56 GRAPE CULTURE AND 



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roots beneath the ground for the means of spreading from 

 vine to vine. Small lumps of earth below the surface of the 

 ground, supplied with the smallest rootlets, were thoroughly 

 infested with the insect. Thus it is evident that the rapidity 

 of infection, or spreading, will surely be influenced by the 

 nature ot the soil, /. e., the greater or less facility with which 

 the insect can travel over it, or along the cracks in heavy 

 soil. In sandy soils the progress of the larvae is very slow 

 and toilsome. 



THE GALL LOUSE. 



Up to August twenty-sixth, 1884, no specimens of the gall 

 louse, or leaf inhabiting form of the phylloxera, had been 

 identified at the University, or elsewhere in California, so far 

 as known. At that time the fresh young leaves near the 

 ends of three canes, which stretched from a " Canada " vine 

 towards an infested stock, bore a few peculiarly formed galls, 

 containing egg-laying mother lice as well as eggs, and numer- 

 ous larvae. A few isolated and abandoned ones were also 

 found on the old leaves nearer the stock of the vine. This 

 arrangement of a few isolated and odd galls nearest the 

 stump, and the peculiar fact that all the canes infested are 

 suckers coming from near the surface of the ground, suggests 

 the probability that the infection comes from the roots of the 

 vine rather than through other means. It is also noticeable 

 that one of these canes passes directly up through a portion 

 of the foliage, and still does not infect the adjoining canes. 

 Why the gall louse should appear just at this time, when the 

 conditions for the rapid production of other forms were fav- 

 orable, and not at other times, is a question not easily an- 

 swered. We are aware that similar freaks of change have 

 occurred in eastern experience in numerous localities, where 

 in 1870 the gall louse prevailed largely, the following year it 

 had almost entirely disappeared, or in some instances had 

 attempted, with more or less success, to locate upon other 



