What are the latest control methods for Gastrodia elata flower stalk disease?
Gastrodia elata black stalk disease mainly occurs on the tubers and flower stalks of sexual reproduction of Gastrodia elata, and is an important disease of the flower stalks in sexual reproduction of Gastrodia elata. Through etiological testing, the pathogen of Gastrodia elata black stalk disease is the fungus Fusarium oxysporum. Below, let us take a look at the control methods for Gastrodia elata flower stalk disease!
Symptoms of Gastrodia elata flower stalk disease
Damage to the flower stalk usually begins at the base near the ground, initially appearing as dark brown or black irregular lesions, then forming a ring-shaped black stem that spreads upward. In severe cases, the diseased part constricts and breaks easily. A longitudinal cut of the diseased stem shows the pith is dark brown and necrotic. Flower stalks infected early die as soon as they emerge from the soil.
Conditions for the onset of Gastrodia elata flower stalk disease
The pathogen Fusarium oxysporum is a soil-inhabiting fungus, and if conditions are suitable, it can infect and cause disease at any time. At the Guizhou Gastrodia elata GAP base in Baiyi Township, Wudang District, Guiyang City, the disease occurrence period for red Gastrodia elata is April to May, and for green Gastrodia elata it is June. This disease begins shortly after the Gastrodia elata flower stalk extends out of the soil layer following the covering of tubers used for sexual reproduction with soil. High temperature and high humidity favor the occurrence and development of the disease. In Longli County, Guizhou Province, this disease has also been found on wild Gastrodia elata. Using tubers infected with black rot disease as sexual reproduction seeds generally leads to this disease, and in fields with continuous cropping for many years, the disease occurs severely.
Control methods for Gastrodia elata flower stalk disease
1. Choose a site with few surrounding disease occurrences as the cultivation site for sexual reproduction of Gastrodia elata. The site must be disinfected and treated for insect pests before use.
2. Select healthy, disease-free Gastrodia elata tubers for sexual reproduction, and do not use tubers carrying black rot disease as sexual reproduction seeds.
3. During the disease period, choose 50% carbendazim wettable powder at 600-700 times dilution, or 70% mancozeb dry suspension powder at 500 times dilution, or 75% chlorothalonil wettable powder at 600 times dilution, or 60% Fangmeibao No. 2 water-soluble powder at 800-1000 times dilution and other agents for spraying or stem coating.