Phaenops cyanea (Fabr.)From: Kolk A., Starzyk J. R., 1996: The Atlas of Forest Insect Pests Occurrence: Europe and the northern Africa. Host plants: Mainly the Scots pine and other pines, also the Norway spruce, common fir and larch. Morphology: Adults are 8-11 mm long. The body is oval, flatted, dark bluish or greenish with metallic shine. The head is wide. Pronotum is as broad as the base of elytrae. Larvae are white, legless, much flatted, thin with widened first segments, characteristically curved in the middle part of the body, up to 23 mm long. The pupa is about 8.5 mm long. Biology: Larvae overwinter in pupal chambers in the bark or wood, and pupate in spring. Adults are active from May through August. P. cyanea favours trees exposed much to sunshine at forest edges. Adults feed on needles. Females lay single eggs under bark scales. Newly hatched larvae feed under the bark and penetrate phloem and cambium. They chew curved galleries up to 10 mm wide, filled with frass. Infested trees are not easily recognized until woodpeckers feed on overwintering larvae. Adults exit through oval exit holes 3-4 up to 4-7 mm in size. It has one generation per year. Damage: The most serious pest of the Scots pine. It is particularly dangerous in warm dry years when attacks weakened trees in places exposed to sunshine. P. cyanea prefers trees with thick bark and infests mainly middle and lower parts of the stem. Infested trees usually die. This species is dangerous in stands with fluctuating ground water level and in stands weakened by pollution or damaged by wind, snow or fire. Preventive measures: Removal of windthrows, weakened trees or timber during the whole year. Control: Removal of infested trees, especially during autumn and winter when woodpeckers pointed them out. Trap trees should be used in threatened stands of middle and older age classes. Two traps per ha or one trap per every 100 m of a forest edge are recommended. They should be placed two or three times per year: the first time, the exposure in mid-May and tree debarking in end-June; the second time, the exposure in mid-June and debarking in end-July, and, eventually, the third time, the exposure in mid-July and debarking in end-August. Generally traps should be debarked before larvae enter the bark (if the bark is thick) or wood (if the bark is thin). Otherwise the bark with larvae inside should be burned or dig into a soil.
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Forest Pests: Insects, Diseases & Other Damage Agents |
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