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Cornell Carbohydrate Model Results for May 8, 2017

Posted: May 8, 2017

We are continuing to experience unusually cold weather across the state, and growers will need to continue to wait for a thinning window.
10mm diameter fruit. Photo: R. Crassweller, Penn State

10mm diameter fruit. Photo: R. Crassweller, Penn State

The latest model run was completed at 9:30 AM this morning. In general the conditions for this week are not favorable for thinning, with highs predicted in the upper 50s to mid-60s. Three sites in PA had an hourly temperature below freezing which may result in some fruit damage. There is also a risk of cold damage for Tuesday morning. Cooler temperatures are not conducive to the use of 6-BA products. The preferred choice of a thinning material is carbaryl. The addition of an NAA product may help thinning in areas that might experience temperatures in the 70s. The predicted 4 day average balance suggests that chemical thinner rates should be increased as indicated by positive averages.

5-8 carb chart1

5-8 carb chart2

5-8 carb chart3

Apple Carbohydrate Thinning Models for Pennsylvania Counties

For more information on the carbohydrate thinning model, visit Carbohydrate Thinning Model. For more details on factors that affect plant growth regulator performance and chemical thinner rates, visit Growth Regulators in Apple and Pear Production.

Contact Information

Robert Crassweller
  • Professor of Tree Fruit
Email:
Phone: 814-863-6163