Department of Horticulture, Iowa State University
Past 2-3 weeks have been extremely brutal in Iowa in terms of high heat and humidity. Most of our daily conversation revolves around 'heat index', a word we constantly hear on television. Plants, similar to us, have their saga to share. Extreme heat has taken its toll on them as well. Crop water requirements depend on crop type, stage of growth, and evaporative demand. In hot weather conditions plants transpire large amounts of water that needs to be quickly replenished to ensure continued growth and development. Failure to replenish water, can lead to several issues apart from wilting. Last week (25 July 2011) I was in the Western part of Iowa visiting some fruit and vegetable growers. One of the problems I noticed in tomatoes is in the picture below (click on the picture to expand):
According to Dr. Hank Taber (Professor Emeritus, Iowa State), the above pictures show what is called 'russetting' or 'micro cracks' in tomato fruit. This occurs under extreme hot conditions coupled with lack of water for plant uptake. Tomato skin becomes patchy, rough, and develops cracks which can cover large areas on the fruit. Such fruits quickly become non-marketable and can lead to significant loss of revenue to the grower. To prevent this from happening growers should provide ample amount of water in a timely and controlled manner. Although, setting up and installing irrigation could be an expensive operation, it is a critical component for successful vegetable production. It is worth an investment which always pays off !