. Dosage tables. Pesticides; Trees. Bulletin 220] DOSAGE TABLES. that follow, but it is still possible to read the dose by noting the diameter on one edge of the rule which corresponds with the given circumference on the other, increasing this one fifteenth and then decreasing by an amount equal to one fifth the number of feet in the difference between the two measurements, circumference and distance over. This rule contains the complete system of dosage based on leakage, and besides, may be used as a measure for trees according to the method given on the concluding pages of this bulletin. THE
. Dosage tables. Pesticides; Trees. Bulletin 220] DOSAGE TABLES. that follow, but it is still possible to read the dose by noting the diameter on one edge of the rule which corresponds with the given circumference on the other, increasing this one fifteenth and then decreasing by an amount equal to one fifth the number of feet in the difference between the two measurements, circumference and distance over. This rule contains the complete system of dosage based on leakage, and besides, may be used as a measure for trees according to the method given on the concluding pages of this bulletin. THE MINIMUM DOSE. This rule shows a fact not hitherto noted, that there is a point for each degree of leakage where the tree requires a minimum dose. With no leakage the minimum point is approximately at zero, and as the leakage increases so does the minimum dose till, as shown on the rule, 8 ounces is the least amount that will do effective work with .40 per cent leakage, which is the dose for a seven and a half foot tree. Smaller trees would require more cyanide, so much, indeed, that the danger to foliage would probably render the method impractical. The reason for increase of dose for smaller trees is the fact that the leakage surface is so large relatively to the volume of gas contained within the tent in such cases, that the percentage of gas present drops very rapidly, and must be made very strong in order that enough remain to the end of the killing period to insure the death of the insects treated. It is probably not wise to attempt to use a tent for a tree much smaller than indicated on the rule. The theoretical minima are as follows: Leakage. Minimum size of Dose. Black Scale. Red Scale. * ounce. ounce. H ounces. 3 ounces. 5 ounces. 8 ounces. 12 ounces. Purple. .10 per cent .15 per cent .20 per cent .25 per cent .30 per cent .35 per cent .40 per cent | ounce. | ounce. 1 ounce. 2 ounces. Sh ounces. 54 ounces. 8" ounces. £ ounce. 1 ounce. 2 ounces. 4 ounces.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttrees, bookyear1911
