The agar plate and washing test methods were evaluated for their efficiency in detecting seed-borne fungi of maize. The agar plate method was the most indispensable for detec¬tion of most fungi associated with maize kernels. Washing method was suitable for surface-borne conidia on maize kernels. The most dominant fungi infected maize kernel samples and the percentages of samples infected with were Fusarium moniliforme (82.5%), Nigrospora oryzae (58.8%) Penicillium spp. (42.5%), Fusarium graminearum (36.3%), Aspergillus niger (28.8%), Drechslera maydis (27.5%), Aspergillus flavus (21.3%), Diplodia maydis (17.5%) and Alternaria alternata (15.0%).
The dry inspection of diseased kernels revealed diffe¬rent symptoms, i.e. pink to reddish-brown discoloration caused by F. moniliforme, a grey mycelium with black dots on the kernels, caused by Nigrospora oryzae and greyish brown shrunken kernels with black pycnidia caused by Diplodia maydis and there are some other kernel rots.
Seed-borne fungi may cause various biochemical changes in infected and stored kernels. F. moniliforme and N. oryzae infection increased protein and fat content in the kernels. Marked decrease in total sugars was observed in response to the Fusarium and Nigrospora infection.
The best seed-dressing fungicides in controlling Fusarium and Nigrospora rots were Captan and Tecto at the rate of 3 g/kg, especially when applied before storage. |
