STRAWBERRY CULTIVATION IN MILD-TROPICS: PROSPECTS AND CHALLENGES FROM DISEASES' PERSPECTIVE

Abstract

Strawberries are one of the most popular fruit crops grown in the world. Although it is native of temperate regions, cultivars are available which can be cultivated in mild-tropical and subtropical climates. In India, strawberries are generally cultivated in the hills but in recent years, strawberry is being cultivated successfully in plains also. A wide variation in climate within these regions and a wider adaptation of the strawberry plants permits harvesting and marketing of fruits round the year. Per capita, consumption of fresh strawberries has increased in the past decade and is predicted to continue to rise in the immediate future. Two of the major hazards of strawberry production in mild tropics are diseases that attack the fruits and plants and the lack of superior day neutral cultivars. The cultivated strawberries are attacked by a large number of diseases caused by fungi, bacteria, nematodes, viruses and virus-like organisms. Among these, fungal diseases are the most troublesome worldwide and can reduce the yield and quality of fruits considerably. Grey mold rot (Botrytis cinerea Pers. Ex. Fr.), Rhizopus rot or leak rot [Rhizopus strolonifer (Ehrenb.Fr)], anthracnose (Colletotrichum fragariae Brooks), Verticillium wilt (Verticillium dahliae), red stele, also called red core, red root rot or brown stele (Phytophthora fragariae Hickman), Black root rot (disease complex), leather rot (Phytophthora cactorum) and powdery mildew (Sphaerotheca macularis), are some of the economically important fungal diseases of strawberry. Although farmers systematically attempt to protect the crop from diseases, some of the diseases are much harder to control. This is because of the rainfall and warm weather that prevail during cropping season in mild tropics make the situation an ideal growing condition for pathogenic fungi that attack both plants and fruit. A grower often would apply pesticides eight to ten times or even more during a cropping season and hence, disease control is a major expense in strawberry production. Increased focus on alternative means of disease control with reduced pesticide use are resulting in improved returns to growers, and a better outcome for the environment as well as consumers and hence it is gaining momentum. A more effective and less expensive method would be to develop strawberry cultivars resistant to prevalent diseases. The development and commercialization of day neutral strawberry cultivars (superior production environments) and resistance to some of the above stated diseases therefore should provide a means of reliable, long-term disease control and offer economic benefits by reducing or even eliminating the need for costly spraying. Howard 17, Aroma Dorsett, Rockhill, Fairfax, Fletcher, Trumpet, Sunrise, ‘Earliglow’, Redstar, Tioga, Temple, Catskill, Surecrop, Lassen and Tyee are some of the genotypes with various degrees of disease tolerance are available choices for usage. Hybridization work has already been initiated at Indian Institute of Horticultural Research, Bangalore to develop superior cultivars utilizing some of these lines.