Pest: Tortoise beetle (species in the Cassidinae subfamily)
Pest/disease identification and lifecycle, most common damage symptoms and crops affected:
These beetles are typically only a very minor pest. They do not typically cause serious damage and do not warrant spraying. The numbers are usually small and the beetles can be picked off by hand, and their eggs squished.
Tortoise beetle species lay their eggs on the undersides of leaves on host plants. Larvae that hatch out protect themselves with a “fecal shield,” which they can raise up for protection against potential predators when found feeding on the underside of host plant leaves.
They are oval to a square shape, clear to metallic looking with a dark square marking on the center of their back. Once you see one you will remember it (see photo). There are a few species of tortoise beetles. The one most commonly seen by produce growers in Maine feeds on eggplants, tomatillos, peppers and potatoes. They overwinter as adults and come out in the mid-spring. Their minor damage is from eating holes in leaves.
There is a species known as the golden tortoise beetle which can be a bit more of a pest, though they are beautiful to look at. They feed on sweet potatoes, and other species in the morning glory family, and can be a larger problem — though only if you are concerned about the aesthetic damage on foliage. When in small numbers, you can ignore them or pick them off by hand, as they are unlikely to cause enough damage to affect yields.
