It’s January and your maize is probably planted, so let’s talk about a few diseases you might run into.
The most common are leaf diseases. They happen when the plant, fungus, bacteria or virus causing the disease, all experience the right conditions. Leaf diseases therefore often strike when the weather changes.
The stage of growth the plant is at also determines what diseases will attack. Therefore, make sure you know the different stages of your crop, so you can correctly identify the disease and decide on the correct treatment. Incorrect identification is often the reason fungicides are used for diseases caused by viruses, bacteria or even sunburn or wind damage.
This wastes money and costs you yields because the real problem is not being solved. Some of South Africa’s most common leaf diseases are northern corn leaf blight, common rust, grey leaf spot, bacterial leaf streak and maize-streak disease. Northern corn leaf blight is the most common and caused by a fungus.
Common rust affects young maize plants and strikes in dew-fog conditions, especially at night when spores on the leaf surface germinate and penetrate the leaf. Early signs of rust infection are seen about five days after infection as small flecks on the leaves. Proper rust pustules then develop and release spores after 10 to 14 days. Another important maize leaf disease is grey leaf spot, caused by a fungus.
This disease likes moderate to high temperatures and high humidity of more Regular inspection of the leaves of your maize crop is incredibly important. To end with a healthy maize cob such as this, you need to be on the look-out for leaf diseases. than 95%. The symptoms can clearly be seen around flowering, but is also visible earlier if the disease is really bad. This leaf disease is common in KwaZulu-Natal and the eastern Highveld with its fog, high humidity and high temperatures.
Grey leaf spot is often confused with sunburn or drought stress. None of the fungal leaf diseases mentioned can be spread by seeds. Bacterial leaf streak is a problem in the western maize-growing areas. Symptoms are sometimes confused with that of grey leaf spot.
A bacterial disease cannot be controlled with fungicides and spraying for it is expensive and pointless. Maize-streak disease is caused by the maize-streak virus. The virus is spread by a leafhopper. Although insecticides prevent the leafhoppers from feeding on the young plants and so spreading the virus, they aren’t always a solution for the disease.