Blossom end rot is a physiological disorder of tomato fruits that affects both greenhouse and field grown plants. Blossom end rot occurs more frequently when plants grown under favorable conditions early in the season are subjected to long periods of drought during the early stages of fruit development. However, it can also occur after periods of unusually heavy rainfall. Losses from this disorder vary from negligible to severe, depending on the environmental conditions. Blossom end rot also affects peppers and eggplant.
Calcium deficiency has been shown to be a contributing factor to the occurrence of blossom end rot. Failure of sufficient calcium to reach the blossom end of the fruit early in fruit development causes the cells in this area to die. Many of the factors that contribute to this physiological process are not known; however, it has been shown that pathogenic organisms are not involved. It is common for secondary fungi and bacteria to invade dead tissue on fruit affected with blossom end rot. These organisms are sometimes mistakenly assumed to have caused the symptoms.
The first evidence of blossom end rot consists of a brown or watersoaked discoloration near the blossom end (opposite the stem end) of the fruit. The discolored area enlarges and darkens until it covers 1/3 to 1/2 the surface of the fruit in severe cases. As the spots increase in size, the tissue becomes shrunken and the area becomes flattened or concave. The skin of affected fruit becomes black and leathery in appearance (Fig. 1). Fruit do not soft rot unless the spots are invaded by secondary organisms.
Tomatoes affected by blossom end rot grow slowly and often ripen prematurely. Under certain conditions the outward symptoms may be suppressed almost entirely, while the inner tissue near the blossom end is completely discolored and collapsed. Blossom end rot is most frequently observed on fruit that is 1/2 to 2/3 its mature size. Symptoms on pepper and eggplant are similar to those on tomato; however, on peppers the discolored area is often tan rather than brown and the rot may occur on the sides of the fruit near the blossom end.
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Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Interim Administrator, 1890 Extension Program, Virginia State University, Petersburg.
May 1, 2009