THE PEAR THEIPS. / 



caused by this "new insect" in the orchard of R. K. Thomas, where it 

 was first observed, many people made special visits to his place to find 

 out what the insect was like, not realizing that by shaking a few blos- 

 soms from almost any tree in their own or a neighbor's orchard the 

 dreaded insects could be found. 



To those people who are not well acquainted with the general appear- 

 ance and, habits of this group of insects, the pear thrips look very much 

 like those found ordinarily in grasses, flowers, etc.; but on close exam- 

 ination one finds very strong individual characteristics as regards their 

 structure and life habits. The thrips which are commonly found in roses 

 and other flowers are not the destructive forms which injure our fruit 

 trees. 



NATURE AND EXTENT OF INJURY. 



It is the adult thrips which first comes to our trees in countless num- 

 bers, and which does the great and serious injury-; it is this stage, also, 

 which is most conspicuous and which is best known to orchardists. 



The manner in which thrips attack trees is, generally speaking, 

 much the same. They arrive just before or 

 while the buds are opening, and enter the bud, 

 if possible, otherwise they begin to feed on the 

 tip and eventually work their way in. When 

 once inside they attack the tenderest of the 

 flower parts and in many cases reveal a rather , 

 fastidious taste, preferring some particular par^^'^ 

 such as the stamen,' petal, or pistil. 



The mouth parts of thrips project from the ^'s-^- Month parts of Thrips, 

 lower posterior side of the head and have some- (Original.) 



what the shape of an inverted cone (Fig. 2). 



The mouth opening, the rim of which is strongly chitinized and rough- 

 ened, rasp-like, is in the smaller distal end of the cone, and through it 

 project two stylets or needles. The insect, when feeding, first pierces 

 the plant tissue with the stylets, thus making an opening; then moving 

 the mouth-cone back and forth it rasps and tears the opening larger, 

 and, pushing the tip of the mouth-cone down into this puncture, sucks 

 in the juices of ihe plant. 



The specific injury to blossoms varies in different plants. Trees may 

 be divided into two groups as regards the structure of the blossom bud: 

 (1) in which a single bud produces one blossom, such as the almond, 

 apricot, and peach; and (2) where one bud opens out into a cluster of 

 blossoms, which later produce a cluster of fruit, such as the prune, 

 cherry, pear, and apple. In the development of the bud, the winter- 

 protecting scales are the first to spread, thus permitting the insects to 

 enter at the tip. In the apricot and peach the insect forces its waj^ in 



