EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS<br />
P133 - Busseola fusca and Fusarium verticillioides<br />
interaction on Fusarium ear rot and fumonisin<br />
production in Bt and non-Bt maize hybrids in South<br />
Africa<br />
E. Ncube 1 , B. C. Flett 1,2 , J. van den Berg 2 , J. B. J. van Rensburg 1 , A. Viljoen 3<br />
1 ARC-Grain Crops Institute, Private Bag X1251, Potchefstroom, 2520, South Africa, 2 Unit <strong>of</strong><br />
Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom,<br />
2520, South Africa, 3 Department <strong>of</strong> Plant Pathology, University <strong>of</strong> Stellenbosch, Private Bag X1,<br />
Matieland, 7602, South Africa<br />
E-mail: FlettB@arc.agric.za<br />
Fusarium verticillioides causes Fusarium ear rot (FER) and produces fumonisin<br />
mycotoxins in maize. The feeding habits <strong>of</strong> stem borers have been associated<br />
with an increase in the incidence and severity <strong>of</strong> Fusarium ear rot in maize.<br />
Insecticidal proteins synthesised in transgenic (Bt) maize are toxic to stem borer<br />
larvae and have been found to reduce FER as well as fumonisin production in the<br />
USA. In this study, the effect <strong>of</strong> the B. fusca x F. verticillioides interaction on FER<br />
and fumonisin production was investigated in a transgenic hybrid (PAN6236B)<br />
which expressed the MON810 Bt event, and in its non-transgenic isohybrid<br />
(PAN6126). Treatments on PAN6236B and PAN6126 included a F. verticillioides<br />
(MRC 826) spore suspension injected into the silk channel at the blister stage, B.<br />
fusca infestation into the plant whorl at the 12-13 th leaf stage, and both F.<br />
verticillioides inoculation and B. fusca infestation. Control treatments which were<br />
neither inoculated with F. verticillioides nor infested with B. fusca were included.<br />
All treatments had six replicates, and the experiment was repeated over three<br />
seasons. FER was visually rated and the B. fusca damage measured on the ears<br />
after harvest. Fumonisins were quantified using HPLC. Results indicated that the<br />
B. fusca x F. verticillioides interaction significantly increased FER in the nontransgenic<br />
hybrid only, but did not significantly increase fumonisin production in<br />
both hybrids, suggesting that B. fusca is possibly a vector <strong>of</strong> F. verticillioides.<br />
There was a significant correlation (r = 0.25; P < 0.05, n = 141) between FER and<br />
fumonisin production in the non-transgenic hybrid, while in the transgenic hybrid<br />
the correlation was non-significant, indicating that transgenic hybrids can have<br />
high fumonisin levels without visible FER symptoms. In conclusion, this study<br />
showed that B. fusca damage to maize ears increases FER, but it has no effect<br />
on fumonisin production.<br />
Keywords: Fusarium, fumonisins, stalkborer, Bt maize<br />
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