Effects of temperature and leaf wetness duration on pathogens causing preharvest fruit rots on tomato

Abstract

Preharvest fruit rots are serious tomato diseases. This study showed that Botrytis cinerea was a significant problem, and that Alternaria (A. alternata, A. solani) was the main pathogen identified from tomatoes showing the symptoms of preharvest fruit rots. Fusarium oxysporum and Rhizoctonia solani were also found causing important preharvest fruit rots in tomatoes. This is the first time F. oxysporum and R. solani have been identified in Greece as pathogens causing preharvest fruit rots on tomatoes. The optimal temperatures for A. alternata, A. solani, B. cinerea, and F. oxysporum mycelial growth and conidial germination were generally found to be between 20 and 30 °C, while the wetness duration of 24 hours seemed to be optimal for conidial germination and 84 hours for R. solani sclerotial germination. Based on the above findings, logistic regression models that adequately described the impact of pre-inoculation temperature and wetness on infection incidence in tomato fruit can be created. As the minimum, maximum, optimal temperatures and wetness duration are generally similar for the main pathogens causing preharvest fruit rots in tomato, it is possibly to develop a predicting predictive model to forecast the preharvest infection of tomato fruit. So enabling advice to be given to growers to when control methods should be applied.