Summer pests and diseases

Summer is a busy time of year in our gardens. The weather is very unpredictable during these months and can be extremely hot and dry or excessively wet, making way for unwanted pests and diseases.

Feed plants regularly in areas that receive a lot of rain as the nutrients can leach into the soil. In very hot and dry areas it is important not to feed with granular fertiliser rich in nitrogen as it may burn the plants; rather use an organic or organic-based fertiliser.


Be cautious of fungal and bacterial diseases such as powdery mildew and black spot on shrubs, especially roses and other flowering plants, brown rot on fruit trees and dollar spot on lawns. As the humidity and high temperatures are an ideal breeding ground for fungi, it is important to regularly treat plants that are susceptible to fungal diseases.

A general, broad-spectrum contact fungicide should be used on a regular basis to prevent most fungal diseases. If plants are already infected, a general systemic fungicide can remedy the disease. In order to restrict the germination of fungi, plants should be watered early in the morning.


A multitude of insects flourish in our gardens during summer. Check your garden for fruit and chafer beetles, fruit flies and codling moths, ants and any of the more than 7000 species of sucking insects, as well as lily borers in amaryllis, aggies and clivias. Ask for the correct product at your local garden centre and apply as per the label instructions.

Remember to not cut your lawn too short, but cut regularly. Water early in the morning to avoid fungal diseases, and fertilise regularly to encourage healthy green growth. Check your lawn for army worm and lawn caterpillar and apply the applicable treatment for effective control.
Above all, love gardening!

The Gardener