What are the key technical points for summer management of walnut trees?
How to manage walnut trees well in summer? Here are the methods. In summer, walnut new shoots grow fastest and physiological activity is strongest; this is the period with the highest survival rate for bud grafting and the most critical time. Pests such as the yellow slug moth, the walnut fruit moth (walnut black), the walnut yellow weevil, the cloud-banded longhorn beetle, the gypsy moth and the walnut tuft moth begin to emerge and lay eggs. Rot disease...
How to manage walnut trees well in summer? Here are the methods
In summer, walnut new shoots grow fastest and physiological activity is strongest; this is the period with the highest survival rate for bud grafting and the most critical time. Pests such as the yellow slug moth, the walnut fruit moth (walnut black), the walnut yellow weevil, the cloud-banded longhorn beetle, the gypsy moth and the walnut tuft moth begin to emerge and lay eggs. Rot disease and branch blight occur in large numbers.
During this period, the bud grafting task must be completed in good time, and major outbreaks of pests and diseases must be monitored at all times.
1. Bud grafting for seedling propagation. After the scions for bud grafting are cut, the compound leaves should be removed immediately, leaving about 0.5 cm of the petiole; wrap them in a wet burlap sack or wet cloth and place them in a cool place. When bud grafting, bring a bucket filled with water 10 cm deep, stand the scions in the bucket, and cover with a wet cloth or wet towel; take one out as you finish one. Before bud grafting, first cut horizontally above and below the bud of the scion with a double-edged knife, then make one vertical cut on each side of the bud and set aside. Then cut off the top of the rootstock seedling, leaving 6-8 compound leaves; at the 3rd-4th compound leaf and a smooth part, first cut horizontally above and below with a double-edged knife, then make one vertical cut on one side, then use the knife edge or a fingernail to pry it open, then quickly pry off the prepared bud from the scion, insert it into the rootstock incision, align one side, and according to the width of the bud on the other side, press the bud with one finger while using the other hand to tear off the rootstock bark so that the bud and the upper incision on the rootstock align left and right (top and bottom generally align because a double-edged budding knife is used), then bind tightly with a plastic strip.
2. Monitoring the occurrence of pests and diseases. In areas where the walnut fruit moth (walnut black) occurs severely, observe the process of the moth changing from pupa to adult, laying eggs, and the eggs hatching into larvae; during the emergence period, egg-laying period and hatching period, spray 25% carbaryl 600 times dilution, or decamethrin 5000 times dilution, or 4% dimethoate emulsifiable concentrate 800-1000 times dilution every 10 days.
In areas where the yellow slug moth (flat slug moth, brown slug moth) and others occur severely, manual control can be carried out: in the early stage of egg hatching, looking from below upward, when a place where leaves have been eaten by the insects is found, cut off that leaf with scissors (or long-handled pruning shears) and crush it underfoot (because slug moth larvae have the habit of feeding in groups); this method is simple and easy and works well. This method is suitable for areas that are not large or where insect density is not high. You can also spray 90% trichlorfon 800 times dilution or 25% phosmet emulsifiable concentrate 1500 times dilution, etc.
For the gypsy moth, walnut tuft moth and others, spraying insecticide in the early stage of occurrence can achieve good results.
In areas where longhorn beetles occur severely, make a small hook from iron wire, insert the small hook into the exit holes where insect frass and sawdust appear, or soak a cotton ball with insecticide and plug it in, then cover the opening with mud to seal it.
In areas where the walnut weevil occurs severely, in addition to control in winter, in June-July dig away the soil at the root crown, use an axe to cut through the bark at intervals of about 10 cm, spray the root crown heavily with 5 times dilution of dichlorvos, or 50-100 times dilution of 50% phosphamidon, then seal tightly with soil to kill the larvae and pupae, with remarkable effect.
In areas where diseases such as rot disease and canker are severe, the control method is the same as above, that is, use a sharp knife to cut away the diseased part, then apply a fungicide such as asomate.
3. Supplemental watering to ensure the tree body is robust. If the weather is dry, water can be added. According to the situation, carry out furrow irrigation, sprinkler irrigation, hole irrigation or the stored fertilizer-water method.
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