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Old 30-07-2006, 05:51 PM posted to rec.gardens.roses
dave weil dave weil is offline
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First recorded activity by GardenBanter: Jul 2006
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Default my rose don't bloom, and japanese beetles are eating my roses

On 27 Jul 2006 13:26:05 -0400, Tom Line wrote:


http://www.uky.edu/Ag/Entomology/ent...rees/ef409.htm

Univ of Kentucky has a good page on jap beetles. Very complete. Says to
collect beetles because they emit phernomes that attract others. Traps
only attract more beetles, and sprays have limited effect. They migrate
during hot days with light wind.


The other thing is that while they're eating, they're also breeding
(if you look close, you can often see this in action!). This means
that they are dropping eggs into your soil, which next year will turn
into grubs, thereby ensuring a constant supply (they don't even have
to migrate in).

So you have to take a two-pronged approach - next spring, you need to
use a grub killer (milky spore or one of the commercial grub killers).
The timing is important, IIRC. I think you have to apply it as the
grubs work their way close to the surface, around May or so. This will
reduce the infestation.

Then, one thing that you can try is misting the top of each bush with
a NEEM oil spray. They don't like the smell. You should do this early
in the morning so that the oil doesn't burn the leaves in the hot sun
(think of what Hawaiian Tropic does to your skin in the mid-summer
afternoon). You can do this two or three times a week without harm
(plus is deters other beasties as well. Some folks in my region swear
by this, and it makes sense, since JBs are scent driven.

The easiest and most environmentally-friendly way, but most time
intensive, is to simply knock them off into a cup of soapy water.

Getting rid of the grubs next year is the best way to keep your
infestation under a semblance of control. Sure, they can still fly in.
But you will eliminate a BIG source of insects, an infestation that
will bring in even MORE of the little irridescent creatures.