It all depends what pests are a problem where you live. If you are east of the Mis. river you will probably need at least two sprays with something like Spectracides "Triazide" a fairly safe synthetic pyrethrin product. You apply immediately after flowers lose their petals and again 10-14 days later.

If weather is hot and humid leading up to harvest brown rot may be a problem, requiring at least one fungicide spray. I'll let someone else suggest materials but you'll get better advice if we know where you live.

Weekly applications of Surround- maybe four of them, starting at petal fall, is the organic alternative to Triazide.

Thanks Harvestman. Sorry, my oversight not to list my location. I'm in Northern Ohio.

You can obtain advice for your region from your county's Extension Service office.

Locate your county's office using this map:
http://www.csrees.usda.gov/Extension/index.html

Here is a link that might be useful: locate your county's Extension Service office

You will generally get better info right here than from your cooperative extension because they have no info source for home cultivation. They are largely restricted by the mission of land grant universities to provide research based information accrued purely for commercial fruit production.

This isn't to say that they are not of use but I relied very much on cooperative extension when I started growing fruit in NY 30 years ago and at least half of the advice was flat out terrible. Now that I'm an experienced fruit grower here I use my cooperative extension for certain diagnostic purposes and information on pest control and pesticides but through the filter of experience.

In short, you should use all available sources of information but there is no substitute for advice from the growers on this forum whose goals and methodology are much different than those of commercial growers.

By the way, I believe my pesticide recommendations are valid for Ohio, but hopefully Olpea or another midwestern grower will respond.

I find with my Stanley plum that I need a late insecticide spray in August.

Hilton, what are you gunning for?

They look like a 2nd generation curculio.

I know they say we don't get those here, but the fruit have larvae and that's what they look like.

With a two spray I get some worms at some sites but those fruit ripen early and are easy to distinguish from undamaged fruit. Usually doesn't affect too much of the crop. By Aug. it would be way too late to spray for it though. The eggs are laid way before the fruit is almost ripe.

That's why I think this must be a 2nd generation. By August, the spring curculio larvae have long since left the fruit and gone to pupate. Larvae in the fruit in Sept has to have been laid in late summer.

lsoh,

I'd start w/ the two spray Triazicide program as Hman outlined above. I might tweak it a bit and spray the first at shuck-split/shucks-off instead of petal fall. Then apply the next spray 10-14 days later. Plum curc is by far the worst insect here for plums, but I don't see egg laying here until the shucks are off.

You may, or may not have trouble with Oriental Fruit moth (OFM). Based on comments on this forum, some people see it and some don't. OFM pressure is pretty high in my neighborhood, but I didn't see any damage on my new trees at the farm 7 miles away (and didn't spray for it).

But for now I'd start with the two early sprays of Triazicide and perhaps apply a fungicide (Montery Fungii Fighter) a few weeks prior to harvest for brown rot, if you're seeing a lot of rain.

It seems unlikely to me you'd experience 2nd generation PC in zone 5 when I don't see it in Z6- but I do get larvae in fruit that doesn't become apparent until a couple of weeks before fruit would normally ripen- especially in later ripening Valor. These worms have been identified as PC but apparently late first generation. Figure a delayed application in mid to late June would probably zap them.

Doesn't much matter whether they're 2nd gen or late 1st gen - they're out there and they need to be addressed to keep them from ruining the fruit.

The question is timing. My thinking is - if I'm seeing larvae in fruit at the beginning of September, they have to have been laid within 3 weeks, in August.

It just may be necessary to spray on a monthly basis through August.

Thanks everyone.

Ltilton, did you give the worm the walk test? Curculio will just flop wildly in your hand and OFM will crawl in a particular direction since they have feet. I was sometimes mistaken about what I had before I learned to use this test.

Scott

That's a great trick Scott.

I cut them out and check them under the magnifier.

afaik, we don't have OFM here.

You have OFM not too far from you, its found everywhere in the US.

Scott

I'm sure it will show up sooner or later.

I have a timing problem. Looking at my plum tree blossoms, about 1/2 half have lost their petals, 1/2 have not. Due to my schedule, I'll need to spray now or wait about another 2 weeks. Would it be better to apply the first insecticide spray now or wait?

I also have a sweet cherry that I'm hoping will produce fruit this year. It's slightly behind the plum. Pretty much in full bloom. Same question for the Cherry. Spray now or wait another 2 weeks?

Thanks.