Well Control of Disease Makes No Worry While Strawberry Nursing Period

Well Control of Disease Makes No Worry While Strawberry Nursing Period

The brightly colored strawberry fruits with sour and sweet tastes, high content of vitamin C capture the hearts of many consumers. It is the nursery plants propagation period of strawberries right now, and also the right time for epidemical anthracnose. Taiwan Seed Improvement and Propagation Station, Council of Agriculture, Executive Yuan (TSS, COA) reminds farmers to pick off infected tissues always. Do not discard them in or surrounding the nurseries directly and apply commended fungicides to control the disease, thus the quality and quantity of nursery plants are assured. The nightmare of lacking planting materials would not happen again.

According to the Agriculture Statistical Yearbook, the cultivation areas of strawberry were 535 hectares in 2013. The number of nursery plants used are estimated to exceed about 26.7 million. TSS, COA points out while the temperature and humidity arising in May, suitable for development of anthracnose, the strawberry nursery plants grown by farmers died often as they are infected. Not only the time and labor costs of farmers were wasted, but also no sufficient supplies of strawberry transplants for cropping for some regions. The income of farmers was affected and the costs for farmers buying seedlings were raised.

TSS, COA explains there are 2 infection ways for the anthracnose pathogen threatening. The pathogen infects the crowns of the mother plants during propagation and results in crown rot and death of the plants. Therefore, no transplant is produced. The other infection way is the runners infected by anthracnose pathogen, with deep brown cylindroid lesions around sunken center. If the infected runners are not removed, the mother plants are threatened as the lesions enlarged. Therefore, TSS, COA suggests farmers to take following control measures to reduce the incidence of this pathogen:

1. Keep sanitary of the field. Always remove the plants infected and put into a black garbage bag.

2. Keep proper distances between plants. While required, nurse in green (net) houses to reduce dispersing opportunities of rain-splashed conidia. Besides, rationalization fertilization and appropriate adding Calcium-containing fertilizers strengthen plants resistance.

3. At the early stage of anthracnose disease, apply following fungicides recommended: difenoconazole, pyraclostrobin or thiabendazole + oxine-copper. In 2014, TSS, COA has tested 2 commercial fungicides for anthracnose control. The result for reference showed that applying thiabendazole+oxine-copper once before pathogen inoculating could depress lesion development on strawberry leaves for 4 weeks. (fig.1) Farmers are suggested to choose 2 of them to apply alternately.