Influence of Potassium and Calcium Levels on Severity of Tomato Pith Necrosis and Yield of Greenhouse Tomatoes

Two greenhouse experiments were carried out between the years of 2004-2006 in Aegean Region of Turkey to determine the influence of different potassium and calcium levels on severity of tomato pith necrosis caused by several pathogens belonging to genus Pseudomonas and Erwinia. The influence of three potassium (100 ppm, 200 ppm and 400 ppm) and two calcium (60 ppm and 120 ppm) levels on pith necrosis caused by four different bacteria (P. corrugata, P. cichorii, P. viridiflava and E. carotovora subsp. carotovora) were determined. The experiments were arranged on a greenhouse bench using a factorial randomized plot design with 30 characters and 3 replications. The plants were inoculated artificially two mounts after transplanting by spraying bacterial suspension (10(8)cfu/ml) onto the pruning sites. Lengths of pith necrosis were evaluated according to 0-5 scale two mounts after inoculation. The yields of the plants were measured for each treatment. In both of the experiments differences in potassium and calcium levels influenced the response of the plants to tomato pith necrosis and significant differences between treatments were observed. Two years results showed that treatments comprising highest levels of potassium (400 ppm) and calcium (120 ppm) not only reduced disease index significantly for most of the bacteria, but also led to the highest yield. http://www.actahort.org/books/808/index.htm