scholarly journals Yield Response of Dual-Toxin Bt Cotton to Helicoverpa zea Infestations

2008 ◽  
Vol 101 (5) ◽  
pp. 1594-1599 ◽  
Author(s):  
J. Gore ◽  
J. J. Adamczyk ◽  
A. Catchot ◽  
R. Jackson
Keyword(s):  
Helicoverpa Zea ◽  
Yield Response ◽  
Bt Cotton

Economic Injury Levels for Bt-resistant Helicoverpa zea (Lepidoptera: Noctuidae) in Cotton

2021 ◽  
Author(s):  
Alejandro I Del Pozo-Valdivia ◽  
Dominic D Reisig ◽  
Lewis Braswell ◽  
Jeremy K Greene ◽  
Phillip Roberts ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
The United States ◽  
Yield Response ◽  
Bt Cotton ◽  
Larval Population ◽  
Cry Toxins ◽  
Economic Thresholds ◽  
Cry Toxin ◽  
Economic Injury ◽  
Larval Number

Abstract Thresholds for Helicoverpa zea (Boddie) in cotton Gossypium hirsutum L. have been understudied since the widespread adoption of Bt cotton in the United States. Our study was possible due to the widespread presence of H. zea populations with Cry-toxin resistance. We initiated progressive spray timing experiments using three Bt cotton brands (Deltapine, Stoneville, and Phytogen) widely planted across the U.S. Cotton Belt expressing pyramided toxins in the Cry1A, Cry2, and Vip3Aa19 families. We timed foliar insecticide treatments based on week of bloom to manipulate H. zea populations in tandem with crop development during 2017 and 2018. We hypothesized that non-Bt cotton, cotton expressing Cry toxins alone, and cotton expressing Cry and Vip3Aa19 toxins would respond differently to H. zea feeding. We calculated economic injury levels to support the development of economic thresholds from significant responses. Pressure from H. zea was high during both years. Squares and bolls damaged by H. zea had the strongest negative yield associations, followed by larval number on squares. There were fewer yield associations with larval number on bolls and with number of H. zea eggs on the plant. Larval population levels were very low on varieties expressing Vip3Aa19. Yield response varied across experiments and varieties, suggesting that it is difficult to pinpoint precise economic injury levels. Nonetheless, our results generally suggest that current economic thresholds for H. zea in cotton are too high. Economic injury levels from comparisons between non-Bt varieties and those expressing only Cry toxins could inform future thresholds once H. zea evolves resistance to Vip3Aa19.

Yield Response of Dual-Toxin Bt Cotton to Helicoverpa zea Infestations

2008 ◽  
Vol 101 (5) ◽  
pp. 1594-1599 ◽  
Author(s):  
J. Gore ◽  
J. J. Adamczyk ◽  
A. Catchot ◽  
R. Jackson
Keyword(s):  
Helicoverpa Zea ◽  
Yield Response ◽  
Bt Cotton

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.

Age-Specific Mortality of Helicoverpa zea and Heliothis virescens (Lepidoptera: Noctuidae) Larvae on Flower Buds of Transgenic Cotton Expressing Vip3A and VipCot™ Insecticidal Proteins

2008 ◽  
Vol 43 (4) ◽  
pp. 349-361 ◽  
Author(s):  
P. L. Bommireddy ◽  
B. R. Leonard
Keyword(s):  
Heliothis Virescens ◽  
Helicoverpa Zea ◽  
Tobacco Budworm ◽  
Bt Cotton ◽  
Age Classes ◽  
Flower Buds ◽  
Insecticidal Proteins ◽  
Cotton Industry ◽  
Cumulative Mortality ◽  
Specific Mortality

The age-specific mortality of bollworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (F.), larvae was quantified on flower buds (squares) of transgenic Bacillus thuringiensis (Bt) cotton expressing Vip3A and VipCot™ (Vip3A + CrylAb) proteins. Cumulative mortality levels for both species and all larval ages (2 d, 4 d, 6 d, and 8-d-old) were significantly higher on squares of the Vip3A and VipCot cotton lines compared with that for the nonBt Coker 312 cotton. In general, H. zea and H. virescens larvae demonstrated significantly lower survival on VipCot squares compared with larvae that were offered Vip3A squares. The final cumulative mortality levels of H. zea larvae occurred more rapidly than that observed for H. virescens larvae on Vip3A squares. On Vip3A squares, the rates of peak mortality were similar among H. zea age-classes. Heliothis virescens in 4, 6 and 8-d-old age-classes survived longer than 2-d-old larvae on Vip3A squares. However, on VipCot squares, 8-d-old larvae of both species survived longer compared with other age-classes. Regardless of age-class, no larvae of either species were capable of completing pupation on squares from the VipCot cotton line. The combination of two insecticidal proteins expressed in the VipCot cotton line improved heliothine efficacy levels above that of the single protein in the Vip3A line and should exceed the requirements of the cotton industry for registration and regulation of transgenic Bt cottons. This level of VipCot toxicity to both target species supports continued development of the technology to provide another useful transgenic tool with considerable IPM and IRM value.

Helicoverpa zea (Lepidoptera: Noctuidae) Oviposition and Larval Vertical Distribution in Bt Cotton Under Different Levels of Nitrogen and Irrigation

2019 ◽  
Vol 112 (3) ◽  
pp. 1237-1250 ◽  
Author(s):  
Lewis R Braswell ◽  
Dominic D Reisig ◽  
Clyde E Sorenson ◽  
Guy D Collins
Keyword(s):  
Vertical Distribution ◽  
Helicoverpa Zea ◽  
Bt Cotton ◽  
Lepidoptera Noctuidae ◽  
Different Levels

scholarly journals Cotton phenology and production response to sowing time, row orientation and plant spacing using CROPGRO-cotton model

MAUSAM ◽  
2021 ◽  
Vol 72 (3) ◽  
pp. 627-634
Author(s):  
ABHISHEK DHIR ◽  
R. K. PAL ◽  
P. K. KINGRA ◽  
S. K. MISHRA ◽  
S. S. SANDHU
Keyword(s):  
Field Experiments ◽  
Growth And Yield ◽  
Yield Response ◽  
Bt Cotton ◽  
Plant Spacing ◽  
Cotton Yield ◽  
Seed Cotton ◽  
Sowing Time ◽  
Seed Cotton Yield ◽  
East West

The DSSAT module for cotton crop has been evaluated as a tool to predict the crop growth and yield response to microclimatic modifications. In this context, multi-location field experiments were laid out at Bathinda and Faridkot, districts of Punjab during Kharif 2018 with Bt-cotton hybrid RCH 773 BGII and sown at three times, i.e., April 30, May 15 and May 30 with two row orientations (North-South : N-S and East-West : E-W) and three plant spacing’s (67.5 cm × 45.0 cm, 67.5 cm × 60.0 cm and 67.5 cm × 75.0 cm) in factorial split plot design and replicated by three times. The model output in terms of simulated phenology showed close proximity over observed value having R2 of 0.51 and 0.61 at Bathinda and 0.43 and 0.87 at Faridkot anthesis and maturity, respectively. Among study locations, observed and simulated LAI ranged from 2.7 to 3.7 and 1.8 to 3.0. Simulated seed cotton yield was found significantly higher with the crop sown on 30th April (3053 and 3274 kg ha-1) than 30th May sowing (2392 and 2511 kg ha-1) at Bathinda and Faridkot, respectively, which was in good agreement with observed yield having higher value of d-stat (0.84 for Bathinda and 0.89 for Faridkot) and R2 (0.75 for Bathinda and 0.83 for Faridkot). Moreover, higher seed cotton yield was simulated under East-West row direction along with wider plant spacing (67.5 × 75 cm) at both locations. Overall, CROPGRO-cotton model can be used as research tool for the prediction of cotton phenology and yield and to explore site-specific adoption strategies such as appropriate sowing time, row orientation and plant spacing to sustain cotton productivity under changing climatic conditions.

scholarly journals Helicoverpa zea and Bt Cotton in the United States

2012 ◽  
Vol 3 (3) ◽  
pp. 213-227 ◽  
Author(s):  
Randall G. Luttrell ◽  
Ryan E. Jackson
Keyword(s):  
United States ◽  
Helicoverpa Zea ◽  
The United States ◽  
Bt Cotton

Development of Spodoptera exigua and Helicoverpa zea (Lepidoptera: Noctuidae) on Transgenic Cotton Containing CrylAc Insecticidal Protein

2000 ◽  
Vol 35 (4) ◽  
pp. 360-372 ◽  
Author(s):  
Muhammad Ashfaq ◽  
S. Y. Young ◽  
R. W. McNew
Keyword(s):  
Helicoverpa Zea ◽  
Spodoptera Exigua ◽  
Larval Mortality ◽  
Transgenic Cotton ◽  
Larval Period ◽  
Pupal Weight ◽  
Feeding Time ◽  
Bt Cotton ◽  
Cotton Pests ◽  
Lepidoptera Noctuidae

The effects of transgenic Bacillus thuringiensis (Bt)-cotton on three instars of Spodoptera exigua (Hübner) and Helicoverpa zea (Boddie) were studied. First, third and fifth instars were fed field-collected Bt-cotton leaves for 1, 2, 3, 4 and 7 d or until pupation, and then transferred to artificial diet. Larval mortality at pupation, length of larval and pupal periods, pupal weights and survival time from hatch to adult were recorded for regular and Bt-cotton. Larval mortality at pupation in S. exigua fed Bt-cotton was low for all instars exposed and feeding periods on Bt-cotton. The mortality in H. zea was high for first and third instars and significantly increased with the increase in feeding period on Bt-cotton (P < 0.05). The length of larval period increased in both species when first and third instars but not fifth instars were fed Bt-cotton. In H. zea, the larval period increased when larvae were on Bt-cotton leaves for only 2 d. Pupal weight was reduced with an increase in feeding time on Bt-cotton in all three instars in both species. An increase in length of feeding time on Bt-cotton reduced survival to adults in both species on Bt-cotton in first and third instars but not in fifth instars. Survival to adults was much lower in H. zea than S. exigua for all instars exposed and feeding periods on Bt-cotton. These results demonstrate the large differences in effectiveness of Bt-cotton against lepidopteran cotton pests, as well as the adverse effects on larvae developing on Bt-cotton.

Synergistic Interactions Between Cry1Ac and Natural Cotton Defenses Limit Survival of Cry1Ac-resistant Helicoverpa Zea (Lepidoptera: Noctuidae) on Bt Cotton

2009 ◽  
Vol 35 (7) ◽  
pp. 785-795 ◽  
Author(s):  
Konasale J. Anilkumar ◽  
Sakuntala Sivasupramaniam ◽  
Graham Head ◽  
Robert Orth ◽  
Edzard Van Santen ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Bt Cotton ◽  
Synergistic Interactions ◽  
Lepidoptera Noctuidae
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