^66 Journal of Agriculture, Victoria. [ioth June, 1912. 



FUMIGATION FOR THE DESTRUCTION OF SCALE 



INSECTS. 



By A. A. Hammond, Orchard Supervisor. 



For many years the Red Scale {Aspidiotus Coccineus) was known to 

 be present in the Doncaster district. When first noted, only a few trees- 

 in one large plantation were infected. For a long time, the scale made 

 no headway, and consequently growers took but little notice of its presence. 

 About five years ago, however, the pest began to multiply and spread to 

 an alarming extent, notwithstanding that every effort was made to destroy 

 it by spraying. Emulsions of kerosene, crude petroleum and red oil were 

 used, as well as several patent spraying mixtures ; but it was found that, 

 although spraying checked the pest for a time, it soon became as bad or 

 worse than ever, and continued to spread. No matter how carefully 

 spraying is done, only about 80 to 90 per cent, of the scale is destroyed 

 on evergreen trees, because it is practically impossible to spray the under- 

 side of every leaf and fruit. 



It may be well to state here that red oil emulsion, i in 30, properly 

 prepared, gave the best results. Scalecide also gave fair results, but is- 

 more expensive than fumigation, to be equallv effective. 



In 1909, scon after I had taken charge of the Doncaster district, the 

 Red Scale was found in most of the citrus plantations. The Olive Scale 

 was also causing a good deal of trouble. 



When it was deironstrated to the Doncaster growers that fumigation 

 was a thoroughly effective means of destroying scale insects, and the cost, 

 in the long run, less than spraying, the leading citrus-growers adopted it. 



To Mr. Ferdinand Finger is due the credit of being the first in the 

 Doncaster district to demonstrate the efficiency and practicabilitv of 

 fumigation. Mr. Finger had five sheets made from strong unbleached 

 calico selected by me. I supervised and assisted in the fumigation of 

 several orange and lemon trees, on 26th March, 1909. These trees were 

 infected with Red Scale, and, on examining the trees a few days later, 

 ail the scale were found to be dead. The charge used was i ounce each 

 of cyanide and sulphuric acid to every 180 cubic feet of inclosed space. 

 Mr. Finger and his son continued the fumigation at intervals during April 

 and May. The Red Scale, on all trees treated, was destroyed ; but the 

 charge was insufficient to kill Olive Scale fumigated earlv in May. Tn 

 all subsequent dem.onstrations, i ounce each of cvanide and sulphuric acid" 

 to 160 cubic feet was used, and was found to be effective against both 

 the Red and the Olive Scales, as well as the eggs of the latter. It is 

 inadvisable, however, to use the stronger charge when treating orange 

 trees, unless they are treated on cloudy days, or at night, as they are 

 much more susceptible to injury than lemons or mandarins. 



The value of fumigation was further demonstrated in July, 1909. In 

 the latter end of June of that year, T discovered the San Jo.se Scale in a 

 Doncaster orchard. 



As this dreaded pest had net previously been found in the district, and'" 

 was confined to one orchard, it was decided to have the infected trees- 

 fumigated. 



