A couple things have prompted this post. First, we have a potentially devastating disease hitting citrus trees in SoCal with the arrival of an insect Asian Citrus Psyllid. To combat it, a pesticide spray composed of two common insecticides is being applied to local trees. Second, I read a Sierra magazine article called Parkinson’s Alley, on the high rate of Parkinson’s disease in a Central California town surrounded by high agricultural pesticide use. Click here for my article on human effects.
The takeaway: Check alternatives to pesticides and when necessary, use them cautiously. Their use causes damage to beneficial insects and other critters, and potentially for you.
I was surprised with the warnings when I looked up the citrus pesticides, both widely used (Merit or imidacloprid – the pesticide used in flea collars – and Tempo or cyfluthrin). Yet when I called the state’s information line they only touted that the pesticides are very common and very dilute.
Below is from the second paragraph in a 2011 Florida Citrus Pest Management Guide about the psyllid & treatment (note: the bolded parts were in the guide, NOT my additions)
… it should be noted that most of these products will have negative effects on natural enemy populations that keep other potential pests below damaging levels. Thus, it is likely that new pest problems may develop as a result of increased insecticide use for psyllid suppression….
In other words, these broad spectrum insecticides may kill everything living in their path, they’re not specific. They’re particularly hard on bees. When I asked the person on the Food and Ag Pest Hotline about guidelines for safe use, she wasn’t sure and referred me on to a technician. The technician did acknowledge that there might be some kind of effect and yes, any bees or insects on the foliage at the time of spraying would be affected (killed) but that you could take precautions by spraying in the evenings and in the early mornings. She also said anyone can buy them at a place like Home Depot.
My concern: why aren’t these precautions provided? I’ve asked the director of the Inland Orange Conservancy here in Redlands on what they’re advising. While less effective, there is also a predatory wasp alternative – see below.
Resources are below for more information, but Josh Vincent of the Northwest Coalition for Alternatives to Pesticides (NCAP), an organization I’ve supported for a long time, provided the following comments:
From NCAP:
Tempo Concerns
- the active ingredient in Tempo is a synthetic pyrethroid called beta-cyfluthrin. Synthetic pyrethroids are often called ‘safe’ and ‘natural’ because they are modeled after pyrethrins, a kind of nerve toxin that occurs in some plants like chrysanthemums. However… pyrethroids are engineered to be more toxic and last longer in the environment than pyrethrins.
- They kill the good insects right along with the bad ones, and are toxic to other organisms like birds, fish, and especially aquatic invertebrates.
- Additionally, pyrethroids may demonstrate additional toxicity due to synergy with their so called ‘inert ingredients.’ In the case of Tempo, the inert ingredients are not disclosed, so who knows what could be in there?
Merit Concerns
- Merit’s active ingredient is imidacloprid, a nicotinoid compound that disrupts the nervous system.
- It is highly toxic to some birds species (canaries, pigeons, sparrows).
- Moreover, it can last for years in the environment. This means there’s more opportunity for people and wildlife to come into contact with the chemical and suffer ill health effects. Long persistence also means more potential to contaminate groundwater.
- It’s worth noting that newer versions of nicotinoid pesticides (neonicotinoids) are now widely suspected to play a role in bee colony collapse
Predatory Wasps Good Alternative
- Josh from NCAP said biological controls, like predatory wasps that feed on insects can be a great alternative. “When properly implemented, they are much less disruptive to the ecosystem and they can be quite effective. That said, the wasps will be less effective if they are used in conjunction with the chemical pesticides as they will surely also be impacted by them,” he said.
For more information/references:
NCAP – Northwest Coalition for Alternatives to Pesticide – 35 year old organization dedicated to seeking methods besides pesticides, pesticide fact sheets. Executive director Kim Leval says considerable research shows pesticide danger to communities and environmental health:”Please check out our fact sheets and alternatives for home and garden solutions.”
Cyfluthrin Fact Sheet (Journal of Pesticide Reform)
Imidocloprid Fact Sheet (Journal of Pesticide Reform) – this is the largest volume of the pesticide used in the world; has many applications, including flea collars
Food and Agriculture Department Exotic Pest Hotline – for residents – 800-491-1899
About Asian psyllids do their damage – CA Dept of Food and Ag