Question:
I just dug up my garden to allow it to dry before tilling and planting. I noticed many Japanese beetle grubs upon turning the soil over. A few questions: 1- Is there anything I can do now before tilling/planting? I don’t ‘necessarily’ want to put chemicals down if I can avoid it but could be convinced otherwise. Any suggestions?
Bacillus popilliae, milky spore bacteria, would be my first choice. Very non-toxic, use it once and it should establish the disease in the soil — that should be all you need to do for many years. Sold as Grub Attack, Milky Spore Powder, Doom, and Japidemic, among other names. 2- Unless I hear differently from the net, I plan onputting Spectricide down this fall. I used this on my lawn and the grubs came right out of the ground. How long does Spectricide last (i.e. will is be gone in time for spring?
Spectracide is diazanon, and has a soil half life of about 30 days. (No, I don’t know its decomposition products). Diazanon is pretty toxic, like all phosphorthioates. Hits a lot of non-target organisms, too, like fish, bees, earthworms…. Kay Klier Biology Dept UNI
Response:
| I just dug up my garden to allow it to dry before tilling and | planting. I noticed many Japanese beetle grubs upon turning the soil | over. A few questions: [ ... deleted ... ] I think there’s a better solution than chemicals. (My memory’s a little hazy, but hopefully someone who knows will write to correct my mistakes.) There’s some kind of fungus that is supposed to do the trick. I think the fungus stays underground and feeds off of the grubs. I’m not sure of the name (milky spore?). It may take a year or two for the fungus to get really well established, you probably shouldn’t use anything else to kill the grubs during that time (what would the fungus live on?)
<resat deleted You’re thinking of the bacterium Bacillus popilliae (spelling is close but probably not exact). It causes milky spore disease in the Japanese beetle grubs, killing them while it multiplies itself, maintaining the bacterial population for the next grub to come along. You’re right, you shouldn’t treat with chemical insecticides during the first few years of milky-spore treatment. As for "never" having to reapply, the manufacturers only claim 15 years, but who knows. Speaking of manufacturers, there are two brands of Bacillus popilliae preparations: Doom and Grub Attack. Grub Attack has had dud lots the past few years (no viable bacteria in the preparation!) and may be unavailable this year. Doom had no such problems. There are some beneficial nematodes that are supposed to be active against Japanese beetle grubs, among other things. Disclaimer: I’ve never used any of these. I’m just going by what the garden and lawn books say. I have a personal and professional interest in "bacterial warfare" of this type, sao Ill be following this thread with great interest… Dorothy Klein Biochemistry and Microbiology, Cook College, Rutgers U.
Response:
Spectricide (aka Diazinon) has been implicated in bird die-offs after use on golf courses in New England, and in chronic human health problems as well. It will not reliably break down within the time frame you suggest, either. Fortunately, there is an alternative. Milky Spore disease, or Bacillus popilliae (sp?), a fatal disease of Japanese Beetle grubs (and not much else) is readily available most places where J. B.s are a problem. Cost per application is quite a bit higher than the chemical, but when you factor in the 20-30 year effective period for Milky Spore, it pays for itself in about 4 years or so. Arlington, Virginia dusted itself with Milky Spore (by plane, i presume) in the Early ’60’s, and when I lived there in ‘84-87, Arlington was like a beetle-free oasis in a "ravaged" countryside. The stuff really works. It’s easy to apply, too: just a regular lawn spreader. chris
Response:
| I just dug up my garden to allow it to dry before tilling and | planting. I noticed many Japanese beetle grubs upon turning the soil | over. A few questions: [ ... deleted ... ] I think there’s a better solution than chemicals. (My memory’s a little hazy, but hopefully someone who knows will write to correct my mistakes.) There’s some kind of fungus that is supposed to do the trick. I think the fungus stays underground and feeds off of the grubs. I’m not sure of the name (milky spore?). It may take a year or two for the fungus to get really well established, you probably shouldn’t use anything else to kill the grubs during that time (what would the fungus live on?). Once the fungus gets established, you never have to retreat. Even for the worst chemical-spewing non-environmentalist, the fact that you don’t have to retreat should be sufficiently appealing. — James B. Reed | If at first you don’t succeed, DAZIX, An Intergraph Company | Find out why, (205) 730-8874 |
Response:
I just dug up my garden to allow it to dry before tilling and planting. I noticed many Japanese beetle grubs upon turning the soil over. A few questions: 1- Is there anything I can do now before tilling/planting? I don’t ‘necessarily’ want to put chemicals down if I can avoid it but could be convinced otherwise. Any suggestions? 2- Unless I hear differently from the net, I plan onputting Spectricide down this fall. I used this on my lawn and the grubs came right out of the ground. How long does Spectricide last (i.e. will is be gone in time for spring? Thanks in advance, John S. Link —