Emailed Apple Pest Message – April 7, 2012

Hello Fruit Growers,
The first twilight meeting of the year will be held Thursday, April 19 at 5:30 PM at Jaswells Farm, 50 Swan Road in Smithfield, RI. Come see what’s going on at Jaswell’s! Chris Jaswell has planted hundreds of apple trees over the last few years.

The meeting will focus on tree fruit horticultural topics such as pruning as well as insect and disease issues.

This season has started out very peculiarly – and annoying! We still have not had an apple scab infection period, though green tissue has been exposed for weeks. Perhaps we will get an infection period this coming week, but perhaps not. It all depends on how long leaves remain wet and what the average temperature is during the wet period. See this link for the Mills Table showing the apple scab infection chart:

It is best to apply a protectant fungicide before an expected apple scab infection period. Protectant fungicides include Manzate, Dithane, Polyram, Captan and others. Remember, if you apply Captan, keep Captan at least 7 days away from an oil application.

Speaking of oil, these cold mornings and windy days have made oil applications very difficult. Oil should not be applied if temperatures are expected to go below 40 degrees for two days after spraying. According to the forecast, night time temperatures should be fine for applying oil. A good oil application suffocates overwintering European red mite eggs. You can use 2 gal oil/100 at the green tip through half-inch green stage, or 1 gal/100 at tight cluster. In Rhode Island, McIntosh bud stages range from half inch green to tight cluster now.

Unfortunately I haven’t been able to check many locations to see where winter moth are. Areas infested last year will be infested this year, but where winter moths have expanded I really don’t know! Winter moths started hatching March 21. Soon after this, temperatures dropped and the caterpillars have been feeding, but growing slowly. Collect buds from your trees, especially near woods, and separate the buds from each other and look for the caterpillars. I’ve attached a picture taken yesterday of an infested blueberry bud, but infested apple buds look pretty similar. Note the chewed holes and the insect frass (droppings). If you find many larvae, apply an insecticide such as Imidan.

I’ve got the 2012 Tree Fruit Pest Management Guides for sale. You can buy one at the Twilight Meeting ($30) or I can mail you one ($35).

Hope to see you at Jaswell’s!