Use Of Dust Research Articles

Control of Hemipterous Cotton Insects by the Use of Dusts1

Journal Article Control of Hemipterous Cotton Insects by the Use of Dusts Get access J. R. Eyer, J. R. Eyer New Mexico Agricultural Experiment Station, State College Search for other works by this author on: Oxford Academic PubMed Google Scholar J. T. Medler J. T. Medler New Mexico Agricultural Experiment Station, State College Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 35, Issue 5, 1 October 1942, Pages 630–634, https://doi.org/10.1093/jee/35.5.630 Published: 01 October 1942

EFFECTS OF PLANT AND ANIMAL HORMONES ON THE ROOTING OF DUST- AND SOLUTION-TREATED DORMANT STEM CUTTINGS

Indolylbutyric acid and oestrone were applied in dusts to dormant stem cuttings of Lonicera tartarica, Spiraea Vanhouttei, and Cornus alba, and in both dusts and solutions to cuttings of Ribes odoratum. Indolylbutyric acid had significant effects on the number of cuttings rooted and the number and length of roots per rooted cutting of three species. Further observations indicated that it also affected the fresh root weight of cuttings of Spiraea Vanhouttei and the green leaf weight of Ribes odoratum. Oestrone had no significant effect on rooting, but in solution treatment showed significant effects on the green leaf weight of Ribes odoratum, both alone and in interaction with indolylbutyric acid. Cuttings of Cornus alba failed to show any significant treatment effects.Dust and solution methods of treating cuttings were compared through the responses of Ribes odoratum. Dust treatment effected 62% rooting, solution 42%; there also was markedly greater leaf development following the use of dusts.

On the circulations caused by the vibration of air in a tube

There seems a need for accurate measurements of the velocity of sound in gases, both at ordinary temperatures with chemically allied series of gases and vapours, and at high temperatures in connection with the quantum theory. The method which suggests itself at once is to utilise in some way the stationary vibrations of a gas enclosed in a tube. One procedure is to use dust to indicate the modes of vibration, in the familiar way first demonstrated by Kundt. Two other methods which do not require the use of dust are now being tested by the writer, and will be described in due course. The successful application of any tube method demands, however, a rather more precise knowledge than has hitherto been available of the behaviour of a real gas when set into vibration in a tube of finite cross section. The present paper deals with certain features of this behaviour which do not appear to have received attention before. These are a general circulation of the air from antinode to node along the walls, returning up the centre of the tube, and a vortex motion which takes place round any obstacle, provided that the amplitude of the vibration exceeds a certain limiting intensity. The effect of this vortex motion is that the forces between two bodies placed in the vibrating gas are fundamentally different from those worked out by Koenig on the tacit assumption of vortex-free motion. It was observation of the behaviour of dust particles that first led to the experiments that revealed the general circulation and the vortex motion round obstacles. It is simpler, however, to discuss the nature of these air movements first and to defer the discussion of their bearing upon the formation of the dust figures described by Kundt, which are of a more varied nature than is always realised, to a second paper. Another series of investigations is devoted to the explanation of the dust movements in terms of these new observations.

Use of Pith Dust in Kundt's Tubes

DURING the summer of 1924, while experimenting at Indiana University with a Kundt's tube, I discovered that the striae could be most readily observed by using pith dust in the tube. I obtained the pith dust by grinding dry pith from sunflower on a fine-grained emery wheel. By the use of this dust I was able to obtain discs that extended completely across the tube and having the same diameter as the inside of the tube.

The Use of Dusts for the Control of Apple Pests and Diseases under Missouri Conditions

During the season of 1925 the dust sprays were tried out for the first time for the control of apple pests and diseases with very good success. Both sulphur dust and the copper lime dust compared very favorably with the liquid sprays while in some cases they gave better control on both the insect pests and plant diseases than did the liquids. It is quite probable that it could be possible to use them as a supplement to liquid sprays for the control of insect pests and diseases.