Pink Hibiscus Mealybug Detected on Florida’s West Coast
The pink hibiscus mealybug has been detected on several hibiscus plants at four residences in Pinellas Point, according to Florida Agriculture Commissioner Charles H. Bronson. This is the first confirmed report of the insect on the west coast of Florida. The pink hibiscus mealybug (PHM) was detected in Broward County, Florida on June 13, 2002, and then in Dade County that same year.
During a routine USDA Sentinel Survey inspection of a Pinellas Point residential area, the inspector observed an infested hibiscus plant. Samples were shipped to the Florida Department of Agriculture and Consumer Services (DOACS), where it was confirmed that the plants were infested with PHM. The Department has started an ongoing survey to determine the extent of the PHM infestation in the Pinellas Point area and any surrounding areas. According to the department, infestation appears to be little at this time due to the cooler temperatures. However, PHM insects have the potential to colonize Florida and spread north to Southern Georgia.
PHM is a serious agricultural pest of fruit trees, vegetables and ornamental plants and occurs in most tropical areas of the world. The insect has a life cycle of 24 to 30 days and can attack more than 200 plant species, including many found in Florida like the hibiscus, mango, guava, citrus, avocado, tomato, cucumbers and peppers.
According to the DOACS, PHM is a sap-sucking insect that forms colonies on the host plant, which grows into large cotton-like masses of white, waxy deposits on branches and leaves. As it feeds, it pierces into the soft tissues of the plant, injecting a toxic substance that results in malformed leaf and shoot growth, stunting and possibly death. When fruits are infested, they are covered entirely in the white, waxy coating of the pest. The fruit will either drop off or remain in a dried and shriveled condition. If flower blossoms are attacked, the fruit will set poorly.
In the egg and crawler stages, PHM is most easily spread by wind, but it can also be spread by ants and other small insects, by a person’s clothing or by an animal’s fur. It can be identified from other mealybug insects by its reddish-brown, smooth body and pink-to-red body fluid. In cooler climates, the pest overwinters on the host plant, either in the egg stage or as an adult. In warmer climates, the insects may stay active and reproduce year round.
Field studies conducted by the Department of Agriculture and Consumer Services indicate that the best way to control PHM is by biological control. The DOACS, in cooperation with the USDA, has launched a comprehensive biological-control program involving the release of two parasitic insect species (Anagyrus kamali and Gyranusoidea indica) into the infected areas. Both are small, parasitic wasps that are currently being reared in USDA laboratories in Puerto Rico. Approximately 6,000 insects will initially be released, and will continually be released weekly until the PHM population is controlled. Another predator known as the "mealybug destroyer" has already been released in Florida at several residential sites. Successful biological control programs conducted on PHM-infested Caribbean islands reported a 60%-80% reduction of PHM within six months of parasite releases at test sites, and 95%-98% after one year.
The DOACS is advising homeowners and lawn/landscape maintenance companies to NOT cut or remove suspect plants or use insecticides at this time. The cutting or treating of these infested plants could interfere with the biological control program and may cause further spread of infestation. Crop production costs will be heavily increased if growers attempt to manage mealybug populations by pesticide applications, which have already been shown unsuccessful. Pesticide applications will also disrupt the effective natural enemies of other crop pests, such as mites, scale insects and whiteflies. The pesticide applications could contaminate food, water and farm workers, and may also increase the damage to ornamental plants, particularly hibiscus.
People who believe they may have plants that have been infested with PHM should call the Department of Agriculture and Consumer Services toll-free to arrange for an inspection at 888-397-1517.