THE PEAE THEIPS IN CALIFORNIA. 9 



The average size of prunes grown in the Santa Clara Valley is 

 60-70; that is, dried prunes requiring from 60 to 70 to make a pound. 

 The price paid for prunes during the years from 1904 to 1911, inclu- 

 sive, was variable, but would average close to a 3-cent basis; 

 that is, 3 cents per pound for dried prunes running 80 prunes to the 

 pound. In order to be conservative, the average size ; 60-70, is 

 disregarded, and the loss is figured on the regular 80-to-the-pound 

 basis. In 1904 the loss was estimated at 500 tons, or 1,000,000 

 pounds (dried prunes), which, at 3 cents per pound, amounts to 

 $30,000. For the year 1905 it was placed at 10,000,000 pounds and 

 the damage at $300,000; in 1906 at 5,000,000 pounds, worth $150,000; 

 in 1907, 15,000,000 pounds, worth $450,000; in 1908, 20,000,000 

 pounds, worth $600,000; in 1909, 30,000,000 pounds, worth $900,000; 

 in 1910, 40,000,000 pounds, worth $1,200,000; and in 1911, 20,000,000 

 pounds, worth $600,000. The total of all of these years would be 

 141,000,000 pounds, valued at $4,230,000.* The estimates for some 

 years probably have been close to the actual damage done, but more 

 frequently the loss has undoubtedly been underestimated. In 1904 

 all the fruit of one orchard, comprising 100 acres of Imperial prunes, 

 was totally destroyed, aod this alone at an average crop of 5 tons of 

 green prunes per acre, on a 3-cent basis for dried prunes, would have 

 been valued at close to $30,000, because of the large size of this 

 variety of prune, only from 30 to 40 of which make a pound. 



In estimating this loss no account is taken of the great deprecia- 

 tion in value of the crop caused by scabbing. The entire yield each 

 year has been counted as merchantable fruit, and estimates of damage 

 made solely from orchards showing total loss or a marked reduction 

 in tonnage produced. 



To explain more fully the commercial quotation of a 3-cent basis, 

 it is meant that 3 cents per pound will be paid for dried prunes 

 averaging 80 prunes to the pound. For prunes which are larger 

 and free from scab or defects the price is usually $1 per ton more for 

 each point in size, and for smaller prunes the price decreases corres- 

 pondingly. 



As to the extent of the damage the pear thrips will cause in this 

 county if left unchecked, it is difficult to estimate, but the fact that 

 thrips were twice as numerous in 1910 as in 1909 shows their ability 

 to double the damage performed in any preceding year. The cause 

 for the notably light prune crop in 1910 is not attributed altogether 

 to the work of the pear thrips, but partly to unfavorable weather 

 conditions, which pervented many of the blossoms from setting fruit. 

 However, all the large producing prune districts of the Santa Clara 

 Valley were very seriously injured by the pear thrips, and hundreds 



1 These estimates are based on fuller and more complete reports than could be obtained in time for 

 Circular 131 of the Bureau of Entomology, and these figures more nearly represent the actual loss. 

 73390°— Bull. 173—15 2 



