76 MISC. PUBLICATION 62 6, U. S. DEPT. OF AGRICULTURE 



Figure 124. — Rose aphid on stems and 

 buds of roses. Slightly enlarged. 



Rose Leaf Beetle 



Another serious rose-blossom pest is 

 the rose leaf beetle {Nodonota puncti- 

 collis (Say)), a small, oval, metallic- 

 greenish insect (fig. 125) about H-inch 

 long. It also feeds on iris and peony 

 flowers, as well as on the tender shoots, 

 flowers, and foliage of blackberry, rasp- 

 berry, strawberry, clover, pear, peach, 

 and plum. The beetles appear late in 

 May or early in June and bore into the 

 buds and partly expanded flowers (fig. 

 126). Frequently they swarm over the 

 flowers and in a very short time riddle 

 them with shotlike holes. Little is 



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JWl. 



Figure 125. — Adult of the rose leaf 

 beetle. About 4 times natural size. 



Figure 126. — Rosebud, flower, and 

 leaves injured by the rose leaf beetle. 



known about this insect, but it is be- 

 lieved that the larvae live in the soil and 

 feed on the roots of various plants. 



Treatment. — No satisfactory con- 

 trol is known. The numbers and injury 

 of these beetles may be materially re- 

 duced by jarring them into a pail of 

 water covered with a film of oil, or by 

 picking the beetle-infested flowers and 

 dropping them into the same container. 

 This operation is most effective when 

 done early in the morning or at dusk. 

 Spraying with pyrethrum will kill the 

 beetles actually hit by the spray, but it 

 is difficult to reach those that are within 

 the buds or flowers. 



Prevention. — Valuable varieties 

 may be protected by screening with 

 cheesecloth or other material before 

 the buds begin to show color. 



Rose Midse 



In the last few years the rose midge 

 (Dasyneura rhodophaga (Coq.)), al- 

 though primarily a pest of greenhouse 

 roses, has caused serious injury to gar- 

 den roses. The first flush of buds may 

 escape injury, but the later ones are 

 often so severely attacked that virtually 

 no flowers are produced. All new shoots 

 and buds, as they appear, become in- 

 fested with the tiny white maggots. 



