TWENTY-FOURTH ANNUAL FRUIT-GROWERS' CONVENTION. 139 



would be entirely worthless by this time. We irrigate very heavily and 

 we have not had any trouble so far as that is concerned. I think that 

 some of the largest crops that were ever raised were raised this year 

 and others upon land that was not only irrigated, but flooded every 

 year for the last sixteen or seventeen years, and several times a year at 

 that. Water is rising rapidly, though, on account of the irrigation, and 

 is getting too near the roots of our trees and vines in many places. We 

 have got to put in tiles in those places. I will say that it is a very small 

 portion of the country that is irrigated in that way. 



Dr. SHERMAN. In the district north of Merced there has been 

 considerable complaint on account of land growing poorer every year on 

 account of irrigation. It s a sandy soil, and the richer portion of the 

 sand seems to percolate totally, and the land seems to be becoming 

 poorer and poorer every year. Even though it has been fertilized, they 

 claim that it continues to decrease in usefulness. The land I speak of 

 is used mainly for sweet potatoes. 



Mr. BERWICK. Are the sweet potato crops continuous with no 

 rotation? If so, wouldn't that account for the poorness of the land. 



Dr. SHERMAN. They raise sweet potatoes only. 



PEACH-BORERS. 



Dr. SHERMAN. I would like to know if there has been anything 

 said about the peach-borer — about the treatment of it, and whether it is 

 proper to leave the holes open during the winter season or to cover them 

 up again after being exposed in digging af i bore ; ? 



E. M. EHRHORN. This county (Santa Clara) has had a great deal 

 of varying experience with the peach-borer. We have tried all kinds of 

 preventives, and the only remedy which has ever been tried with prom- 

 ise of success is the carbon bisulphide. However, there is a difference 

 of opinion in regard to it, as some damage has been done, and also 

 some success has been attained. The damage has been invariably 

 found to be where the liquid has been placed on the bark of the tree and 

 on the roots. Where the liquid has not been applied directly to the bark 

 success has been attained, although at times it has been a failure. The 

 failures we cannot account for; my opinion is that it is owing to the 

 liquid itself. We find in some liquids that the carbon will not kill the 

 insect, and in others that it will. We also find that where the carbon 

 has failed to kill the insect, a can of the same stuff purchased by 

 another party will kill it. I believe there is a difference in the strength 

 of it. If we ever get hold of another can where it fails to kill the 

 peach-borer, we will have it analyzed and find where the trouble lies. I 

 believe the carbon should be applied when the soil is sufficiently moist 

 to crumble in your hand. If it is too wet the carbon will perco- 



