Q. The leaves of my tomatoes are beginning to yellow and they also have spots on them. My eggplant leaves are riddled with holes, and my beans look like they are scorched. I am ready to give up. Please help us!
A. It can be difficult to maintain a healthy garden during drought periods. Its a little strange but we actually receive more samples of plants at the extension office with fungal issues during dry periods compared with wetter periods during the summer. This phenomenon occurs because people are just watering more and with water often come fungal issues in the garden. Other insect pests of the garden love the hot dry weather.
It sounds as if your tomato plants are becoming infected with early blight. Early blight is a common fungal disease of tomatoes, with yellowing spotted leaves that appear first at the bottom of the plant. If you do nothing, the disease will move from the bottom of the plant up – until the entire plant looks as if it had been hit with a flame thrower. No one wants this effect on their tomatoes. There are several options that will help to control early blight and other common fungal leaf diseases of tomatoes.
Make sure to water in the morning and try to water at the ground level rather than sprinkling the foliage of the plants. Use a mulch of untreated grass clippings, compost, pine needles or clean straw under and around the plants. Mulching will help prevent fugal pathogens from splashing up onto the plant from the soil. Pick off any leaves close to ground level that look like they could be infected. Use a fungicide registered for use on tomatoes. Serenade is an organic fungicide that can be effective. Ortho vegetable disease control is also an option. Apply a fungicide at the first sign of disease on your tomatoes, and follow label instructions.
It sounds as if flea beetles are the issue on your eggplant. They are difficult to control. I have found that regular dustings with Diatomaceous Earth can really help reduce the leaf damage. This organic product is made from crushed diatoms – a prehistoric sea creature that is mined in Western areas of the U.S. This material basically dries out the insect. Sometimes it can be difficult to find this product, although most garden centers and even some health food stores (such as Three Rivers Co-Op) carry this product.
Mites can be a real issue on beans during hot dry periods. The leaves appear scorched, with a bronzed appearance. Looking closely at the leaf, one can sometimes observe fine webbing. Regular dustings with Diatomaceous Earth can help control mites. Products containing permethrin (Eight dust) can also be effective. Wash off the mites with a high pressure water spray periodically.
Hot, dry summers can lead to difficult problems in the vegetable garden. Dont give up – just manage the garden drama if and when it appears.