Due to warm days (>80F) and intermittent cloud cover, the MaluSim carbohydrate model is showing a strong carbohydrate deficit for both Winchester and Central Virginia over the next four to five days. Expect an aggressive to very aggressive response to chemical thinners applied today through early next week. Reduce rates, and/or do not include oil or other surfactants if overthinning is a concern.
Pay close attention to the weather forecasts. If actual temperatures are closer to 90F and/or there are prolonged periods of cloud cover, then overthinning will likely occur.
The greatest amount of thinning occurs when fruitlets are on average between 8-12 mm in diameter. Thinning when fruitlets are slightly smaller or larger will result in less thinning, which may be desirable if there is a severe carbohydrate deficit.
Cooler temperatures forecasted for the middle to end of next week should result in less carbohydrate stress and reduced chances of overthinning. However, fruitlets that are greater than 15 mm in diameter are more difficult to thin with NAA or 6-BA.
During these warm days, expect the average fruitlet size to increase by at least 0.5 mm per day.
Full MaluSim model output:
Peck Winchester MaluSim 5_7_15.pptx