By:
Chris Eversole

Source(s):
Marjorie Hoy (352) 392-1901 ext.153
Lance Osborne (407) 884-2034
Ru Nguyen
Avas Hamon (352) 372-3505

GAINESVILLE — The war on bugs needs you and the other 14.7 million Floridians.

Your mission, should you choose to accept it, is to inspect your hibiscus plants for the pink hibiscus mealybug. The critter has caused tens of millions of dollars of damage to a multitude of plants — including hibiscus, citrus trees, corn, sugarcane, beans and ornamental shrubs — in the Caribbean and is expected to arrive in Florida soon.

Once the pest is spotted, University of Florida researchers and state officials can start raising tiny wasps to combat it. The wasps, which are harmless to humans, keep pink hibiscus mealybugs in check in Asia, where they originate, and have reduced the pests’ damage since they invaded the Caribbean in 1994.

This mission isn’t for the squeamish. “You’ll need to squash one or two of the insects you suspect are pink hibiscus mealybugs,” said Marjorie Hoy, an eminent scholar in biological control at UF’s Institute of Food and Agricultural Sciences. “If pink blood oozes out, you may have captured one of the villains.”

Although pink hibiscus mealybugs are only a quarter inch long, they leave telltale clues that will help you find them. They inject a toxic substance into the leaves and flowers of plants they attack, stunting their growth and causing them to become gnarled. The mealybugs also are protected under white, fluffy wax on the stems of plants.

The request for help is serious, Hoy said. “It’s only a matter of time before pink hibiscus mealybugs arrive in Florida. They may already be here, and we just don’t know it.

“We have to be ready. Each female lays up to 800 eggs, so mealybugs develop large populations rapidly.”

Hoy and officials of the Division of Plant Industry of the Florida Department of Agriculture and Consumer Services are preparing to mount a defense against the pest, which preys on 200 different species of plants.

The wasps will be a key to that defense. “They lay their eggs inside the mealybugs,” Hoy said. “When the eggs hatch, the larvae eat the bugs” internal organs, which kills the mealybugs.”

Hoy is preparing to raise the wasps under strict controls in her quarantine laboratory, and she’s growing Japanese pumpkin squash, a vegetable that the mealybugs relish.

Her hands are tied until pink hibiscus mealybugs are found in Florida. “We need to have some of the insects so the wasps can reproduce, but we can’t take the risk of importing any of them on the chance that some might escape,” she said.

Wasps have a good record in controlling pink hibiscus mealybugs. “When the insects showed up in Hawaii a few years ago, the wasps arrived with them, and the pests never got out of control,” Hoy said. “The wasps also were used in Egypt in the 1940s.”

In the Caribbean, the wasps helped dramatically reduce the insects’ damage, which had left much of the vegetation in Grenada barren and at one point was causing $125 million in plant losses annually in Trinidad and Tobago.

A type of ladybug known as the mealybug destroyer also might be used against the insects. “The ladybug is already here in Florida, but the wasps will do more to reduce mealybug levels more than the ladybug will,” Hoy said.

Insecticides won’t work well because mealybugs protect themselves from the chemicals By producing waxy, cottony egg sacs and By burying themselves underground or inside hibiscus buds.

The limited effectiveness of insecticides poses a threat to Florida’s $1.3 billion-a-year ornamental plant industry, said Lance Osborne, an entomologist with a UF research center in Apopka.

“If an outbreak occurs, we won’t be able to use the wasps in plant nurseries because the insecticides routinely used in the nurseries will kill them,” Osborne said. “There could be a quarantine that would stop shipments of Florida plants to other states, which is the main market for them.”

Hoy and Ru Nguyen of the Division of Plant Industry recently visited a U.S. Department of Agriculture laboratory in St. Thomas of the Virgin Islands that raised wasps used to beat back the insects in the Caribbean.

“These mealybugs are a real menace, but using their natural enemies is a key to controlling them,” Nguyen said. “It is very important to get an early start so we can get the mealybugs under control before they spread.”

More information is available on two Web sites. The first site, http://www.ifas.ufl.edu/~insect, is maintained By UF’s Department of Entomology and Nematology in cooperation with the Division of Plant Industry. The second site, http://bugweb.entnem.ufl.eud/bugclub/pink.htm, was set up for the 4-H Bug Club sponsored By UF’s Cooperative Extension Service.

If you find insects that you suspect are pink hibiscus mealybugs, cut off the plant stem on which you find them and put the stem in a sealed jar or sealed plastic bag with rubbing alcohol. Use a sturdy package and attach a note stating your name, where you found the insects and when you collected them.

Send your package to Avas Hamon, Division of Plant Industry, P.O. Box 147100, Gainesville, FL 32614-7100.

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