Diversity and comparative phenology of Lepidoptera on Bt and non-Bt maize in South Africa

Hamburg, H. van; Berg, J. van den; Wyk, A. Van

doi:10.1080/09670870701523074

Cited by 18 publications

(7 citation statements)

References 18 publications

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“…Although H. armigera is a non‐target species for Bt maize in South Africa this species is adversely affected by Bt maize. Van Wyk et al. (2008) observed that at field level, the incidence of damage caused by H. armigera was always significantly lower on Bt maize than on non‐Bt maize.…”

Section: Discussionmentioning

confidence: 89%

Transgenic Bt maize: farmers’ perceptions, refuge compliance and reports of stem borer resistance in South Africa

Kruger¹,

Rensburg²,

Berg³

2011

J Applied Entomology

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Based on surface area, South Africa is currently ranked the eighth in planting genetically modified (GM) crops in the world. Bt maize (MON810) has been grown to control lepidopterous stem borers in South Africa since its first release during 1998. The first report of resistance of the African maize stem borer, Busseola fusca (Lepidoptera: Noctuidae) and poor compliance to refuge requirements that could have contributed to resistance development prompted this study which was done in the main maize production area of South Africa. Objectives were to evaluate farmer’s perceptions of the regulatory aspects guiding the planting of Bt maize and refugia and how it was applied between 1998 and 2010. This study involved 105 commercial farmers covering 87 778 ha of maize throughout the main maize production region on the Highveld of South Africa. A questionnaire survey was conducted and addressed signing of technical agreements upon purchasing GM seed, refuge compliance, pest management practices, perceived benefits and risks relating to Bt maize. Compliance with refugia requirements was low especially during the initial 5–7 years after release. An alarmingly high number of farmers applied insecticides as preventative sprays on Bt maize and refugia irrespective of stem borer infestation levels. A large proportion of farmers reported significant borer infestation levels on Bt maize and between 5% and 93% farmers in all districts applied insecticides to Bt maize to limit borer damage, indicating that the occurrence of resistance is more wide‐spread in the country than previously thought. This study shows irresponsible management of GM crop technology by farmers, chemical and seed companies. Concerns and perceptions of farmers in South Africa seem to differ from those in Europe. South African farmers perceived little, if any, negative impact on non‐target organisms and remain positive about the technology in spite of resistance development. Other studies indicated that European farmers were concerned about these aspects. A shared concern, however, was consumer acceptance of GM maize and marketability on the export market.

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Section: Discussionmentioning

confidence: 89%

Transgenic Bt maize: farmers’ perceptions, refuge compliance and reports of stem borer resistance in South Africa

Kruger¹,

Rensburg²,

Berg³

2011

J Applied Entomology

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“…Moths possibly prefer irrigated maize, which could have contributed to increased selection pressure toward the evolution of resistance to the Bt toxin (Van Rensburg 2007). Van Wyk et al (2008) also indicated that the strong linkage of stem borers to the maize ecosystem in irrigated areas and especially the planting of Bt maize in these systems results in strong selection pressure for evolution of resistance.…”

Section: Discussionmentioning

confidence: 96%

Resistance to Bt Maize in <I>Busseola fusca</I> (Lepidoptera: Noctuidae) From Vaalharts, South Africa

Kruger

Rensburg²,

Berg

2011

env. entom.

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“…Due to their sensitivity for low humidity (Van Rensburg et al, 1988), it is highly likely that B. fusca moths give preference to irrigated fields which could result in an additional component adding selection pressure on the borer population. Van Wyk et al (2008) indicated that the strong association of stem borers to the maize ecosystem in many areas in South Africa, and planting of Bt-maize in these systems resulted in strong selection pressure for evolution of resistance. The reliance of B. fusca on maize is strong since no wild hosts are present, and in areas where adoption rates are high, no unstructured refugia are present in the form of large non-Bt maize fields.…”

Section: Other Complicating and Contributing Factorsmentioning

confidence: 98%

“…These infestation levels are typical of those observed in non-GM maize fields prior to introduction of Bt maize in South Africa and were often higher than the recommended economic threshold value (10%) for chemical control(Van Rensburg et al, 1988). The general tendency observed in these field surveys was a sharp increase in the number of damaged plants and in some instances the presence of larvae on plants from the flowering period onwards(Van Wyk et al, 2008).Van was the first to officially report field resistance of B. fusca to Bt maize, with field collected larvae in the 2005/06 crop growing season. Laboratory studies showed that significant numbers of the F1-generation diapause larvae collected on Bt maize in the Christiana area in the Northern Cape province survived on Bt maize.…”

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confidence: 92%

Pest resistance to Cry1Ab Bt maize: Field resistance, contributing factors and lessons from South Africa

2013

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Diversity and comparative phenology of Lepidoptera on Bt and non-Bt maize in South Africa

Cited by 18 publications

References 18 publications

Transgenic Bt maize: farmers’ perceptions, refuge compliance and reports of stem borer resistance in South Africa

Transgenic Bt maize: farmers’ perceptions, refuge compliance and reports of stem borer resistance in South Africa

Resistance to Bt Maize in <I>Busseola fusca</I> (Lepidoptera: Noctuidae) From Vaalharts, South Africa

Pest resistance to Cry1Ab Bt maize: Field resistance, contributing factors and lessons from South Africa

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