Aporia crataegi Linnaeus

Alternative names

Hawthorn silk butterfly, hawthorn white butterfly.

Morphology (Figure 3-100)

Figure 3-100 Silk White Butterfly

1. Adult 2. Larva 3. Pupa

The adult body length is 22-25mm, the wingspan is 64-76mm, and the body is black. The antennae are club-shaped, black, with light yellowish white ends. The wings are white, the female moth is slightly off-white, and the wing veins are black. Except for the hip vein, there is a triangular black spot at the end of each vein on the outer edge of the forewing. The eggs are 1.5mm long. The eggs are columnar, with a slightly pointed top, like a bullet. There are 12-14 longitudinal ridges on the surface. They are golden yellow at first and gradually turn into light yellow. The larvae are 38-40mm long, with sparse yellow-white long hairs all over, mixed with yellow and black hairs, and many small black spots. The head, pronotum and rump are all black. There are 3 black longitudinal bands on the chest and back, with 2 yellow to tan longitudinal bands sandwiched between them. The sides of the body are gray, the ventral surface is purple-gray, there is a black spot on the outside of the ventral foot, and the hooks of the ventral toes are in a single sequence. Overwintering larvae are 4-5mm long. The head is dark brown, and the trunk is yellow-brown to orange-yellow. The backline is lavender, and there is 1 lavender vertical stripe on each side of the body. The body surface is densely covered with long light yellow hairs. The pupa is 20-25mm long and has two colors: a black body with yellowish-white color and many small black spots; the head, mouthparts, feet, antennae, compound eyes, longitudinal ridges of the thorax and back, wing edges and ventral surface are all black, and the head The tumor-like protrusions are yellow; the yellow-type body is yellow, smaller, and has small and few black spots.

Life history and habits

One generation occurs every year, and the 2-3rd instar larvae spend the winter in clusters in nests with curled dead leaves on trees. Overwintering larvae in Liaoning emerge from hibernation in mid-April, with peak season in mid-May. The larvae swarm during the day and damage buds, flower buds, petals and young leaves, and return to the nest on cloudy days and at night. Later, a net was spun on the branches. When the larvae mature, they disperse and cause damage, and their food intake increases greatly. The 4th to 5th instar larvae have suspended animation. In early and mid-May, the larvae mature and pupate on trees, small shrubs, weeds, etc. The tail end of the pupa is fixed on the silk pad, and the abdomen is tied horizontally to the branches by silk. Overwintering larvae take 40 days from emergence to pupation. The pupal stage lasts 14-21 days. Late May is the peak emergence period for adults, and early June is the peak egg-laying period. Adults are active during the day and lay eggs in piles on the underside of leaves. There are about 32-220 eggs in each pile. Females lay 239-801 eggs in a single cycle. The egg stage lasts 10-19 days. Late June is the peak hatching period, when the larvae gather on the leaves and eat the mesophyll. When the larvae develop to 2-3 instars in early July, 3-5 leaves are connected with silk to make a nest, in which the larvae spend the winter.

Prevention and Control Methods

Cut off the nests of overwintering larvae. When the larvae grow up, they use their habit of suspended animation to kill them by shock. Before the larvae are dispersed and cause damage, spray 4% dima powder or 2% fenitrothion powder or 2.5% trichlorfon powder. After the larvae are dispersed, spray 50% malathion emulsifiable concentrate or 50% fenitrothion emulsifiable concentrate. 1000 times solution, 80% dichlorvos EC 1500 times solution, 10% cypermethrin EC, 20% cypermethrin EC 3000 times solution to kill larvae.