David, for fireblight actinovate is not as effective as copper or streptomycin. I have not tried it due to all the studies not rating it highly enough.

For your general question.. first step is to figure out precisely what is causing you problems. For the crabapple, fireblight doesn't defoliate, it causes shoots to bend over and look dead. Defoliation is more likely from a bad case of apple scab. The most common cause of defoliation of plums is bacterial spot, but you need an accurate diagnosis before spraying. If its bacterial spot that is your problem, the Japanese plums are no better than the europeans. Its not so hard to get under control once its diagnosed, just spray copper right before leaves appear in spring and just after they fall off in fall. Every disease is different and requires a different treatment, so step one is get an accurate diagnosis. If you can't figure it out on your own feel free to post some pictures here.

Even more generally, if you are not planning on spraying much I would not expect much from apples or plums. I would either switch to figs/persimmons/mulberries, or decide you want the apples and plums and are willing to do half a dozen sprays per year.

Scott

Thanks. Well, at least blueberries, grapes and blackberries are pretty trouble free for me. I only wanted the green gage because I've had them in Europe and they are incredibly hard to find here. I wouldn't mind if it merely functioned as an ornamental and only bore every few years, but I can't deal with a tree lhat looks dead by mid-August.

I might try one of the so-called American hybrids...

Here is a link that might be useful: http://www.garden.org/foodguide/browse/fruit/plum/1398

There's a good reason Green Gage plums are hard to find here- they crack when rain comes while they are ripening, and they rot in humidity. You may be to far south to reliably produce them, no matter how much you spray.

They can be a wonderful plum, though.

David, you will have problems with plum curculio on any plum. If you don't spray for them you will never get any plums. If it were not for the curculio you could probably grow the American-Japanese hybrids plums without spraying. Like harvestman says, the gage plums are some of the most difficult to grow. I get only a few fruits a year on them and this is with spraying.

Scott

Thanks Scott. That's a shame. I'm going to completely cut the tree down this weekend when it gets warmer. No sense in having it hog space anymore.

BTW There's a relatively non-toxic treatment for these insects.
http://www.organicgardening.com/learn-and-grow/plum-curculio-control
http://forums2.gardenweb.com/forums/load/fruit/msg0117400323829.html

I might try that on a better plum for this climate.

Here is a link that might be useful: http://www.organicgardening.com/learn-and-grow/plum-curculio-control

This post was edited by davidrt28 on Wed, Nov 13, 13 at 18:41

Right, thats what I use. Once you learn the ins and outs of mixing and spray timing and refreshing after rains the Surround works great. If you get an early ripening (and thus more rot resistant) Japanese-American hybrid plum you may be able to get a good harvest with spring Surround sprays only. The one other issue that has been major for me is bacterial spot, but it only requires copper in late fall and early spring to get under control. Make sure to avoid spot-prone plum varieties. Shiro has been extremely reliable for me for example. Its not tops for flavor but the thing is bulletproof in my orchard.

Scott

Scott were do you get streptomycin? I 've been looking for it since losing 6 apples and at least 1 pear to fireblight. I know it also goes by agrimycin but haven't found anyone who stocks it.

Amazon sells Ferti-lome, a streptomycin fireblight spray