54 MISC. PUBLICATION 62 6, U. S. DEPT/ OF AGRICULTURE 



pleting their development within the 

 seed pods. Spraying with lead arsenate 

 may be effective against the adults if 

 applied on the first evidence of injury. 

 Prevention. — Where seeds are de- 

 sired, as in the case of choice or ex- 

 pensive varieties, the blossoms should 

 be covered with cheesecloth bags to 

 prevent the weevils from laying eggs in 

 them. Clean up and burn all remains of 

 iris plants late in the fall or early in the 

 spring to destroy the overwintering 

 weevils. 



Lesser Bulb Fly 



The lesser bulb fly (Eumerus tuber- 

 culatus Rond.) may sometimes be en- 

 countered along with the iris borer in 

 rhizome or root iris, or where plants have 

 become weakened for one reason or 

 another. The maggots do not appear to 

 be responsible for primary injury 

 because they generally feed on injured, 

 weak, or decaying tissue. The maggots 

 (fig. 99, p. 61) are of a dirty whitish 

 color and about % inch in length. The 

 adult (fig. 98, A, p. 60) is somewhat like 

 a housefly in appearance. This same 

 insect is frequently found in bulbous 

 iris, narcissus, and other flowering 

 bulbs, and is discussed more fully on 

 page 61. 



Treatment. — When rhizome iris is 

 infested, cut out and destroy the in- 

 fested portions at the time the plants are 

 lifted for dividing the clumps. For 

 bulbous iris use the hot-water treatment 

 as given on page 61. 



Aphids 



Among the aphids encountered on 

 iris are the green peach aphid (p. 88) 

 and the potato aphid (p. 75). In addi- 

 tion to weakening the plants by punc- 

 turing the tissues and sucking the plant 

 juices, they serve as carriers for certain 

 plant diseases. The tulip-bulb aphid, 

 or iris aphid (p. 87), feeds chiefly on 

 bulbous iris but sometimes attacks rhizo- 

 matous iris. 



Treatment. — For aphids on the 

 bulbs or rhizomes see treatment for the 

 tulip-bulb aphid (p. 87). For aphids 

 on the foliage, buds, or flowers see treat- 

 ment for aphids (p. 9). 



Other Pests of Iris 



Page 



Red spiders 11 



Verbena bud moth 88 



Rose chafer 66, 75 



White grubs 14 



Wireworms 15 



Slugs and snails 16 



IVY 



Oleander Scale 



The oleander scale (Aspidiotus hede- 

 rae (Vallot)), also called the ivy scale, 

 often incrusts the leaves and stems (fig. 

 87) of English ivy, where it sucks the 

 plant juices. It also attacks palms and 

 many other semitropical plants. Heav- 

 ily infested plants lose their vigor, turn 

 pale, and die. The scales are usually 

 circular, somewhat flattened, and about 

 the size of a pinhead. The tiny male 

 scales are pure white and often more 

 abundant than the females. The fe- 

 males are light buff, with a faint tinge 

 of purple, and from two to three times 

 as large as the males. Several other 

 species of scale insects may at times 

 infest English ivy, especially in the 

 warmer regions. 



Figure 87. — Oleander scale on ivy stem. 

 About 3 times natural size. 



Treatment. — Spray several times 

 with a white-oil emulsion (p. 100), 

 preferably during the late fall or early 

 spring. Prune out all severely in- 

 crusted vines. 



Other Pests of Ivy 



Page 



Red spiders... 11 



Leafhoppers 10 



Aphids 9 



Mealybugs 31 



Soft scale 43 



Eight-spotted forester 91 



Horn worms 4 



Cabbage looper 3 



Puss caterpillar . 6 



