The best of EcoWatch, right in your inbox. Sign up for our email newsletter!
As Pesticides Fail, California Citrus Growers Turn to Natural Solutions
Citrus growers in California are now turning to a natural solution after pesticides have been shown to be ineffective. Teams of invasive species experts have started releasing tamarixia radiate, a tiny parasitic wasp, to control the invasive Asian citrus psyllid population. Asian citrus psyllid can spread a disease which causes greening, devastating citrus production. This use of biological pest control demonstrates that the use of toxic chemicals is unnecessary as safer alternatives have already been proven effective.
Photo courtesy of Shutterstock
California’s citrus production is a $2 billion industry, which accounts for 80 percent of the U.S. fresh market produce and after Asian citrus psyllid was detected in southern California in 2010 growers have spent close to $15 million annually to fight this pest. The psyllids were first discovered in Florida in 1998 and has since spread to all of its 32 citrus growing counties. The U.S. Department of Agriculture (USDA) has quarantined nine states, including California and Florida. The quarantines prohibit interstate movement of citrus trees and require labeling of citrus nursery stocks from areas where greening has been detected.
The psyllids cause greening by spreading a disease known as Huanglongbing (HLB) to citrus trees. A pysllid that is infected with HLB can transfer the bacterium every time it feeds on the tree. Once a tree is infected with the disease there is no known cure. HLB is one of the most severe plant diseases in the world and can affect any variety of citrus trees. The disease can lie dormant for several years before tests are able to detect it. In California, the disease was first detected in November 2012 and has only been found in nine counties that are south of the commercial growing areas, but because of this dormancy California commercial operations may already be infected. After trees become infected fruit from these trees is not suitable for consumer markets because of its green color, misshapen appearance and distinctly bitter taste.
Since 2011, teams of invasive species experts have released more than 75,000 tamarixia wasps across southern California to combat the pysllids. In 2012, agricultural officials halted pesticide spraying in Los Angeles County because it proved ineffective. Six out of 10 trees in the county grow in backyards which if pesticides were used could lead to high levels of pesticide exposure for urban environments. To curb pysllids, teams of invasive species experts have been going to individual homes, releasing the wasps and tracking the parasites success.
The wasps are imported from Pakistan’s Punjab region and extensive tests were conducted to make sure that the wasp would not disrupt other California species or become yet another invasive species. The wasps curb pysllid populations by wasps laying eggs inside the psyllid nymph’s stomach. As the eggs hatch, larvae slowly eats away at the nymph. The teams hope that after the wasps hatch they will fly to neighboring trees and lay eggs in new nymphs and establish a growing population. Even though the team is only about a year and a half into this effort, at some release sites the population of psyllids has dramatically declined. Mark Hoodle, Ph.D., an invasive species expert at University of California Riverside, said to the Los Angeles Times, “We have no other choice except to use this natural enemy or do nothing. And the ‘do nothing’ option is unacceptable.”
Beyond this recent use of tramarixia wasp, there are many other examples of effective pest management through biological controls. Last summer, several counties in New Jersey used crustaceans, which are voracious predators of mosquito larvae, to control West Nile Virus. The most effective copepod species have the capacity to kill more than 40 mosquito larvae per copepod per day, typically reduce mosquito production by 99-100 percent, and can maintain large populations so long as there is a reliable water source. A report in 2007 found that Muscidifurax raptor, another parasitic wasp, was effective in controlling fruit flies in vineyards. Goats have also been used across the country to weed airports, cemeteries and to restore soil and improve land quality. The uses of biological controls are important because they prove there are alternatives to toxic pest management.
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. Beyond Pesticides’ Keeping Organic Strong page provides information on the practices and management strategies of organic agriculture.
Visit EcoWatch’s BIODIVERSITY page for more related news on this topic.
EcoWatch Daily Newsletter
By Emily Deanne
Shower shoes? Check. Extra-long sheets? Yep. Energy efficiency checklist? No worries — we've got you covered there. If you're one of the nation's 12.1 million full-time undergraduate college students, you no doubt have a lot to keep in mind as you head off to school. If you're reading this, climate change is probably one of them, and with one-third of students choosing to live on campus, dorm life can have a big impact on the health of our planet. In fact, the annual energy use of one typical dormitory room can generate as much greenhouse gas pollution as the tailpipe emissions of a car driven more than 156,000 miles.
By Lorraine Chow
Kokia drynarioides is a small but significant flowering tree endemic to Hawaii's dry forests. Native Hawaiians used its large, scarlet flowers to make lei. Its sap was used as dye for ropes and nets. Its bark was used medicinally to treat thrush.
States that invest heavily in renewable energy will generate billions of dollars in health benefits in the next decade instead of spending billions to take care of people getting sick from air pollution caused by burning fossil fuels, according to a new study from MIT and reported on by The Verge.
Hawaii's Kilauea volcano could be gearing up for an eruption after a pond of water was discovered inside its summit crater for the first time in recorded history, according to the AP.
By Kristin Ohlson
From where I stand inside the South Dakota cornfield I was visiting with entomologist and former USDA scientist Jonathan Lundgren, all the human-inflicted traumas to Earth seem far away. It isn't just that the corn is as high as an elephant's eye — are people singing that song again? — but that the field burgeons and buzzes and chirps with all sorts of other life, too.
Humanity faced its hottest month in at least 140 years in July, the US National Oceanic and Atmospheric Administration (NOAA) said on Thursday. The finding confirms similar analysis provided by its EU counterparts.
By Hans Nicholas Jong
Indonesia's president has made permanent a temporary moratorium on forest-clearing permits for plantations and logging.
It's a policy the government says has proven effective in curtailing deforestation, but whose apparent gains have been criticized by environmental activists as mere "propaganda."