2019 – 2020 Midwest Fruit Pest Management Guide

Cherry is between bud swell and side green and apples are between silver tip and green tip here at the station. Grapes are still at winter bud. Based on the weather forecast, there will probably be little in the way of crop development over the next week.

Below is a degree day comparison of the last five years.

Date 4/30	2015	2016	2017	2018	2019	5 yr average
Base 50	36	43	45	21	18	31
Base 42	126	123	162	65	76	106

As we go through the next month or so, remember that critical temperatures for flower bud damage change dramatically between dormant buds and flowering. Whereas it may need to reach -20°F to -25°F to damage dormant cherry or apple buds in mid winter, cherry or apple flower buds may sustain 90% damage at 2°F to 5°F at the green tip stage of bud development. Later, during bloom, a temperature of only 25°F can result in 90% bud kill for apples and tart cherry.

Overwintering mite eggs can be controlled now through tight cluster on apple with a 1-2% oil application (1-2 gal dormant oil per 100 gal water). Waiting until green tip or tight cluster is more effective as temperatures will be warmer and the unhatched or newly hatched nymphs will be much easier to kill. Be aware that the later you make this type of application, you might consider the lower 1% application rate as phytotoxicity can be a risk, especially if you combine a copper fungicide for the control of early scab. Do not apply oil 48 hours before or after a frost. Captan should be avoided when making early season oil applications.

Green fruit worm have begun to fly but do not yet pose a damage threat. Scout for presence of their larva as well as overwintering oblique banded leafroller larva starting at the half inch green stage of development through petal fall.

INSECT & DISEASE CONTROL

APPLE

Disease Pressure – Little to worry about because of plant stage

Insect Pressure – Little to worry about because of plant stage

CHERRY

Disease Pressure – Little to worry about because of plant stage

Insect Pressure – Little to worry about because of plant stage

GRAPE

Disease Pressure – Little to worry about because of plant stage

Insect Pressure – Little to worry about because of plant stage