Lesser Grain Borer

Category: LW
Minimum Life Cycle: 25 days.
Distribution: Worldwide; cereal and coarse grains; both adults and larvae are voracious feeders.
Biology:
Eggs - Up to 500 per female.
Larvae - Eat into grain and feed on grain dust.
Pupae - Usually form inside grain.
Adults - Also feed and are long lived compared to other stored-product beetle pests.

Lesser Grain Borer (Rhyzopertha dominica). The lesser grain borer is a small, highly destructive insect that is related to certain wood boring insects. The eggs are laid outside the kernels and young larvae bore inside. Both the larvae and adults are voracious feeders and leave fragmented kernels and powdery residues. The larvae may complete their development in the grain residue. Grain infested with the lesser grain borer has a characteristic sweet and slightly pungent odor. This odor contains the male produced aggregation pheromone that has been demonstrated to be an effective lure for use in traps. The insect is a strong flier and recently has been discovered in northern areas of the U.S. and in Canada (Figure 4).

(Slide and top caption courtesy of ICI Americas, Inc.)

illustration of a lesser grain borer

Figure 4. Lesser grain borer.