field and reared to adult under laboratory conditions. Therefore, we recommend the use of pheromone traps for sourcing insects for F2 screening as a more cost- and time-efficient alternative to traditional methods of sampling.

Empowering Australian insecticide resistance research with genetic information: the road ahead

“…For example, research towards characterising H. armigera 's genetic mechanisms for oxadiazine resistance has progressed at a fast pace since it was first discovered (Bird et al . 2017), narrowing the list of candidates to a cluster of P450 genes using genome‐wide association analyses (Chen et al . 2020).…”

“…2007, 2012; Bird 2015, 2018; Bird et al . 2017). Yet few published records of resistance monitoring in H. armigera have utilised genetic markers.…”

“…2016; Bird et al . 2017). Australian M. persicae is a pest in canola, pulse, fruit, cotton and vegetable crops (Attia & Hamilton 1978; Herron et al .…”

Relative fitness and stability of resistance in a near‐isogenic strain of indoxacarb resistant Helicoverpa armigera (Lepidoptera: Noctuidae)

“…7 In Australia the levels of indoxacarb resistance reported in H. armigera are generally low. 8 However, reduced levels of susceptibility have been recorded at certain times of the year and in certain locations. 9 High levels of genetic dominance and a probable metabolic mechanism of indoxacarb resistance in H. armigera 10,11 suggest there is a high risk that resistance will develop rapidly under certain conditions of selection.…”

Linkage mapping an indoxacarb resistance locus in Helicoverpa armigera (Lepidoptera: Noctuidae) by genotype‐by‐sequencing

“…Such methodology was introduced in 2002 for monitoring toxins produced by the bacterium Bacillus thuringiensis including Cry1Ac, Cry2Ab and Vip3A . In 2013, an F 2 screen was introduced to monitor chemical resistance to emamectin benzoate, chlorantraniliprole and indoxacarb . The methodology identified the first case of indoxacarb resistance isolated from a field population of H. armigera in Australia .…”