The tiny “thrip” is chomping and sucking its way through flowers and vegetables in Haines, breaking the hearts of gardeners.
“They kill things. They’re awful. People have done things to stop them but have only been minorly successful,” said Stephanie Scott, a commercial flower grower and advocate of home-based agriculture.
“People have lost entire pea crops. They’re a major hit,” Scott said.
The black, flying pests, about a millimeter long, have claimed fuschias on Fourth Avenue and begonias on Beach Road. They’ve killed columbines and laid waste to lilacs and lettuce.
Thrips are endemic, part of the area’s environment, but their numbers have become epidemic in the past two or three weeks, gardeners say. “You always see them. One or two isn’t a problem. It’s this massive invasion,” Scott said.
Dick and Carol Flegel, who’ve grown flowers and vegetables at their place on Portage Cove for years, say they haven’t seen anything like it. Thrips have killed their flowering plants, kept others from flowering, and are turning a lettuce patch brown after hitting their peas and potatoes.
“They’re all over the place,” said Dick Flegel, who had one under a microscope while researching them over the Internet this week. He worked up a solution of ammonia, dish soap and olive oil that killed the bugs, but said new swarms arrive each day.
According to Flegel’s research, thrips have “rasping and piercing-sucking mouth parts” that create wounds in plants. Through the wound they insert a “stylet” they use to draw out the plant’s vital juices.
Thrips appear attracted to the color white and Flegel pointed to a propane tank and a cooler lid covered with them. They’re also on wild plants at his property, including fireweed, he said.
By midweek, Flegel was using white plastic as “traps” and spraying down clusters of thrips that landed there. That seemed to be successful in knocking back numbers, he said.
Toni Smith, co-owner of Whiterock Nursery, says thrips have also become a problem for her. “They’re everywhere, but the stuff outside the greenhouse is a lot worse than the stuff inside.”
Smith said she’s never seen an infestation like it in the nursery’s 13 years. Some pots of plants kept outside there have turned brown and she’s gone to regular spraying with a solution similar to Flegel’s. “We spray them off every day and every day they’re back. There doesn’t seem to be a cure. Until they come up with something else, I’m cruising the Internet.”
Smith said she’s been bitten by the tiny pests. “If we can feel it, imagine what they’re doing to those soft, leafy plants.”
University of Alaska cooperative extension agent Darren Snyder examined specimens sent by Scott and confirmed they were thrips. “They’re bad news” and also hitting plants in Anchorage, Palmer and Fairbanks this summer, he said.
“They do seem to respond to a hot, dry weather cycle. That great spring for us was a great spring for the thrips as well,” he said.
Gardens with a lot of surrounding weedy areas could be hit especially hard, as those areas would tend to serve as refuge for pests, he said.
Gardeners should remove affected plants as well as mulch and other material around them that could harbor thrips’ eggs or larvae. Pruning should be done carefully as indiscriminate hedging could cause new growth and attract more pests.
Snyder did not encourage spraying, saying it could also kill bugs like lacewings, which prey on thrips. Commercial sprays should be used only as recommended and not broadly, he said.
Scott said Lois Dworshack, an extension worker who specializes in pests, are scheduled to be at the Southeast state fair next week and they plan to inspect local gardens hit by the bug.
Concerns about energy costs and food security have spurred gardening here in recent years, Scott said. “It’s a story, given people are seriously trying to produce food. If we find out what’s causing this and how to respond, at least next year we’ll be better prepared.”
Growth of thrip populations hasn’t been reported in Juneau or southern communities, UAF’s Snyder said.