There have been some reports from growers of several sets of tomato fruit with catfacing or that are deformed (Fig 1). Catfacing results in fruit with deep indentations in the blossom end or fruit with significant distortions. It is thought to be caused by a problem during the formation of the flower that results in the fruit not developing normally. However, there is little information as to its exact cause.
At times the first set of tomatoes in fields looked good, but the second, third and in some cases 4th sets are having problems in some fields. The problem is most probably due to the cool night temperatures we had in May and June in some areas. Tomato flowers do not develop or pollinate properly if temperatures fall below 52-54oF. This is just the nighttime temperatures; the day time temperatures could be in the 80s, but night temperatures at or below 54oF will cause the fruit to develop abnormally.
At several places on the Eastern Shore, where the damage seems to be worse, low temperatures were at or below 54o F from 1 May through the 25 May. This extended period of cool night temperatures is just the scenario that is needed for catfacing to occur over several tomato fruit sets. These temperatures are from official reporting sites and can be lower or higher depending on your location.
Some varieties will be more sensitive to these lower temperatures than others. It seems the ‘rounder and larger’ the fruit the greater the chance of catfacing. So in the same field that has several cultivars of round tomatoes that have catfacing the plum tomatoes would have less and the cherries and grapes much less, if any.
Unfortunately there is little that can be done to control the problem, except selecting varieties that are not prone to catfacing (there are very few that do). Older cultivars appear to be more susceptible. If possible removal of the catfaced fruit would be beneficial as these fruit are unmarketable, but will continue to drain nutrients from the plant. For more information go to: http://extension.umd.edu/learn/catfacing-problems-tomatoes.