PINE CHERMES Chermes pinicorticis Fitch Many years ago Dr. Fitch recognized this species (Fig. 42) as injurious to pine and indicated its potential possibilities as a forest pest. Since the time of his publication the species has shown itself at many localities and frequent intervals to be eapable of serious injury to pine trees and it deserved attention in any discussion of insects connected with forest problems. The species was ob served on a number of small trees in the vicinity of the summer camp and in some instances in sufficient numbers to be counted injurious. If in large numbers on older and larger trees they were too far from observation to be recognized. In nurseries at the Ranger School it is frequently a very serious pest.
The infested trees are readily recognized by the appearance of numerous small flecks of white cottony material covering the bodies of the insects and adhering to the bark especially around the bases of the branches or in the aril of the twigs. They do not occur on the leaves but the twigs, branches and even the trunk may be thickly dotted with little thin white tufts. The white cottony secretion consists of Ivax filaments secreted from glands on the upper surface of the abdomen and may be readily separated from the insect by touching with a needle or brush or dissolved away by application of creosote.
Since the description by Fitch the species has been studied in Iowa by Osborn ('80) in Illinois by Storment and in Maine by Patch and referred to by other writers. The more essential points in the life cycle with reference to control may be stated briefly as follows: The winter is passed in egg stage and in part by adult wingless asexual females. The progeny of early spring broods develop ing first from stem mother are wingless oviparious but about May there is a generation of winged individuals that by a general fight serve to scatter the species in all directions. The later sum
mer generations are wingless and wingless oviparous females pro vide the eggs which are destined to survive the succeeding winter and produce the stem mothers for the succeeding season. The cottony covering protects them fairly well against sprays unless driven with such force as to dislodge them and this may be done for lawn trees where water pressure is available by drenching, the trees with a stream of water as well as with a contact spray, although the latter if under equal pressure might have added advantage of killing the insects and preventing a return of pests by development of new generations from chance individuals sur viving the spray.
In extensive forest areas or in large parks where direct applica tions are impracticable or impossible it may be advisable to cut the badly infested trees and burn the infested branches and twigs to prevent them from serving as centers for the multiplication of the insect and their distribution to healthy trees. This has the further advantage of directing the natural enemies which on the whole are the main factor in preventing wholesale damage by the pest to those trees that are less infested and thereby reducing the numbers of the pest. Care in freeing nursery stock by spraying or fumigating before planting should serve to prevent some of the damage in newly planted forest areas.
Natural enemies that have been noted are ehrysopas, syrphids and mites; and these play an important role in reducing the num bers of the 'pest.