We try to garden organically and to plant to attract and sustain wildlife and beneficial insects. Our neighbor loves roses, so Japanese beetles will always be present. I crush the grubs I find while digging/planting, and few of our plants interest the adults. But the perennial hibiscus is having a harder time each year with the Japanese beetles; this year it again put on nice new growth and flowered beautifully, but the blasted beetles have virtually skeletonized the foliage. What can I do to reduce/control the Japanese beetles that won't harm the ladybugs, bees, butterflies, etc. who are thankfully regulars in the garden now? I've heard mixed reviews on milky spore, and fear that anything I spray for the adult beetles will also harm the beneficials, which I definitely don't want to do. Any advice will be appreciated, and thanks-
I've had good luck with Milky Spore. I also just don't plant 'beetle-bait" plants like perennial hibiscus. There are so many other plants, it's not worth the effort. When I put those bag-traps out, I put them way in back of my property to lure the beetles away from my plantings. You might even be able to talk your neighbor into letting you put bag-traps on HER property "to help the roses", which would lure them away from your property!
Hoosier, you've said what I've been thinking but not wanting to admit; the hibiscus probably isn't worth it, though it's hard to convince myself of that during the brief but gorgeous time frame when it's blooming. And the neighbor actually does use the bag traps; but no doubt to try to draw the beetles away from the roses (good luck with that!), the traps are sited fairly close to our property - and then the hibiscus draws them over here. I've thought of trying your idea of using the traps far from any attractive plants; may resort to that if I can't bring myself to kill off the hibiscus.
Ecrane, I was hoping to hear from someone who'd tried the beneficial nematodes; saw them from Gardens Alive, and wondered if they work. Can you apply them with the typical pump sprayer, or how are they distributed?
I've never used the nematodes, but from another thread where someone was using them, it sounded like the ones they had came as some sort of solid stuff that you dispersed in water, but since it makes a dispersion rather than being soluble in water I think it would tend to clog a pump sprayer and you'd want to use a watering can instead. Unless maybe you have a pump sprayer that's capable of handling material like that--I know the one I have would clog but there might be other ones that can handle things like that.
Putting out the bag traps is working against you. The traps will attract far more beetles than you would normally have, so even though many will go into the trap, plenty of them will choose your plants instead. It's rather like putting out carrots for deer, with the thought that they'll eat the carrots and not your garden. The result will be your original deer and many more of their cousins who are drawn to your buffet, all of whom will enjoy both carrots and your veggies.
I've had the best luck simply brushing the beetles off the plant into a container of soapy water. They usually drop straight down when disturbed. Their season is pretty short--only three weeks or so when they're heaviest--so I go out once or twice a day during that time.
Kneff, I've always felt as you do about the traps; but with the neighbor's traps drawing the beetles close to our property, the hibiscus does the rest to draw them here. We're in the country, so I've considered putting a trap or two in the drainage ditches at the far limits of the property, well beyond our plantings; if nothing else, this might draw the ones escaping our neighbor's traps away from our plantings. Or I could just pull out the hibiscus...
Does your neighbor understand that putting out the traps probably exacerbates the problem? Perhaps you could direct him or her to a web site or two that discusses this issue, or print something out for them.
Kneff, I have tried to politely explain that the traps draw the beetles, thus ensuring there are more on the property than there would be without the traps. What can I tell you? These are lifelong southern country folks, while we just moved here from the north and suburbs a few years ago; we aren't awarded much credibility. Perhaps in forty years or so we might earn some cred, but thankfully I won't live that long (lol). We've also tried to gently tell them that the ailanthus (Tree of Heaven) seedling now ten plus feet tall, that is within a few feet of their mobile home, will give their home structural problems one day. Mind you, they certainly didn't plant the ailanthus; everyone is plagued with the beasts thanks to another neighbor whose property line is defined by mature 60' Trees of Heaven. I've been fighting the seedlings and root suckers every year since we moved in, so thought they (the rose-loving neighbors) might want to know what I've learned about the trees' destructiveness. Nope, the ailanthus still grows up close to their trailer, and I have no doubt that its roots will someday be an intimate part of their home. All in all, I've learned to just keep quiet.