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Two insecticides used to protect citrus against citrus-killing disease

SanBernardino Sun – April 11, 2012

There are two insecticides that are being used to fight the Asian psyllid after the discovery of a citrus-killing disease in a Los Angeles County suburb last week had agriculture officials ramping up efforts to curb its spread and promote awareness with local residents.

Commonly referred to as huanglongbing, or citrus greening disease, citrus owners are taking precautions by having their citrus groves sprayed.

According to John Gardner, county of San Bernardino agriculture commissioner/sealer, a synthetic pyrethroid is used as a foliar spray (sprayed directly on tree and leaves) which kills the psyllids that are on the tree.

The second insecticide used is a systemic spray sprayed into the ground, which helps to kill any insects that show up later.

“The synthetic pyrethroid will kill all insects, including the beneficial ones. If you wait a little bit the beneficial insects will repopulate once they have other bugs to feed off of. They can also fly across the street to a neighbor’s tree that has not been sprayed and re-establish itself,” Gardner said.

The spraying will also kill any honey bees that are visiting foliage on trees at the time.

“There is a significant impact on the bees present at the time of spraying but there is no significant impact on them for the long term,” said Gardner.

As for concerns about being able to eat the citrus after spraying has taken place, Gardner explained that one day after spraying you can eat the citrus. There is a one-day harvest interval.
“If you are still worried, you can wash your citrus with warm soapy water before eating,” said Gardner.

HLB is a bacterial disease that attacks the vascular systems of plants. It does not pose a threat to humans or animals.

The Asian citrus psyllid can spread the bacteria as the pest feeds on citrus trees and other plants. Once the tree is infected, there is no cure, though entomologists are working doggedly to find a cure, according to the CDFA.

“Residents with citrus trees on their property need to keep an eye out for signs of HLB, which include the blotchy mottling of leaves, misshapen fruit bitter in taste, and fruit that retains its green color at the navel end when mature (hence the name citrus greening disease,)” said Ted Batkin, president of the California Citrus Research Board.

Gardner said that these insecticides can be purchased at lawn and garden supply stores and that trees will look healthier a couple of months after spraying.

Anyone who suspects that citrus on their property may be infected should report it to either their county agriculture commissioner, the CDFA or the USDA, Larry Hawkins, spokesperson for the U.S. Department of Agriculture said. Concerned citizens can call 800-491-1899.

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