Picture of Margaret Reeves

Margaret Reeves

No brain-harming insecticide needed

Citrus groves account for quite a bit of chlorpyrifos use — a highly hazardous insecticide that’s been banned from use in homes and on pets because of risks to children’s developing brains. It also has serious impacts on farmers, farmworkers and rural communities and for years, we’ve been calling to restrict its use in agriculture as well.

But the pesticide industry continues to heavily promote the use of chlorpyrifos. And one of the pernicious pests it’s purported to control — the Asian citrus psyllid — can indeed introduce a deadly disease, but organic citrus growers from California to Florida are successfully managing the pest in ways that avoid use of harsh poisons. No brain-harming insecticide needed.

A new(ish) pest

Since 2008, we’ve been hearing that California’s citrus industry is at risk of massive loss from citrus greening disease, also known as Huanglongbing, or HLB. It’s a bacterial disease transmitted by the tiny psyllid. HLB-infected trees first show blotchy patches of yellowed leaves, then produce bitter, hard, misshapen fruit that falls off the tree before getting ripe. After a few years, the tree is dead and must be removed, roots and all, in order to prevent further spread of the disease.

The first diseased trees appeared in California in 2012. Last month the California Department of Food and Agriculture announced new quarantine requirements in an attempt to limit the spread of the psyllid (and the diease). 

Unfortunately, the California Department of Pesticide Regulation (DPR) lists the psyllid as one of the citrus pests for which chlorpyrifos can be an effective treatment, and part of the justification for its continued use — despite the fact that better, safer and ultimately more effective alternative treatments exist.

Effective, safer alternatives

For years, California citrus has been an excellent example of successful application of Integrated Pest Management, or IPM, as a means to reduce the use of the most hazardous pesticides.

Unfortunately, DPR’s continued justification for use of chlorpyrifos on citrus crops seems to overlook this fact. The agency also fails to recognize that even this relatively new psyllid pest is already developing resistance to chlorpyrifos, further arguing against the pesticide’s continued use.

In contrast, organic citrus growers in California and Florida have demonstrated that alternatives to chlorpyrifos can effectively and safely manage the citrus psyllid. Using a general agroecological approach, growers combine techniques to both build greater resilience among the trees and to reduce the pest populations (and transmission of disease).

Specific techniques include use of yellow sticky traps to monitoring psyllid populations; growing a diversity of crops, including cover crops, to protect and feed the soil; and using kaolin clay or essential oils as insect repellents.

Ant pests in citrus are another presumed justification, in fact the primary justification, for continued use of chlorpyrifos in citrus. And they too can be effectively controlled with much safer methods. These include cultural controls (non-chemical barriers) and least toxic traps with bait that gets carried back to the nest, providing more effective control than direct chlorpyrifos treatments on roaming worker ants.

Over my nearly twenty years at PAN, I have been frequently asked about alternatives to highly hazardous pesticides like chlorpyrifos. For virtually every crop on which these harmful chemicals are used, there are examples of economically viable alternatives — often used in organic production.

True, when new pests come along (and they always do), finding the right solutions is not necessarily easy. This citrus story is just another example of why it’s so important to push for continued research, outreach and support of farmers looking to do the right thing by replacing the use of hazardous pesticides with safer pest and crop management tools while keeping their businesses successful.

Picture of Margaret Reeves

Margaret Reeves

Margaret Reeves is a PAN Senior Scientist with expertise in agroecology and soil ecology. As a long-time farmworker advocate, Margaret serves on the Board of the Equitable Food Initiative and works with partners around the country to ensure worker-protective federal and state policy. Follow @MargaretatPAN

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