170 PROCEEDINGS OF THIRTY-THIRD FRUIT-GROWERS , CONVENTION. 



CONTROL OF SCALE PESTS IN SUBDIVISIONS. 



My article is necessarily very brief, simply in relation to control of 

 scale pests in subdivisions. 



With the great demand for building lots in desirable locations, a 

 large number of lemon groves in Hollywood, my district, have been 

 purchased for subdivision, and as a result of neglect to properly treat 

 the trees thereon, they in time have become badly infested with red 

 scale. To eradicate this pest, and thereby protect adjacent orchards, a 

 universal system of notices issued by the Horticultural Commission and 

 served by the Inspector upon each individual owner has been adopted, 

 with the result of a thorough fumigation over the valley, and a com- 

 plete clean-up. To date, about twenty thousand lemon trees have been 

 fumigated under forcible procedure. This has required eight hun- 

 dred notices. 



L. M. Mayet. 



FUMIGATION WITH HYDROCYANIC ACID GAS. 



Fumigation of citrus trees and nursery stocks with hydrocyanic acid 

 gas as a means of insect control has now reached a degree of efficiency, 

 when conducted by competent and careful men, as to surpass all other 

 artificial means to this end, at least in the southern part of the State, 

 where almost constant warfare has been pursued against black scale 

 infestations. Until recent years results obtained by this method of 

 treatment were so variable (owing to the want of accurate knowledge of 

 the process) as to invite the trial of many other methods in competition. 

 The most popular of these was the application, by means of high-power 

 spraying machines, of distillate mixtures. It was claimed for this 

 latter process that it was much cheaper than fumigation, and that 

 it would by the single treatment destroy not only the scale pests, but 

 also the citrus mites, whereas the latter were but slightly affected by 

 the fumigation. So popular for a time did this spraying process 

 become that fumigators were put practically out of the business, 

 especially as they attempted to compete in prices with the sprayers by 

 reducing the amount of chemicals used in fumigation, thus bringing the 

 latter process in still greater disrepute. The better practitioners, how- 

 ever, by increasing their dosage and perfecting each detail of the work, 

 soon demonstrated the fact that one perfect treatment by fumigation 

 was not only cheaper but more effectual than two treatments by the 

 spray methods, while the citrus mites, where they did occur rarely in 

 threatening numbers, could be effectually controlled for two cents or 

 three cents per tree by the sulphuring process. It also became apparent 

 that actual damage to trees and fruit by the application of the dis- 

 tillate sprays was reaching into the hundreds of thousands if not 

 millions of dollars, and that just the opposite effect was produced upon 



