SPRAYING AND INSECT CONTROL

It is possible to grow fruit without the use of poison sprays. To do so, you must have perserverance and a commitment to learning as much as you can about the life cycle of the pest or disease involved. In other words, there is no “silver bullet.” There are a few good books with information on organic pest and disease control, (see The Apple Grower: A Guide for the Organic Orchardist, by Michael Phillips, listed under Books in our catalog) and many excellent sources on the world wide web. Seek out and pester other organic growers. What have they used to counter pest and disease problems? What worked and what didn't? Do not just go down to your nearest garden supply store and buy “fruit tree spray.” Even if you intend to attack pests with chemicals, don't use the “shotgun” approach. Identify the problem before you choose your solution. What follows is a general summary of some of the more commonly used natural and organic remedies.

There are many tiny critters that hide in bark crevices over the winter and will wake up in Spring and start chewing on your tree. A good natural “dormant oil” spray, with no pesticides or fungicides added, works effectively to smother overwintering egg cases and insects, and is a preventive measure recommended annually for all fruit trees. It kills pear leaf blister mite, scale, and pear psylla. Dormant oil, as the name implies, should be applied in late winter (February through April) before bud break. However, some of the new lighter horticultural oils (“summer” oils) can be applied even after leaf emergence. If your tree is fairly short, most backpack or handheld spray units will reach the topmost branches. If you use a “summer”oil after bud break, make sure you keep applications of oil and sulfur separated by 2 weeks; oil can cause the sulfur to burn leaves and fruit.

Aphids are often a problem on young fruit trees, sucking the juices from the undersides of the leaves and causing them to crumple and wither.  We use a spray of Safer’s Insecticidal Soap to control aphids in the spring.  Aphids in summer and autumn are not as detrimental to the tree’s growth and may actually encourage hardening-off in cold climates.

If you notice that the leaves of your young trees are being chewed, look carefully for some kind of leaf-eating caterpillar.  There are many kinds, some tiny and some large. The Eastern tent caterpillar makes an easily-identifiable nest between two twigs, and is a common Spring plague on fruit trees. If the tree is small and there are only a few worms, the finger-pinch method is most effective...watch for caterpillars or for developing nests...with caterpillars just squish them as you see them, with the nests wait until evening or early morning when the caterpillars are all inside the nest, then collect up the spider-webby nest, throw it on the ground and stomp on it. This is easiest when the nests are small, so get right on it as soon as you see one. If there are too many or you are too squeamish for squishing, most can be controlled with the biological spray “bt,” a natural bacterial agent (Bacillus thuringiensis) which infects only leaf-eating caterpillars

Codling moth, apple maggot (alias “railroad worm,”) and plum curculio are common pests that affect the fruit of apple trees:

Codling moth. Pheromone traps lure male codling moths with a sex attractant and trap them. These can hang in the tree from bloom time on through the summer, 2 traps per mature tree. Replace them in 8 weeks. Spinosad, marketed under the names “Entrust” and  “Bulls-Eye,” is an natural control made from soil fungi. It contains a neurotoxin that kills the codling moth larvae, as well as a broad range of other pests,  yet reportedly has only a limited toxicity to most beneficial insects. Bacillus thuringiensis (bt) works on the codling moth larvae and affects only caterpillars, but needs to be timed just right. Virosoft  is a commercial preparation of the granulosis virus that attacks codling moth larvae.

Apple Maggot.  Apple maggots (alias railroad worms) overwinter in the soil after emerging from fallen fruits. Therefore, you can help break this cycle by keeping all drops picked up around the tree.Yellow monitoring traps and red spheres coated with tanglefoot can be up to 95%  effective against apple maggot. It takes up to six spheres per mature tree, and they should be hung 3 weeks after the flower petals fall. Repeated applications of the clay solution “Surround” also suppress apple maggots. (see Plum Curculio.)

Plum Curculio. The only natural control to date that has been successfully used against plum curculio is a kaolin clay solution, presently being marketed under the name “Surround.” This compound forms a physical barrier against the curculio via a thin grey film over the leaves that does not interfere with photosynthesis or respiration in the leaf but inhibits the bug's attack. It must be reapplied several times during the season, beginning at full bloom and continuing through late June, but can provide good control.

VARMINT CONTROL

Voles (meadow mice): A new product, “VoleBloc,” from PermaTill  is a made of heat-puffed slate particles that can be placed in a moat pattern around trees, shrubs and bulbs. Voles do not like to dig through it.
 
 

PROTECTION AGAINST SUN-SCALD

Sometimes honeydew from aphids or sap from an injury will drip on the trunk and turn black. This black spot can absorb heat, contributing to sunscald in late winter.  Use a small brush with soap and water to wash such deposits off the trunk.