Q: What is wrong with my tomato leaves?
A: The long thin lines on your tomato leaf are probably caused by the vegetable leafminer, Liriomyza sativae Blanchard. The information I am giving you is adapted from a University of Florida/IFAS publication called, “Vegetable Leafminer.” This insect is found commonly in the southern United States from Florida to California. It cannot survive cold areas except in greenhouses; therefore the vegetable leafminer is found only in southern states. Eggs are inserted into plant tissue just beneath the leaf surface and hatch in about three days. Females may deposit eggs at a rate of 30 to 40 per day, which potentially means they can deposit up to 400 or more eggs in their lifetime. An application of foliar insecticides may be require more than once. Many organophosphate and carbamate insecticides are no longer effective. Overuse of the pesticides listed above may kill beneficial insects which keep the leaf miner fly under control. As a result, leafminer outbreaks sometimes increase when pesticides used. Some crops vary in susceptibility to leaf mining, but they are commonly found on several varieties of tomato, cucumber, cantaloupe, and beans. You might consider using horticulture oil for control. Be sure the product can be used on vegetables and follow the directions on the label. Removal of some of the leaves may help, but be sure you don’t remove too many. Although tomatoes are not the easiest crop to grow because they require a lot of attention, many of us feel the effort is well worth it once you taste a home grown tomato. Yum!