SOME INSECTS AFFECT] NG 511 AlE TREES Shade trees and fruit trees have many insect enemies in et aninun. There are some that are peculiar to limited groups. Tits.oc•-moths, with the Gypsy moth as its most notorious type, are conspicuous enemies of shade trees in towns. The gathering and destroying of ere. clusters easily seen on the trees in winter, is one means of checkin• the pest. Spraying with Paris green in spring destroys the laryfe. The Gypsy moth is a European insect which was imported by a scien tist for purposes of study. It escaped from his care, and millions of dol la•s have been spent in trying to exterminate it. The El th-lolf Beetle Las become a serious menace to elm trees in the Hudson river valley.
Fungi are low' forms of vegetation. As they have no leaf green, they must obtain their food by stealing from other plants which possess this substance and are able to elaborate crude sap. A typical fungus produces vans, exceedingly small bodies which are set free in the air. When they lodge in favorable situations they germinate, sending forth threads, called hyplue, which absorb food, and multiply, forming a web called the mycelium. Certain parts of this organism finally develop spore-bearing organs.
Trees are hosts" to a wonderful variety of fungi. The ment of these parasites interferes with the physiological work of the living cells, and impairs the vigor of the tree. Some fungi live on the surface, some within the wood.
Soule infest the roots, others the parts above ground. Contact of root tips is a means of spread ing sonic fungi. The air scatters more. Every crack or wound on the surface of a tree offers lodg ment to spores that float invisible in the air.
Amolig fungous diseases of fruit trees may be mentioned seal). irrlrlcre, rust. and rot.
rut ve]low spots on the leaves am) frta of in early summer illustrates the peculiar phenomenon of alter of generations." The spores, set free during the summer, germi
nate only un the cedar. producing curious fleshy cedar apples which develop outgrowths in which spores are borne. These spores develop wily on the apple and there produce the yellow rust spots again. The destruction of cedar trees eradicates apple rust from a region. Another interesting example is afforded by aspens and larches. A cer tain rust that develops upon the aspen casts forth its spores which will germinate on no host but the larch. The fungus then develops into a form very unlike its parent. When it fruits. the spores will germinate only upon the aspen. Ilere the characteristics of the first generation reappear. The extermination of either aspens or larches will cause the fungus to disappear.
The (prof Fungi that grow out like brackets on the trunks of trees are signs that the tree is dying. Toadstools and mushrooms are not the whole plants; they are simply the fruiting bodies which hear the spores. For fifty years a fungus may grow inside of a great tree. Sometimes you NVill find such an old tree that is full of matted nivcelium which looks like felt. It is only when the tree is cut down or wounded or about to die that the fungus turns its attention to the production of spores.
How to Spray. There are no end of free pamphlets telling just how to spray plants, and especially fruit trees. Send to the agricul tural college or experiment station in your state and von will get full directions. In every rural paper you will see the advertisements of dealers in spray pumps and nozzles, and if you lint give these people your name and address they will deluge you with information.