“In August of 2002, we received a frantic call from Campbell’s Scottish Highlands Golf Course in Salem. They reported caterpillars destroying thousands of sunflowers, marigolds, geraniums, and zinnias used to decorate the grounds,” says UNH Cooperative Extension entomologist Stan Swier.

Swier identified the caterpillar as the larval form of the sunflower moth, a pest not previously seen in New Hampshire. “The sunflower moth causes problems in the southern and western states, particularly where sunflowers are grown as a crop,” he says. “In the Eastern U.S, it hadn’t previously been reported north of New Jersey.”

Swier has also seen the sunflower moth in Durham and Madbury. “This moth must like New Hampshire, because it returned in 2003 and now again in 2004,” he says. “Originally, it blew up from the south and laid its eggs on late summer flowers. But this year we began seeing active larvae in late June. They’ve attacked nearly every plant on the golf course grounds.”

Swier hypothesizes the larvae may have overwintered in Salem and started a new generation this spring, leaving enough time for a second generation to mature before frost. “It could be here to stay, he says, “although it’s still too early to tell whether they really survived the winter or simply wafted up from the South on warm air currents generated by a freak spring storm.”

“The sunflower moth larvae are gregarious feeders. They’re striking in appearance, with dark brown and pale yellow stripes down their backs. You can find them feeding on undeveloped seeds in the flower heads,” says Swier. “Any pesticide labeled for caterpillars on outdoor flowers will control this pest. If caterpillars are small, the bacterial pesticide, Bacillus thuringiensis (B.t.) should work. Follow label directions.”

For more information

• Fact sheet on sunflower moth
• Photos of sunflower moths and larvae
• This fact sheet helps you identify which moth you have on your sunflowers