23August 10, 2017
The weather appears to be in favor of fungus diseases growing on many different plants. I have always been an advocate of walking around your yard at least once a week and looking for signs of trouble on your plants. So often, customers will tell me that their tomato plants looked good 2 days ago and now they have found some type of fungus disease on their plants.
It is so much easier to stop a fungus disease from spreading if you catch it early. If your plants are having an issue with the leaves turning color or if the leaves are developing spots, take a few of the leaves off the plant, put the leaves in a sealed clear plastic bag and bring them into the store. This will allow us to correctly diagnose the problem and get you the right control method.
Speaking of tomato plants, are the leaves disappearing on your tomato plants? The culprit is probably the tomato hornworm. The hornworm is bright green in color and it has white, V shaped marking on its sides. A giant moth lays the eggs on the leaves and eventually a small green caterpillar hatches from the eggs. The problem is that the tomato hornworm has a huge appetite and will quickly grow into a caterpillar that can be the diameter of your thumb and at its biggest about 4 to 5 inches long. They do tend to blend in with the leaves on your tomato plants.
If you see leaves disappearing on your plant, it is time to take a closer look at your plants to find the caterpillar. As gross as it may sound, you can hand-pick the caterpillars off the plant. They don’t bite and the horn that is on the end of the caterpillar won’t sting you. There are many insecticides that will kill this caterpillar. Which one you use is dependant on the size of the caterpillar.
If you find one of the caterpillars on your plant that has what would appear to be white grains of rice on its back, leave that caterpillar alone. The rice looking things are eggs of a parasitic wasp. The eggs hatch out and burrow into the caterpillar and will eventually kill the caterpillar. Once the caterpillar is dead, the larvae of the wasp emerge, pupate and eventually emerge as new wasps that will lay more eggs on new hornworms.
We have had a lot of people come into the store complaining about this caterpillar. This means that the hornworm moth has laid its eggs and they may be on your tomato plants. During that walk around the yard, take a look at the tomato plants and see if you discover any tomato hornworms on your plants.
Many people have asked me about Japanese beetles. In most areas, there doesn’t appear to be any beetles feeding on plants. My guess is that it goes back to last year’s drought. The female beetles lays eggs in the lawn during July and August. The eggs hatch out in September and the grubs feed on the roots of the grass.
If you remember last year, most lawns died back from the drought. If there were no healthy roots for the grubs to feed on, the grubs probably died from lack of food. This doesn’t mean that you won’t ever again have grubs in your lawn. All it takes is a few female beetles to lay eggs in your lawn this summer. This will start the cycle again, with the grubs feeding on your lawn again this fall and again in the spring.
Well, that’s all for this week. I’ll talk to you again next week.