Horticulture Principles and Practices

FIGURE 7–10 A Colorado potato beetle. (Source: Photo provided
courtesy of Oklahoma Cooperative Extension Service, Oklahoma State University)
FIGURE 7–11 Cucumber beetle. (Source: USDA)
7.4.5 STORAGE PESTS
Insects inflict considerable damage on stored food. A variety of weevils, moths, beetles,
and flies are known postharvest pests that damage stored products. Examples include the
sawtoothed grain beetle, dried fruit beetle, raisin moth, and Drosophila.
7.4.6 SOME IMPORTANT GENERAL INSECTS AND MITES
Horticultural plants are plagued by numerous insects and mites. The following are some
of the important types:
1. Colorado potato beetle (Leptinotarsa decimilneata). Commonly called the potato
beetle, this insect also feeds on tomato, eggplant, and others. Both the larvae and
adults are pests. They occur throughout the country, wherever the host plants are
found (Figure 7–10).
2. Cucumber beetles (Diabrotica undecimpunctata [12-spotted beetle]; Acalymma
trivittata [striped beetle]). Cucumber beetles feed on leaves, stems, and fruits.
The larvae attack plant roots. Two species are very important—the 12-spotted
and striped beetles (Figure 7–11).
3. Cutworms. Cutworms are pests of vegetable garden crops. They are nocturnal
and thus hide under rocks and debris during the day. They especially damage
recently transplanted seedlings by cutting them off at or below soil level.
4. Cabbage looper (Trichoplusia ni). The cabbage looper feeds on cruciferous
garden plants (cabbage family) and many other garden species. It is one of the
most common garden caterpillars and is identified by a characteristic loop made
by its body as it moves forward. The larvae make holes in the plant parts as they
feed, but sometimes the plant may be completely devoured.
5. Corn earworm (Heliothus zea). Sometimes called tomato fruitworm, corn
earworm prefers to feed on corn and tomato fruits. The larvae damage corn by
eating the succulent kernels. In the feeding process, the larvae leave behind large
quantities of feces. In tomato, the earworms bore through the succulent fruits
(Figure 7–12).
6. Squash vine borer (Melittia calabaza). The squash vine borer attacks the vines
of pumpkin, squash, cucumber, and melon, among others. They tunnel through
the vines of these plants, resulting in wilting and eventual death.
228 Chapter 7 Biological Enemies of Horticultural Plants