Fruit Pest Update
August 28, 2020
Apples are putting on color and certain varieties are ready or almost ready for harvest including Zestar, Early MAC, SweeTango, and Paula Red.
Most grape varieties are at past veraison and accumulating sugars as we move towards harvest.
Apple and Grape maturity data are available upon request by sending an email here.
GDD Base 50 is approximately equal to the 20 year average, but varieties are maturing 1-3 days later than normal.
| Date 9/3 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 20 yr avg |
| Base 50 | 1803 | 2037 | 1787 | 2060 | 1693 | 1939.5 | 1960 |
CHERRIES
Diseases
Some orchards in the county are defoliating early and fertilization rates may need to be adjusted next spring. Taking soil samples this fall is also helpful for determining nutrient requirements next season. Details for how to submit soil samples to the UW soil lab can be found here.
This is the time of year to open tree canopies, hedge prune, and/or eliminate low hanging branches. Hedging should be completed by September 15 to allow wounds to heal before the first freeze.
Insects
While there are currently no insect pressures, orchards with rodent pressure can deploy rodenticides anytime between mid-October and snow fall.
Apples
Maturity testing has started and updated information will be available upon request by sending an email here.
Diseases
Late season fungicide treatments should be applied to protect against diseases and rots, particularly those that appear right before going into cold storage. Be aware of PHI on all products used. Stop drop applications, to keep fruit on the trees and encourage even ripening, can be combined with fungicide applications. For more information on the benefits of using a stop drop spray approaching harvest see this article from Michigan State University.
Keep track of various diseases at an EnviroWeather or NEWA weather station site located nearest your orchard.
Insects
Second generation Codling Moth flight appears to be over in most orchards and Apple Maggot pressure is decreasing. If trap counts are still high, an insecticide can be applied, but watch PHI’s closely.
A final note on the end of spraying season; it’s the best time of year to make repairs before harvest calls for our full attention.
GRAPES
Most grape varieties are at or through veraison. Hedging should be done to increase the light environment in the canopy and encourage even ripening.
Netting or other bird repellent strategies should be put in place before pressure starts. Request maturity data for any varieties on the station here.
To aid in fruit management decisions, you can access the 2019-2020 Midwest Fruit Management Guide
NEWA (Network for Environment and Weather Applications) can be reached at www.newa.cornell.edu
Links to individual EnviroWeather stations: