Common pest of flowers and plants: control methods for the Cynthia silk moth (Philosamia cynthia)
Philosamia cynthia Walker et Felder belongs to the order Lepidoptera, family Saturniidae. Its main host plants include walnut, pomegranate, citrus, castor bean, prickly ash, tree of heaven (chushu), Chinese tallow tree, ginkgo, Machilus, camphor tree, white michelia, pagoda tree, willow, and others.
Damage characteristics
The larvae feed on leaves and tender buds. In mild cases they eat the leaves into notches or holes; in severe cases they strip the leaves completely.
Morphological characteristics
Adult body length 25—30mm, wingspan 110-130mm. Body blue-brown. The area around the head, the front end of the collar plate, the rear margin of the pronotum, the dorsal surface of the abdomen, the lateral lines and the tip are all white. The dorsal surface of the abdomen has 6 pairs of white markings on each segment, with an interrupted white longitudinal line between them. Forewings brown, the rear margin of the forewing apex is blunt-hooked, the apex rounded and protruding, pink-purple, with a black eye-shaped spot, the upper edge of the spot is a white arc. There is a relatively large crescent-shaped spot in the center of both the forewings and hindwings; the upper edge of the crescent spot is dark brown, the middle is semi-transparent, and the lower edge is earth-yellow; on the outer side there is a broad band running the full length of the wing, the middle of the band is pink, the outer side white, the inner side dark brown, the base angle brown, and its edge has a white curved line. Eggs grayish-white or pale yellowish-white, with a few dark spots, flat oval, about 1.5mm long. Young larvae pale yellow, with black spots. After the middle instars the whole body is covered with white powder, blue-green. Mature larvae body length 55—75mm. Body thick and large, head, pronotum and mesothorax with symmetrical blue-green spine-like protuberances, these protuberances slanting slightly backward. Those on the subspiracular line are larger than the other two rows, and there are small black dots between the protuberances. Spiracular sieve pale yellow, peritreme black. Thoracic legs yellow, prolegs blue-green with yellow tips. Cocoon pocket-shaped or olive-shaped, about 50mm long, open at the upper end, small at both ends and thick in the middle, formed by binding leaves with silk, earth-yellow or grayish-white. Cocoon stalk about 40-130mm long, often with one host leaf wrapping half of the cocoon. Pupa reddish-brown, 26—30mm long, 14mm wide. Oval, with many transverse wrinkles on the body.
Occurrence pattern
In the north there are l—2 generations per year, in the south 2—3 generations per year, overwintering as pupae. In Sichuan, overwintering pupae begin to emerge as adults in late April; adults are phototactic and capable of long-distance flight, flying up to more than 3000m. Newly emerged adults mate immediately. The female moth has a very strong sexual attraction; unmated female moths placed in indoor cages continuously attract male moths, and removing both wings of the female moth promotes mating, while moths reared indoors mate with difficulty. Adult lifespan 5—10 days. Eggs are laid on the underside and upper surface of host leaves, gathered in piles or in masses; each female lays about 300 eggs, and the egg stage lasts 10—15 days. Newly hatched larvae are gregarious, and after the 3rd—4th instar they gradually disperse to cause damage. On branches and leaves they feed from bottom to top, day and night, and can migrate. The 1st-generation larvae cause damage in May, and the larval stage lasts about 30 days. After molting, the larvae often eat all or most of the shed skin. When mature, the larvae bind leaves on the tree and form cocoons; when there are no leaves on the tree, they descend to the ground cover and form thick brown cocoons to pupate. The 2nd-generation cocoon stage is about 50-odd days; late July to early August is the time when 1st-generation adults emerge and lay eggs. September—November is the damage period of the 2nd-generation larvae, after which they successively form cocoons and pupate to overwinter. The 2nd-generation overwintering cocoons last as long as 5—6 months, with the pupae hidden in the thick cocoon. The overwintering generation often forms cocoons on the fine branches of dense shrubs such as citrus and pomegranate; on a single pomegranate or citrus tree, as many as 30-40 overwintering cocoons can often be found in severe cases.
Control methods
(1) Manual collection. After adults lay eggs or larvae form cocoons, manpower can be organized to remove them, or they can be directly killed; the removed cocoons can be used for silk reeling and oil pressing.
(2) Light trapping. Adults are phototactic; by mastering the emergence period of adults of each generation and using black light lamps at the right time to trap and kill them, good pest control results can be achieved.
(3) Chemical control. In the early stage of larval damage, spray 90% trichlorfon at 1500—2000 times dilution; 20% dichlorvos heavy smoke agent can also be used, at 0.5—0.7kg per 667 sq m, with very good effect against young larvae. Pyrethrum preparations or derris extract can also be used for control.
(4) Biological control. The natural enemies of the Cynthia silk moth larvae discovered so far include the braconid wasp Apanteles and three ichneumon wasps: the Himalayan Pimpla, the rice leaf roller black-spot Pimpla, and the Cynthia silk moth black-spot Pimpla. These natural enemies should be well protected and utilized.
Control methods for the garden and landscaping pest Cynthia silk moth (Philosamia cynthia)
Philosamia cynthia Walker et Felder belongs to the order Lepidoptera, family Saturniidae. It is distributed in many regions. The larvae damage tree of heaven, Chinese tallow tree, holly, plane tree, Paulownia, white magnolia, Michelia, black locust, camphor, sumac, oriental cherry, cherry, pear, hibiscus, ginkgo and willow, among others.
Adult body length about 28mm, wingspan about 128mm, body blue-brown. Forewings yellowish-brown, apex rounded and protruding, base with a >-shaped white band, center with a crescent-shaped white marking, outer lines all white, with slender brown edging, wing surface with pink-purple markings. Eggs flat oval, grayish-white, with brown spots. Mature larvae body length about 70mm, body thick and large, blue-green. The body is covered with white powder, and each body segment has 6 spine-like protuberances, with dark brown spots between the protuberances. Pupa reddish-brown, lotus-seed shaped. Cocoon silky, olive-shaped, with an opening at the upper end, cocoon stalk long, often with 1 leaf wrapping half of the cocoon.
[Integrated management]
(1) Protect and utilize natural enemies such as the braconid wasp Apanteles and the Cynthia silk moth black-spot Pimpla.
(2) Trap and kill adults Use black light lamps or sex attractants to trap and kill adults.
(3) Chemical control When outbreaks are severe, spray high-efficiency Bt powder at 1 500 times dilution, or Bacillus thuringiensis var. aizawai powder at 600 times dilution for control.
Control methods for the Cynthia silk moth (Philosamia cynthia) on ornamental trees
Philosamia Cynthia Walker et Felder, also known as the Chinese tallow silk moth. It belongs to the order Lepidoptera, family Saturniidae. It is widely distributed in China. The larvae damage tree of heaven, Chinese tallow tree, southern magnolia, citrus, holly, Paulownia, white magnolia, Michelia, black locust, camphor, sumac, oriental cherry, cherry, hibiscus and ginkgo, among others.
Adult body length about 30mm, wingspan about 128mm, body blue-brown. Forewings yellowish-brown, apex rounded and protruding, with 1 black round spot. Base with a “>”-shaped white band, center with a crescent-shaped white marking, outer lines all white, with slender brown edging, wing surface with pink-purple markings. Eggs flat oval, grayish-white, with brown spots. Mature larvae body length about 70mm, body thick and large, blue-green. The body is covered with white powder, and each body segment has 6 spine-like protuberances, with dark brown spots between the protuberances. Pupa reddish-brown. Cocoon silky, olive-shaped, with an opening at the upper end, cocoon stalk long, often with 1 leaf wrapping half of the cocoon.
Integrated control
(1) Protect and utilize natural enemies such as the braconid wasp Apanteles and the Cynthia silk moth black-spot Pimpla.
(2) Trap and kill adults Use black light lamps or Cynthia silk moth sex attractants to trap and kill adults.
(3) Biological control When outbreaks are severe, spray high-efficiency Bt powder at 1500 times dilution, or Bacillus thuringiensis var. aizawai powder at 600 times dilution for control.