570 DISEASES OF CULTIVATED PLANTS 



of chlorosis, which can be transmitted from one plant to 

 another in tomatoes, Lima beans, and musk melons. In 

 some instances the disease could not only be transmitted by 

 infection with the juice from a diseased to a healthy plant of 

 the same kind, but also from a tomato to a tobacco plant, 

 and back again to a tomato plant ; the general appearance of 

 the disease resembles in all instances the so-called ' calico 

 disease' of tobacco, which is considered to be of a physio- 

 logical nature. 



Clinton, G. P., Connecticut A gric. Expt. Sta. Rep., 1908. 



Resin wash. As the result of numerous experiments made 

 with the object of checking the attacks of aphides and other 

 insects that deposit 'honey dew' on foliage, and conse- 

 quently encourage the growth of 'black mould' or 'sooty 

 mould,' Webber recommends spraying with a solution pre- 

 pared as follows : 



Resin, . . . . 20 pounds. 



Caustic soda (98 p. c.), . . 4^ pounds. 



Fish oil, crude, . . .3 pints. 



Water, to make, . . . 15 gallons. 



Boil the resin, fish oil, and caustic soda, mixed with water, 

 until the resin is dissolved, then make up to fifteen gallons 

 with water. This is the stock solution. To use, add nine 

 parts of water to one part of the stock solution. 



A modification of this solution is recommended by Professor 

 Webber. 



Resin, .- . . .8 pounds. 



Sal soda, . . . -4 pounds. 



Water, . . . i quart. 



After boiling together, add water to make up five gallons of 

 stock solution. 



Place the resin and sal soda in a large kettle with one 

 quart of water. Boil, meanwhile stirring briskly, until the 

 resin and sal soda are thoroughly melted together and form a 

 frothy mixture without lumps. Now add about four gallons 

 of cold water, pouring it in rather slowly and with short 

 intervals between to avoid chilling the mixture too suddenly. 

 When all the water has been added, bring it to a boil, then 

 pour out the hot solution, straining it through a coarse cloth, 

 and add sufficient water to make exactly five gallons of the 

 solution. This, if properly made, forms a thick, dark brown, 

 translucent, syrupy solution, which may be preserved as a 



