PhD student, University of Ghent
Customise variety maturity, planting and harvesting of maize when fumonisin content is lowest
Fumonisins are toxigenic compounds produced by some Fusarium fungi. The toxins contaminate the maize grains, the major staple food produced mainly by smallholder farmers in Tanzania. Biotic (insect pests, varieties) and abiotic (climate and soil) factors play key role in fumonisin production. Beginning in the field, contamination can occur before and after harvest. Consumption of fumonisin contaminated food and feed results into various illness including cancer. Pre harvest good agricultural practices are front-line defense strategy against fumonisin contamination in maize. There various cultural practices proposed but for them to be effective they need to be adapted to local conditions of climate and the commonly grown maize varieties. Time of maize maturation and harvesting can have significant influence fumonisin contamination. This research was carried out to evaluate the effects of sowing and harvesting time of an early and late maturity open pollinated maize varieties. Findings suggested that cultivating an early maturity bu planting early in the seasons and harvesting at physiological maturity can reduce fumonisin content in maize by up to 50% as compared to growing the late maturity variety thereby enhancing food safety to majority Tanzania especially the infants who are often times most vulnerable. Infants consuming fumonisin contamination food are at risk of reduced growth rate. Reduction in fumonisin content in maize can reduced risks of neural tube defects in unborn babies which is already in very high levels in Tanzania
Abstract: Fusarium ear rot, caused by Fusarium verticillioides, is one of the most common diseases of maize, causing yield and quality reductions and contamination of grain by fumonisins and other mycotoxins. Drought stress and various insects have been implicated as factors affecting disease severity. Field studies were conducted to evaluate the interactions and relative influences of drought stress, insect infestation, and planting date upon Fusarium ear rot severity and fumonisin B1 contamination. Three hybrids varying in partial resistance to Fusarium ear rot were sown on three planting dates and subjected to four irrigation regimes to induce differing levels of drought stress. A foliar-spray insecticide treatment was imposed to induce differing levels of insect injury. Populations of thrips (Frankliniella spp.), damage by corn earworm (Helicoverpa zeae), Fusarium ear rot symptoms, and fumonisin B1 levels were assessed. There were significant effects of hybrid, planting date, insecticide treatment, and drought stress on Fusarium ear rot symptoms and fumonisin B1 contamination, and these factors also had significant interacting effects. The most influential factors were hybrid and insecticide treatment, but their effects were influenced by planting date and drought stress. The more resistant hybrids and the insecticide-treated plots consistently had lower Fusarium ear rot severity and fumonisin B1 contamination. Later planting dates typically had higher thrips populations, more Fusarium ear rot, and higher levels of fumonisin B1. Insect activity was significantly correlated with disease severity and fumonisin contamination, and the correlations were strongest for thrips. The results of this study confirm the influence of thrips on Fusarium ear rot severity in California, USA, and also establish a strong association between thrips and fumonisin B1 levels.
Pub.: 04 Feb '10, Pinned: 31 Aug '17
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