156 



APPLIED ENTOMOLOGY 



also helpful. Spraying the plants with nicotine sulfate 40 per cent, 

 % pint., 4 Ib. more or less of soap, and 50 gal. of water is a fairly 

 effective treatment. Fish-oil soap is better than laundry soap when 

 obtainable, and the amount to use is determined by spraying a leaf with 

 the mixture. If the spray gathers together into larger drops, leaving 

 parts of the leaves dry, more soap is needed, for its use is mainly as a 

 " spreader" over the leaf surface. This treatment should be repeated 

 every 8 or 10 days as long as the Thrips are present in any abundance, 

 until within a month of harvesting. Use a fine, misty spray with con- 

 derable pump pressure. Only thorough spraying will give effective 

 results. 



The Pear Thrips (Tceniothrips inconsequens Uzel). This insect was 

 first discovered in the United States in the central part of California, 



FIG. 150. Adult Pear Thrips (Tceniothrips inconsequens Uzel), greatly enlarged. (From 



U. S. D. A. Bull. 173.) 



attacking deciduous fruit trees, particularly pears, prunes and cherries, 

 blighting the blossoms by the abstraction of their sap. Later it was found 

 in British Columbia, in the Hudson River Valley in New York, and still 

 later in Pennsylvania, Maryland, and in England. Recently it has been 

 learned that the insect was first discovered in Bohemia, feeding in 

 blossoms. 



The destruction caused by this pest in California has been very great 

 some years. The crop of prunes in the Santa Clara Valley alone has 

 been estimated as having been reduced in the 7 years, 1905 to 1911, 

 141,000,000 Ib. The injury is caused by the feeding of the young and 

 adults on leaves, buds, flowers and fruit, and by laying eggs in the leaves 

 and fruit stems and also in the small fruit. 



