469 



Reply.— The small green insect on yonr plums is one of the plum plant-lice, 

 known as Phorodon inahahb. The best remedy for this insect would he to spray your 

 trees with a dilute kerosene emulsion, made according to the formula given in Cir- 

 cular Xo.l, New Series, of the Division of Entomology. The other insect is the so- 

 called Pear-blight Beetle (an erroneous designation, as it has nothing to do with the 

 pear blight), known scientifically as Scolytus rugulosus. This insect is a very diffi- 

 cult pest to tight, and there are no direct remedies of a practical value. Although the 

 beetle feeds, as you describe, upon healthy trees, it breeds only in trees which are 

 diseased or dying from some other cause. The best preventive, therefore, is a 

 trapping system. If there are any dead or dying trees in your orchard these should 

 be cut down and burned, from the 1st to the middle of June, after the beetles have 

 laid their eggs. In this way you will greatly lessen the number of next year's crop of 

 beetles. If your orchard is large and you have one or two old worthless trees I would 

 advise you to girdle them this summer and burn them entirely next year, about the 

 first week in June. The great majority of the beetles will be attracted to these trees 

 and will lay their eggs in them, which will thus be destroyed. — [June 3, 1691.] 



Caterpillars and Spiders migrating in Midwinter. 



I send you by to-day's mail a box containing some larvte and spiders found to-day. 

 They were all traveling upon the ice in an easterly direction, I should like to know 

 how larvcTB as lively as these can subsist at this season of the year. The ground has 

 been covered with snow and ice for the last two months, and the place where they 

 were found was covered wifh a sheet of ice about three inches thick. There were a 

 few hardbacks and bulrushes sticking up here and there, but these could not have 

 furnished food for the worms, since they were dried up. While cutting white birches 

 a few days ago, I noticed that they were thickly covered vrhhMyiilasjns pomorum, but 

 not quite as thickly as the x)iece of apple wood you will find in the box. The scales 

 on the birch seemed more numerous within a foot or two of the ground than elsewhere 

 on the trees. Is this scale of common occurrence on birch ? — [John D. Lyons, Mon- 

 ticello, New York, January 16, 1891. 



Reply. — The larva is the so-called Bronzy Cut- worm (Xepltelodes violans). The 

 insect hibernates in the larval state, and you will find a precisely similar instance to 

 this you describe, mentioned in the Fourth Report of the New York State Entomolo- 

 gist (Albany, 188S), page 56. Why the caterpillars should come out of their winter 

 quarters in midwinter is unexplained. The spiders which you send are immature 

 specimens of some species of Pardosa. They can not be determined specifically on 

 account of their immaturity. 



Mytilasjns jHjmorum occurs upon a number of trees other than Apple, but so far as I 

 know has not been recorded from Birch, although it is quite to be expected upon 

 these trees, as it is found upon Linden, Maple, Willow, Poplar, Ash, Elm, and other 

 trees. — [January 21, 1891.] 



The Grape-vine Plume-moth. 



I send some samples of our latest acquisition— shoots from our grapevines matted 

 together by a small fuzzy or, rather, hairy, light-green larva about one-half an inch 

 long. The twigs are all with distorted leaves, and of course no healthy bunches of 

 grapes can be expected. Some of these twigs are covered with tiny white globules, 

 clear as ice ; scarcely a branch has escaped their ravages. Can I do anything to pre- 

 vent their further increase ? I have nipped olf the aft'ected parts and destroyed them, 

 but of course many are left.— [Miss Amy J. Brown, Somers, Westchester County, New 

 York, May 24, 1891. 



Reply. — * * » Your grape tips are injured by the larva- of the Grapev'ne Plume- 

 raoth {Pterophorus perisceJidafty'lm) . The insect is single-l)rooded and the damage 

 will soon cease, but it will be (inite important to pick off all of the infested tips from 

 now on. Their number will not increase the present season. It is doubtful whether 



