Japanese beetles have arrived

[St. Louis gardener]

Yesterday I found my first Japanese Beetles on my Ozark Sundrops. They weren't there a couple days ago but still did a lot of damage very quickly. I started picking them off one or two at a time. Now I have about 40-50 in a coffee can. I thought I might have caught the "scouting party" before they let the rest of the colony know about my garden, but isn't that many beetles in just a couple of days considered an infestation? Should I buy a trap (with the lure that brings them in from surrounding area), or use sticky traps painted yellow, or just continue to pick them off? I guess I want to know when do you think I should give up picking them off and realize it is an infestation and go for the traps, or even spray with insecticide (I hate to do that because the bees just love the flowers). Also, I read somewhere you can grind up the beetles to make a spray that will keep new ones from attacking the same plants. Is that true? If so, how many beetles do you need to make a useful amount of the solution?

[gixxerific]

Sorry to hear that. I found tons and tons of larvae early this spring when getting gardens ready and in the dead patches of grass.

I would not suggest getting one of the pheromone traps. They will actually attract them to your yard. The ideal method for those is to get your neighbor a few house down to get one. That way they will be taken care of and attracted away from your yard.

As far as grinding them and making a spray I have heard about that but don't know enough to comment.

Good luck

[url=https://www.gardensalive.com/article.asp?ai=482&bhcd2=1276455207]Here[/url] is a link that you might find helpful. Oh and forgot about the sticky traps they can be useful as well.

[St. Louis gardener]

Thanks. That's the first info I've seen that actually gives a quick "formula" for the "bug juice." If all that's needed is a "handful," I've certainly got enough. It's funny. There were plenty on the plants this morning, but as they day's worn on, and it's gotten very, very hot, their numbers have dropped precipitously. Guess they don't like mid-90s temps anymore than humans do!

[gixxerific]

About a month ago I was out barbecuing and there were thousands, maybe hundreds of thousands of some type of small beetle flying around. They were super extra thick, unbelievable, this was about 5:00 'ish. I went in to eat and came back out about 1/2 to an hour or so later and they were just about gone. Maybe a few stragglers but nothing even close to the numbers that were out before eating. This went on for 2-3 day's and than I never saw them again.

They are a strange breed.

Again good luck.

[rainbowgardener]

Interesting... I don't (unfortunately) have any helpful suggestions for you. I just found it interesting, because I have LOTS of the sundrops (I call them missouri sundrops, I think they are the same species, but different variety). Anyway I have lots, because they spread pretty quickly. But I have never seen either a japanese beetle OR a honey bee on them. My honeybees go to the salvia and herb flowers and hummingbird flowers and stay away from the sundrops.

Especially if you want to preserve your honey bees (thanks! ) I don't think there's much to do but keep hand picking them. Neem oil may help (be careful to spray it in the evening when honey bees aren't around, it will harm them if they get sprayed directly) or some have said a garlic oil spray might help.

It might help to realize the adult beetles are usually only around for about 6 weeks in the summer and then they are gone (leaving behind eggs and grubs in the lawn!), so there is an end to this!

[garden5]

Well, if this were earlier in the season, I'd tell you to put some Bt on your lawn. It's a bacteria that feeds on the larvae of the Japanese beetle. However, they're out and it's a little too late for that, now. Your neighbor's beetles from his un-treated lawn would have probably just come over to yours anyway so don't feel too bad.

The best advice I can give you is to not use a pheromone trap: it will only attract them. Like Gix said, get one your neighbors to use one .

Really, though, I had them last year and they really didn't bother my garden, so hopefully you'll get the same luck this year.

[St. Louis gardener]

Thanks for all the helpful suggestions. Considering I have only seen them in one place, that I was able to pick off most of them yesterday, and that their numbers dropped to about a half dozen this morning, maybe it WAS just the scouting party? I wish I knew how many were in a colony so I'd know how many more are likely to visit my yard.

I never gave a thought to whether I had grubs in my lawn, but yesterday I checked and there are a few small patches of brown. Perhaps that was the grubs eating the roots. Since I missed my first opportunity to check (April-June), I have a notation on my gardening calendar to sample the grubs the next time they are in the ground (Aug.-Oct.) to determine the severity of the problem. It requires digging up an 8 inch square of sod (by 3 inch deep), turning it over on newspaper, counting the grubs and multiplying by 2.25 to get the grubs per square foot. According to "Managing the Japanese Beetle: A Homeowner's Handbook," if the lawn has more than 10 grubs/ft2, it should probably be treated. Just goes to show: It really helps if you understand the life cycle of the pest you are trying to control!