Introduction and control of Spodoptera litura in bamboo shoots

Bamboo shoots have been regarded as "treasures in dishes" in China since ancient times. Bamboo shoots are a traditional Chinese delicacy with a crispy taste and a long history of eating and cultivation. In the Book of songs, there are poems such as "add beans, bamboo shoots and fish fish" and "its sounds, but bamboo shoots and cattails", indicating that people have eaten bamboo shoots for 2,500 or even 3000 years.

Growth habits of bamboo shoots

The underground stems of scattered bamboo species such as Phyllostachys pubescens and Phyllostachys pubescens are deeply buried in the soil, and the bamboo whips and shoot buds are protected by the soil layer, so they are not easy to suffer frost damage in winter, and the shooting period is mainly in spring. The underground stems of tufted bamboo species such as Phyllostachys pubescens and green bamboos are shallow in the soil, and the shoot buds are often exposed to the soil, which are easy to be damaged by freezing in winter, and the shooting period is mainly in summer and autumn.

Bamboo is native to the tropics and subtropics. It likes temperature and is afraid of cold. It is mainly distributed in the area of annual rainfall 1000~2000mm. The optimum temperature for the growth of Phyllostachys pubescens is 16-17 ℃ per year, less than 30 ℃ in summer and 4 ℃ in winter. Dendrocalamus latiflorus and Phyllostachys pubescens require an average annual temperature of 18-20 ℃, and the average temperature in January is above 10 ℃. Therefore, bamboo forests are luxuriant in southern China, while bamboo forests are rare in the north of Qinling-Huaihe River. Bamboo needs a soil with deep soil layer, loose, fertile, moist, drained and well ventilated soil, and the soil pH value is 4. 5%. 5-7 is appropriate.

Bamboo shoots are the buds of bamboo, also known as shoots. Bamboo is a perennial evergreen herb, the edible part is primary, tender fat, short and strong buds or whips. Bamboo is native to China with many types, strong adaptability and wide distribution. Bamboo shoots taste sweet and slightly cold, with the effects of clearing heat and eliminating phlegm, diaphragm and refreshing stomach, relieving thirst and benefiting qi. Bamboo shoots also contain a lot of fiber, which can not only promote intestinal peristalsis, remove food accumulation, prevent constipation, but also be a good food for obese people to lose weight.

Introduction and control of Spodoptera litura in bamboo shoots

Another name for Spodoptera litura: Spodoptera litura, bamboo shoot borer

Orders of Spodoptera litura: Lepidoptera, Noctuidae.

The scientific name of Spodoptera litura: Oligiavulgaris

Distribution of Spodoptera litura in Henan, Shaanxi, Jiangsu, Zhejiang, Anhui, Jiangxi, Hubei, Hunan, Fujian, Taiwan, Guangdong, Guangxi, Guizhou, Sichuan, Yunnan, Chongqing and other regions.

The harmful objects of bamboo shoot night moth are Phyllostachys pubescens, Gramineae and Cyperaceae weeds.

The harmful symptoms of Spodoptera litura: the larvae eat bamboo shoots, the injured shoots form bamboo shoots and cannot become bamboo shoots. A small number of adult bamboo also break their heads, wormholes are numerous, and the heart is rotten and brittle, which affects the ornamental and bamboo quality.

Morphological characteristics of Spodoptera litura in bamboo shoots

(1) Adult: the body is 14-25 mm, the wingspan is 32-50 mm, the body and wings are brown, there is an inverted triangular dark brown spot at the base of the forewing and at the top angle, the inner horizontal line, outer horizontal line and sub-outer marginal line are faintly visible, and the hind wings are yellowish brown.

(2) eggs: subglobose, ca. 0pm 8 mm, yellowish white.

(3) larvae: the body length is 30mm to 45mm, and the head is orange-red. The body is purplish brown, the topline is thin and white, and the subtopline is wide and white, but there is a shortage in the first half of the second segment of the abdomen.

(4) pupa: 15mm long, reddish brown, 4 gluteal spines.

The occurrence regularity of Spodoptera litura: one generation a year, overwintering with eggs in the edge wrinkle of dead leaves of Gramineae weeds; hatching at the end of February of the following year, when the bamboo shoots were not unearthed, the larvae drilled into the heart leaves of Gramineae and Cyperaceae weeds, resulting in withered heart and white ear symptoms. The larvae molted in the grass heart for 2 or 3 times and stopped growing. When the bamboo shoots were unearthed in the early and middle of April, the larvae turned from weeds to eat into the bamboo shoots, first from the shoot tip leaflets, then molted again, crawled out of the leaflets, turned into the bamboo shoot sheaths and ate into the bamboo shoots, and if the bamboo shoots sheaths were thin, they could directly eat into the bamboo shoots. The larvae were mature for 18-25 days after eating in the bamboo shoots, and the mature larvae could turn to the bamboo shoots when they were young. In the early and middle of May, the mature larvae climbed out of the bamboo shoots and formed a thin cocoon and pupated in the loose soil, and the pupa period was 20-30 days. The adults emerged in the early and middle of June, and the adults were nocturnal and phototactic, mating and laying eggs on the same day or every other day, and each female laid more than 380 eggs. Eggs are laid at the edge of withered leaves and leaf rolls in the lower part of Gramineae weeds, that is, eggs survive the winter. Therefore, the occurrence of this insect is directly affected by the presence and quantity of weeds in bamboo forest.

Control methods of Spodoptera litura in bamboo shoots:

(1) artificial control: there are no dewdrops and no luster at the tip of the injured bamboo shoots in the early morning, commonly known as "retreating bamboo shoots", which can be dug up as early as possible to destroy the larvae in the bamboo shoots.

(2) Horticultural control: ploughing and weeding and eliminating the overwintering eggs on the grass is the key to the control of this pest.

(3) physical control: black light traps and kills adults.

(4) Pesticide control: 20% fenvalerate EC was sprayed on the weeds under and around the bamboo forest before shooting in the middle and late March, once every 7 days, a total of 2 times and 3 times, in order to kill the larvae on the grass.