SUBSEQUENT CARE OF THE PLANT 



175 



plant bug.— a sucklnc 

 insect. 



ontsi Ic. Tliore is no oxtornal ^owlh of a functus, uiul nmly nny 

 Will detiiii'd small spots on the leaves. Fig. ""J shows the spots of 

 a funpoiis ilist-aso ; if this leaf had been attaeked by a hacterial 

 or physiological disease, the entire leaf would probably have 

 shown signs of failing, for the food supply is usually out off in 

 the leaf-stalk or the main veins. In Fig. 72, however, ea<'h 8|)Ot 

 represents a distinct attack of the fungus. 

 Fig. 73 is a type of phy.iiologial trouble, the 

 edge of the loaf dying from the cutting-ofT of 

 its food supply ; this dead border will widiii 

 until the leaf dies. 



294(1. Physicians treat some diseases by 

 prophylaxis, — that is, by giving attention to 

 means of sanitation and of preventing the 

 spread of the disorder. Farmers must do the 



same. Wire-worms are rarely troublesome fig. To. Tlu> t«riii«»i«l 

 in short and quick rotations, particularly in 

 tiiose in which sod is not a prominent fea- 

 ture. Club-root of the cabbage is rarely 

 tn)uble8ome on land which has not grown 

 cabbages or allied plants for a few yean*. 

 Apple-scab is lea.st serious in those orchards Fig. 71. Thc»tr»wlwrr> 

 which have been thorough'y sprayetl in pre- wccvU. — a cbewlug 

 vious years. Plum- rot is least troublesome •«>»•«»• 

 when the fruit is well thinned. Rose-bugs seldom trouble vine- 

 . nrds which are on strong or lieavy lands. 



296a. Kerosene emulsion may be made as follows; Hard, 

 ••oft or wliuU<-oil soap, 'j lb ; water, 1 gal.; kenisene, 2 gals. 

 I>i!f»<>ivo the soap in hot water; remove from the fire and whilo 

 • fill hot add the keroNfiie. I'ump the litpiid back into ititelf 

 for five or ten minutes or until it becomes n creamy mast. If 

 properly made, the oil will not separate out on cociling. For n)«e 

 on dormant tree»«, dilute with from 5 to 7 parts of water. For 

 killing plant -lice on foliage, dilute with 10 to 1.5 parts water. 



(Vuiio oil emnlsinn i<« maile in the same way by substituting 

 crude oil in place of keroHi-ne. 



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