Back to top

IPM Message for Cranberry Growers: Aug 17, 2015

Aug 17, 2015

The weather has been and will continue to be very hot.  This can be stressful for the vines.  Monitor as needed to make sure the vines and fruit are not lacking for water.

No unusual levels of rot have been reported and upright dieback symptoms have been reported in beds with a history of the disease or in beds with some sort of heat and/or water stress. Remember that fungicide applications at this time of the year will have a very small impact on field rot infection and upright dieback. Over the next couple of weeks, monitoring of weather conditions may be critical to avoid sunscald on berries. Scalding can occur with air temperatures as low as 85°F, especially on days with low cloud cover and low relative humidity (< 65%) and  keep in mind that the risk of sunscald and heat injury varies from site to site and may depend on specific bed conditions. In addition to weather, irrigation practices, fruit size, and vine density can influence the risk of scalding. Scald damage can be prevented by using overhead sprinkler irrigation to cool down the fruit. Short irrigation periods can decrease canopy temperature by 4-10°F and avoid scalding as long as soils are not saturated and no puddling occurs.