Control Methods and Technical Key Points for Root Rot Disease in Papaya Seedlings

Papaya root rot disease is also called papaya root rot.

Symptoms: The disease mainly affects the root collar and roots, and seedlings during the nursery period and shortly after planting are more susceptible. It is especially likely when the groundwater level in the nursery site and cultivation site is relatively high or poor drainage causes waterlogging, and when the soil is highly clayey. At the early stage of infection, a water-soaked appearance appears at the stem base, which later turns brown and rots, the leaves wither, the plant dies, and the roots turn brown and necrotic.

The pathogen is Fusarium spp.; the pathogen overwinters in the soil and becomes the infection source for the following year, spreading through flowing water.

Control methods: The seedling shed should be well ventilated and allow light through to lower the temperature; the nursery site and planting site should have good drainage and avoid waterlogging. Before the rainy season arrives, phosphorous acid at 1000 ppm (about a 1000-fold dilution) can be sprayed 2 to 3 times, once every seven days, with good preventive effect. When using it, phosphorous acid must be prepared on the same day, and its acidity must be neutralized with an equal weight of potassium hydroxide.

Avoid continuous cropping, and do not rotate continuously with vegetable land (especially where the previous crop was Cucurbitaceae); pay attention to controlling snails and ants; when diseased plants are found, pull them out, and drench the diseased holes with a medicinal solution for protection. Use 70% dexon wettable powder at a 1000-fold dilution, or 50% carbendazim wettable powder at a 500-fold dilution, drenching each plant with 0.3-0.5 kg of the medicinal solution, once every 7-10 days, continuously drenching with 0.3-0.5 kg of the medicinal solution, once every 7-10 days, for 2-3 consecutive drenchings.