The outputs of the carbohydrate model for Central Virginia area is based on the Batesville (Crown Orchard) weather station. The solar radiation and temperature values suggest carbohydrate deficiency through this week (until Friday, April 21). Since it’s rainy today in most parts, thinning applications (at the standard rate) tomorrow and till Friday should be efficient. Although it will be sunny and warm tomorrow and probably Saturday, leading to some carbohydrate accumulation (the blue line), interruptions with hot and/or cloudy days will reduce the 4-day average (red line) balance and promote fruit abscission.

For Winchester area, I ran the model based on the data retrieved from our weather station at the AHS Jr. AREC. As it appears in the figure below, the outputs look similar to that of Batesville and hence the timing for thinning applications will be similar as well. However, the predicated temperature and solar radiation values for Winchester don’t support any carbohydrate accumulation this week and hence it’s recommended to decrease the chemical thinner rate by 15%.