Published on 08/19/04

Pink hibiscus mealybugs enter state

By Sharon Omahen
University of Georgia
and Jackie Sosby
Ga. Dept. of Agriculture

As bugs go, pink hibiscus mealybugs are cute. They're light pink and look as if they've walked through powdered sugar. But if you're a greenhouse grower or homeowner with new hibiscus plants, they're not so cute.

Georgia Commissioner of Agriculture Tommy Irvin issued an alert this week asking University of Georgia Extension Service county agents to be on the lookout for the exotic pest.

Florida fighting pest for two years

"They came into south Florida about two years ago from the Caribbean," Irvin said. "These insects are a problem to stop and contain because there's no effective chemical treatment."

First Foliage Nursery in Homestead, Fla., shipped as many as 44,000 infested hibiscus plants into Georgia from early March to early June, GDA officials said.

The plants were shipped to Lowe's and Home Depot stores in Georgia. All but four of the 41 stores are in metro Atlanta and north Georgia.

Has potential to hurt ag crops

Cotton and okra are hibiscus family members, too. Peanuts could also be affected by the insect. But UGA entomologist Will Hudson says it's unlikely the tiny intruder will affect the state's farm crops.

"Hibiscus doesn't survive outdoors here, even in the Tifton area," he said. "The annual ones die back to the ground in the winter, and the tropical ones will, too, if you leave them outdoors. Most of this insect's host plants aren't cold-hardy, because it's primarily a tropical- and subtropical-area pest. It remains to be seen if it can thrive in south Georgia."

Hudson and his UGA College of Agricultural and Environmental Sciences colleagues work on ways to control insects on both crops and ornamental plants.

Outdoor plants should be safe, he said. But indoor plants aren't.

"It's really giving us fits in interior-scapes," Hudson said. Interior-scapes include mall and hotel areas decorated with plants.

If you're managing an interior-scape, Hudson says, inspect plants for mealybugs and pull out as many as necessary to make sure you're rid of all infected plants.

Interior-scapes should be inspected

"To fight a bug like this in an interior-scape would be really expensive and ultimately a losing proposition," he said. "These areas are typically close to human traffic and sometimes to food courts, so spraying pesticides isn't an option."

If you buy indoor plants, Hudson says, inspect them, particularly hibiscus, for signs of mealybugs.

Adult mealybugs are about 3 millimeters long and pink. Males are smaller than females and have one pair of wings and two long, waxy tails.

"Chances are, you aren't going to see the adults, because by the time you can, the plant will have a lot of distorted growth," he said.

"The first signs are waxy, dirty, sooty mold growing on the leaves and distorted plant growth," he said. "Also pay attention to the stems, where early infestations occur, and look for little, cottony masses the size of a Q-tip. This is an egg mass that can contain hundreds of eggs."

If you spot any of that, don't buy the plant.

With most mealybugs it takes a while for the plant to succumb. "But this one injects a toxin as it feeds so that you get a lot of distorted growth and death of the plant pretty quickly," Hudson said.

Trash 'em is the best control method

If you find mealybugs on houseplants, Hudson doesn't recommend trying to control it with a pesticide.

"Most of the time it's going to be cheaper and more effective to discard that one plant and buy another," he said. "But discard it quickly before they can spread to your other houseplants."

The GDA recommends double-bagging infested plants in black plastic, tying the bags securely and leaving them in the hot sun for at least two weeks. Hudson agrees.

"Our nursery and greenhouse growers may elect to fight it with pesticides," Hudson said. "We just want to get rid of them the quickest way and not let them get established in our state."

Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.