Summary. This, then, seems to us the true explanation of the death 

 of vines in the Santa Clara Valley, stated in a few words: Slow starva- 

 tion, due to excessive prolonged drought following two exceptionally heavy 

 crops. That some vines have died and others have lived is due, as we 

 have shown, to cooperating influences, the principal of which are the 

 character of the soil, the variety of grape, the age of the vines, and the 

 exhausting effect of late spring frosts in certain vineyards. 



The objection to the drought theory which has been made, that irri- 

 gated vines have suffered as much as unirrigated, does not appear to be 

 valid, as, in all the cases which we could find, the irrigation was applied 

 too late. Very little irrigation was practiced until 1899, and then only 

 upon the worst vineyards where the vines were already injured beyond 

 redemption. The irrigation to have been effective, should have been 

 given during the winter of 189798, the season of greatest drought, and 

 immediately succeeding the two years of abnormally heavy crops. 

 This would have insured the strong growth of foliage during the fol- 

 lowing summer needed to repair the drain of the preceding years and 

 to replenish the depleted stores of reserve food-supply in the trunk and 

 branches. That irrigation was of some value, even when practiced 

 late, is indicated by the record of vineyard B in the foregoing table, 

 which shows that the irrigated portion of the vineyard produced four 

 times the crop per acre produced by the unirrigated portion, though 

 the amount of water used was only about three inches, or just enough 

 to make up for the shortage in rainfall of the year. 



Young vs. Old Vines. The immunity of young vines, and of old vines 

 which had been grafted about 1897, is explicable on the theory that they 

 were enabled to withstand the drought because they did not bear in 1897 

 and were thus saved the drain of that heavy crop. The same reason may 

 account to some extent for the immunity of certain light-bearing varieties. 

 That vines on other soils and in other localities have escaped the destruc- 

 tion that has overtaken the West-side vineyards is due doubtless to the 

 fact that the three destructive factors of drought, heavy bearing, and 

 leachy soil have not elsewhere been so great nor simultaneous. 



Not Anaheim Disease. The reasons which have led us to reject as 

 unproven the theory which ascribes the death of the vines to the Anaheim 

 disease are based upon the divergence of the symptoms from those which 

 distinguish that disease as characterized in Bulletin 2 of the Division of 

 Vegetable Pathology of the U. S. Department of Agriculture, entitled 

 " The California Vine Disease," by Newton B. Pierce. This pamphlet 

 must be considered as the highest authority on this disease, as it is 

 almost the only, or at least the most complete and voluminous, publi- 

 cation on the subject. 



