Veteran gardeners often claim a drop of mineral oil placed on the end of a developing ear of
corn will discourage earworms. But Bt (Bacillus thuringiensis) sprinkled on the emerging corn
silk is more effective. The best way to avoid earworms altogether is by planting a short-season
variety like ‘Early and Often’ or ‘Early Choice’ as early as possible. Earworms usually cause
the most damage in late summer. So, if you can harvest early, the corn will be on the dinner
table long before the earworms have a chance to damage the crop.