66 BULLETIN 416, U. S. DEPARTMENT OF AGRICULTURE. 
were hit by the preparation were killed. Since the making of this 
and since its efficacy appears to be just as good, it would appear 
thatthis simple mixture should be given further consideration. 
Resin Was. 
thorough test on heavily infested beans and cotton. In both cases 
all red spiders were killed. This preparation possesses the valuable 
quality of spreading, and is an excellent red-spider spray. The only 
objection to its general use is the fact that it is not quickly or easily 
prepared. 
Soar SOLUTIONS. 
A common brand of fish-oil soap, at the rate of one-fourth pound 
to 2 gallons of water, was applied to mites on beans and cotton. The 
mortality was complete and the spreading quality of the insecticide 
was ideal. Other strengths of this solution were tried, and combina- 
tions of the fish-oil soap with other substances were tested, but noth- 
ing seemed to be added to the efficiency of the soap through these 
modifications. 
In addition to the tests discussed in the foregomg paragraphs, we 
have conducted several large-scale demonstrations in affected cotton 
fields. The sprays used in these operations were either potassium 
sulphid or lime-sulphur, and a barrel pump mounted on some type 
of horse-drawn vehicle was used for applying the material. 
It should be noted that all tests with sprays were conducted durmg 
hot, sunny days in the South. This is important to consider in rela- 
tion to results, since it is becoming known that similar sprays often 
yield very different results when applied under diverse climatic 
conditions. 
SPRAYING OUTFITS. 
The sort of outfit to be used for red-spider spraying* depends 
mainly upon the extent of the occurrence. Many prefer to use a 
75-cent tin atomizer when only a score or so of plants are to be treated. 
This instrument is very economical of hquid and throws a fine, vapory 
spray which penetrates and blows to all accessible parts, but it is not 
economical of time, and should be employed only where a quart or 
two of spray material will complete the jobs The bucket pump and 
knapsack pump (fig. 20, p. 58).come into use in cases of considerable 
scattered infestation or for treatment of a few plants in tall cotton 
where the platform pump would be impractical. The most economi- 
cal outfit for a severe case involving several acres consists of a barrel 
1 Our recommendations regarding spraying methods apply primarily to cotton. 
_— a a 
