

THE GRAPE SCALE. 121 



becomes too thick. As soon as the lime has completely slaked add 

 cold water to make the 50 gallons. Strain the liquid before pouring 

 it into the spray tank. 



OTHER SPRAYS. 



In addition to the lime-sulphur sprays other contact insecticides 

 may be employed, as whale-oil-soap solution, kerosene or crude 

 petroleum emulsion, etc. For winter treatment, however, probably 

 nothing would be better than the strong lime-sulphur wash above 

 mentioned. For some unexplained reason, sulphur sprays when used 

 on grapes in foliage produce harmful effects in checking the growth 

 of the foliage. When it is desired to treat the grape scale during the 

 period of foliage of the vines, the use of whale-oil soap at the rate of 

 1 pound to 3 or 4 gallons of water, or of 10 to 12 per cent kerosene 

 emulsion, may be advisable. 



There are on the market certain proprietary sprays, known as 

 miscible oils, and also concentrated lime-sulphur solutions. These 

 have only to be diluted with water and are ready for use. Where but 

 a small amount of spraying is to be done, their employment will often 

 be found advantageous in preference to making washes at home. 



WHEN TO SPRAY. 



Summer spraying. — The larvae appear in the vicinity of Washington, 

 D. C, about the middle of May, and it is necessary to give the first 

 application about one week after their first appearance. Of course 

 south of this locality one would expect them to appear a few days 

 earlier and north of it a few days later. Close examination has shown 

 that the larvse are constantly hatching and crawling over the plant 

 during a period of about two months, each " louse" settling down, 

 however, within about 48 hours. On May 5, 1910, some grapevines 

 which were badly infested with this insect were sprayed with self- 

 boiled lime-sulphur wash, only one application being made, and upon 

 a later examination only a few living insects were found. On account 

 of the habit of the young "lice" of settling under the shreds of dead 

 bark it is very difficult to apply the liquid so that it will come into 

 contact with all the insects. This makes it advisable to give a second 

 and sometimes a third application. 



Winter spraying. — As the foliage is very susceptible to burning, the 

 stronger caustic sprays must be applied during the dormant period 

 of the plants. The concentrated lime-sulphur wash and strong whale- 

 oil soap wash, as well as strong kerosene emulsion, are used during 

 this season of the year. As the winter is passed by the insects under 

 the protective scale covering, an application, in order to be effective, 

 must be very thoroughly made. 



