Release: June 10, 2004
PAPAYA MEALYBUG FOUND ON MAUI
Honolulu - A plant pest called the papaya mealybug (PM), Paracoccus marginatus, which could cause serious damage to papayas, avocados, hibiscus, plumeria and other plants, has been identified on Maui. The Hawaii Department of Agriculture (HDOA), the U.S. Department of Agriculture Animal & Plant Health Inspection Service (USDA-APHIS), and the University of Hawaii's College of Tropical Agriculture and Human Resources (CTAHR) are working collaboratively after infestations of PM were identified in Kahului and Puunene, with possible unconfirmed infestations in Kihei. USDA-APHIS confirmed the identification of the pest on June 2. PM has not yet been detected on other Hawaiian islands.
Female PM grow to about 1/16 of an inch long and are yellow in color with a white waxy coating. Males are smaller. PM infestations are typically observed as clusters of cotton-like masses on the leaves and stems of plants. The insect feeds on the sap of plants and in doing so injects a toxic substance into the plant, causing stunted growth, deformed leaves, early leaf and fruit drop and death of the plant.
On papaya plants, PM causes leaves to turn yellow and dry up. Younger leaves become crinkled and shoots become bunched and distorted. Heavy PM populations produce a large volume of honey dew, which causes black sooty mold to cover the infected fruits and leaves.
On plumeria, PM infestation causes leaves to become distorted. On hibiscus, the young shoots covered by mealybugs become scorched.
The PM is native to Mexico and Central America. In 1995, it was first reported in St. Martin in the Caribbean and since then has spread to other Caribbean islands, Florida, Puerto Rico and South America. Heavy infestations of PM were found in Guam in 2002 and in Palau in 2003. There are more than 60 plants identified as hosts for PM.
In 1999, USDA initiated a biological control program for PM on the mainland and found parasitic insects that have been highly successful in controlling PM in other infested areas, including Palau. HDOA will be working with USDA to determine if those biocontrol agents will work in Hawaii without affecting native insects.
If Maui County residents suspect that they have PM, they should call the Maui Office of HDOA at 873-3555. Possible cases of PM on other islands should be reported to the nearest HDOA office or to the Plant Pest Control Branch in Honolulu at 973-9522.
Left: Close up of adult PM Right: Papaya tree infested with PM