What Is Papaya Brown Rot? A Guide to Diseases in Papaya Cultivation
What is papaya brown rot? What methods can be used to control it? Here is an introduction to the damage caused by papaya brown rot: brown rot mainly affects the fruit, but it can also affect flowers and young shoots. When the fruit is infected, small brownish nearly round spots appear first, and as the disease progresses the spots keep expanding; under suitable conditions, the spots quickly spread across the entire...
What is papaya brown rot? What methods can be used to control it? Here is an introductionDamage caused by papaya brown rot:Brown rot mainly affects the fruit, but it can also affect flowers and young shoots. When the fruit is infected, small brownish nearly round spots appear first, and as the disease progresses the spots keep expanding; under suitable conditions, the spots quickly spread across the entire fruit surface and gradually extend into the flesh, and in severe cases the entire fruit rots.
After the diseased fruit loses water, it becomes a brown mummified fruit that hangs on the branch and does not fall off for a long time. The pathogen on the flower stalk or fruit infects the branches, forming brown canker spots, which affect the normal transport of nutrients and water, inhibit the growth and development of the branches, and cause the branches to die.
Causes of papaya brown rot:Brown rot is a fungal disease. The pathogen overwinters on mummified fruits, and the pathogen on diseased branches can also cause infection after overwintering. In the spring of the following year, after the temperature rises, the pathogen on the diseased fruits and branches produces conidia, which spread by wind and rain.
Around early May, after the young fruits have formed, the pathogen mostly invades through wounds on the fruit. Therefore, when insect damage is severe and there are many insect wounds, brown rot is also severe. In years with early or abundant rainfall, the disease occurs early and severely; low-lying cultivation sites that are prone to waterlogging and weak tree vigor are also favorable to the disease. During the fruit expansion period, if natural disasters such as violent storms and hail occur, many wounds are created on the fruit surface, which also favors pathogen invasion and disease development.
Control methods for papaya brown rot:
1. Handling of diseased papaya plants: After the papaya harvest, in combination with winter pruning, cut off diseased branches, remove diseased fruits, and burn them in a centralized manner, which can effectively reduce the overwintering sources of inoculum.
2. Chemical control methods for papaya brown rot: In early spring before papaya sprouting, spray 1 time with 5 degrees Baume lime sulfur mixture; from March to April, after papaya flowers drop and before fruit harvest, spray 1 time every 10-15 days with 50% carbendazim 500 times or 50% thiophanate-methyl 800 times solution, for 2-3 consecutive sprays, and it can also control leaf diseases at the same time.
3. Control of papaya brown rot by preventing insect wounds: The peach fruit borer is an important pest damaging papaya fruits. In mid-to-late June, just as papaya fruits are expanding, the female moth lays eggs in the recesses of the fruit stalk and in the gaps where the fruit touches, and after the larvae hatch, they bite through the fruit skin and bore into the fruit. They not only tunnel back and forth feeding on the flesh, but also create insect wounds, which favor pathogen invasion. Control method: during the larval hatching period, spray 90% crystalline trichlorfon 1000 times solution or fenitrothion emulsion 1500 times solution, 1 time every 7 days, for 3 consecutive sprays.
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