The Consequences of Pesticides in Citrus Pest Treatment – and references

The Consequences of Pesticides in Citrus Pest Treatment – and references

An op-ed article I wrote for the Redlands Daily Facts, entitled “Understanding the Consequences of Asian Psyllid Treatment,” is being published tomorrow. It was prompted when I noted that articles were not mentioning the negative effects of the recommended pesticide treatments for an alarming pest that is attacking citrus trees. Some important background first: our area is resuming treatments for the Asian Citrus Psyllid, the bug responsible for devastating Florida citrus, which has made its way to Southern California. Most commercial groves have been treated. Now residents have the option to have their backyard citrus trees treated. Many of these points apply these common pesticides being used of other uses also.

Here are my main points after doing research on this subject, plus references are listed below:

  • Bee on orange tree blossomThe two recommended treatments – very common insecticides – carry many toxic warnings that people should be aware in their decision-making. Tempo SC Ultra is cyfluthrin, applied as a spray to the leaves. It’s a wide-spectrum pyrethroid insecticide, and affects hundreds of insect species. It’s listed as being highly toxic to bees. It’s also partially toxic to birds and very highly toxic to fish. The second is Merit or imidacloprid, the most commonly used neonicotinoid, which is applied to the soil. Neonicotinoids are the insecticide group that has been linked to bee collapse, and are restricted in Europe. It’s the insecticide in flea collars.  It is also highly toxic to bees, and moderately toxic to birds and fish.
  • These insecticides carry limitations and overuse can lead to increases in other pests. The psyllid has many life stages, making it difficult to eradicate. One local orange grower here in Redlands said Florida has lost 70% of its citrus crop and is now spraying its remaining citrus 12 times a year. They can kill the very bugs, such as ladybugs, that predate on the psyllid. And insecticides an cause other pests to rebound between treatments.
  • Hotline personnel and others need to be upfront about the impacts. In my earlier 2012 post Pesticide Use: Consider the Collateral Damage, I had called the California Department of Agriculture (CDFA) Exotic Pest Hotline at 1-800-491-1899. I  was concerned they didn’t acknowledge any negative impacts. I called Monday, and was pleased, when I probed, that the insecticides could negatively impact beneficial insects including bees. But they explained the pesticides would not be applied if bees were present, and the person still minimized negative effects, saying the treatments were designed for the Asian psyllid. I wish they would be more upfront about these wide-spectrum insecticides.
  • It’s a tough situation. Organic methods aren’t sufficient, and people who do not treat their citrus risk losing their trees.

The Decision for our Backyard Citrus

We have a half dozen mature citrus trees in our backyard. We also have created a healthy and balanced ecosystem through very minimal pesticide use and through mature trees and native plants that attract bees, butterflies and insects, and in turn, birds and other critters. We will not be treating at this time. We risk losing our citrus but at this point, we’re willing to take that risk.

Other references/articles

Asian Psyllid Treatment Guidelines

2014 Florida Citrus Pest Management Guide: Asian Citrus Psyllid and Citrus Leafminer – University of Florida Extension – Florida’s most recent guidelines

University of California Management Guidelines – UC’s Integrated Pest Management website on the Asian psyllid. also gives info on the psyllid

Neonicotinoids and Imidacloprid

A Review of Research into the Effects of Neonicotinoid Insecticides on Bees – Xerxes Society, 2012 publication –  Neonicotinoids are absorbed into the plant, and can be present in pollen and nectar, mak- ing these floral resources toxic to pollinators that feed on them. Because of the long-lasting presence of neonicotinoids in plants, they may harm pollinators even when the initial application is made outside of the bloom period. The review includes three sections: 1)impacts supported by an extensive body of research, 2) what can be inferred from the available research, and 3) knowledge gaps in the understanding of pollinator and neonicotinoid interactions.

Cyfluthrin Fact Sheet and Imidocloprid Fact Sheet – both from the Journal of Pesticide Reform

Decline in birds linked to common insecticide articleScience News, July 2014: This research studied imidacloprid use in Holland and noted that in areas where the insecticide had run off into waterways, bird populations were reduced, linking the decline to the killing off the insects that bug-eating birds relied on.

Potential Solutions

Spinach may save Florida’s Citrus Crop –  Spinach genes inserted into genetically modified orange stock could be weapon against citrus greening, a bacteria spread by the Asian Citrus Psyllid.
Citrus Greening Forces Florida Growers to Trust a Controversial Savior – Huffington Post 8/13 article about a Florida grower successfully using micronutrients along with insecticides to boost the immunity of his sick trees.
Article on farmer methods to attract beneficial insects for pests  – Organic methods for pest control, such as using no-till practices and diverse cover crops to attract good bugs


About Linda Richards

My goal is to educate about the science of nature in layperson speak, through my writing, science and education background. I grew up in the Chicago area, loved living in Minneapolis before gravitating to the West, which is now home.


  1. Eleanor H. Borkowski says:

    I only have 6 citrus trees and they were included in the spraying. I do see many bees on other bushes that have orange blossoms, but have not examined the trees for bees. What else could be used to discourage the bugs?

    • there’s a lot of research being done but not that much definitive at this time. Vermicomposting (worm composting), or organic composting has been found to aid other diseases so that can’t hurt. Also keeping them well watered and non-stressed helps. Glad to hear about the bees!

  2. Christine says:

    Linda – thanks for this article, and sharing the underlying research. There are no “easy-outs”, and its really important for folks to consider the broader effects as you outline here. Really poignant that the insects which naturally protect citrus by preying on the Asian Psyllid are also harmed by the pesticides.

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