Diatomaceous Diluents for Dusts12

Publisher Website
Google Scholar
Abstract
15 laboratory samples of diatomaceous diluents were studied as diluents for pure ground derris root in the laboratory. Toxicity tests on Aphis rumicis showed that one (No. 69) was superior to pyrophyllite, 2 others (Nos. 54 and 63) approached pyrophyllite and a 4th (No. 60) was somewhat less effective but produced a steeper dosage-response curve. It was not possible to cor- relate toxicity with derris to the physical data available. However, materials of extremely fine particle size were not most effective as diluents for pure ground, derris. Tenacity studies showed that 3 types of curves were produced, flatter than, parallel with, and steeper than the standard Bancroft clay. Two of the materials of high tenacity (60 and 63) were relatively effective as diluents for derris. Materials were selected for field trials on the basis of effect on the toxicity and tenacity as detd. in the laboratory. Field tests on the Mexican bean beetle with cube showed that the materials performed in approx. the same order as in laboratory. The materials performed more in order of toxicity tests than of tenacity. The more effective materials performed relatively better in comparison with pyrophyllite in the field than in the laboratory. In field tests of cryolite, materials of high tenacity performed well on both beans and cabbage, but less tenacious materials performed surprisingly well.
Keywords