As any fastidious backyard apple grower knows, it's a lot of work to bring in a bountiful and healthy crop. In some regions 10 or more sprays are necessary each season. Insect pests still require spraying in most areas, but apples are mainly sprayed to prevent disease, primarily scab. Ignore insect pests and you'll lose fruit. Neglect the diseases and you risk more than just the crop: Tree health suffers. So eliminate the disease problem and apples instantly become much easier. In many parts of the country you can now bring in a prime crop of new disease-resistant varieties with no fungicides at all. At most you'll need two or three insect sprays, applied many weeks before harvest.
The quest for disease-free apples began in 1907 at the University of Illinois. But it wasn't until 1943 that researchers found a source of immunity to scab in a crabapple. The first scab-free variety tasty enough to merit release, 'Prima', came in 1970.
By the end of the 1970s, a dozen scab-immune varieties were available. But very few commercial apple growers or gardeners made the switch, in part because good ideas are often slow to catch on. Most gardeners stuck with their old favorites. There just wasn't enough flavor variety to satisfy apple lovers. After all, why add one or two disease-free apples to an orchard of older varieties that still requires disease control?
Moreover, a fair number of the new varieties were 'McIntosh' wannabes. 'McIntosh', a big-money variety in the Northeast, is very scab susceptible. Researchers wanted a substitute badly. But none tasted as good, and most grew best only in the Northeast.
Now the second wave of scab-free apples, introduced in the '80s and '90s, is changing attitudes. 'GoldRush', which just became available this year, is getting rave reviews, not only for its rich and exotic flavor but also for its superb keeping ability. It will last in prime condition for more than seven months in cold storage. In taste tests it has equaled hot new varieties like 'Braeburn' and 'Fuji'. One enthusiast likened it to the powerfully flavored Esopus Spitzenburg, Thomas Jefferson's favorite apple and a benchmark among connoisseurs. 'Pristine', which will be available for the first time in the spring of 1995, has an exceptional sweet/tart taste and is extra early (ripening with the last raspberries and the first peaches). Now, with a wealth of different flavors and ripening times from which to choose, gardeners can plant exclusively disease-resistant varieties, and forget about disease sprays for good.
What About Insect Pests?
Most gardeners (the exceptions are isolated and arid places in the West) will have to spray to control three pests that otherwise ruin apples. In the West and South, the biggest challenge is the codling moth. The apple maggot fly has also become established almost everywhere apples are grown in the northern half of the country. The eastern half of the country sees both of those, plus the plum curculio, which is often devastating.
Here's a simple schedule to eliminate most damage from the major insect pests:
In all regions for plum curculio and codling moth, apply Imidan (a synthetic pesticide especially effective against curculio) at petal fall and again 10 to 14 days later. Rotenone and pyrethrum don't work, even if applied more frequently.
In the West and South, where the codling moth has multiple generations, monitor with pheromone traps set about a month after the petal fall sprays. Five to seven days after the number of moths trapped (all males) begins to rise, apply Imidan again and repeat about 10 days later. Or use Bt for the moth larvae, reapplying it every two days for two weeks.
In northern regions, trap apple maggot flies by hanging red spheres (decoy apples) covered with sticky adhesive every four to six feet in the tree canopies. Refresh the sticky adhesive in midseason.
Good Culture Minimizes Pest Problems
The surest way to keep apple insect and disease problems in hand is to keep the trees small enough to tend without ladders. Insist on trees on the most dwarfing rootstocks -- M9 or M27. By using these rootstocks, plus limb-bending and summer pruning, apples can be kept under seven feet tall, which makes it much easier to produce high-quality fruit. This may mean ordering custom-grafted trees from specialty nurseries but the benefits are well worth the extra trouble.
It is also very important to locate the fruit planting carefully. You'll need to spray for insects early in the season, so keep apple trees well away from the vegetable garden where lettuce, beets and other early crops would be affected.
Finally, consider bagging the fruit when it reaches the size of a golf ball. Fasten small brown paper bags carefully to the stems with twist ties and staple the bottoms closed if necessary. This not only excludes late-season insects but also prevents cosmetic skin diseases like sooty blotch and fly speck. A week or two before harvest, remove the bags to allow the fruit to color in the sun. You will get fruit of the very finest quality that has not received sprays of any kind for at least two months prior to the day you pick it.
Low-Spray, Scab-Free Apples
These apples are all are scab immune. Susceptibility to cedar apple rust and powdery mildew is noted below, but most of these new varieties have at least moderate resistance to both. Mild-winter adaptability or chilling requirement is untested.
Rust: Moderately suceptible Powdery mildew: Moderately resitant Fruit description and flavor: Deep red but needs full sun to color fully. Flesh texture like Jonathan. Flavor very similar to Prima: slightly spicy, tart-sweet and juicy.
Rust: Moderately resitant Powdery mildew: Resistant Fruit description and flavor: Yellow background, covered heavily with deep red. Flavor is excellent after a month in cold storage: sprightly and rich with a little hint of McIntosh. Fruit hangs well.
Rust: Resistant Powdery mildew: Slightly resitant Fruit description and flavor: The fruit is large and predominantly red. The flavor is sprightly with a good sugar-acid balance.
Rust: Susceptible Powdery mildew: Resistant Fruit description and flavor: Looks much like Golden Delicious. The flesh is pale yellow and a little coarse. The flavor is excellent: spicy and moderately tart. Highest quality develops after six weeks in cold storage.
Rust: Moderately resitant Powdery mildew: Moderately resitant Fruit description and flavor: Similar to Jonathan, but redder and not quite so tart. The flavor is slightly spicy, rich and fragrant. Not as susceptible to bitter pit as Jonathan.
Rust: Resistant Powdery mildew: Moderately resitant Fruit description and flavor: Very deep red with crisp and tender flesh. The flavor is sprightly with a good sugar-acid balance. It repeatedly scores well in taste tests.
Rust: Resistant Powdery mildew: Moderately resitant Fruit description and flavor: Similar to McIntosh in appearance. Flavor is pleasantly tart and improves after several weeks in storage.
Rust: Unknown Powdery mildew: Moderately resitant Fruit description and flavor: Looks like McIntosh. Firm, juicy flesh. The flavor is mild with slight tartness.
Rust: Resistant Powdery mildew: Very resitant Fruit description and flavor: Similar to Cortland. The background color is green-yellow, striped and washed with red. The flesh is creamy white, firm and crisp. The flavor is pleasant and sweet with low acidity.
Rust: Resistant Powdery mildew: Moderately resitant Fruit description and flavor: Very similar to McIntosh in appearance and flavor but somewhat sweeter.
Rust: Susceptible Powdery mildew: Very resitant Fruit description and flavor: Yellow green, with bright red where fruit is struck by sun. Flavor is reminiscent of Jonathan: mildly acid, rich and juicy.
Rust: Resistant Powdery mildew: Resistant Fruit description and flavor: A smallish apple with green-yellow base color very heavily striped with red. The flesh is unusually crisp and snappy. The flavor is rich, similar to a tree-ripe Red Delicious sparked with a pleasing hint of anise.
Rust: Moderately resitant Powdery mildew: Moderately resitant Fruit description and flavor: Clear, smooth yellow, with slight blush. Crisp, melting flesh with full flavor and good sugar-acid balance. A superior early apple.
Rust: Resistant Powdery mildew: Very resitant Fruit description and flavor: Mostly bright red over pale yellow-green background. Crisp but tender flesh. Mild flavor, slightly acid to sweet. Heavy crops must be thinned. Hangs well when ripe.
Rust: Moderately resitant Powdery mildew: Resistant Fruit description and flavor: Very large, tall fruit, yellow with red blush. Rich acid flavor, distinct aroma and and very juicy. Flavor improves after several weeks in cold storage. Ripe fruit hangs well but bruises easily when handled.
Rust: Very resistant Powdery mildew: Moderately resistant Fruit description and flavor: Bright red with small area of pale green to yellow. Firm, very crisp flesh. Mildly acid, rich flavor.
Jack Ruttle is a former senior editor at National Gardening.
Photography by National Gardening Association.