Articles
THE CONTROL OF POWDERY MILDEW OF CAPSICUMS WITH CERTAIN SYSTEMIC AND NON-SYSTEMIC FUNGICIDES
During 1970, a total of 285,560 kilogrammes of fruit was exported by air to Europe, Anon. (1970).
The crop suffers from a number of diseases, the most serious being a powdery mildew caused by the fungus Leveillula taurica (Lev.) Arn.
In the past, fungicides commonly available for the control of powdery mildews have not proved successful in controlling this disease effectively.
It was proposed, therefore, to screen a number of fungicides, for their efficiency in controlling the disease.
Commonly observed symptoms of the disease, as described by Natour et al (1971), are pale green to yellow round spots on the upper surface of the leaf.
Spots are indefinite and vary a great deal in size, but may coalesce to cover a large proportion of the total area of the leaf.
A powdery white-grey to purple growth of the causal organism, similar to that of downy mildew is observed on the lower side of the leaf.
Later, infected areas of leaves dry up and turn black.
When infection is severe, the disease causes defoliation; up to 100% defoliation has been observed on capsicums.
No disease symptoms were observed on stems and fruits.
Infection usually progresses from the older to the younger leaves and both seedlings and mature plants are attacked.