There are more than 15 walnut pests, the most important of which is “turnip worm”. Infected provinces are: Kerman, Hamedan, Fars, Isfahan, Tehran, Alborz, Razavi and North Khorasan, East and West Azerbaijan, Qom, Markazi, Qazvin and Zanjan, which on average 50-70% damage to walnut fruits brings.
Larry butterfly larvae are present in low altitude areas as well as in hot and dry areas, which in case of drought and water shortage cause holes and corridors in the trunk and main branches and dryness and loss of branches and leaves and Gradual death of the walnut tree. Therefore, before pruning, it is necessary to completely physically remove and cover the corridors on the main branches and the main trunk with poison and grafting glue. In the growing season, visit the new branches around the end of June and July. Remove the pest and spray at least 2-3 times at a distance of 15 days with smoke pesticides and using sex pheromones and plant protection experts on the advice of experts. Cup with modified central axis) and burning of infected branches and feeding with organic fertilizers and principled irrigation in the shade of the tree fought against this pest.
Walnut pest control methods:
– Installing pheromone traps (at the height of the upper third of the tree canopy) and installing optical traps and attracting full insects of this pest before spawning and larvae entering the trees
– Strengthening trees, regular and adequate watering of the garden, fertilizing and observing the principles of gardening
– Pruning infected and dry branches and burning them
Blockage of active larval corridors: These corridors are characterized by the accumulation of a brown mass of larval excrement, sawdust with the secretion of tree leachate protruding from the trunk hole and the head of the branch. To fight, we can first inject into the holes with a poison syringe such as a dorsal and then cover the larval entrance with adhesives such as aquarium glue or materials such as painting paste or even available materials such as clay.
Extermination of larvae by flexible metal wire
However, in order to fight against Zeuzera, which is a very dangerous pest and polyphagous, it is necessary to use a combined fight, in which case the following methods are suggested:
– Pruning of highly infected branches, especially sub-branches located in the upper parts of the tree canopy and transferring them out of the garden and burning and burning them.
– Corrective pruning in old walnut trees in the form of a cup with a central axis changed in 2-3 years and finally selecting three to four main branches (arm) for each tree in different directions and at a distance of at least 30 cm from each other and with Open center system or modified method (modified central leader) Cup form with modified central axis
Irrigation in tree shade with irrigation cycle once every 7-10 days and also strengthening the trees with macro chemical fertilizer (phosphate and potash at the rate of one kilogram each in March and nitrogen at the rate of one kilogram for each fruiting tree twice, half in April And the rest one month later) all in the shade and with irrigation water. Also, spread manure of 30 tons per hectare in late autumn to late winter between the trees and return them to the soil (to a depth of 30 cm).
Observing planting distances of 8-10 meters for seed walnut trees and, if necessary, uprooting infected, frostbitten, low-yielding or very damaged trees from turnip worms and transferring them outside the garden and burning and burning completely infected branches
Apple worm is one of the most important pests of walnut, which is the main pest of apples and causes severe damage to the crop and the amount of damage is higher in early flowering cultivars. The larvae of the first generation enter the small fruits through the end of the flowerbed and cause them to fall. The second and third generations of this pest cause blackening of the brain and decrease in fruit quality.
To combat this pest, it is recommended to spray twice in early May and late June with phosphorus toxins at a rate of 1.5 per thousand.