HANDBOOK OX INSECT ENEMIES OF FLOWERS AND SHRUBS 73 



Treatment. — See treatment for aphids 

 (p. 10). Begin the treatments soon 

 after the new leaves start to come out 

 and before the aphids are protected in 

 the curled leaves. 



Other Pests of Privet 



Page 



Lilac leaf miner 58 



Lilac borer 56 



Red spiders 11 



Mealvflata 90 



C itrus whitefly 31 



RHODODENDRON 

 Rhododendron Lacebug 



The leaves of rhododendron and 

 mountain laurel often become mottled 

 and white-peppered in appearance on 

 the upper surface, with numerous specks 

 of blackish or brownish excrement on 

 the lower surface (fig. 119). The pep- 

 pered appearance is caused by the suck- 

 ing of the plant juices by the adults and 

 voung of the rhododendron lacebug 

 (Stephanitis rhododendri (Horv.)). This 

 species is closely related to the azalea 

 lacebug (p. 22), and although it pro- 

 duces only two generations a year it is 

 still sufficiently like the latter not to re- 

 quire further discussion. 



Treatment. — Same as recommended 

 for the azalea lacebug (p. 22). 



Figure 119. — Work of the rhododren- 

 dron lacebug on lower leaf surface. 



Rhododendron Borer 



The stems and branches of rhododen- 

 dron are often severely injured by the 

 caterpillars of the rhododendron borer 

 (Ramosia rhododendri (Beut.)). These 

 caterpillars bore into the stems (fig. 

 120), usually those about a foot or 

 more above ground. On young plants 



Figure 120. — Tunnel of the rhododen- 

 dron borer in a stem. 



the foliage may wilt and die or the stems 

 or twigs break off because of the boring. 

 On older branches ugly scars are pro- 

 duced, and later, as the injury continues, 

 the affected branches may die. This 

 insect also attacks azaleas and mountain 

 laurel when these are growing nearby. 

 The larva, when mature, is about half 

 an inch long and has a yellowish-white 

 body and reddish-brown head and legs. 

 The adults are clear-winged mot lis, 

 which appear in May or June and lay 

 eggs on the bark. The larvae reach 

 maturity in October and overwinter in 

 the burrows. Pupation occurs in the 

 spring. There is only one generation a 

 year. 



Treatment. — Cut off and burn all 

 infested parts in late fall, winter, or 

 early spring. Other methods suggested 

 for the lilac borer (p. 56) may also be 

 used. 



Pitted Ambrosia Beetle 



Rhododendrons and dogwoods, espe- 

 cially those that are heavily mulched or 

 growing in shaded places, are often 



