Mar 29, 2016

West Michigan degree days ahead of schedule

Degree day totals for the general west Michigan area jumped ahead of the normal average at the beginning of March, but have slowed recently, according to Amy Irish-Brown, Extension educator with Michigan State University.

Irish-Brown said west Michigan is about 12 days ahead of normal averages for base 42 and seven days ahead for base 50. By the end of March 29, degree-day totals for the Sparta, Michigan, weather station should be 125 Base42; and 38 for Base50. The Standale station is ahead of Sparta, and Sparta is slightly ahead of Kent City. Belding is similar to Sparta for degree-day totals, according to Irish-Brown.

Apple scab

Because of the early start that seemed to be coming a few weeks ago and because other eastern fruit-growing areas in Pennsylvania and New York were reporting early scab spore development, Irish-Brown put her monitoring equipment out early this year, on March 12. Given the up and down temperature and moisture levels experienced over the winter months, she was not surprised to catch spores with the March 13 rain and those since. Spores might be ahead in their maturity this season, and the first infections that occur once green tissue is present could be very important and should be taken seriously. There was considerably higher levels of scab last summer and inoculum levels are most likely higher coming into a new season. Delayed dormant copper sprays will definitely help with apple scab and possibly fire blight, she said.

Dormant oil

A few pests (mites, San Jose scale, aphids, pear psylla) that have been making a comeback in recent years are all managed well with dormant oil sprays. With so many other pesticide choices for in-season management, many have gotten away from dormant oil, but it is still the best management option for mites, scale, aphids and psylla, and if you haven’t been able to get a handle on these pests you might want to consider it, according to Irish-Brown.

To aid spray decisions, the Spring Spray Meeting will be held Thursday, April 21, from 4-6 p.m. at the Goodfellow Farm, 2267 12 Mile Road, Sparta, MI 49345. It’s located on the north side of 12 Mile, just west of M-37, near Sparta. Use the orchard entrance near Laubach Road, west of the house drive. Meet in the large white building behind the houses.