So it`s high summer and I have about 6 types of beans in my garden, the bean beetles are getting the leaves of all of them and making a huge mess. They are spotted and long bodied (not like the little pseudo-ladybird bean beetles) like some of the ones here. http://ipm.uiuc.edu/insects/bean_leaf_beetle/ The things I`m finding online don`t have any real options for non-chemical controls. I have access to papaya and castor bean, and could conceivably get neem oil (which are all used for other pests where I live, although nobody seems to have any ideas about this specific insect), but not diatomaceous earth (which seems to always be the answer in the US-based permie resources I see). Any suggestions? Thanks!
Two ideas....hose the plants off with a strong blast of water from a hose...the goal being to knock the pests off. Perhaps after this, or instead of it, get some fluffy wood ash and dust it all over the plants, being careful to get it onto the undersides of the leaves also...wetting the plants ahead of time will help it stick. I often find this helps control infestations of many kinds of leaf-eating insects, slugs, and such like. Apparently most critters don't like their salad covered in ashes any more than I would.....
One reason where compost teas as foliar sprays fall down is where they plug up the pores through which the leaves respire. I would be concerned that the same would happen with the application of fluffy wood ash.
With some species, manual picking is the only option. Spraying them off, or blowing them off with judiciously applied blasts from a pressure sprayer on low could work. I would look to see if beer or honey traps work for the beetles as well as they do for things like slugs and earwigs.
Do you have any trap crops? Are there any types of bean that they seem to like over the others? If so, you could potentially use that type of bean as a sacrificial trap crop. You could trap them there and abuse the plants as much as necessary to harvest the beetles without worrying about affecting yield.
You might also consider what you do with the harvested beetle carcasses. Most things don't like the smell of the decomposing bodies of their own kind, so if you make a sort of beetle corpse mulch and apply it around the beans, perhaps the beetles will be driven off.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein
Thanks, Alder and Chris! I have been trying to remove them manually, they are speedy and smart little #%&s and catch on pretty quickly. I am able to maybe get one or two before they catch on, but that is one or two less that are eating my leaves. But a regular blasting sounds like a good fate for them.
I will try the ashes too, maybe on one of the less precious plants (the normal green beans) to see if the plants are harmed, ashes seem like a great idea..... and I saw something about a product made of kaolin clay, which apparently is mixed with water and sprayed on, I think ashes would be an even better option. On the other hand, if the plants aren`t able to breathe, that is a problem!
As for the decoys-- I planted Christmas beans (like a stripey fava), scarlet runners, and lablab, thinking the bugs could eat them (since I`m not super partial to anything about those three). The bugs seem to greatly prefer my green beans and especially the long asian noodle beans. (OF COURSE!) I am being outfoxed by beetles.
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