Aflatoxin accumulation in preharvest maize kernels: interaction of three fungal species, European corn borer and two hybrids
1982
Lillehoj, E.B. (Southern Regional Research Center USDA, New Orleans (USA)) | Kwolek, W.F. | Guthrie, W.D. | Barry, D. | McMillan, W.W. | Widstrom, N.W.
The interaction was studied among: (1) developing maize kernels (Zea mays L.); (2) European Corn Borer (ECB) (Ostrinia nubilalis Hubner);(3) and three fungal species, Aspergillus flavus Lk. ex Fr., Penicillium oxalcium Currie and Thom, and Fusarium moniliforme Sheld. Two hybrids with varying degrees of resistance to ECB stalk damage were grown in Iowa, Georgia, and Missouri in 1980. One-half of the plots were hand-infested with ECB egg masses. Fungal spores of individual isolates or combinations of the three species were introduced into the silk channels of developing ears in designated plots. ECB larvae were subsequently collected from developing ears. A higher incidence of A. flavus group isolates was observed in ECB larvae collected from ears that had been inoculated with A. flavus than from insects collected from control ears. Although the resistant hybrid exhibited reduced ECB stalk damage compared with the susceptible variety, no consistent pattern of hybrid effect on the association between A. flavus and ECB was observed at all three locations. Differences in aflatoxin B(,1) levels in mature kernels from the 3 locations ranged from 8 ppb in Iowa samples to 419 ppb in Missouri kernels. Conditions during crop development at the Missouri location were particularly conducive to elevated presence of A. flavus propagules in ECB larvae, increased ECB-mediated stalk damage, and greater toxin concentration in mature kernels.
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