Apple Tree Spraying
Is it too late to spray my apple trees for insect fruit damage? If not, what do you recommend--I have a hand sprayer.
Moody County South Dakota
I will send an excerpt form Dr. John Ball's May 25th, 2016 tree pest report. It may be too late to spray for insects but he gives additional actions.
Cedar-apple rust galls on the junipers have expanded during the past week and this is an indicator to begin treatments to protect susceptible apples and crabapples from cedar-apple rust. The galls form on the junipers (cedars) and release spores that infect the apples and crabapples. The infection on apples and crabapples results in discolored foliage and fruit and premature drop of the leaves. Fungicides containing Myclobutanil as the active ingredients can be applied beginning now and repeat three more times at 7 to 10 day intervals. Captan, a common fungicide for apple scab is NOT effective against cedar-apple rust. Codling moth adults are flying and laying eggs on the newly forming apples. Once the larvae hatch, they will burrow into the developing apple, usually near the base of the fruit, resulting in a trail of brown, powdery frass through the apple. This frass often extrudes from the entry hole as in the picture to the left. The treatment is usually Malathion, though there is much evidence that carbaryl (Sevin) provides better control. The first treatment begins about 10 to 20 days after petal fall, as the fruit just begins to form and then three more applications spaced about 10 days apart. This treatment will also control plum curculio, an insect that cannot usually get through the tough skin of an apple but the egg laying leaves the fruit dimpled and distorted. The picture to the right shows bird pecks (the large hole) and plum curculio damage (the dimples). The other option is bagging the individual apples using the Japanese fruit bags when the apples reach about ½-inch diameter. This is no guarantee of control as 3 the fruit may become infested before that size but they do provide reasonable control of this pest and many others as well as improve the shine to the fruit. And finally, if you want to hang jugs of bad smelling liquid to attract codling moths and repel unwanted visitors consider mixing molasses and water in a 1:7 solution with a few drops of dishwashing soap. Pour this solution into a onegallon milk jug with the top cut out of it and hang from the tree. The fermenting mix is attractive to codling moths (as well as wasps and critters) and they may prefer this to your apples. It also creates a mess if you bump the bucket while mowing your lawn…….