Mealybug infestations
threatening Maui papayas
A new pest is threatening the papaya industry on Maui.
CORRECTION
Saturday, June 12, 2004A sign of severe papaya mealybug infestation on papaya trees or other plants is honey dew, which are large cottonlike masses on leaves and stems. A Page A6 story yesterday incorrectly said such infestations are noticeable on honeydew plants.
The Honolulu Star-Bulletin strives to make its news report fair and accurate. If you have a question or comment about news coverage, call Editor Frank Bridgewater at 529-4791 or email him at corrections@starbulletin.com.
The papaya mealybug was confirmed on June 2 by the U.S. Department of Agriculture as causing infestations in Kahului and Puunene. There are unconfirmed infestations in Kihei.
The mealybug can seriously damage papayas, avocados, hibiscus, plumeria and other plants, the state Department of Agriculture announced yesterday.
Although it has hit mostly the plants of backyard growers, "it's more a question of when than if" the bug will infest papaya trees of major growers, said Mach Fukada, state agriculture entomologist on Maui. "Should it move to the Big Island, it would be a big concern for the papaya industry."
Jan McEwen, University of Hawaii extension agent on Maui, noticed the infestation at UH's educational garden six weeks ago, where 50 to 60 papaya trees grow.
"We've been getting a lot of calls in the past two weeks," she said. "It seems to spread very quickly. I'm hoping if people do see it, they will report it."
Severe infestations are noticeable on honeydew plants -- large cottonlike masses on leaves and stems and black sooty mold on fruit and leaves. On papaya the leaves turn yellow and dry; younger leaves crinkle and shoots become distorted. On hibiscus the shoots become scorched. On plumeria the leaves become distorted.
The insect feeds on plant sap, excretes the white substance and injects a toxin that stunts plant growth, deforms leaves and causes early leaf and fruit drop and the death of the plant.
Female mealybugs grow to one-sixteenth of an inch long and are yellow with a white waxy coating; males are smaller.
The state and federal Agriculture departments and the University of Hawaii's College of Tropical Agriculture and Human Resources are working together to identify the problem and a solution.
It could not be managed with pesticides because the mealybugs reproduce too quickly.
Fukada said three parasitic wasps, which feed on the mealybug's eggs, have been tested by the USDA and used on Palau.
Heavy infestations of the mealybug, native to Mexico and Central America, were found on Guam in 2002 and Palau in 2003.
"It came on pretty suddenly," said Pukalani resident Al Nyberg, who has had 12 to 15 of his hibiscus plants infested within the last three weeks.
The infestation occurs by moving infested plant material, such as papayas or hibiscus cuttings, Fukada said.
