572 EXPERIMENT STATION RECORD. 



The tents now employed are the sheet tent and the ring tent. Thirty- 

 six to forty of the latter may be handled by 4 men, and an experienced 

 crew with 1 director can treat 350 to 400 five-year-old trees, averaging 

 10 ft. high, per night of 12 hours, at a cost of 8 cts. per tree. With 12 

 to 15 of the other tents about 50 trees 30 ft. high can be treated in the 

 same time at a cost of about 75 cts. per tree. The method of gassing 

 is thought the most thorough of all methods. 



An oil for the tents, better than ordinary oils used it is stated, may 

 be obtained from the leaves of the prickly pear (Opuntia englemanni). 

 It is obtained by soaking the chopped leaves in water for 24 hours, 

 giving body by an addition of yellow ocher or Venetian red, and apply- 

 ing to both sides of the canvas. 



The steam method is claimed to be cheaper than the method of gas- 

 sing and not to affect the beneficial insects, but it does not kill the 

 scales on the fruit. Further, the apparatus necessary renders it very 

 clumsy. The superheated water method, which has the advantage of 

 dispensing with a pump is noted in this connection also. 



Kerosene emulsion' is used to a very considerable extent, especially 

 at San Diego and Santa Barbara. The distinctively California insecti- 

 cide, the resin wash, is more generally used than the last remedy. The 

 formula employed varies in different localities, the general one for the 

 summer wash being 20 lbs. resin, 5 lbs. crude caustic soda (78 per cent, 

 or ?>h lbs. 98 per cent) in 2£ pt. fish oil. For the winter wash 30 lbs. 

 resin, 9 lbs. crude soda, 4i pt. fish oil. In both cases the mixture is 

 diluted to 100 gal. 



The Dayton wash, which has been recently introduced, is said to be 

 cheaper, costing but 2 cts. per gal., and is diluted 1:80 or 1: 100 for the 

 young of the black scale and used in stronger solution for the red scale. 

 The salt, lime, and sulphur wash is very effective in California, though 

 not so in the East. It is less successful in California along the coast 

 where moist conditions prevail. The chief consideration in making it 

 seems to be prolonged boiling, forming practically a wash of sulphid of 

 lime with free lime and salt. The proportions of the ingredients differ 

 according to locality. 



The apparatus employed in the State is practically as used elsewhere. 



The use of steam apparatus for spraying, L. O. Howard ( U. 8. 

 l><l>t. Agr. Yearbook 1896, pp. 69-88, Jigs. 15, pis. 2). — After a few gen- 

 eral remarks, in which it is noted that the adoption of steam power 

 spraying apparatus has been a necessary outcome of the great extension 

 in the use of hand spraying machines during the past decade, the 

 author considers machines for orchard spraying and those for spraying 

 shade trees in cities and towns. Several machines for each purpose 

 are described. 



1 It is stated in a footnote that kerosene emulsion was used 30 years ago by Schoen- 

 feldt, the head gardener of the Royal Gardens of Bavaria, which is very much earlier 

 than has heretofore been noted. 



