West Michigan tree fruit regional report – May 13, 2014
Heavy rains have led to apple scab infections in West Michigan.
Daily temperatures have been more in the normal range for the past week and tree growth has responded quickly. Most apples are in a pink stage with a few blooms open on early varieties in sites that typically show earlier development.
Apricots are in full bloom on the Ridge. Sweet cherries are in full bloom to the first petal fall. Tart cherries are nearing full bloom. Peaches are also in the early stages of bloom.
Tree planting will be halted due to the heavy rains in the last week. Some areas report over 3 inches of rainfall in the last seven days.
Tree fruit diseases
Several rain events in the last week have led to apple scab infections. Heavy rainfall amounts have made it difficult to maintain adequate fungicide covers, but growers are keeping up. Tree growth took off with the warmer weather and newly expanding leaves and heavy rain will stretch a scab management program to its maximum, so this is not the time to cut corners. Apple scab spores have been trapped for every rain.
The warm and humid weather of late is perfect for powdery mildew development and mildewcides are highly recommended in apple susceptible to this disease.
Stone fruits now need fungicides for brown rot with open bloom present.
Tree fruit insects
Many growers put pink sprays on prior to the heavy rain. If you have a particular hot spot for insects controlled well at pink, such as rosy apple aphids, San Jose scale, etc., you might want to consider a reapplication of a pink spray in those areas only. The warmer weather will be good for insect development until cooler weather moves back in later in the week, which will delay the time before you can get a petal fall spray on.
Michigan State University Extension advises to have traps and lures up for oriental fruit moth, redbanded leafrollers, green fruitworms, spotted tentiform leafminers and perhaps even codling moth. Mating disruption dispensers for codling moth in apples and pears can be deployed if not done already.