How to prevent and control stem blight in asparagus cultivation? A detailed guide to practical control methods
What harm does stem blight do to asparagus? How to prevent and control stem blight in asparagus cultivation? Experienced growers are also asked to help explain. Asparagus stem blight is a widely distributed, severely damaging and devastating disease known as the cancer of asparagus. In rainy summer seasons it often causes large-scale destruction. Zhongdi Wang has compiled information on asparagus stem blight...
What harm does stem blight do to asparagus? How to prevent and control stem blight in asparagus cultivation? Experienced growers are also asked to help explainAsparagus stem blight is a widely distributed, severely damaging and devastating disease known as the cancer of asparagus. In rainy summer seasons it often causes large-scale destruction. Zhongdi Wang has compiled the harm and control methods of asparagus stem blight, listed below for growers' reference.
Harm of stem blight to asparagus cultivation:
The affected parts are mainly the stems and branches, while the leaves are not attacked. In the early stage of the disease, small water-soaked bronze spots appear, which gradually expand to form spindle-shaped lesions with reddish-brown or brown edges; in the middle and late stages, the center of the lesion turns grayish-brown and slightly sunken, densely covered with small black dots, namely the pycnidia. The lesions can penetrate deep into the pith, and once they encircle the stem or branch, the part above the lesion dries out, loses water and dies. July to September is the peak period of the disease, and late October marks the beginning of the overwintering stage. The annual disease period lasts nearly 6 months.
Control methods for asparagus stem blight:
Method one,Reducing the pathogen is an important part of controlling asparagus stem blight. Generally speaking, new asparagus fields have milder disease, while old asparagus fields have a large base of inoculum and develop the disease earlier and more severely. The pathogen in new asparagus fields mainly comes from two sources: one is seed-borne infection; the other is the pathogen from old asparagus areas spread by wind or rain. Therefore, keeping the asparagus field clean and sanitary and reducing the sources of infection is one of the effective methods for controlling stem blight.
Method two,When planting asparagus, apply more organic fertilizer and phosphorus and potassium fertilizer, and appropriately control the amount of nitrogen fertilizer. The ratio of nitrogen, phosphorus and potassium is preferably 1:0.6:0.8. Applying a certain amount of organic fertilizer each year can increase the soil organic matter content, loosen the soil, promote robust growth of the asparagus root system, stems and leaves, and improve disease resistance.
Method three,Chemical control should implement the principle of "prevention first". After the young spears emerge, spray must be applied in time to achieve good results.
In spring, in conjunction with cleaning the field, drench the roots with 50% carbendazim at 1:300 dilution; in May to June, in the early stage of stem blight, use 80% Dacotech at 1:400 dilution or 75% thiophanate-methyl at 1:500 dilution, spraying once every 7 to 10 days; in the peak period from July to September, spray once every 5 to 7 days. When spraying, focus on the stems and branches 60 cm above the ground, with the upper branches and leaves as secondary, and spray evenly and thoroughly. After rain, apply one additional spray. The above chemicals should be used alternately to avoid the development of resistance.
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