Greenhouse green asparagus underground pest land tiger control
Ground tigers, also known as root-cutting insects, soil silkworms, and ground silkworms, belong to lepidoptera, nocturnal moth family, and are one of the main pests that harm asparagus. There are many types of ground tigers, and the most harmful asparagus in the Beijing area are mainly small land tigers and yellow ground tigers.
Pest characteristics: mainly larvae harm the newly unearthed asparagus seedlings, often dragging the bitten off seedlings into the hole, resulting in missing seedlings and ridges; also often in the near ground stem borer hole hazard, so that the aboveground stems die or form hollow seedlings; and bite the young stems of asparagus, the green shoots are the most seriously harmful, which has a great impact on yield and quality.
Morphological characteristics: Adults of the small ground tiger are 16 - 23 mm long, have a wingspan of 42 - 54 mm, dark brown, and the forewings are divided into 3 segments by the inner and outer transverse lines, with significant kidney-like spots, ring stripes, rod stripes and 2 sword-like stripes. The hindwings are grey without markings. The egg is 0.5 mm long, hemispherical, with a transverse rumbly surface, initial milky white, followed by red markings, and grayish black before hatching. The larvae are 37 – 47 mm long, greyish-black, the surface of the body is covered with particles of varying sizes, the hips are yellowish brown, with 2 dark brown longitudinal bands. Pupae 18 - 23 mm long, russet, glossy, the incision on the back of the 5th-7th abdominal segment is larger than the lateral incandescence, the gluteal spines are 1 pair of short spines; the adult yellow-ground tiger is 14 to 19 mm long, yellowish brown or gray-brown, the forewings are not pronounced, the kidney-shaped spots, rings and rod-like stripes are obvious, and are inlaid with black brown edges, the wings are scattered with brown dots, the terminal larvae are 33 - 42 mm long, the body surface particles are not obvious, and the hip plate is two yellow-brown spots. rules
Occurrence law Occurs 3-4 generations a year in North China. In mid-to-late May, the larvae are the most infested, and the 1st and 2nd instar larvae are mostly concentrated on the stems or leaves, and disperse after the 3rd instar. Lurking during the day, coming out at night, biting seedlings or young stems, agile movements, sexual cruelty, cannibalism. The mature larvae are suspended dead and are frightened into rings. The adult insects of the ground tiger are strongly active, day and night, and have a strong tendency towards black light and sweet and sour wine.
Prevention and control methods:
(1) Remove the weeds in and around the bamboo shoot field in early spring, reduce the shelter, and prevent adult tigers from laying eggs.
(2) Trap adult insects with black light, sweet and sour liquid or poisonous bait.
(3) Before asparagus colonization, the ground tiger only feeds on field weeds, so you can choose the gray cabbage, thorny vegetables, small spiny flowers, alfalfa and other weeds that the tiger likes to eat, or artificially capture, or mix into the poison to kill.
(4) The larvae of the ground tiger have poor resistance at the age of 1-3 and are exposed to the host plant or the ground, which is the appropriate period for drug control. The main agents are 50% octathion 800 times liquid, 90% dimethoate 800 times liquid, 40% chlorpyrifos emulsion, 2.5% diethyl killing emulsion or 2.5% cypermethrin.