Lettuce is grown throughout various areas of the United States. It’s extremely popular in part due to its very short maturation period of 45-90 days. For that reason, it can be grown as a rotational crop. However, if you’ve tried to grow lettuce yourself you know that your plants can be devastated by a variety of pests. Here is a brief guide to the villains you are likely to encounter.
This is the most common danger to your lettuce plants. There are multiple varieties of Lepidoptera larvae or caterpillars that feed on lettuce including cutworms, armyworms, corn earworms, cabbage worms, and cabbage loopers.
Cutworms are large-sized caterpillars with a greasy appearance. They are called cutworms because they chew through young plants at or below the soil line. They can also drill into lettuce heads. They are nocturnal feeders and hide during the day.
Armyworms generally damage lettuce plants by consuming the plant as well as burrowing holes into the lettuce head itself. They can cause a lot of damage in a very short period of time so take action as soon as you see any activity in your garden. They are also night feeders so grab the flashlight and start plucking them off your plants.
Corn earworms are not faithful only to corn and are also known as tomato fruitworms or cotton bollworms. These caterpillars feast on the outer leaves of lettuce and just one little worm can create havoc. They have also been known to bore holes into mature lettuce heads.
Cabbage loopers prefer cabbage but will definitely feed on lettuce. In particular, they will focus on the lower surface of outer leaves resulting in a windowpane appearance on the upper leaf surface.
Aphids are the primary insects that will infest your lettuce and damage the plants. They come in a variety of colors and Aphids are primarily sucking insects that feast on plant sap and cause significant damage to the outer leaves. Affected leaves will become discolored, crumpled or misshapen. There are different species of aphids including tomato aphid, green peach aphid, potato aphid, and wooly apple aphids.
Thrips are small but they are mighty. They are extremely active and can destroy your lettuce crop by sucking the juice out and damaging the leaves. It has also been known to transmit tomato spotted wilt virus (TSWV) which will also impact your lettuce plants.
Leafminers do exactly what you think they would. They attack the delicate leaves of your lettuce plants and mine all the nutrients leaving behind plants devastated by tunnel scars. You need to destroy affected plants immediately and cover remaining plants if you hope to save any of them.
Darkling beetles are scavengers and will eat both young lettuce plants as well as any decaying plants. Their larvae are mealworms which may be more recognizable to you.
This is but a small selection of the pests that are hazardous to the lettuce plants in your home garden. While some of these can be controlled with natural means, you may need to investigate the use of pesticides for more effective protection.