The most common grasshopper species in Texas cotton are the lubber grasshopper, differential grasshopper, and migratory grass- hopper (Fig. 49). Lubber grasshoppers move quite slowly and travel by feebly walking and crawling over the soil surface. They most commonly damage presquaring cotton, while the other winged and more agile species invade large-bloom to open-boll stage cotton as pastures dry down.
Depending on the conditions in a particular year, early in the spring, populations may be high in pastures, rangeland, and other noncrop areas. Large populations of winged grasshoppers occasion- ally occur mid-to-late summer.
Usually, grasshoppers feed on cotton foliage without causing much damage. But, they can be very destructive to seedling cotton and destroy stands during large outbreaks, especially at the field edges. Grass- hoppers rarely damage older cotton.
Scouting and Decision Making
Treat when unacceptable stand loss or severe defoliation (more than 30 percent) is evident and grasshoppers are present (Fig. 50). Control damaging infestations early while the grasshoppers are small, wingless, and still in crop border areas (Fig. 51). In many cases, field edge treat- ments can stop the damage.