I stumbled across some third party info (so could not find the original link), but it may be worth trying:

Scientists in Vietnam have discovered the means to prevent the
citrus greening disease which infects a majority of fruit trees in
the country's south. Nguyen Minh Chau, head of the Southern Research
Institute on Fruit Trees, said to prevent the disease farmers should
grow guava trees along with citrus trees in a 1:1 proportion.

After four years of research, scientists from the institute and
other nations like France, Australia, and Japan found that
terpenoids, a substance present in guava trees,
kills the insects causing the greening disease.

The delta has 40,000 hectares under citrus trees. In some provinces
like Ben Tre, Vinh Long, and Tien Giang over 60 percent of the
orchards are hit by the disease. Affected trees become stunted, bear
multiple off-season flowers, and produce small, irregularly shaped
fruits with a thick, pale peel.

Joe, Ned posted this in "Citrus Disease & Pests" a few days ago. I think it's what you were looking for

http://www.thanhniennews.com/features/?catid=10&newsid=23928

Thanks, it shows that I only have a limited time browsing nowadays and can't get to all the good stuff.