ENTOMOLOGY 



Oil of Citronella. This oil has a rather pleasant but very per- 

 sistent odor, and is frequently employed as a deterrent against mos- 

 quitoes. In sand and soil a few drops of it persist for weeks, and even 

 months, which property recommends it for use against insects at- 

 tacking the young corn plant immediately after it germinates, the 

 oil being applied to the seed before planting. The oil is obtained 

 from a grass, Andropogan nardus, of Ceylon and other eastern 

 countries, where it is said to be regarded as a remedy for rheumatism 

 when rubbed on the affected parts. 



Sticky Preparations, Tanglefoot, Etc. Adhesive preparations 

 are of value for insects which creep up or down the trunks of trees, 

 and have become well-known in most households from their use in 

 the form of sticky fly-paper. The sticky substance can be bought 

 in cans and pails of the manufacturer, 0. & W. Thum Co., Grand 

 Rapids, Mich. It may be applied directly to the bark as a deterrent 

 against the attacks of peach and other borers, or may be used on 

 bands of paper, tin, or straw-board, secured about the trunk. For 

 the elm leaf-beetle we have used at the Station a trough-shaped 

 band made of carpet paper, or tin, securing its lower edge close 

 against the tree, but leaving the upper edge free and at a distance of 

 several inches from the trunk. The inside of the trough is smeared 

 with the sticky material, which entraps large numbers of the de- 

 scending larvae. Used in connection with spraying arsenate of lead 

 on the leaves, it affords a very satisfactory means of keeping the 

 elm pest in subjection. 



Tar. This substance was once used for the canker worm of 

 apple, being applied to the trunk to keep the wingless females from 

 ascending. It hardens when exposed, and proves very injurious to 

 the trees when applied directly to the bark. The latter difficulty 

 can be avoided by using tarred bands, and the former by renewing 

 the tar from time to time. The sticky papers can be made to serve 

 every such purpose, however, and are much more convenient. For 

 soil-infesting seed-eating insects, such as the wire-worm, tar may be 

 used with good effect. A teaspoonful is stirred among about a peck 

 of shelled corn after dampening with a little warm water. It should 

 then be allowed to dry before planting. (Bui. 147, Ken. Exp. Sta.) 



Records kept of the entire cost of spraying and of the yield 

 and value of the fruit from the sprayed and unsprayed trees, showed 

 that spraying produced a net gain per tree of $1.70 in one orchard 

 and of $2.56 in the other orchard. It increased the yield of fruit by 

 1.7 bushels per tree in one orchard and by 2.1 bushels per tree in the 

 other orchard. The improvement in the quality of fruit was also 

 very noticeable. In one orchard the sprayed trees gave 44.9 per 

 cent of No. 1 fruit while the unsprayed trees gave only 4 per cent of 

 No. 1 fruit. In the other orchard 61.8 per cent of the crop on the 

 sprayed trees was first grade fruit while only 22.4 per cent of the 

 crop on the unsprayed trees was first grade. The cost of spraying 

 was found in one orchard to be 28.8 cents per tree for four .j>iMyin.us, 

 and 40.3 cents per tree in the other orchard for five sprayings. 

 (Bui. 106, Neb. Agr. Exp. Sta.). 



