Fitness Cost of Chlorpyrifos Resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) on Different Host Plants

Abstract

Spodoptera frugiperda (J. E. Smith, 1797) is a polyphagous pest of global relevance due to the damage it inflicts on agricultural crops. In South American countries, this species is one of the principal pests of maize and cotton. Currently, S. frugiperda is also emerging as an important pest of soybeans and winter cereals in Brazil. Chemical control is one of the main control tactics against S. frugiperda, even though resistance against numerous modes of action insecticides has been reported. To support insect resistance management programs, we evaluated the fitness costs of resistance of S. frugiperda to the acetylcholinesterase inhibitor chlorpyrifos. Fitness costs were quantified by comparing biological parameters of chlorpyrifos-resistant and -susceptible S. frugiperda and their F1 hybrids (heterozygotes) on non-Bt cotton, non-Bt maize, non-Bt soybean, and oats. The results revealed that the chlorpyrifos-resistant genotype showed lower pupa-to-adult and egg-to-adult survivorship and reduced larval weights on oats; longer neonate-to-pupa and egg-to-adult developmental periods, and lower pupal weights and fecundity on maize; lower pupal weights on soybean; and reduced fecundity on cotton compared with the chlorpyrifos-susceptible genotype. Fitness costs also affected fertility life table parameters of the resistant genotype, increasing the mean length of a generation on cotton and maize and reducing the potential for population growth on all hosts. These findings suggest fitness costs at the individual and population levels of chlorpyrifos resistance in S. frugiperda, indicating that removal of the selective agent from the environment would result in reduced resistance and opportunities for the restoration of susceptibility.

Field‐evolved resistance to chlorpyrifos by Spodoptera frugiperda (Lepidoptera: Noctuidae): Inheritance mode, cross‐resistance patterns, and synergism

“…41 From F 2 to F 8 , early L3 larvae were exposed to selection pressure at a single dose of 3200 ppm of chlorpyrifos (Lorsban 480 BR) diluted in water and applied over the diet surface [equivalent to 51 μg active ingredient (a.i.) cm −2 ] as described by Garlet et al 42 From F 9 to F 15 , the selection process was performed in topical bioassays using technical grade chlorpyrifos (98% purity; Sigma Aldrich, São Paulo, SP, Brazil) diluted in acetone (99.5% purity; Sigma Aldrich) at a single dose of 10 μg chlorpyrifos per larva. This concentration was applied to the dorsal thoracic region of early L3 larvae (1 μL per larva) using a hand microapplicator (Burkard Manufacturing, Rickmansworth, UK).…”

“…Using topical bioassays as previously described, cross-resistance patterns were evaluated to acephate (99.5% purity; Sigma Aldrich), methomyl (98% purity; Sigma Aldrich), and thiodicarb (99.8% purity; Sigma Aldrich). Concentrationresponse bioassays were also carried out using diet-overlay bioassays as described by Garlet et al 42 In this bioassay method the insecticides chlorfenapyr (Pirate, 240 g a.i. L −1 ; BASF SA, São Paulo, SP, Brazil), flubendiamide (Belt, 480 g a.i.…”

Susceptibility monitoring and the molecular characterization of resistance of Spodoptera frugiperda (Lepidoptera: Noctuidae) to lambda-cyhalothrin and chlorpyrifos

“…Chlorpyrifos is also a broadly used insecticide, having a significant share of the insecticides marketed in Brazil, and S. frugiperda is certainly under high selection pressure due to the continuous exposure to this pesticide (IBAMA, 2021)The continuous exposure of S. frugiperda to the selection pressure of this pesticide, and the steady low survival probability observed during our monitoring indicate that resistance to chlorpyrifos is associated with very high fitness costs. In fact, analysis of the fitness costs of chlorpyrifos resistance in a laboratory-selected strain of S. frugiperda, demonstrated resistance affected several biological traits at the individual and population levels (Garlet et al, 2021). The fitness costs associated with chlorpyrifos resistance in S. frugiperda is so high that Garlet et al (2021) concluded populations of S. frugiperda would restore their susceptibility to chlorpyrifos with the suspended use of the selecting agent.…”

“…In fact, analysis of the fitness costs of chlorpyrifos resistance in a laboratory-selected strain of S. frugiperda, demonstrated resistance affected several biological traits at the individual and population levels (Garlet et al, 2021). The fitness costs associated with chlorpyrifos resistance in S. frugiperda is so high that Garlet et al (2021) concluded populations of S. frugiperda would restore their susceptibility to chlorpyrifos with the suspended use of the selecting agent. The fitness cost associated with chlorpyrifos resistance is also reported to several other insect species, and in chlorpyrifos-resistant Plutella xylostella (Lepiodptera: Plutellidae) it has been suggested to occur due the excessive energy use for the over-production of detoxification enzymes and heat shock proteins when these proteins are not required (Zhang et al, 2015;Yang et al, 2018).…”

“…Unfortunately, the indiscriminate application of insecticides, mainly pyrethroids and organophosphates contributed to the evolution of S. frugiperda resistance to several compounds (Diez-Rodríguez and Omoto, 2001;Carvalho et al, 2013). High levels of resistance have been reported to the pyrethroids lambda-cyhalothrin, permethrin, cyhalothrin, tralomethrin, bifenthrin and fluvalinate (Diez-Rodríguez and Omoto, 2001;Carvalho et al, 2013), and to the organophosphates malathion, chlorpyrifos, methyl parathion, diazinon and sulprofos (Yu, 1991(Yu, , 1992Garlet et al, 2021). Resistance to pyrethroids and organophosphates has been commonly associated with mutations in genes coding for proteins of target sites and/or with modifications in the expression profile of genes encoding for detoxification enzymes, particularly monooxygenases of the cytochrome P450, esterases and glutathione-S-transferases (Scott, 1999;Daborn et al, 2002;Kasai, 2004;Djouaka et al, 2008;Feyereisen, 2012).…”