Spodoptera litura

Cydia strobilella (Linnaeus), also known as Cydia strobilella (Linnaeus), belongs to Lepidoptera. It is distributed in Heilongjiang, Inner Mongolia, Shaanxi, Gansu, Ningxia, Qinghai, Tibet and other places in China. It mainly damages Picea spruce and larch.

Damage characteristics larvae damage cones and seeds, damaged cones curved, fat, fruit consequences often do not open scales.

morphological characteristics

The adult is about 6mm long and has a wingspan of 10-13 mm. Head, chest, abdomen gray black. The lower lip must be forward and slightly curved, with sparse long scales. Brown and black front wing is narrow and long, light black base spot is convex forward in the middle, brownish black in the middle, extending from the middle of front edge to the rear edge near hip angle, and the middle is slightly curved convex; 3-4 groups of gray and bright hook-like patterns are formed from the middle of front edge to the vertex angle, and the hook-like patterns extend downward into 4 silver-gray oblique spots with metallic luster extending to the rear edge, hip angle and outer edge. hind wing brownish black, base pale, ciliate yellowish white.

Ovoid or slightly flattened, yellow.

The larvae are 10-11mm long, slightly flat, yellow-white to yellow. The head is brown and the back is brighter. The valves are very small and brown. On the last segment, stomata flank the midline.

The pupa is 4-5mm long and brown. The forehead bulges, the protuberances on the penultimate second section have thorns, and there are 4 hook-shaped hip spines.

It occurs every 1-2 years and overwinters as mature larvae. Overwintering larvae begin to move in early April, pupate from early May to mid-June, peak in mid-May; emerge and lay eggs from early May to mid-June, peak in mid-June and late June; hatch from early June to early July, peak in mid-June; mature larvae enter fruit axis to overwinter from late July to late August.

Adult emergence is concentrated at 9-15 o'clock, flight is active at 8-16 o'clock, and shell slightly exposes scales after emergence. 1-2 The ratio of female to male is about 2.36:1, and the life span is about 5 days. The egg yield is above the inner wing of the young cone. There are 1-6 eggs per cone, the maximum is 29 eggs, 34-105 eggs per female, the average is 53 eggs. The number of eggs dropped on the sunny side of the crown is more than that on the shady side. After hatching, the larvae drill into the scales, bore into the immature endosperm of the young seeds, and then transferred to the adjacent seeds to continue to harm them. Each damaged seed has 2 holes, and the larvae can move back and forth between the damaged seeds. When the larvae are mature, they bore into the fruit axis and overwinter in an oblong chamber. A few overwinter in the scales and damaged seeds. Injured cones curved, fat, fruit drop consequences scales often do not open. The density of young forest, sparse forest and pure forest was higher than that of middle-old forest, dense forest and mixed forest.

There are 2 species of parasitoid wasps and 1 species of parasitoid fungus in natural enemies. About 65% of overwintering larvae are often pecked by birds.

control methods

1) Agricultural control.

Build mixed forest, strengthen tending, strengthen tree vigor, prevent damage; combine seed collection, remove damaged cones, and concentrate treatment.

(2) Protection and utilization of natural enemies.

(3) Chemical control.

Spraying omethoate 500 times solution at the peak of larva hatching period has good control effect.

Common agent omethoate.