THE MONTHLY BULLETIN. 



35 



Control.— So far the best results in controlling the citrus thrips have 

 come from spraying; experiments being conducted in California and 

 Arizona with very good results. Two sprays were used in the work, 

 lime-sulphur diluted at the rate of one part to eighty parts of water, 

 and tobacco extract (40 per cent nicotine) diluted one part to eighteen 

 hundred parts of water. The lime-sulphur causes slight burnings, but 

 otherwise is as effectual and much less expensive than the tobacco 

 extract. Four applications are recommended : the first just after most 

 of the petals have fallen; the second in ten to fifteen days after the 

 first; the third from three to four weeks after the second and the 

 fourth during the months of August or September, wheu the thrips 

 are numerous on the foliage. In spraying for this insect it is advisable 

 to use angle nozzles and from 175 to 200 pounds pressure, care being 

 taken that every portion of the tree is thoroughly drenched. 



THE PEAR THRIPS. 



Eiithiips pijri Daniel. 

 (Fig. 32.) 



General Appearance. — The eggs are very minute, white and bean 

 shaped. They are embedded in the tender tissues of the host. The 

 first born larvae are white, with distinct red eyes, and move slowly. 

 They are often very thick on the trees and are known as "white thrips." 

 Pupation takes place in the ground, the pupai being white and .seldom 

 met with except by careful investigation. The adult insect is dark in 



Fig. 32. — The pear thrips ( Euthrips pyri Dan.). 



(After Moulton. ) 



Adult female and nymph. 



color, varying from an amber to a dark brown or almost black. The 

 presence of this species is usually told by ravages on the tender tissues. 

 of the expanding flowers and leaf buds and later by the attacks on the 

 young fruit. In badly infected orchards the buds often fail to openi 

 and the whole orchard may present a brown fire-swept appearance. 



