HANDBOOK OX INSECT ENEMIES OF FLOWERS AND SHRUBS 55 



JUNIPER 



Juniper Webworm 



The small caterpillars of the juniper 

 webworm (Dichomeris marginella (F.)) 

 web together in masses the needles and 

 tips of junipers (fig. 88). They feed on 

 the surface of the needles, causing the 

 foliage in the webbed portions to turn 

 brown and die. The caterpillars spend 

 the winter in the webbed nests in a 

 partly grown condition and complete 

 their feeding the following spring. 

 They are reddish brown, with lighter 

 stripes along the body, and when full- 

 grown are about }{ inch long. The 

 moths emerge from the webbed nests in 

 the late spring to lay eggs. There is 

 probably only one generation of cater- 

 pillars a year in the Northern States, 

 but it is possible that more than one 

 might develop farther south. 



Figure 88. — Needles and tips of juniper 

 webbed by the juniper webworm. 



Treatment. — Spray with lead arse- 

 nate about midsummer to poison the 

 young caterpillars. Where the infesta- 

 tion is heavy, additional spraying may 

 be necessary later in the summer and 

 again the following spring. A pyre- 

 thrum or nicotine sulfate spray will kill 

 many of the caterpillars if applied with 

 enough force to penetrate the webbed 

 nests and wet the insects. Better 

 penetration would no doubt be obtained 

 if the webbed tips were first separated. 

 Where only small branches are infested 

 these could be cut out and destroyed. 



Juniper Scale 



badly infested with the 

 (Diaspis carueli Targ.) 



Junipers 

 juniper scale 



appear sickly and make poor growth. 

 The foliage may have a grayish appear- 

 ance where covered with these minute, 

 white, sucking scale insects (fig. 89). 

 Arborvitae, incense cedar, and cypress 

 are also sometimes infested. The scale 

 covering the female insect is round and 

 convex and about l Ao inch in diameter. 

 It is white and has a yellow center, 

 which is the shed skin of the young 

 insect. The male scale also is white, 

 but is smaller and narrow and has a 

 ridge down the center. The insect 

 passes the winter in a nearly full-grown 

 condition. The young are usually 

 hatching during the first half of June. 



Figure 89. 

 juniper. 



—Juniper scale on needles of 

 About twice natural size. 



Treatment. — Spray with a miscible 

 oil or oil emulsion in the spring just be- 

 fore the plants begin to grow. A lime- 

 sulfur spray may be used in place of the 

 oil, but it leaves a yellowish deposit on 

 the foliage for some time, and will also 

 discolor paint. For the young scale 

 insects in late spring, spray with a com- 

 bination of nicotine, soap, and summer 

 oil (p. 101), or spray several times at 10- 

 day intervals with a nicotine sulfate and 

 soap solution. 



Oil sprays may injure certain pyram- 

 idal-type junipers, such as Juniperus 

 excelsa stricta, because the oil col- 

 lects in the small cavities or pockets 

 formed by the upright needles. On 

 such trees use lime-sulfur or the nico- 

 tine sprays. 



Red Cedar Aphid 



The red cedar aphid (Cinara sabinae 

 (Gill, and PalnO) usually attacks the 

 junipers of the type called red cedars. 

 The aphids occur in masses along the 

 twigs and smaller branches, where they 



