KATYDIDS INJURIOUS TO ORANGES IN CALIFORNIA. 3 



1911 and 1912 showed the injury to be very widespread. Very few 

 orchards were examined which failed to indicate the presence of this 

 katydid by the unsightly chewed fruit, either in the boxes or dis- 

 carded as worthless upon the ground about the trees (PI. II, fig. 2). 



In 1912, before the picking season commenced, an examination was 

 made of all the fruit on 10 or more trees in each of 53 orchards of 

 Washington navel oranges scattered throughout the orange district 

 to determine the total injury to the mature fruit. Only 3 of these 

 orchards were entirely free from katydid-injured fruit. In 3 of the 

 remaining orchards the damage, though present, amounted to less 

 than 1 per cent. In the remaining 47 orchards from 1 per cent to 39 

 per cent of the maturing crop was rendered totally unfit for sale by 

 the katydids. Fourteen of the 47 orchards suffered a loss of 10 per 

 cent or more of the crop. The total loss of fruit from this cause for 

 the 47 orchards averaged 8.2 per cent of the entire maturing crop. 

 These estimates do not, of course, include the very young fruits 

 which are completely destroyed soon after the petals are off, and 

 this loss is rarely noted at all by orange growers. 



The orchards in which the injury is excessive are not necessarily 

 in isolated locations, as has been supposed, nor are they growing 

 under any unusual conditions. The katydid, however, appears to 

 be slightly more abundant in the foothills regions, and it shows some 

 preference for young and vigorously growing orchards. 



Several groves which had previously suffered but slightly from 

 katydids were called to the attention of the writers in 1911 and 1912 

 because of the increasing injury. Thus an orange grower informed 

 the writers that he had seen the familiar circular holes cut in the 

 fruit by katydids on his place for 14 years. Such a small percentage 

 of fruit was affected, however, that he had paid no special attention 

 to it until the fall of 1911, when he noted a material increase in 

 injury. Just after the crop was picked in 1912 a visit was made to 

 his orchard and the injury found much worse than in 1911. The 

 pickers had just finished a 6-acre plat of young navel trees, from 

 which they had discarded 12,000 oranges because of katydid injury. 

 About 100 boxes of oranges were therefore ruined in this 6-acre block 

 of trees, and as 800 boxes of good oranges were picked from these 

 trees a complete loss of II per cent of the mature crop plus an 

 undetermined percentage, of young fruits and blossoms which might 

 have become fruit was sustained. A 15-acre orchard of young 

 Washington navel trees, which were but slightly infested in 1911, 

 became seriously infested in 1912. When the final picking was made, 

 533 boxes of good oranges were secured from the orchard, while 



approximately L75 boxes, 21,000 oranges by count, wcro rejected as 



worthless because of splits, gashe , and holes caused by katydids. 



The most Striking example of injury by this katydid that has come 



to the attention of the writers was that of a navel-orange grove so 



