scholarly journals Performance and cross-crop resistance of Cry1F-maize selected Spodoptera frugiperda on transgenic Bt cotton: implications for resistance management

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Fei Yang ◽  
David L. Kerns ◽  
Sebe Brown ◽  
Ryan Kurtz ◽  
Tim Dennehy ◽  
...  
2013 ◽  
Vol 63 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Franklin M. Cunha ◽  
Valéria Wanderley-Teixeira ◽  
Jorge B. Torres ◽  
Álvaro A.C. Teixeira ◽  
Thiago J.S. Alves ◽  
...  

Despite the efficiency of transgenic plants expressing Bacillus thuringiensis (Bt) toxins as insecticides against several lepidopterans, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is one species that presents low susceptibility to most Bt crops. This study investigated the effects of the Cry1Ac toxin expressed by Bt cotton in the midgut of S. frugiperda and its effects on the humoral and cellular immune responses. Three hypotheses were proposed and tested with contributing factors for the natural tolerance of S. frugiperda: (i) midgut regenerative cells are activated by the Cry1Ac toxin, and thus renew the epithelial cells damaged by the protein, (ii) Cry1Ac increased production of nitric oxide or phenoloxidase in the hemolymph, and (iii) there are qualitative and quantitative variations in the hemocyte levels of S. frugiperda. Caterpillars were reared using Bt cotton (Acala 90B) and non-Bt isolines (Acala 90), from the first to the fourth instar. The Bt cotton promoted elongation of the epithelial cells in the midgut of S. frugiperda caterpillars. Hence, evidence only supported the hypothesised increase of phenoloxidase (ii) and qualitative and quantitative differences in hemocyte levels (iii) in insects that were fed with Bt and non-Bt cotton. These parameters seem to explain the low susceptibility of S. frugiperda to Cry1Ac toxin and they are a viable set of responses for the evaluation of other xenobiotic factors.


2021 ◽  
Author(s):  
Rubens Hideo Kanno ◽  
Aline Guidolin ◽  
Fernando Padovez ◽  
Juliana Rodrigues ◽  
Celso Omoto

Insecticide resistance is usually associated with fitness costs. The magnitude of fitness costs is affected by environmental and ecological factors. Here, we explored how host plants could affect fitness costs associated with insecticide resistance. Initially, spinetoram-resistant (RR) and susceptible (SS) strains of Spodoptera frugiperda were selected using F2 screen from a population collected in Sao Desiderio, Bahia State, Brazil in 2018. Besides de RR and SS strains, fitness costs were also assessed for a heterozygous strain (RS). Life-history traits were evaluated to estimate population growth parameters of neonate larvae of each strain fed on corn, soybean and cotton plants. Compared to the SS strain, the relative fitness of the RR strain, based on intrinsic rate of population increase, was 1.06, 0.84 and 0.67 on plants of corn, soybean and cotton respectively. The relative fitness of the RS strain was similar to the SS strain regardless the host plant, suggesting a recessive fitness cost. No differences were found between the strains fed on corn plants. The larval development time was greater for RR strain fed on soybean and cotton plants compared to RS and SS strain. Low survival rate and fecundity of the RR strain were found when larvae fed on plants of soybean and cotton. The results of this study demonstrated that fitness costs of spinetoram resistance in S. frugiperda depend strongly on the host plants that S. frugiperda larvae fed on. Such information can be used to design resistance management strategies considering the host plants of the agricultural landscape. Keywords: fall armyworm; spinosyns; insect resistance management; relative fitness.


2016 ◽  
Vol 73 (3) ◽  
pp. 485-492 ◽  
Author(s):  
Sharon Downes ◽  
Darren Kriticos ◽  
Hazel Parry ◽  
Cate Paull ◽  
Nancy Schellhorn ◽  
...  

2017 ◽  
Vol 16 (7) ◽  
pp. 1624-1633 ◽  
Author(s):  
Jun-yu LUO ◽  
Shuai ZHANG ◽  
Xiang-zhen ZHU ◽  
Li-min LU ◽  
Chun-yi WANG ◽  
...  

Author(s):  
Y.N. Venkatesh ◽  
N.V.V.S.D. Prasad ◽  
K.B. Ramesh ◽  
N. Srinivasa ◽  
D.V. Sai Ram Kumar

2003 ◽  
Vol 27 (5) ◽  
pp. 610-616
Author(s):  
BAI Li-Xin ◽  
ZHANG Long-Wa ◽  
CHEN Xiao-Bo ◽  
FENG Han-Jin

2019 ◽  
Vol 112 (4) ◽  
pp. 1741-1751
Author(s):  
Lewis R Braswell ◽  
Dominic D Reisig ◽  
Clyde E Sorenson ◽  
Guy D Collins

Abstract Helicoverpa zea Boddie is a common economic pest of cotton (Gossypium hirsutum L.), including transgenic cotton varieties that express Bacillus thuringiensis (Bt). Helicoverpa zea oviposition is similar in Bt and non-Bt cotton, but behavior of H. zea larvae can be different in the presence of Bt, with neonates moving away from terminals faster in single-toxin Bt than non-Bt cotton or avoiding Bt-treated diet in the lab. We quantified H. zea oviposition and larval distribution on structures within cotton plants in small plot experiments of Cry1Ac + Cry1F cotton for 2 yr under different irrigation and nitrogen treatments. More eggs were oviposited on plants receiving nitrogen application during 2016 and on leaves in the top section of irrigated plants during 2017, but other treatment effects on eggs or larvae were minimal. Helicoverpa zea eggs were most common on leaves in the top third of plants at position zero and middle section of cotton plants throughout the season, but some oviposition occurred on fruiting structures as well. First and second instars were more common on squares in the top section of plants during 2016 and bolls in the middle and lower sections during 2017 due to oviposition lower in the canopy during 2017. During both years, third through fifth instars were more common on bolls in the middle and lower section of plants closer to the main stem. These findings have resistance management implications as extended larval feeding on bolls could optimize nutrition, decrease Bt susceptibility, and potentially influence behavioral resistance.


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