scholarly journals Growth of Wild Pseudoplusia includens (Lepidoptera: Noctuidae) Larvae Collected from BT and Non-BT Cotton

2000 ◽  
Vol 83 (3) ◽  
pp. 354
Author(s):  
Douglas V. Sumerford ◽  
Walter L. Solomon
Keyword(s):  
Pseudoplusia Includens ◽  
Bt Cotton ◽  
Lepidoptera Noctuidae

Impact of Bt cotton on the immune system and histology of the midgut of the fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

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 ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
Bt Cotton ◽  
Contributing Factors ◽  
Qualitative And Quantitative ◽  
Cry1ac Toxin ◽  
Cellular Immune ◽  
Natural Tolerance ◽  
Lepidoptera Noctuidae

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.

Helicoverpa zea (Lepidoptera: Noctuidae) Preference for Plant Structures, and Their Location, Within Bt Cotton Under Different Nitrogen and Irrigation Regimes

2019 ◽  
Vol 112 (4) ◽  
pp. 1741-1751
Author(s):  
Lewis R Braswell ◽  
Dominic D Reisig ◽  
Clyde E Sorenson ◽  
Guy D Collins
Keyword(s):  
Helicoverpa Zea ◽  
Resistance Management ◽  
Larval Feeding ◽  
Bt Cotton ◽  
Larval Distribution ◽  
Cotton Plants ◽  
Small Plot ◽  
Nitrogen Treatments ◽  
Behavioral Resistance ◽  
Lepidoptera Noctuidae

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.

Resistance Allele Frequency to Bt Cotton in Field Populations of Helicoverpa armigera (Lepidoptera: Noctuidae) in China

2008 ◽  
Vol 101 (3) ◽  
pp. 933-943 ◽  
Author(s):  
Fengyi Liu ◽  
Zhiping Xu ◽  
Juhua Chang ◽  
Jin Chen ◽  
Fengxia Meng ◽  
...  
Keyword(s):  
Allele Frequency ◽  
Helicoverpa Armigera ◽  
Bt Cotton ◽  
Resistance Allele ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

SOYBEAN FOLIAGE CONSUMPTION BY PSEUDOPLUSIA INCLUDENS (WALKER) (LEPIDOPTERA: NOCTUIDAE) LARVAE INFECTED WITH NUCLEAR POLYHEDROSIS VIRUS1,2

1987 ◽  
Vol 22 (3) ◽  
pp. 212-223 ◽  
Author(s):  
M. Z. Alam ◽  
W. C. Yearian ◽  
S. Y. Young ◽  
A. J. Mueller
Keyword(s):  
Glycine Max ◽  
Leaf Area ◽  
Nuclear Polyhedrosis Virus ◽  
Pseudoplusia Includens ◽  
Mortality Level ◽  
Total Leaf Area ◽  
Larval Instars ◽  
Glycine Max L ◽  
Nuclear Polyhedrosis ◽  
Lepidoptera Noctuidae

Consumption of greenhouse and field grown ‘Bragg’ soybean, Glycine max (L.) Merrill, foliage was determined for Pseudoplusia includens (Walker) larvae treated with varying dosages of Pseudoplusia nuclear polyhedrosis virus to produce different mortality levels. Uninfected P. includens larvae consumed an average of 158.3 and 78.7 cm2 of greenhouse and field grown soybean foliage, respectively. More than 84% of the total leaf area consumed was by the final two larval instars. The amount of foliage consumed by larvae infected as first (greenhouse and field) or second (greenhouse) instars was significantly reduced with increasing NPV mortality level. Foliage consumption by larvae infected as second (field) and third (greenhouse and field) instars at all dosage levels was significantly reduced when compared to the untreated checks, but differences in foliage consumption at the two lower mortality levels were not significant. Frass produced by infected and uninfected larvae was significantly correlated with the amount of greenhouse or field grown foliage consumed.

SEASONAL INCIDENCE OF METEORUS AUTOGRAPHAE1 ON SOYBEAN LOOPER2 LARVAE ON SOYBEAN IN SOUTH CAROLINA, AND THE INFLUENCE OF HOST DENSITY ON PARASITIZATION3

1986 ◽  
Vol 21 (4) ◽  
pp. 338-345 ◽  
Author(s):  
J. F. Grant ◽  
M. Shepard
Keyword(s):  
South Carolina ◽  
Host Density ◽  
Pseudoplusia Includens ◽  
Cylindrical Container ◽  
Seasonal Incidence ◽  
Percent Parasitism ◽  
Soybean Looper ◽  
Lepidoptera Noctuidae

The seasonal incidence of Meteorus autographae Muesebeck (Hymenoptera: Braconidae) on larvae of the soybean looper, Pseudoplusia includens (Walker) (Lepidoptera: Noctuidae), in soybean fields in South Carolina was monitored at two locations during 1981, 1982, and 1983. In most instances, parasitism of soybean looper larvae by M. autographae was detected 7 to 14 days after soybean looper larvae were first found in the fields. During this three-year study, maximum parasitism of soybean looper larvae by M. autographae within a season ranged from 4.6 to 19.8%. In the laboratory, numbers of hosts parasitized per 24 hours by M. autographae increased with each successive increase in host density. At a host density of 40 larvae per 1.75-liter cylindrical container, an average of 26 hosts were parasitized by one M. autographae during 24 hours. Percent parasitism remained about the same (64 – 70%) at all host densities.

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