The apple trees have flowered heavily in Avery County, maybe even more than last year. This should set us up for a good crop. However, I would like to mention two things of importance.
First, for those of you interested in spraying your trees for pest and disease issues, petal fall is a very important time for treatment. Petal fall is when the flower petals (blossoms) have all dropped off the tree. Plum Curcullio and the Oriental Fruit Moth are two pests we primarily deal with in Avery County. If your trees are bearing apples, both pests can cause serious damage to the fruit.
Another pest to keep in mind that will cause damage is the Codling Moth. The first generation of Codling Moth are better controlled by waiting until a first cover treatment is performed. This is performed 7 to 10 days after the petal fall treatment. The cool weather has slowed down the population of Codling Moth in Avery County, but populations will pick up significantly with warmer weather.
An apple spray program is under way this year in Avery County. The program will evaluate the effectiveness of a minimal spray program (3 treatments) for homeowners and backyard orchards. Last year there was an abundance of pest and disease issues in Avery County and the surrounding counties. Of course, many of our Heirloom apples do fine most years without treatments.
If you are planning on spraying, the first treatment should contain a fungicide such as Captan or Mancozeb (Manzate). These fungicides should be used along with an insecticide. If using Mancozeb as the fungicide, make sure to use it in earlier treatments as it has a 77 day preharvest interval. The insecticides being used this year in Avery County include the Imidacloprid product Macho 2.0 and Acetamiprid products Assail and Voliam Flexi. These products have varying degrees of effectiveness on our targeted pests. Remember in order to avoid contact with bees, never spray an insecticide while flowers (blossoms) are still on the tree.
The next area of importance is borer damage. I have been observing a lot of apple tree mortality due to the Round Headed Apple Tree Borer. The adult borer is a beetle that will lay its eggs on the trunk. The eggs hatch into larvae and will tunnel into the trunk. The adult beetle overwinters and if your apple trees are close to woods you have a greater chance of borer damage.
Trunks must be treated each year for the first several years. May is the month to begin spraying. The spray needs to be applied to the bottom two feet of the trunk to be effective. A material which I would recommend to many homeowners is Permethrin. This is the active ingredient found in several different products. One such product sold in Avery County is Permatrol.
This product will need to be sprayed on the trunks every 30 days. Begin this process in May and continue all the way through August.
Although painting trunks with white latex paint certainly helps repel the borer, and is a good practice to avoid southwest injury, it is not a guaranteed borer control. I have seen borer damage on trees with painted trunks. Some growers are doing both, painting trunks and spraying with an insecticide.
If you have any questions concerning spray treatments, borer control or general apple growing, contact me at the Avery County Cooperative Extension at (828) 733-8270.