106 



DECIDUOUS FEUIT INSECTS AND INSECTICIDES. 



uninjured seedlings soon became injured in the same way, vet no 

 thrips were observed on these plants. 



ECONOMIC IMPORTANCE. 



Concerning losses in Maryland, Mr. Johnson, in the Entomological 

 News/ states that over 125,000 trees were rendered worthless during 

 1896 and 1897; and, writing in 1900, 2 he affirms that the injury 

 still continues about as previously reported, causing dwarfed, crooked, 

 and unsalable trees, and adds: 



The extent of the damage, however, this year is not so great as last, as the mite did 

 not appear until after the young trees had made from 2 to 3 feet of growth, while last 

 season the most injury was done when the trees were from 10 inches to 1 foot in height. 

 As a result, a much larger proportion of trees this season are salable. The mites are 

 still active and ruining terminals in many places. On the 9th instant I found eggs of 

 this species behind injured buds in the cavities occupied. 



Dr. John B. Smith states (loc. cit.) in reference to New Jersey that 

 in almost all of the nurseries which he visited during 1899, a large 

 percentage of the trees showed this affection, and, as already noted, 

 Prof. W. B. Alwood in a letter to Dr. Smith also refers to the 

 prevalence of the trouble in Virginia, as noted by him since 1891. 



Concerning the extent of injury in Virginia Mr. Phillips states 

 (loc. cit., p. 52) : 



No peach trees had formerly been grown in the soil where these observations were 

 made prior to 1903. In that year a large block of peach was grown on one section of 

 the. farm, about 400 yards distant from the block under discussion. 



The plants grew very rapidly at this place, and were from 1^ to 2 feet high on the 

 17th of May, at the time this examination was made. In the 8,500 plants examined 

 the injury varied from 10 to 20 per cent, depending upon the local conditions. It 

 was much worse in the slight depressions where water stood for a while after heavy 

 rains. 



At this time (May 17), however, the injury had just begun to show plainly. Later 

 in the season it was found that not more than 20 to 30 per cent of the trees had escaped 

 injury in many sections of the field. Less than 20 per cent of the trees were injured in 

 some sections which were located mainly at points where the drainage was good. 



A large block of seedling peach, standing about one-half to three-fourths of a mile 

 from the budded stock, and just across the fence from the land that grew peach the year 

 before, was examined June 22. In the section of seedlings nearest to land that stood 

 in peach the previous year (just across the fence) 28 per cent of the plants had been 

 attacked at this date. At another point, about 300 feet from the land that was in 

 peach the previous year, but on a slight knoll where the soil was a little drier, only 

 14 per cent of the plants were attacked; but in a lower place, about 900 feet distant, 

 30 per cent of the plants were injured. 



At this date (June 22) about 80 per cent of the budded peach had been injured by 

 this trouble in many sections of the field, a much larger percentage than was injured 

 in the seedlings ; but as the seedlings were grown and budded on the land the previous 

 year, it is but natural to suppose the injury would be worse in the budded stock. 



i Ent. News, vol. 8, Dec, 1898, p. 225. 



2 Ent. News, vol. 10, May, 1900, p. 471. 



