温室土壤连作对黄瓜主要病害的影响

在温室条件下,通过田间系统观察和室内测定相结合的方法,研究了不同连作年限温室土壤对黄瓜主要病害发生的影响.结果表明:随种植年限的延长,土壤中病原微生物数量增加,是导致黄瓜土传病害加重的主要原因;黄瓜植株生长发育不良,黄瓜的光合速率及抗性酶活性降低,植株自身抗病性下降,是引起黄瓜病害发生加重的内因;温室内温度降低、湿度提高、光照下降,是导致黄瓜病害发生加重的外部条件.随着连作年限延长,黄瓜病害发生依次加重,土传病害对连作的反应比气传病害敏感,病害是土壤连作障碍的重要原因之一.

Effect of different crop successions on main disease development in cucumber under sunlit greenhouse

Under sunlit greenhouse condition, systematic field and laboratory surveys were carried out to study the effects of different crop successions on main disease development in cucumber. The results show increasing numbers of soil pathogenic microbes with prolonged planting, the main reason for disease occurrence and spread of soil-borne diseases. Hypogenetic plant, lower photosynthetic rates and enzyme activities decrease self-resistance of the cucumber plant to disease. These form the internal-causes of cucumber disease outbreak. Increases in humidity, decreases in temperature and sunlight are the external-causes of cucumber disease outbreak. The longer the succession, the severer is the spread of soil-borne diseases. The effect of continuous cropping is more a sensitive factor in the spread of soil-borne diseases than in the spread of air-borne diseases. Diseases are one of the main impediments to succession production systems.