How to Manage Pests
Pests in Gardens and Landscapes
Leaf spot diseases
Many fungi cause leaf spots on different hosts. Spots may vary from small discrete dots and raised areas
to irregular yellow or brownish patches that cover much of the leaf surface. Leaves may fall off the tree
if the problem is severe, but these pathogens rarely cause long-term damage to trees. Similar spots can
be caused by bacterial pathogens, insects and mites, or abiotic factors on some plants.
In most cases, infections can be tolerated. Remove fallen leaves and debris promptly. Many of the pathogens
are favored by moisture, so avoid overhead sprinklers and irrigate early in the day so that the foliage
dries more quickly. Generally, fungicide treatment is not warranted.
Phyllosticta leaf spot on maple
Leaf spot on Freesia