Wendy,

Hawaiian root mealy bugs?

Root Mealybugs

Arnold H. Hara,
CTAHR Dept. of Entomology, Hilo

Root mealybugs occur only on roots of their host plants. Because they are
undetected, occurring below-ground, root mealybugs can be a serious pest.
Currently, the Hawaiian Islands have 7 species of root or hypogaeic
mealybugs. The most pestiferous species have been the coffee root mealybug,
Geococcus coffeae, and Rhizoecus hibisci. Plant host range of these root
mealybugs are very wide, infesting grasses, palms, citrus, cyperus,
pineapple, coffee, mango and syngonium.

In pots, root mealybugs occur throughout the root mass; however, they are
concentrated between the root-ball and the pot. Infestations of root
mealybugs are noticeable only if the root-ball is removed from the pot. The
white waxy material is the most important sign of root mealybug infestation.
Mealybugs secrete lots of white waxy material that covers their bodies.
Female mealybugs lay eggs or give birth to live young (crawlers).If eggs are
laid, they usually hatch in less than 24 hours. Crawlers are the dispersal
stage and are highly mobile. Once the crawlers find a suitable site, they
settle down and begin to feed on roots with their sucking mouthparts. The
entire life cycle ranges from 2-4 months depending on the species. Adults
live from 27-57 days, also depending on species.

Prevention

Because the root mealybug is very difficult to control, every effort should
be made to prevent spread and establishment. The following practices are
recommended to prevent spread and establishment:

1.. Inspect roots of newly purchased plants for root mealybugs by removing
the pot.

2.. Avoid root-bound plants by re-potting as needed; root-bound plants
encourage mealybugs.

3.. Use clean pots and media; if infested wash with soap and water.

4.. Treat or remove infested plant hosts from your premises.

5.. Do not allow water from infested areas to drain into clean areas;
crawlers can be transported in water.


Control

Research by the University of Hawaii, CTAHR, has demonstrated that
insecticides and/or a hot water dip are effective treatments. Dursban WP
applied as a liquid drench and Marathon G are effective against root
mealybug. Watering plants prior to drench application will significantly
reduce problems with phytotoxicity. Consult the Cooperative Extension
Service, Hawaii Department of Agriculture or a reputable agrochemical
professional for a specific product registered for use. Submerging potted
Rhapis palms in 120° F (49° C) hot water until the internal root ball
temperature reaches 115° F(46° C) is 100% effective in killing root
mealybugs. Hot water at 120° F does not significantly affect potted
Rhapispalms.

For more information or a detailed report contact Arnold Hara in Hilo at
Ph: (808) 974-4105, Fax: (808) 974-4110 or e-mail: .


Bob Walsh


"Wendy7" wrote in message
...
My Oncidium Twinkle 'Red Fantasy' seemed to be struggling then I noticed
the
white
stuff through the clear plastic pot.
To be cont. . . . . . . . .