Boll weevils Anthonomus grandis are not only the most destructive cotton pest in North America causing $300 million in crop losses each year, but they are also stored product pests that contaminate a variety of food grains. These small beetles measure 6 mm across and, like most weevils, are distinguished by their long snout_like rostrum. Boll weevils originated in Mexico and Central America and migrated north to the US in the 1890s.