I live in Beltsville, in the DC suburbs. Here are my thoughts. Hopefully Jellyman and Scott Smith can reply to your post too, as they have more experience at this.

Apples: I've done well with dormant lime-sulphur oil spray + a couple of sprays of Surround, followed by bagging. I grow Williams Pride and Enterprise; I've also some heirloom varieties, but they are too young to report on. Both WP and Enterprise are mega disease resistant. Williams Pride is tasty but very early; must be refrigerated to keep, but you will only get a few weeks. Probably fine for applesource. Enterprise ripen later (October) and keep much longer. Liberty would be another good choice. These are all good apples if you wish to avoid spraying for disease.

Pears. I grow Seckel. No problems with fire blight. A little brown rot last year and some codling moth. In general, pears are not hit as hard with Plum Curculio as apples, and you might get away with a few sprays of Surround and then benign neglect. I know my neighbor's Bartlett were hit hard with fire blight, though. I would recommend looking into Asian pears too.

Sweet cherries: have not grown myself, but my neighbor has, and has major problems with rot in Maryland. You would need to spray with fungicides. I only grow sour cherries, which usually do ok without sprays and, in my book, are a more versatile cherry (cherry brandy, pies, drying etc.). I grow Montmorency and North Star, but I'd also try some of the Eastern European varieties now available, such as Ballaton. Cherries must be netted, or the birds will get them. Plums -- Scott Smith can help here. I grow the Euro prune plum Stanley; needs spraying for curculio early on. Does not seem to strongly attract the other main pest, Oriental Fruit Moth, later in the season if you have the much preferred nectarines or peaches also growing. I have had more brown rot and splitting this year with recent heavy rains (occasional heavy rains are a real problem in MD).

Quince: I have an Aromatayna. Serious problems with galls and some fire blight. I suspect this plant was diseased when I bought it. This is probably going to be a problematic fruit -- a pity.

Medlar: have a couple growing. So far no problems with insect pests or disease. Heavy rains cause splitting, but as the trees get older this problem seems to be diminishing. A pretty tree and Medlar jelly is very tasty.

Juneberries; I have Regent from Edible Landscaping. Slow grower and has got rust. Fruited last year and fruits are interesting - sort of like a blueberry with an almond after taste (from seed). Juneberries are probably worth growing, but do some research on varieties. I suspect Regent is not a particularly good variety.

Figs: take a few years to start production. In early years need to be covered in winter (caged with leaves or straw around them). After a couple of years mine have survived MD winters without protection or significant die back -- but try to plant in a protected south facing area. I have Celeste and Brown Turkey. Celeste is much superior in flavor, but has smaller figs and not as many. Definitely worth growing in MD.

Hardy Kiwis: probably 3-4 years before fruit. Must buy male and female. A little tricky getting started, but once they get going, pretty bullet proof. Need a trellis or some sort of structure to grow on. No spray.

Blueberries: grow well, few pests, provided they have acid soil. I've had mixed experience with varieties. Jersey, for example, is a poor choice. You need to net blueberries against birds.

Raspberries are pretty easy, but here too variety choice is important. The much touted Heritage has been a dog for me. Asian persimmons, both astringent and non-astringent, are my choice for a no trouble delicious fruit, and I would highly recommend them. I have no experience with Jujubes or paw paws. The jujubes I have tasted at Edible Landscaping did not taste good (I'd love to know of varieties that do taste good off the tree). I've tasted good Paw Paws, but not grown them. They are on the list of future things to grow.

Other possibilities: blackberries, provide a trellis, prune and they are trouble free. Che fruit from Edible Landscaping; so far no pests. Elderberries: no good for fresh eating, but excellent for jam, wine, syrup for flu. A greatly underrated fruit. Goumi: grow well, but must net to keep birds off. They stripped mine well before they were close to ripe. Gooseberries: a trouble free, underrated fruit - highly recommend. Currants: relatively trouble free, though tend to get mildew later in the season. Grow well in filtered light area.

Send me a personal email if you'd like to discuss these things more or come out and see what I am growing.

Heres my rankings of the Baltimore area. Main problems for me are in parens.

Very hard: quince, medlar (rust, fireblight, codling moth)
Hard: plums (curculio, fruit moth, black knot, bacterial spot), cherries (cherry fruit fly, bacterial canker), apples (fireblight, curculio, codling moth, cedar apple rust)
Not too bad: pears (fireblight, blister mite, codling moth)

The quince and medlar have proved to be a huge pain for me, they are much more susceptible to the indicated problems than apples. Just this year I started to get quince rust badly on them. Just what I need, yet another disease on these disease magnets.

A friend had an old untreated apple tree we would make sauce out of but to cut out the bad bits would take so much time that it wasn't worth it (our friend gave us bags for free so we felt obligated to use them). So I would say you need to at least to some minimal protection so not all fruits are gnarled. For disease-resistance, look for CAR resistance, many of the disease-resistant apples can still get that badly. That has been my biggest disease problem by far; scab has not been much of a problem and I have few disease-resistant apples.

I don't know much about juneberries.

Scott

I live in Anne Arundel County and my Figs, Pears, Grapes and Apricots are doing fine. I have an Apple tree but no luck. Banana, so far so good but I have not eaten one yet.

I am in Montgomery county. Here is my experience as well as my sisters, who leaves less than one mile from my house and is very dedicated orchard gardener. We don't spray fruit trees
Quince -was complete failure, rust fireblight and insects. Died painful death after suffering for several years.
Apples -didn't work w/o spray. Tried Liberty, Jonagold, Antonovka, several from StarkBros.
Plums, european pears - no success. Tried a lot of different varieties.
Sour cherries -so far so good, growing Balaton (still young), Danube (young) and English Morello.
Aisian Pears - Korean giant, Seinko (sp?)-mixed results depending on the year. Last year was good, this year is bad.
Aisian persimmons -many varieties, easy to grow here.
Figs -need several years to star fruiting. A lot of dieback in first years ( I don't protect). Eventually build size and become quite hardy. Hardy Chicago, Verte, Celeste, several others.
Currants -red and black -very easy here
Gooseberries -depends on variety, some are very easy
Raspberies and Blackberries- grow like weeds
jujubes -easy
Cornell cherries- easy

Olga

I'm many miles and a zone or some away from you (W. Montana) but I've come to view my beloved Liberty as a fire blight magnet, FWIW. Other than that it's a weed -if anything a bit hard to control and a good base for grafting other varieties to. We enjoy the fruit (not great storers) a lot, but I think in my next attempt I'll do something different.

Trying to raise truly organic tree fruit may be an exercise in frustration for you, but I wish you luck. A lot of people have success with bagging, and that can make a huge difference.

M

Wow, thanks for the responses so far everyone! It sounds like individual experiences have varied quite a bit.

I am sure I have hundreds of hours (including many calls to the local extension agent) of planning before any planting starts. There's bound to be many ups and downs trying to grow without lots of chemical spraying (and even with it, pollination can be hit or miss with some stuff), but I think my strategy is going to be to grow a bunch of different stuff (including some surefire varieties) so if some stuff doesn't work out it won't be the end of the world.

I'm running out of time to finish writing this post, but here is some info on jujubes that are supposed to be good for fresh eating that I'm come across:

http://forums2.gardenweb.com/forums/load/fruit/msg100853165840.html

http://www.texasgardener.com/pastissues/janfeb08/Jujube.html

I'll try to write a more in-depth post next time . . .