Prevention Methods for Deformed Fruit in Strawberry Cultivation

The main cause of deformed strawberry fruit is poor pollination and fertilization, but the degree of occurrence is related to factors such as variety, flower order, flower-visiting insects, temperature and humidity, and pesticide spraying during the flowering period. Therefore, to prevent the occurrence of deformed strawberry fruit in production, the following countermeasures should mainly be considered.

Planting suitable pollinator varieties: Because strawberries differ in female and male fertility, varieties with abundant pollen should be selected as pollinator varieties and mixed with the main cultivated variety. Varieties such as Baojiao Zaosheng and Chunxiang have abundant pollen. For Yantai greenhouse strawberries, the main cultivated variety is Baojiao Zaosheng, and the pollinator varieties are Chunxiang, Fengxiang, etc., with pollinator varieties accounting for 5%-10%, which can effectively reduce the rate of deformed fruit. Place beehives in the greenhouse: Strawberries cultivated under protection flower early, and few natural flower-visiting insects appear in the early stage, so it is best to place beehives in the protected area. This method has been widely used in Japan with very good results. The flight distance of bees is generally 400 m. The flower-visiting time is from 8-9 a.m. to 3-4 p.m., and the activity temperature range is generally 15-30°C. Other flower-visiting insects should also be protected and utilized. Control temperature and humidity: During the flowering period, the temperature and humidity in the protected area should be strictly controlled. The temperature should preferably be controlled at 20-28°C. Ventilation should be carried out in a timely manner to lower temperature and humidity. Using anti-drip film can prevent the effects of water droplets. Drip irrigation can effectively reduce the air humidity in the protected area. During the flowering period, as long as the surface soil is not dry, generally no irrigation is needed. Thin flowers and fruit: Removing higher-order flowers that are prone to female sterility can significantly reduce the rate of deformed strawberry fruit and is also beneficial for concentrating nutrients and increasing single fruit weight and fruit quality. Reduce the number of pesticide applications: For pest and disease control in protected strawberry cultivation, comprehensive measures based mainly on agricultural control should be adopted, and pesticides should be used as little as possible or not at all. If pests and diseases are severe, care should be taken to apply pesticides before or after flowering. Carry out artificial pollination: At the peak of anther dehiscence from 11 a.m. to 12 noon, using artificial gentle wind (with a fan, etc.) for supplementary artificial pollination also has good results.