Cold Temperatures and Row Covers

Row covers are very important for protecting tender flower buds in late winter and early spring from freezing temperatures and frost.  However at this time of year we need to be careful if we apply row covers to “protect” our developing plants.

There are two main reasons that growers apply row covers:  The first is to enhance plant growth and flower bud development.  The second is to protect flowers and fruit.  I will agree that even in Georgia the use of row covers in late winter and early spring is helpful, but I will disagree with anyone that uses row covers to enhance or advance the crop with fall and early winter row crop usage.

I also understand the investment that growers have in a field so I will just offer this advice.  Row covers create an environment that is warmer and dryer.  Even on cool days in Georgia temperatures under the row covers can get very warm.  This environment is ideal for the growth and development of spider mite populations.

I would bet good money that most of our strawberry patches have some level of spider mite infestation right now.  Many growers monitor populations all winter and will see varying levels of spider mites.  I would warn anyone using row covers for extended periods to monitor these populations closely.  Over the past 5 years spider mites have been the most damaging pest that I have seen on Georgia strawberries.

Miticides can be applied prior to row cover application if you plan to leave them on.  If not, monitoring populations in the field by examining leaves weekly is good enough.

Another issue that can arise under row covers is powdery mildew.  Some of our newer varieties are more susceptible to this disease and it is favored high humidity and reduced leaf wetness.

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