|My basil plants are being attacked by what I think are leaf miners. There are black spots with halos appearing on the leaves. Friends in other parts of the county aren't having this problem. How can I stop it?|
|See if you can locate the miners (little maggots) in the center of the spots. If they are the culprits and the problem is extensive, then you may as well harvest the unaffected leaves and start a new batch, since there's no way to stop them once they're inside the leaves. Cover the new crop with lightweight row cover supported by wire hooops (available from Gardener's Supply Co., www.gardeners.com; ph# 800/863-1700). The cover forms a barrier to the adult flies.
If you don't see miners, the problem is probably a fungal disease, and basil is succeptible to many. Thin the plants to increase air circulation. This helps leaves stay drier which will cut down on fungal growth. If the problem persists, contact your extension service (305/370-3730) for a fungicide spray recommendation. Basil has tender leaves that are easily damaged by chemicals, test the fungicide on a few leaves to see how it works before spraying the whole crop. Follow label directions closely, and take care to wear protective clothing if it's suggested. Hope this helps!