ARTIFICIAT.LY SPREADING FUNGOUS DISEASES. 53 



hand the ends of the branches of the wliitc-dy-infested tree can bo 

 momentarily imnu>rsod. This method is es])ccially dcsirid)le where 

 there are (nily a few trees to infect with the fungus and Jio satisfac- 

 tory spray pump is available; also when only a few fungous-infected 

 leaves can be obtained — -as is frecpienlly the case — and the f^eatest 

 economy in the use of the water mixture is needed. The branches 

 and twigs most heavily infested with the insects sliould be selected. 

 For the dissemination of the brown white-fly fungus this is ])rol)ably 

 as satisfactory for gcMieral use as any method now known, the mixture 

 being prepared as hereafter described in a slightly different manner 

 than in the case of the mixtures of Aschersonia spores. 



The brushing method consists in dii)])ing a whisk broom or a sub- 

 stitute in the unstrained water mixture and brusliing the under- 

 side of the leaves of the trees to be infected as far as within reach 

 and throwing the water by means of the brush against the under- 

 side of the leaves higher up in the trees. This method, like the 

 dipping method, can sometimes be employed with advantage in the 

 case of the red and yellow Aschersonias and is especially usefid in 

 the case of the brown fungus, where unstrained solutions are naturally 

 more desirable. 



MISCELLANEOUS EXPERIMENTS AND OBSERVATIONS, 



As infection was almost invariably secured. in favorable seasons 

 with fresh fungus material when spores of either the red or yellow 

 Aschersonia were introduced by spraying, dipping, or brushing, it 

 became apparent that the problem to be solved in connection with 

 the introduction of fungi was not that of how to secure an infection, 

 but by what means the ordinary infection secured by haphazard 

 work coidd l)e increased by careful attention to the details. The 

 results, however, of over 500 experiments conducted by the authors, 

 together \\dth those of growers, have been so variable that, at the 

 end of three years of experimentation, little has been added to our 

 practical knowledge of how to insure satisfactory infections. These 

 same statements apply to the brown fungus, although the securing 

 of an infection with this fungus is at no time so certain as with the 

 red or yellow Aschersonias. 



Results of straining water mixtures of spores through cloth strainers.—^ 

 In straining the solution before spraying, the authors have found a 

 fine- wire strainer (about one-sixteenth-inch mesh) of most value. 

 Under no circumstances should cotton cloths be used as strainers, 

 for microscopic examination of strained and unstrained solutions 

 shows that a large percentage of spores fails to pass through the cloth. 

 Mr. E. L. Worsham found, as a result of 36 microscopic examinations 

 of solutions strained and unstrained, that about one-third of the 

 spores were lost when ordinary cheesecloth was used as a strainer. 



