Fitness cost of resistance to Bacillus thuringiensis in velvetbean caterpillar Anticarsia gemmatalis Hübner (Lepidoptera, Noctuidae)

Sosa–Gómez, Daniel Ricardo; Miranda, J. E.

doi:10.1590/s0085-56262012005000050

Cited by 9 publications

(2 citation statements)

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“…It is well‐known that resistant insects may display the fitness cost in the absence of selection pressure with higher larval mortality, longer larval and/or pupal developmental time, decreased pupal weight, lower fecundity and fertility, or morphologically abnormal adults (Bird & Akhurst, ; Anilkumar et al., ; Jakka et al., ). Significantly higher larval mortality, longer pupal duration, lower pupal weight, decreased emergence rate, and shorter adult longevity of Bt10 S. exigua after exposed to chlorpyrifos agree with the literature, highlighting fitness costs associated with resistance to Bt toxins in Bt10 S. exigua that have led to its vulnerability to conventional pesticide treatments (Williams et al., ; Sosa‐Gómez & Miranda, ).…”

Section: Discussionsupporting

confidence: 83%

Sublethal effects of Bt toxin and chlorpyrifos on various Spodoptera exigua populations

Jiang

Wang

et al. 2015

Entomologia Exp Applicata

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Bt cotton (Cry1Ac) has been commercially grown in China since 1997, saving China's cotton production from attack by Bt-target pests and also tremendously reducing pesticide usage. In recent years, however, Bt cotton, with 4.2 million ha of cultivation, has suffered from a secondary target pest, Spodoptera exigua (H€ ubner) (Lepidoptera: Noctuidae). In China, growers have even had to re-adopt conventional pesticides to control the pest, and this practice has already caused serious pesticide residue. In order to clarify the sublethal effects of chemical pesticide, the responses of a Bt-susceptible and a Bt-tolerant (Bt10) S. exigua strain to three treatment combinations were examined, including Bt toxin, sublethal chlorpyrifos, and Bt + sublethal chlorpyrifos. The susceptible and the Bt10 strain responded differently to dual pressure. Bt toxin + sublethal chlorpyrifos treatment lowered larval mortality and stimulated population increase of the susceptible S. exigua, whereas it delayed growth and development of the Bt10 strain. Under dual pressure, although larvae of the Bt10 strain developed faster than larvae of the susceptible strain, the Bt10 population experienced higher larval mortality, prolonged pupal duration, decreased pupal weight, decreased emergence rate, and shortened adult longevity. Compared with the susceptible strain, the Bt10 strain was deleteriously affected by sublethal chlorpyrifos. The Bt-tolerant/resistant S. exigua population was more vulnerable to chemical pesticides like chlorpyrifos regardless of whether it was exposed to Bt toxin or not. Our study provides a reference for increasing the efficacy of control of S. exigua in Bt-cotton planting areas.

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