Sugarcane Rootstalk Weevil

If you are examining injury to small plants, you may notice some leaves exhibiting a pattern of round, scattered, pinpoint-sized holes. This could be feeding by sugarcane rootstock weevils. Look for tiny black weevils near affected plants. The larvae develop during the summer. By slicing into the base of mature plants later in the summer, you may see the very small, whitish grubs, usually located within a blackened or reddish cavity in the stalk close to where brace roots are attached.

Some damage to roots and weakening of the stalk are associated with larval feeding, but it usually is not serious unless plants are under drought stress. Without careful examination, injury can be confused with some types of herbicide injury.