Jujube fruit rot causes the jujube flesh to become soft, with a wine-like odor and a moldy, sour taste. How can it be comprehensively controlled?
Jujube fruit rot can occur before harvest, after harvest, and during storage, and is caused by numerous diseases. The main ones are jujube ring rot, jujube soft rot, jujube pink mold rot, and jujube aspergillus rot. The most important are jujube ring rot and jujube soft rot, which lower jujube quality and selling price. To effectively control jujube fruit rot, experienced farmers have formulated comprehensive control measures based on the disease-causing factors, with remarkable results, for reference only.
Jujube fruit rot
I. Symptoms
1. Ring rot: Occurs during the crisp-ripe stage of jujube. After the jujube is affected, the lesion centers on the jujube's lenticels, first appearing as a water-soaked light brown spot, then expanding into a reddish-brown round spot. The affected jujube flesh turns brown and soft, with a wine-like odor; in severe cases, the jujube rots and drops off. Some lesions have concentric rings of alternating light and dark colors, causing the jujube to drop, resulting in serious losses.
2. Jujube soft rot: Occurs before and after jujube harvest and during storage. The jujube fruit becomes moldy and rotten, unfit for consumption, causing great losses. After the jujube is affected, the flesh becomes soft and turns brown, with a moldy, sour taste; first white filamentous growth appears, and then small black spots develop on the white filamentous growth.
II. Occurrence pattern.Jujube fruit rot is caused by spores of various pathogens distributed in the air, soil, and various parts of the jujube tree. When the jujube has wounds such as injuries, insect bites, bruises, damage during picking, or crushing during loading and transport, pathogen spores invade through the wounds and cause fruit rot. The main factors affecting jujube ring rot are rainfall and ambient temperature. The pathogen spreads by wind and rain, spreading from the young fruit stage until the jujube is nearly mature, with a very long incubation period. If there is more cloudy and rainy weather in the later stage of jujube development, the disease can occur. After jujube harvest, because the jujube has high moisture content, if it is not ventilated and air-dried in time, various diseases are very likely to occur and cause rotten jujubes. During the storage and freshness-preservation period of jujube fruit, improper temperature, humidity, and air composition ratios in the warehouse are even more likely to cause jujube fruit rot.
III. Control methods
1. Ring rot: (1) Strengthen management, enhance tree vigor, and fundamentally improve the disease resistance of jujube trees. (2) During the young fruit stage and expansion stage of jujube, spray 50% thiophanate-methyl wettable powder at 800 times dilution, once every 10-12 days, for 2-3 consecutive sprays. (3) Before the fruit rot stage, spray 50% carbendazim wettable powder at 800 times dilution, once every 7 days, for 3 consecutive sprays. (4) After the disease occurs, promptly remove diseased jujubes and bury them deeply in a centralized manner, so as to reduce the chance of re-infection by the disease.
2. Jujube soft rot: (1) During jujube harvest, try to prevent damage and reduce the chance of pathogen invasion. (2) After jujube harvest, air-dry or dry in time to reduce mold and rot. (3) Before storage, spray the entire warehouse or the containers holding the jujubes with 1% formalin. (4) Remove damaged jujubes, insect-infested jujubes, and diseased jujubes, and place them in a dry, ventilated, low-temperature location to prevent moisture. (5) For jujubes entering the warehouse, fumigate and disinfect with sulfur in advance. Generally, use 4-5 grams of sulfur per cubic meter; after disinfection, seal for more than 24 hours.