On the other hand, some insects, 
such as blister beetles, grasshop- 
pers, and cutworms, feed on a wide 
variety of plants. Others, such as 
cabbage worms (caterpillars) and 
harlequin bugs, feed on closely 
related crops like cabbage, col- 
lards, kale, and broccoli. The Mex- 
ican bean beetle feeds only on 
beans, the striped cucumber beetle 
on squash and other members of the 
sguash family, such as pumpkins 
and melons. 
Insects feed on plants by chewing 
holes in the leaves, sucking plant 
juices, or tunneling into the roots, 
stems, or leaves. The presence of 
the chewers is easy to detect; the 
injury caused by the other kinds 
shows up as wilting, curling, or 
stunting of the different parts of the 
plants. 
Some insects are beneficial, be- 
cause they feed on other insects that 
are pests. Some of the beneficial 
insects are ladybeetles, wasps, syr- 
phid flies, and lacewings. 
