MySheen

Angelica yellow tigers

Published: 2024-11-24 Author: mysheen
Last Updated: 2024/11/24, 1. Morphological characteristics of adults: body length 14,19mm, wingspan 32mm 34mm. Yellowish brown or taupe. The front wing is grayish yellow, the horizontal line of the wing surface is not obvious, but the reniform pattern, ring pattern and rod pattern are clear. The center and outer margin of the wing are dark brown. The hind wings are white and the leading edge is slightly yellowish brown. Eggs: hemispherical, about 0.5 mm in diameter. There are 16-20 longitudinal ridges on the surface of the eggshell. Larva: the length of the growing larva is 33mm to 43mm. Yellowish brown, shiny. There are many wrinkles on the body surface, and the particles are not significant. Buttock

1. Morphological characteristics.

Adults: 14mm in length and 32mm in wingspan. Yellowish brown or taupe. The front wing is grayish yellow, the horizontal line of the wing surface is not obvious, but the reniform pattern, ring pattern and rod pattern are clear. The center and outer margin of the wing are dark brown. The hind wings are white and the leading edge is slightly yellowish brown.

Eggs: hemispherical, about 0.5 mm in diameter. There are 16-20 longitudinal ridges on the surface of the eggshell.

Larva: the length of the growing larva is 33mm to 43mm. Yellowish brown, shiny. There are many wrinkles on the body surface, and the particles are not significant. The gluteal plate is divided into 2 yellow spots by the central yellow longitudinal bar.

Pupa: body length 15mm-20mm. There is a sparse inconspicuous notch in the center of the back of the fourth ventral segment.

2. Occurrence regularity

The yellow tiger overwinters with larvae and a small amount of pupae in host fields and grasslands. In the second year, the overwintering larvae pupated in mid-March and began to Eclosion into adults in early April. The peak period of moth eggs is in the first and middle of May, and the peak period of egg hatching is in the middle of May. The period from late May to early June is the peak period of larva damage. The peak of moth occurrence in later generations occurred in mid-July, mid-September and late October, respectively.

The adult has a strong phototaxis, and the female moth lays eggs on the soil surface stubble, grass stalks and many kinds of weed leaves, often dozens of grains arranged in strings. Larvae lie dormant during the day and come out at night. The newly hatched larvae ate the tender leaves and growth points of the host seedlings, and the 1st and 2nd instar larvae ate small holes or lacerations. After the 3rd instar, they mostly ate the base of the stem in the topsoil layer, which could bite off the tender stem or become incomplete at the base of the thicker stem. When the damage is serious, a large number of seedling stems are bitten off or the stem base is incomplete, resulting in withering and death. Sometimes some larvae can climb to the top of the seedlings to feed and bite off the tender head.

The damage degree of the first generation larvae of the yellow tiger is related to the overwintering base number and the overwintering larval instar period, such as the large number of overwintering old larvae, the large number of adults in the following spring, and the first generation larvae. The yellow tiger is not tolerant to high temperature, and the second generation occurs in the hot summer season. In North and East China, the first generation larvae are the main damage in general years. The insect has low requirements for Rain Water and humidity, so the damage is more serious in the northwest region with drought and little rain.

 
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