Control methods for pests that feed at the door in spring on jujube trees
Autumn management of young jujube orchards mainly involves controlling fertilizer and water, strengthening loosening of the soil, promoting continuous thickening and lignification of the trunk, and creating good conditions for young trees to overwinter. The key technical points for autumn management of young trees are summarized as follows: Control irrigation. Jujube trees are drought-tolerant, prefer warmth, sprout late, and shed leaves early. Young trees should be watered appropriately, with the basic principle...
In mid-to-late April, when jujube trees sprout, it is often found that the newly grown tender buds are eaten by a kind of insect. This pest is the jujube looper, commonly known as "door-feeding." When the larva crawls, its body forms an "arch" shape and it moves in a looping manner. After the jujube tree unfolds its leaves and blooms, because the larvae have grown older and their food intake increases greatly, they often eat the leaves into notches of various sizes. In severe cases, they can eat all the leaves and flower buds on the entire tree. Not only is there no yield that year, but fruit setting the following year is also affected. Therefore, fruit growers should pay attention to its control.Digging for pupae: Before mid-March, within a diameter of 1 m around the tree trunk, dig into the soil layer to a depth of 15 cm to look for overwintering pupae, and pick them up and take them outside the orchard for centralized destruction. This work can be carried out together with turning over the tree plate.
Catching moths: The female adult of the jujube looper (female moth) has no wings and cannot fly. After emerging from the soil and eclosing, it needs to climb up the tree to find a male moth to mate and lay eggs. Based on this characteristic, before adult emergence in mid-to-late March, wrap a plastic film around the base of the trunk at 30-50 cm above the ground. The film should be 8-9 cm wide, with a 3 cm overlap at the joint, and fastened with two jujube thorns. The film should fit tightly against the trunk with no gaps. This can prevent female moths from climbing up the tree to mate and lay eggs, and moths can be caught every morning.
Destroying eggs: After the trunk is wrapped with plastic film, female moths cannot climb the tree and mostly concentrate under the plastic film in cracks in the rough bark to lay eggs. The rough bark can be pried open and the eggs scraped off and destroyed. Two loops of straw rope can also be wrapped under the plastic film to lure female moths to lay eggs, and the straw rope should be replaced once every half month and burned centrally to eliminate the eggs. Generally, replacing the straw rope 3 times is sufficient.
Knocking the tree to shake off insects: Newly hatched larvae of the jujube looper have a death-feigning habit. When startled, they immediately spin silk and hang down, so knocking the tree can shake the larvae off and eliminate them in time.
Chemical control: When jujube buds are 3 cm long, spray for the first time. Options include Bt emulsion at 500-1000 times dilution, or 25% diflubenzuron No. 3 at 1500 times dilution, or Zaochong Kuaibi at 1200 times dilution to control newly hatched larvae. When jujube buds are 5-7 cm long, spray for the second time. Options include Zaochong Kuaibi at 1200 times dilution plus beta-cypermethrin at 1000 times dilution, or 75% phoxim at 800-1000 times dilution plus beta-cypermethrin at 1000 times dilution, or 20% fenvalerate at 6000 times dilution to control larvae of all instars.
Manual collection of larvae: For older mature larvae remaining after spraying, take advantage of their habit of resting quietly on branches at noon and collect them manually.