VT Apple IPM- Apple maggot fly traps should be prepared and hung

Assuming that you have dealt with codling moth, we’re in a calm spot between insects but it is time to hang your apple maggot fly (AMF) traps. These are some of the easiest pests to manage using an IPM strategy, so there’s really no excuse. The idea is to assess the population in the orchard before applying prophylactic sprays. By using red sticky traps, you can time treatments for best effectiveness, and maybe even skip treatments if the populations are low enough. Traps are red plastic balls that you coat with Tanglefoot adhesive. Kits including traps and adhesive are available from Gemplers and Great Lakes IPM.

Traps should be hung at least four per 10-acre block, preferably at the orchard perimeter and especially near sources of the insect, like wild or unmanaged apples. Placement in the tree should be about head-height, and surrounding foliage should be trimmed away- this trap is largely visual, and you should be able to see it from 10-20 yards away. The traps may be baited with an apple essence lure that improves their attractiveness dramatically. For monitoring to time sprays, unbaited traps that catch one fly per block (as an average of all the traps in the block) would warrant treatment; the lure makes them much more attractive such that you can wait until an average of five flies per trap are caught before treating. For most growers, the main insecticide used against AMF is Assail, Imidan also works but it has a long reentry interval and tends to leave visible residue on fruit. Remember to rotate your insecticide chemistries to avoid resistance development in pest populations. Resistance isn’t a huge issue with apple maggot fly that has one generation per year, but codling moth and other lepidopteran pests are still about and subjecting successive generations of them to the same class of materials can induce resistance. For organic growers, Surround works well, but its use in midsummer may increase European red mites, and it can be hard to remove at harvest; spinosad (Entrust) works pretty well too. First AMF treatment is still a few weeks off, most likely.

Think about including calcium in all of your foliar sprays until harvest, and on Honeycrisp and other large-fruited varieties, you may want to make some specific trips just to get more Ca on. Also, if you see any fire blight, please let me know as I have colleagues at Cornell and Connecticut Agricultural Experiment Station who are looking to sequence samples to test for streptomycin resistance.