Unbeknownst to me, there are three main strains of Bt used to target specific pests. Bt is not a broad-spectrum pesticide. Information about the three strains and their specific targets can be found on the Colorado State University Extension Website site.
The most commonly used strain is Kurstaki,which targets caterpillars, including cabbage worms, tent caterpillars and leaf rollers. It is sold under the trade names Biobit, Dipel, MVP, Steward, Thuricide.
Mosquitoes and flies are treated with a separate strain Israelensis.
The third and fourth strains San diego/tenebrionis target beetles, like the Colorado Potato Beetle and others.
Check the ColoState page for more in depth info.
Sorry to scare you all. Bt is a safe pesticide, especially when compared with the alternatives.
Sheesh, I’d better stop using Wikipedia as the be all, end all. It certainly isn’t.
Thank you for clearing that up Daphne!
I love growing potatoes. What I don’t love are the pests that come with them. My archenemy in this department is the leaf-eating Colorado Potato Beetle (CPB). Not only are the beetles gut-wrenchingly disgusting, they spread diseases as they move from plant to plant. With diligence these pesky bugs can be controlled without toxic chemicals.
The key to controlling the CPB is understanding its life cycle. There are three stages in the maturation of the beetle, eggs, larvae, and adults, they can killed during any one of these phases. Adults are easy to identify due to their distinctive striped exoskeleton. (Sorry, I dusted them up trying to get them in the shot.)
Adults can be found feeding on the leaves and also near the base of the potato plant, where they emerge from their underground pupation chambers.
Black beetle poop on the leaves are a tell-tale sign of beetle activity.
Adults lay masses of bright orange colored eggs on the underside of the leaves. These should be wiped off and smooshed (I like to use gloves for this,) before they hatch anywhere from 4-10 days. If the eggs hatch, reddish brown larvae with black spots will emerge. These larvae will eat their fill of leaves before retreating to underground chambers where they will complete the pupation process, emerging a few weeks later as full grown adults.
The best time to perform search and destroy missions is the early morning when the beetles are still sluggish from the cooler nighttime temperatures. I like to use the bottom of a stick to squish them. Okay, I don’t like it. It’s a matter of necessity. Be careful these guys will try to play dead, so make sure to squish ’em good!
For more information on the life cycle of the Colorado Potato Beetle see this article provided by a cooperative between the Universities of Wyoming, Nebraska, Colorado State, and Montana State.