Successful development and implementation of a practical proactive resistance management plan for <scp>Bt</scp> cotton in <scp>Australia</scp>

Knight, Kristen; Head, Graham P.; Rogers, D.J.

doi:10.1002/ps.6490

Cited by 15 publications

(11 citation statements)

References 55 publications

(100 reference statements)

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“…In Australia, where resistance management rules have been more stringent than in the United States, decreased susceptibility of H. armigera to Cry1Ac produced by Bt cotton has not been reported after 25 years 64 . A minimum refuge of 70% non‐Bt cotton was required in Australia from 1996 to 2003 for cotton producing only Cry1Ac 65 .…”

Section: Discussionmentioning

confidence: 99%

“…62 In Australia, where resistance management rules have been more stringent than in the United States, decreased susceptibility of H. armigera to Cry1Ac produced by Bt cotton has not been reported after 25 years. 64 A minimum refuge of 70% non-Bt cotton was required in Australia from 1996 to 2003 for cotton producing only Cry1Ac. 65 In 2004, when farmers in Australia switched completely from Cry1Ac cotton to Cry1Ac + Cry2Ab cotton with a 10% non-Bt cotton refuge required, H. armigera was still fully susceptible to Cry1Ac, maximizing the immediate and longterm benefits of the two-toxin cotton.…”

Section: Discussionmentioning

confidence: 99%

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Practical resistance to Cry toxins and efficacy of Vip3Aa in Bt cotton against Helicoverpa zea

Yang

Kerns

Little

et al. 2022

Pest Management Science

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BACKGROUND: Crops genetically engineered to make insect-killing proteins from Bacillus thuringiensis (Bt) have revolutionized management of some pests. However, the benefits of such transgenic crops are reduced when pests evolve resistance to Bt toxins. We evaluated resistance to Bt toxins and Bt cotton plants using laboratory bioassays and complementary field trials focusing on Helicoverpa zea, one of the most economically important pests of cotton and other crops in the United States. RESULTS:The data from 235 laboratory bioassays demonstrate resistance to Cry1Ac, Cry1Fa, and Cry2Ab occurred in most of the 95 strains of H. zea derived from Arkansas, Louisiana, Mississippi, Tennessee, and Texas during 2016 to 2021. Complementary field data show efficacy decreased for Bt cotton producing Cry1Ac + Cry1Fa or Cry1Ac + Cry2Ab, but not Cry1Ac + Cry1Fa + Vip3Aa. Moreover, analysis of data paired by field site and year shows higher survival in bioassays was generally associated with lower efficacy of Bt cotton. CONCLUSIONS:The results confirm and extend previous evidence showing widespread practical resistance of H. zea in the United States to the Cry toxins produced by Bt cotton and corn, but not to Vip3Aa. Despite deployment in combination with Cry toxins in Bt crops, Vip3Aa effectively acts as a single toxin against H. zea larvae that are highly resistant to Cry toxins. Furthermore, Vip3Aa adoption is increasing and previous work provided an early warning of field-evolved resistance. Thus, rigorous resistance management measures are needed to preserve the efficacy of Vip3Aa against this highly adaptable pest.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Practical resistance to Cry toxins and efficacy of Vip3Aa in Bt cotton against Helicoverpa zea

Yang

Kerns

Little

et al. 2022

Pest Management Science

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“…Subsequently, annual monitoring in Arizona showed that no pink bollworm larvae were found on cotton from 2010 to 2018, and no wild pink bollworm moths were found in fields from 2013 to 2018. Based on similar conditions in other states, the US Secretary of Agriculture announced in October 2018 that pink bollworm had been eradicated in the continental commercial cotton producing areas in the United States [ 16 , 70 , 71 , 72 , 73 , 74 , 75 ]. In India, the cotton seeds provided by cotton seed companies not only include 450 g of Bt cotton seeds per bag but also contain 120 g of non-Bt cotton seeds in order to set up structural refuges.…”

Section: Resistance Management Tactic Type Ii: Seed MIX Refuge For Ol...mentioning

confidence: 99%

“…At present, the insecticidal protein species expressed by commercially cultivated Bt cotton around the world include Cry1Ac, Cry2Ab, and Vip3Aa, with an annual planting area of more than 33 million hectares [ 2 , 5 , 13 ]. This plays an important role in controlling the occurrence of lepidopteran pests (see Tabashnik and Carrière (2019) [ 14 ], Li et al, (2019) [ 15 ], Knight et al, (2021) [ 16 ] review).…”

Section: Introductionmentioning

confidence: 99%

Managing Practical Resistance of Lepidopteran Pests to Bt Cotton in China

Quan

2023

Insects

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China is one of the major cotton producers globally with small farmers. Lepidopteran pests have always been the main factor affecting cotton production. To reduce the occurrence of and damage caused by lepidopteran pests, China has employed a pest control method focused on planting Bt (Cry1Ac) cotton since 1997. Chinese resistance management tactics for the main target pests, the cotton bollworm and pink bollworm, were also implemented. For polyphagous (multiple hosts) and migratory pests such as the cotton bollworm (Helicoverpa armigera), the “natural refuge” strategy, consisting of non-Bt crops such as corn, soybean, vegetables, peanuts, and other host crops, was adopted in the Yellow River Region (YRR) and Northwest Region (NR). For a single host and weak migration ability pest, such as the pink bollworm (Pectinophora gossypiella), the seed mix refuge strategy yields a random mixture within fields of 25% non-Bt cotton by sowing second-generation (F2) seeds. According to field monitoring results for more than 20 years in China, practical resistance (Bt cotton failure) of target pests was avoided, and there were no cases of Bt (Cry1Ac) failure of pest control in cotton production. This indicated that this Chinese resistance management strategy was very successful. The Chinese government has decided to commercialize Bt corn, which will inevitably reduce the role of natural refuges; therefore, this paper also discusses adjustments and future directions of cotton pest resistance management strategies.

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“…Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have improved control of some key pests and reduced conventional insecticide use, while remaining safe for most nontarget organisms (Gould et al 2016, Dively et al 2018, ISAAA, 2019, Romeis and Meissle 2020, Knight et al 2021, Krogh et al 2020, Tabashnik et al 2021). However, these benefits decrease when pests evolve practical resistance to Bt crops (Tabashnik and Carrière 2019).…”

mentioning

confidence: 99%

Population Genomics of Nonrecessive Resistance to Bt Toxin Cry1Ac in Helicoverpa armigera From Northern China

Guan

Dai

Yang

et al. 2023

Journal of Economic Entomology

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Transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) have provided control of some key pests since 1996. However, the evolution of resistance by pests reduces the benefits of Bt crops. Resistance to Bt crops that is not recessively inherited is especially challenging to manage. Here we analyzed nonrecessive resistance to Bt toxin Cry1Ac in eight field populations of Helicoverpa armigera sampled in 2018 from northern China, where this global pest has been exposed to Cry1Ac in Bt cotton since 1997. Bioassays revealed 7.5% of field-derived larvae were resistant to Cry1Ac of which 87% had at least one allele conferring nonrecessive resistance. To analyze this nonrecessive resistance, we developed and applied a variant of a genomic mapping approach called quantitative trait locus (QTL)-seq. This analysis identified a region on chromosome 10 associated with nonrecessive resistance to Cry1Ac in all 21 backcross families derived from field-collected moths. Individual sequencing revealed that all 21 field-collected resistant grandparents of the backcross families had a previously identified dominant point mutation in the tetraspanin gene HaTSPAN1 that occurs in the region of chromosome 10 identified by QTL-seq. QTL-seq also revealed a region on chromosome 26 associated with nonrecessive resistance in at most 14% of the backcross families. Overall, the results imply the point mutation in HaTSPAN1 is the primary genetic basis of nonrecessive resistance to Cry1Ac in field populations of H. armigera from northern China. Moreover, because nonrecessive resistance is predominant, tracking the frequency of this point mutation could facilitate resistance monitoring in the region.

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Successful development and implementation of a practical proactive resistance management plan for Bt cotton in Australia

Cited by 15 publications

References 55 publications

Practical resistance to Cry toxins and efficacy of Vip3Aa in Bt cotton against Helicoverpa zea

Practical resistance to Cry toxins and efficacy of Vip3Aa in Bt cotton against Helicoverpa zea

Managing Practical Resistance of Lepidopteran Pests to Bt Cotton in China

Population Genomics of Nonrecessive Resistance to Bt Toxin Cry1Ac in Helicoverpa armigera From Northern China

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