■S 



TJIK PEAR THKIPS 



at the tip and down between the sheath scales and the blossom; it feeds 

 first on the outer side of the blossom, and especially on the very tender 

 blossom stalk in the center at the base; later it feeds on the inner parts 

 of the flower. When the insect is once inside the bud it takes but a 

 comparatively short time to destroy the blossom. Many buds on peach 

 and apricot trees, thus injured, will fall with a slight tapping of the 

 limb. 



Many instances can be cited where thrips were especially numerous 



in almond blossomsi 

 yet the trees set and 

 matured a large crop 

 of nuts. The prob- 

 able explanation of 

 this is that the trees 

 were almost in bloom '■ 

 liefore the insects ar- > 

 rived in dangerous 

 numbers. The thrips 

 did not get a chance 

 at the newly open- 

 ing buds, and, after 

 the blossoms had 

 opened, the nature 

 of the insects' feed- 

 ing was such that no 

 Serious injury to the 

 fruit followed. The 

 insects did not at- 

 tack a vital part of the blossom, but seemed to prefer the inside of the 

 calyxvcup at the base of the stamens, and they did not seem to injure 

 any other part of this particular blossom, although they were often 

 present in very large numbers. Soon after pollination the calyx-cup 

 is sloughed oft and the fruit left apparently no worse for the presence 

 of the insects. 



Thrips do even more serious injury to blossoms of the second 

 group (prunes, cherries, etc.) than they do to those of the first. The 

 insect enters at the tip of the swelling bud and forces itself down the 

 center of the cluster, injuring each blossom on the inner, contiguous 

 side. When thus affected, natural growth ceases. For a time the 

 untouched outer side of each budlet grows in the natural way, while 

 the injured inner side has ceased growing. The deformity thus pro- 

 duced causes each budlet to turn in toward the center, and all of the 

 cluster eventually fall. The injury done by thrips during this early 

 opening of the bud is by far the most serious. As blossoms develop 



Fig. 3. Imperial Prune brandies. Blossoms and leaf buds 

 affected. Every blossom on these twigs has been killed. 

 On the two inner branches many of the clusters have 

 fallen. 



