Because the caterpillars of many crambid species specialize in eating the stems of grass plants, that means they can cause problems for the many crop species that are grasses: corn, oats, rice, sugarcane, and more. The European corn borer is an example.
The crambids include several other agricultural or landscaping pests, including grass sod webworms, bean pod borers, and the grape leaffolder.
Meanwhile, other crambid species help people by serving as biological controls of invasive plant species. The water hyacinth moth, native to the Amazon basin, was imported to North America, where it helps control the overgrowth of water hyacinth, also imported from the Amazon. Another crambid, called the water veneer, helps control invasive Eurasian water milfoil.
One crambid, the bamboo borer, is eaten as a high-protein delicacy by people in parts of Thailand, Laos, Myanmar, and China. They are sometimes called rot duan (“express train”) for their streamlined trainlike shape. In Thailand, people shrug off the Western bias against “eating bugs” and are farming them profitably and sustainably. The “bamboo worms” are deep-fried and flavored up with spices, herbs, and sauces.