Carbohydrate Model Results for May 25, 2018

Posted: May 25, 2018

Warm temperatures are affecting thinning. Most stations across the state are forecasting high temperatures to be in the 80’s today and for the next several days.

The warm temperatures will be an added stress to the developing fruit and combined with a thinning application may result in good fruit drop. In looking at the orchards at Rock Springs this morning, I noticed many nonpollinated fruits were dropping. You can check your trees for fruit drop by sharply striking branches to see what will be abscising. There also seems to be some late bloom in the orchards.

For those of you that are using the model with data from either the Lake City or the Scott Township, you should be aware that the model may not be as sound due to the short period between the reported green tip and full bloom. Normally the model works best when there is at least 21 days between green tip an full bloom. This year while we waited for full bloom in many locations in those two places green tip occurred at the first of the month and bloom followed within a couple of weeks due to the unseasonably warm temperatures.

For other comments on factors that can impact the model, please review the article Apple PGRs—Evaluation of Your Chemical Thinning Program.

Apple Carbohydrate Thinning Model Data

Contact Information

Robert Crassweller
  • Professor of Horticulture
Phone: 814-863-6163