Sinopsis
Excerpt from Experiments With Insecticides for the San Jose Scale
It was the principal object of these experiments to test the ef feets of rains on the two washes used, but other important results appeared in the outcome besides those immediately aimed at. Counts of dead and living scales on the check trees not treated and on the experimental trees before treatment, showed a surprising percentage of half-grown scales already dead, the ratio of dead young to living scales varying on different trees and on different parts of the same tree from twenty-one per cent. To sixty-nine per cent. This fact had already been observed in other localities where our insecticide work was in progress, and had, indeed, been noticed and reported as early as 1898 by another assistant of the office, Mr. E. B. Forbes, engaged in distributing to infested trees in southern Illinois the spores of a fungus parasite of the San Jose scale.
This Spontaneous death of many of the scales which might have been expected to pass the winter alive, was apparently due in great measure and in both instances to a severe drouth of the pre ceding year. Consistently with this explanation the dead scales were most abundant on trees worst affected by the drouth, and on parts of trees to which the flow of sap would naturally be least.
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Reseña del editor
Excerpt from Experiments With Insecticides for the San Jose Scale
March 25; that is, twenty-two days for the first two lots, twenty days for the third and fourth, and five days for the lot under tents. The experiments consisted of a single application of the insecticide in every case, with varying subsequent treatments of the different trees with water. Frequent counts of dead and living scales were made for all of the trees, no attention being paid in these counts to old scales, outworn and dead, but only to those whose size and immature character showed that they belonged to the new generation of the preceding fall. Counts of dead and living scales were made in all cases either before or shortly after the applica tion of the insecticide spray. It was. In this way ascertained that an average of about fifty per cent. Of the immature scales were al ready dead on these trees before the insecticide was applied; and that the action of the insecticide was scarcely perceptible within the first twenty-four hours.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
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