By Pat Welsh, first published in Let's Talk Plants! October 2008, No. 169.
Have you noticed how few bees are about this season? Have you seen any bumble bees in your garden, or are there none of these sweet fuzzy creatures visiting your flowers and vegetables this year? Mankind has been causing mass extinctions of plants and animals for thousands of years. It was human beings, for example, who hunted the woolly mammoth to final extinction, and Easter Island is living proof of what can happen to a society that has chopped down all its trees. Right now we are at it again, flattening the Amazon forests, and now it appears as if we are also willy-nilly killing the world’s bees. If we kill all the bees, starvation will result, but many good people, even including gardeners are totally unaware of the threat or of the fact that they are contributing to the problem.
A number of disasters threaten domestic and wild bees, but this brief article is just to alert you to some of the hazards to bees from pesticides and to let you know, as gardeners, how you can help. Those of you who attended my talk in August already know that I am on the warpath against Spinosad. Spinosad is a pesticide used by farmers and gardeners and touted by the UC system, the Master Gardeners, and even by organic gardeners as a control for budworm, bougainvillea looper, rose slug, and other caterpillar- like pests. It is a product similar to BT (Bacillus thuringiensis) in that it contains fermented soil-bacteria, in this case Saccharopolyspora spinosa, an organism originally found under the floorboards of an abandoned rum factory in the Caribbean. This product is totally organic, thus it received the OMRI (Organic Materials Review Institute) seal of approval. But if you read the label, which one would hope all consumers do, you immediately discover in the first line that Spinosad is “highly toxic to bees.” How, I wonder, did Spinosad get the OMRI seal of approval? Worse yet, this product is sold in containers with spray attachments on the top of them, inviting the unsuspecting public to broadcast the spray on everything in sight. This is what people did with DDT before Rachel Carson exposed its hazards, and DDT was used against the same pest: the lowly caterpillar. Couldn’t we rely on birds and trichogramma wasps to control caterpillars and save our bees?
The instructions on the label of Spinosad suggest spraying in such a way that the spray will be dry before bees return to the sprayed area. What are we supposed to do, put up warning signs? Even if bees could read and would obediently stay away, the dry product will be in the pollen, and this pollen will weaken the bee larvae when the parent bees lovingly take it back to the hive and feed it to their young. Infected pollen will make some of the larvae sick and kill a few of them. (The label won’t tell you this. I had to do some research to find it out.) Now if I were a bee I would be more than a little upset if I took food home to my young and discovered it made them all sick and that it even killed a few of them. I wouldn’t want any of my babies to be weakened or sickened, let alone killed. And yet organic gardeners are using this product and recommending it to others. It’s bad enough knowing the Master Gardeners recommend it. I am an honorary Master Gardener and have always loved that organization, but when it comes to recommending pesticides that damage beneficial creatures such as bees, here is where we part ways.
Please help save the world’s bees by your own actions and by spreading the word. Please never spray with Spinosad unless in the evening hours and in very small quantities while using a small hand sprayer (the kind sold for moistening laundry), and then only moistening the leaves of plants at a distance from flowers or only on geranium blossoms, since bees never visit them. Never purchase or use Spinosad in a broadcast spray container. Never use Sluggo Plus in moist spots visited by bees, because it contains Spinosad.