Greg:

1. Dormant pruning has its place, such as removal of larger limbs, and any pruning is better than none, but I have improved the bloom and fruiting of my trees by pruning in late summer, usually August and into early September. Dormant pruning stimulates a flush of vegetative growth, while summer pruning favors the formation of fruiting wood and spurs. Improvement is not instant, but will become evident over a period of 2-3 years. Keep your trees open and uncrowded, and do not allow them to become too tall for you to deal with.

2. Most dormant oils have the same basic mode of operation; they are intended to break the cycles of overwintering insects by cutting off oxygen and smothering their eggs. All spray oils must be miscible, which means they can fully emulsify when mixed with water. Standard oil sprays come in various weights, but the type intended for dormant use is normally a standard weight oil such as "Bonide All Seasons spray oil". Oil sprays are effective in controlling or preventing insects such as scale, mites, and aphids, but they have no effect on growing season insects that actually attack the fruit. So, while your trees may be protected against some pests, you won't get any protection from insects on the fruit with oil sprays, whether applied in dormant season or the lighter "summer weight" oils that can be used during the growing season. I use standard Bonide spray oil in the dormant season, at a mixing rate of 4-5 ounces per gallon, somewhat stronger than the label recommendation, and my oil applications usually are made on a nice sunny day in mid-February or so, and again just before or at bud break.

3. We would all like to eliminate the use of chemical pesticides to raise our fruit, but wishing and doing are not the same. Without the aid of some effective chemicals, plum curculio, codling moth, and apple maggot will make a mess of most unsprayed apples, especially in eastern and midwestern locations, to the point that they are unusable. I find it necessary to apply 2-3 early sprays with imidan or permethrin (some, but not all others are effective, and "combination" sprays are useless), to protect little apples from plum curculio for the first two weeks before thinning. But the news is not all bad because..........

4. At that point, I bag the single apple remaining in each cluster in a ziploc sandwich bag, which protects it against further damage from remaining PC, as well as codling moth and apple maggot for the balance of the season. No further sprays are normally required. Much has been written about bagging apples, and you can find a lot of it here with a search. Of course, to properly thin and bag apples, you must be able to reach all parts of the tree where there is fruit, and for semi-dwarf trees or larger, you will have to use a ladder. See para. 1, the pruning part, about that. I prefer to keep apple trees pruned to an open center with spreading branches, which makes it easier for me to reach all the fruit from my 3-point Stokes orchard ladder. If bagging apples does not interest you, spraying will be necessary on a week to 10-day schedule throughout the season (it wouldn't be oil spray), and you may still see some damage.

Don Yellman, Great Falls, VA

Thanks, for all the great information. I agree with what you said about pruning in the winter as it seems that when I winter prune, by the following year, my trees look like they were never pruned at all. Lots of reoccurring leafy growth. I plan to refrain from pruning this winter and wait until just after next seasons crop. Here in New England we are not harvesting apples until late September and thru the end of October.

I will have to check our calender for when to apply dormant oil here in New England, most likely sometime in late March or April, just before budding.

Greg Watkevich

Funny, if summer pruning alone is the best way to manage fruit production why don't the commercial growers go this route?

Of course big apple trees will grow vigorously after winter pruning and I agree with Don that summer pruning is less invigorating, but I use both- I do most of my big wood, structural pruning in winter and most fine pruning in summer.

In my experience, apple trees on vigorous rootstocks require the regular removal of rather large wood and structural pruning during summer will knock a lot of fruit off the trees. It is also easier to see branch structure in winter.

As far as pest control, New England is much different than Virginia and you may only need 2 insecticide sprays (the materials Don mentioned), one at petal fall and one 10 to 14 days later and no plastic bags.

You can also try Surround, spraying at petal fall and once a week 4 times. It is organic and somewhat affective against plum curculio. If you aren't trying to grow Macintosh or other highly scab-prone types you may not need fungicide. Cedar apple rust is another potential problem. Search this site for more info on pest control.
Don, I and many others have posted on this in great detail.