APPLE PESTS 



533 



emulsion is useJ, and is applied just as 

 the eggs are hatching in the spring. Con- 

 siderable difficulty may be experienced 

 here as the young are at that time con- 

 siderably protected by the foliage. To 

 secure the best possible results a high 

 pressure pump should be used by means 

 of which a pressure of 150 to 200 pounds 

 can be secured. Apply spray to all parts 

 in as thorough a manner as possible. (Use 

 kerosene emulsion 8 to 10 per cent 

 strength.) For preparation of kerosene 

 emulsion see sprays for aphis. 



Pe.\k Blight Beetle. — See Shot Hole 

 Borer, under Cherry. 



Periodical Cicada 



Tihican septendecim Linn. 



H. P. Wllson 



There are probably very few of us who 

 are not acquainted with this insect in 

 the adult stage on account of the large 

 numbers which appear at one time or an- 

 other in various sections of the country. 

 The name is applied on account of the 

 fact that the adults only appear at 

 periods of every 17 or 13 years. In the 

 northern part of the United States it is 

 17, in the south 13. During the interven- 

 ing time they live in the ground as 

 nymphs and live by sucking the juices 

 from the roots of trees. Having reached 

 that point where they are ready to become 

 adults, they crawl out of the ground and 

 on to a stone, tree trunk or anything 

 above ground, and shedding the skin for 

 the last time, come forth as adults. 



After leaving the old shell they are 

 ready to fly about in a day or two, and 

 within a week the sexes have mated and 

 the females shortly proceed to make their 



I * 



Fig. 1. Periodical Cicada : Egg punctures in 

 twigs; pupal case and adult insect. (After 

 Cordley. ) 



egg punctures and deposit eggs here and 

 there in the twigs. 



In selecting trees for egg oviposition 

 oaks are shown a preference and among 

 fruit trees apples seem to be preferred. 

 Almost any plant may be attacked. 



The part of the plant selected is almost 

 invariably the twigs of the previous year's 

 growth. Occasionally a single nest or two 

 will be constructed in a larger limb. 



The result of such work must of a 

 necessity be quite detrimental to the trees 

 as the twigs are often so weakened that 

 they break very easily and an excessive 

 pruning results. In the nursery consider- 

 able damage may be caused by the after- 

 effect, which is shown in the deformities 

 of slow-healing wounds. These wounds 

 offer excellent entrance ports for fungus 

 diseases and other insects. The woolly 

 apple aphis oftentimes locate in these 

 scars and instead of healing over they 

 become more deformed and susceptible to 

 the attacks of fungus and insects. 



In depositing her eggs the female ci- 

 cada passes from one limb to another 

 until she has deposited all of her eggs, 

 which have been estimated to number 

 from 400 to 600. The eggs measure about 

 one-twelfth inch in length. They hatch 

 in six or seven weeks, are pearly white 

 in appearance, tapering to an obtuse 

 poirt at either end and slightly curved. 

 Upon hatching from the eggs the young 

 larvae run about for a very short time, 

 drop to the ground where they seek out 

 a crevice and immediately work their 

 way into the soil and begin their long 

 underground existence. 



Remedies 



A number of insecticides are quite ef- 

 fective against this species, but to be of 

 real value must be applied each day as 

 long as the insects issue in numbers. 

 Pyrethrum powder is a perfectly satisfac- 

 tory remedy against newly transformed 

 individuals. This should be applied in 

 the morning, before the insects have 

 gained full strength and while the plants 

 are wet with dew. The powder may be 

 puffed on the insects while clinging to 

 shrubbery or on the lower branches of 

 trees. This powder is absolutely worth- 



