15
May
USDA Advances Biological Controls for Citrus Greening Disease
(Beyond Pesticides, May 15, 2014) Last week, the U.S. Department of Agriculture (USDA) announced  that it is broadening the use of tiny parasitic wasps, Tamarixia Radiata, to combat the rampant problem  of Huanglongbing, also known as citrus greening disease, which has killed thousands of orange trees in Florida. The citrus industry is valued at $2 billion dollars. Citrus greening is an incurable disease that is spread by the Asian citrus psyllid. Symptoms of this disease include yellow shoots, uneven discolored patches, and deficiencies with chlorophyll production. Chlorophyll is the green pigment found within plants. It is extremely important for photosynthesis, which allows plants to absorb energy from the sun. The disease is usually found in warmer climates like Asia, India and the Saudi Arabian Peninsula; however, it made its way to Florida in 1998 and is now endangering California’s citrus industry.
USDA has already committed to provide $1.5 million dollars to the T. radiata  breeding and release program in California, Texas, and Florida. Congress has also allocated more than $125 million dollars over the next five years to fund more research on containing the spread of the Asian citrus psyllid. Although the psyllids do not directly kill citrus trees, they are carriers of the disease, Huanglongbing. Alarmingly, these pests are being found more and more in prime citrus-growing areas, which could seriously harm California’s citrus industry, responsible for around 80% of fresh citrus fruit in the U.S.
“Citrus greening poses a significant threat to the citrus industry and the thousands of jobs that depend on it. It could also further drive up fruit and juice prices if we don’t act,” said Secretary Tom Vilsack. “USDA is committed to fighting and beating this destructive disease.”
In addition to threatening the citrus industry, the disease has caused significant difficultly between beekeepers and citrus farmers  who are combating the spread of the psyllid  with toxic chemicals. Local beekeepers are worried over the increasing use of harmful neonicotinoid pesticides, and citrus growers are concerned about the increasing population of Asian citrus psyllids. In September of last year, there was an organized meeting that brought together the Florida Agriculture Commissioner, a former U.S. Congressman, a citrus farmer, and beekeepers. Communication is a vital piece of this process, since beekeepers and citrus farmers rely on each other. Honey bees are responsible for pollinating several different types of citrus fruit, and they also forage within those same areas. While the Florida meeting focused on the accidental spraying  of foraging bees, it did not address the systemic nature of neoncotinoid  insecticides, which are taken up by the plants’ vascular system and are expressed in contaminated pollen and nectar.  Clothianidin, a neoncotinoid, can last up to 19 years in the soil according to a recent  study.
Fortunately, the use of these harmful pesticides are unnecessary, as biological agents. such as  parasitic wasps, are proven effective. The wasps curb pysllid populations by laying their eggs inside the psyllid nymph’s stomach. As the eggs hatch, larvae slowly eats away at the nymph. This non-toxic, biological approach eliminates the use of lethal pesticides. Additionally,  farm operations that are USDA certified organic already avoid the use of toxic chemicals by implementing organic systems plans that can include biological pest management.
To learn more about the policies and management strategies of organic agriculture, please visit Beyond Pesticides’ Keeping Organic Strong page.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Â The Los Angeles Times
