Bayer Advanced Fruit, Citrus, & Vegetable Insect Control -- a good idea?!?

“I’ve heard there is a new systemic insecticide for vegetables and fruit trees.”
Yes, indeed: Bayer CropScience has introduced Bayer Advanced™ Fruit, Citrus & Vegetable Insect Control, which you pour on the ground around edible crops. It goes up into the plant and kills insects that are feeding on the plant.
My god, what a terrible idea!
“Keeping your plants protected from listed damaging insects has never been easier.”
Just because you can do something, doesn’t mean you should!

The active ingredient imidacloprid (Merit) is a widely used neo-nicotinoid systemic insecticide. We recommend it for control of some pests on ornamentals, in situations where you and bees won’t be exposed to it, and it is useful on houseplants. It is the active ingredient in a popular flea control product on pets. It is heavily used on some agricultural crops in California, including head and leaf lettuces and citrus, as well as on turf and ornamentals.

I understand the basic principle of toxicology: the dose makes the poison. How toxic a material is depends on how much you ingest. There are doses that are considered safe for humans. Neonicotinoids are especially toxic to insects and much less so to humans. But the regulatory agencies base their safe dosage on assumptions about our current intake of the product by other sources. You are ingesting imidacloprid regularly when you eat conventional produce, walk across commercially-maintained turf, pet a cat that has been treated with Advantage®, etc.

Ok, so you put this insecticide on the ground, it is taken up by the roots, goes up into the plant and kills anything that sucks or chews on the plant. Then it breaks down steadily in the plant over time. Apparently Bayer and various regulatory agencies believe that it’s ok for you to eat whatever the plant produces because it has diminished to less harmful levels in the plant.

This all assumes you follow the label instructions for the rate per square foot, that you only apply it once a year, and that you wait the specified interval before harvest. Why, one wonders, is it a 21 day waiting period for lettuce, but a 45 day waiting period for Swiss chard?

You can download the 10-page label from bayeradvanced.com. Read about imidacloprid at the cooperative-extension maintained site http://extoxnet.orst.edu/

Here’s what anybody selling, buying, or using this product needs to know:
• You must carefully follow the rate of application per square foot of garden space.
• The product is in the plant, including the part you consume. If it provides “Season-Long Protection!” then it is in the plant all season. Including when you harvest.
• It is important to check the interval before harvest for a particular crop, which ranges from 14 to 45 days after application.
• You cannot use this product more than once a year. In California we have two full vegetable growing seasons.
• Imidacloprid is very toxic to bees of all kinds. Bees are exposed to it through pollen.
• You should not apply it when trees are blooming or bees are foraging nearby. It can be taken up by the roots of nearby flowering plants. Your garden needs to be entirely separated from plants that bees might visit. Sub-lethal doses to bees have unknown effects. It is one possible factor being reviewed in Colony Collapse Disorder, but has neither been ruled in or out as a cause.
• It is very toxic to earthworms.

I am concerned that the manufacturer and the regulatory agencies have not considered California’s unique gardening climate.

I don’t know if the baseline for acceptable “average” intake from other approved uses has been updated since the mid-1990’s (that is the only data I could find online). There have been many new approved uses of imidacloprid in the last decade, including urgency permits for new pests. Imidacloprid is the pesticide of choice for many of the new pests that arrive in California, so I would guess that we are consuming more and more of it.

I personally would not use it or sell it for edible crops, and urge nursery professionals, Master Gardeners, and landscape gardeners to discourage its use.