THE MONTHLY BULLETIN. 39 



aphides, recommends spraying the trees, just before the buds start to 

 show green, with commercial crude oil emulsion, one part to nine parts 

 of water or one part to ten part^ of water (when the concentrate con- 

 tains about 85 per cent of crude oil) ; home-made crude oil emulsion 

 from 10 to 15 jier cent strength, made from a crude oil running from 

 19 degrees to 23 degrees Baume; connnercial lime-sulphur solution, one 

 p/art to six parts of water. The distillate oil emulsion, if used, should 

 be made of heavy distillate, so diluted that the material when sprayed 

 (111 the trees will run from 7 to 8 per cent oil. 



MISCELLANEOUS. 

 The Potato Eelworm. 



About 500 species of plants are known to be subject to the attack of 

 the eelworm. In this list we find fruit trees, almost all of our vegetables, 

 clover, alfalfa and many of our common weeds. 



The ad\dt female eelworm, which is whitisli or darkish in color, is 

 flask .shaped, and is about I/2.5 "ich in length. The adult male is spindle 

 shaped, and is much smaller than the female. The illustration shows 

 the effect of eelworm attack on potatoes. If a tuber is cut across the 

 location of the colonies will be visible as small dark spots, just inside the 

 peel. The surface of a badly infested eelworm potato is uneven or wart- 

 like. These colonies are seldom more than -| inch under the surface of a 

 potato. Infested tubers are unfit for seed and should be rigorousl}- 

 excluded. 



No practical means of control are known. Rotation of crops, not 

 sul)ject to the attack of the eelworm, should be practiced. 



PLANT DISEASES. 

 What Are Fungi? 



The organisms known as fungi belong to the lowest forms of plant 

 life, and among the fungi are some of the most important enemies of 

 our fruit trees. Examples of destructive fungi are peach blight, peach 

 leaf curl, potato scab, gummosis of citrus trees, shot-hole fungi, apricot 

 rust, toadstools, and brown rot of stone fruits. 



A fungus consists generally of a mass of branching filaments, Avhich 

 penetrate the tissues of the host from which it obtains its nourishment. 

 It may secrete a poisonous substance, which will cause that part of the 

 host attacked to die, or to become destroyed. From the filaments or 

 mycelium the reproductive structures are formed at certain times, these 

 giving off spores which spread the disease to other plants, the cari'ving 

 agencies being wind, water, animals, etc. It is to kill these spores that 

 we spray, so that we may check the disease before the spores germinate 

 and enter the host. Spraying will not be effective after the filaments 

 liave entered the host. 



There are thousands of species of fungi, and their study must neces- 

 sarity be a big item to the orchardist. He should procure a work on 

 fungos diseases and become familiar with them in a general way, in 

 order to treat them intelligently. 



