Oidium or powdery mildew of the vine . cand d, Lower figures, American machines. nearly all extremely cumbersome and wasteful of sulfur. The best ofthose tested is shown by the photograph of fig. 9, d. They all haveseveral very serious defects for the purpose tested. The regulation ofthe flow of sulfur is very imperfect and it is necessary to use an unnec- 336 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. essarily large quantity in order to cover the whole vine. This is espe-cially true in the case of high vines. The machines worked fairly wellonly when the outlet tube was held in a downward di
Oidium or powdery mildew of the vine . cand d, Lower figures, American machines. nearly all extremely cumbersome and wasteful of sulfur. The best ofthose tested is shown by the photograph of fig. 9, d. They all haveseveral very serious defects for the purpose tested. The regulation ofthe flow of sulfur is very imperfect and it is necessary to use an unnec- 336 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. essarily large quantity in order to cover the whole vine. This is espe-cially true in the case of high vines. The machines worked fairly wellonly when the outlet tube was held in a downward direction. Whiletreating the tops of high vines the sulfur accumulates in the tube,which finally chokes up. In order to clear the tube it is necessary tohold it down, upon which the accumulated sulfur runs out and iswasted on the ground. The European machine, on the contrary, gave most excellent results.(See fig. 9,a.) The regulation device enables the operator to governthe amount of sulfur blown out with great precision. This is a very. Fig. 10. Sulfur cloud to cover the whole vine. important point, as it makes it possible to use various grades of sulfureffectively and economically. The reservoir of the machine holdsenough sulfur to treat two or three acres without refilling, but is lessfatiguing to carry than the other machines, which hold only one-quarter as much. The sulfur is blown out in a fine impalpable powder(see figs. 10, 11, and 12), and owing to the form of the machine it canbe applied to any part of the vine. By standing a little distance fromthe vine a single puff can be made to distribute the sulfur over thewhole exterior of the vine. (See fig. 10.) Then after poking the end OIDIUM OR POWDERY MILDEW OF THE VINE. 337 of the tube into the center of the vine another puff will thoroughlysulfur the interior. (See fig. 11.) By a small attachment placed onthe end of the tube the cloud may be forced upwards and the underside of the leaves more thoroughly treated (see fig.
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