496 ANNUAL REPORT OF THE Off. Doc. 



parents iu nearly every regard excepting that they do not have wings 

 and are smaller. Also, they do not have a chrysalid or ret^ting stage, 

 and thns there are but three .stages in their liie histoiy: The egg, the 

 nymph or wingless young, and the adult or imago, which is repre- 

 sented by the winged form in all species having wings. The insects 

 of the second group are said to have completed metamorphosis, as 

 their change is more distinct, comprising four stages: the egg, the 

 larva or worm-like stage, the chrysalid or pupal stage, and the adult 

 or imago. 



The insects do all their growing and often all their feeding iu the 

 second stage, which is that of the nymph or larva. It is consequently 

 in this stage that they are generally most destructive. They do not 

 grow after the wings have developed, and many have no mouth parts 

 fitted for taking food in the adult stage, and consequently can not 

 feed in this last stage. Sometimes the injury by insect pests is done 

 by the female in depositing her eggs, w^hile the injuries by feeding 

 are not conspicuous. The work of the Cidada or ''Locust" is an ex 

 ample of this. 



In the following remarks, insects will be discussed according to the 

 plants they infest, but it must be remembered that some insects are 

 liable to attack a great many varieties or species of plants, while 

 others may be limited to but a few or even one only. When an insect 

 lilie the codling moth is described under "Apple," this does not imply 

 that it attacks no other fruits, and the description of its work or 

 effects, for the fruit under which it is_ discussed is practically th;* 

 same as for its elTects on any other fruif or plant. If the description 

 and name can not be found under one particular kind of plant, it 

 should be sought under another, which it may also attack. Details 

 of remedies have been published in previous issues of our bulletins, 

 and may be further pul>lished in the May issue. 



Apple Pests. 



Aphids or Plant Lice. — These are small, round-bodied, greenivsh 

 insects, with two long antennae or feelers, and a piercing mouth])art. 

 by which they pierce the tissue of the leaf or growing twig and suck 

 the juices, after having injected a saliva that is more or less detri- 

 mental to the tree. Plant lice belong to the group of insects without 

 metamorphosis, and consequently tliey do not have a worm-like 

 larval stage. The apjtle aphis remains during the winter in the form 

 of black, shiny eggs on the twigs of the tree. At this time spraying 

 with such insecticides as are eii'ective in killing scale insects will de- 

 stroy them. About the time the buds are bursting, the young aphids 

 hatch from the egg and commence to suck the juices from the new 

 green parts. This is the best time to kill them by mild contact 

 sprays, such as dilute whale oil soap, eight per cent, kerosene emul- 

 sion, tobacco decoction, or dilute soap washes of other kinds. As 

 they feed on the undersides of the leaves, the infested leaves become 

 deformed or twisted and curled in such a way as to form protecting 

 places for the insects within, and sprays can not reach them. Con- 

 sequently, after the leaves are curled, it is impossible to kill them by 

 spraying, but if delayed until then the infested twigs may be bent 

 over and dipped into pans containing the contact insecticide, or 

 the leaves may be i)i(ked and destroved. 



