Biological characteristics of the pathogen of root rot of Cucumis melo in the suburb of Beijing.

摘要

Recent years, root rot of melon (Cucumis melo) has been found in the suburb of Beijing. We collected the typical diseased plants, isolated and identified the pathogen, and studied its biological characteristics in order to provide the basis for the melon breeders to screen the resistant germplasm resources and select resistant melon cultivars to the disease. The results of morphological investigations of the isolate from the diseased plants indicate that it is Fusarium solani (Mart.) Sacc. that causes root rot of melon in the suburb of Beijing. The results of biological characteristics of the pathogen is showed as follows: the temperature affects pathogen growth greatly, the range of temperature for the pathogen growth is 10-40 degrees C, and the optimum is 30 degrees C. The pathogen grows slowly at pH 4, but grows rapidly and different pH has little influence on its growth at the range of pH 5-12. It can utilize many kinds of carbon sources very well. Nitrogen nutrient has a strong effect on the growth of the pathogen, and nitrate-nitrogen [NO₃-N] is suitable for its growth, but ammonium-nitrogen [NH₄-N] does not favor the pathogen. Both the temperature and relative humidity are the key factors for the conidia germinating, and 100% and 30 degrees C are the optimal relative humidity and the optimal temperature for the conidia germinating, separately. The conidium lethal temperature is 57 degrees C, 10 minutes lasted.