Detailed Explanation of the Latest Control Measures for Powdery Mildew on Green Jujube
Green jujube is an excellent tropical and subtropical fruit. The fruit is rich in nutrients, crisp and sweet, and contains large amounts of vitamin C, calcium, phosphorus, vitamin B, carotene and other nutrients. However, when growing green jujube, powdery mildew is a major obstacle to green jujube production. The disease is widespread and causes serious damage, so how should powdery mildew on green jujube be controlled? Let us learn about it together.
1. Symptoms
Powdery mildew on green jujube mainly damages leaves, fruit and young shoots. After the fruit is affected, the fruit at the swelling stage is mainly affected, followed by young fruit. White mycelium first appears on the affected fruit and then spreads. In severe cases, white mycelium and white powdery material can cover the entire fruit. After the fruit is affected, the peel becomes mottled, shrinks, and turns brown or yellowish brown, and the fruit is prone to dropping or dying. Fruit with milder disease will continue to grow. After the white exposed layer falls off, the diseased part appears grayish brown, and the peel of the diseased part is rough, cracked, lusterless and suberized, seriously affecting fruit quality and yield and causing huge economic losses.
2. Occurrence Pattern
Green jujube is damaged throughout the entire growing season. When the branches of green jujube sprout and grow leaves in April, the pathogen gradually begins to become active and cause damage. In May, the damage worsens. After entering June, the rainy season arrives, the pathogen activity weakens somewhat, and the damage is reduced. After the rainy season, disease begins again in August. September to October is the peak period of disease occurrence. After that, as the temperature drops, pathogen activity tends to stabilize, and sexual spores are produced to overwinter in dead branches, fallen leaves and soil. When the temperature rises in spring the following year, they continue to cause damage.
⟦NL>3. Control Methods
Fertilizer and water management should be strengthened to enhance tree vigor. During the dormant period of the fruit tree, apply more than 30 kg of decomposed organic fertilizer per mu, as well as an appropriate amount of nitrogen, phosphorus, potassium and other chemical fertilizers. In addition, an appropriate amount of micronutrient fertilizer and biological fertilizer should be added. In the early stage of disease occurrence, when white mold layers are found on diseased leaves, they should be removed promptly. At the same time, clean up the orchard, eliminate infection sources, carry out timely intertillage and weeding, and prune reasonably so that the tree canopy has good ventilation. During the dormant period, in combination with orchard cleaning, spray the whole orchard once with lime sulfur mixture to eliminate overwintering pathogens. When disease occurs, agents such as Yangnai fruit fenxiuling, thiophanate-methyl and chlorothalonil can be used for control. When using them, to avoid resistance, one can choose one or mix two for use at a time, and the number of applications of each agent should be controlled at about 2-3 times.
The above is an introduction to control measures for powdery mildew on green jujube. We hope it can help you. If you want to learn more related knowledge, please follow us.