From China to Peru
A plant of the same genus, with like properties, has been found also in Peru. Derris, pyrethrum and tobacco are the plants which supply the best defences against insect plagues. The derris holds its poison in the root, the pyrethrum in the flower and the tobacco in the leaf. Derris has other than chemical excellences. It is found, by owners of small gardens as of orchards and hopfields, that there arc mechanical advantages of a dust over a spray ; and in fact the art of dustings is in reference to many maladies supplanting the art of spraying. The dust has a longer and therefore often a more thorough period of operation, though of course both must be used for different chemicals. A wholly unexpected value of the popular tar-distillate sprays is the effect on the grass. I found growers of cider apples in Herefordshire convinced that the sprays killed the biological pests which infest over-grazed orchards. It is remarkable to see the apparent ruin of the grass followed by a lush reaction, obvious to the least observant.
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