Hello apple lovers. It’s fall and the apples are ripening, at least on those trees that had apples this year. I believe the May freeze prevented many trees from bearing apples. Let’s hope for no late spring freeze next year.
This season I worked with a grower interested in spraying his trees. The growers’ primary interest was to reduce the amount of disease incidence on the fruit. We conducted three treatments using conventional pesticides to see how minimal amount of spraying could help prevent insect and disease incidence or our “summer rots.” Three spray treatments were made using a 20-gallon spray unit mounted on a UTV. Commercial apple production utilizes many more treatments to obtain the quality of apple found on most grocery store shelves.
Our first treatment occurred after petal fall, which is typically one of the most important times for preventing insect damage and disease development on fruit. Captan was the fungicide used in each of the three treatments. Assail was chosen for the insecticide at petal fall primarily targeting codling moth, oriental fruit moth and plum curculio.
The second treatment was made 11 days later using Voliam Flexi to target remaining moths and plum curculio. The last treatment was made August 3 using Macho (imidacloprid). Red ball traps were hung to monitor apple maggot populations. The threshold for treating apple maggot is five cumulative apple maggot flies caught.
Two apple trees were left untreated to compare with treated trees. The untreated trees showed fungal disease on the leaves. There wasn’t much fruit on the untreated trees this year, so it was difficult to assess disease and insect damage on fruit, but with the fungal disease on the leaves it would likely have spread to the developing fruit.
The apples with three treatments were very clean of disease or insect damage. Anyone interested in treating next year can contact me and I will share the rates for each of the materials used. I will also be discussing spray treatments in meetings next March.
As there is a lot of interest from homeowners for organic spray treatments, next year I hope to set up spray treatments using various organic materials such as spinosad, neem oil, kaolin clay, and sulfur to evaluate efficacy. Click to https://content.ces.ncsu.edu/apple-maggot for viewing apple maggot damage. It has good pictures so you have something to go by as you pick your fall apples.
I find the exterior damage from plum curculio and apple maggot (the cat facing and dimpling) to be similar but the interior damage seems to be more pronounced from the apple maggot than the plum curculio. Of course, our early apples won’t have apple maggot damage because they ripen before apple maggot is present.
Don’t forget one of the best sanitation practices to reduce disease pressure next year is to remove or mow (mulch) the leaves under your apple trees this fall and winter, and remove those mummy (dead) apples still hanging in the trees this winter.
Another point worth mentioning is to be on the lookout for the pine vole this fall. One grower has mentioned that he is having issues with them again. The pine vole is more active in the fall and winter months. The pine vole is the one that stays underground burrowing, chewing the tree roots and stem collar. If you see the small piles of dirt close to your trees, scoop away the dirt to expose their tunnel. You can place crushed ramik green rodenticide in the hole. Make sure to cover that hole back up and place a rock or small log on top of it to protect pets. For more information, click to https://content.ces.ncsu.edu/voles-in-commercial-orchard-and-ornamental-nurseries.
Be on the lookout for the plant sale catalog in January. We are offering new apple varieties and dwarf apples again. I look forward to being able to hold meetings again next spring.