196 INJURIOUS WO BENEFICIAL INSECTS OF CALIFORNIA. 



Food Plants. The known hosl plants of the citrus white fly arc: 

 allamanda, banana shrub, Boston ivy, cape jasmine (Gardenia florida 

 and (>'. jasminoides) , California privet, laurel cherry, citron, erape 

 myrtle, coffee, English ivy, Ficus macrophylla, golden privet, green ash, 

 Japanese persimmon, Jasminum fruticans, kumquat, laurestinus, lemon, 

 lilac, pear, orange, Mexican orange, mock olive, myrtle, osage orange, 

 Portugal cherry, pomegranate, prickly ash, smilax, tangerine, tree of 

 Heaven, trumpet vine, umbrella tree, water oak, wild persimmon, wild 

 olive or devilwood and yellow cape jasmine. 



Control. — By far the most effectual control measure is fumigation, 

 as used for scale insects, two-thirds of schedule No. 1 being recom- 

 mended. Emulsions and resin sprays are also effective remedies. 



THE IRIS WHITE FLY 

 Aleyrodes spirwoides Quaintance 



(Fig. 173) 



Description. — Th e adults are light yellow with dark markings on 

 lead, thorax and the dorsum of the abdomen. The eyes are red and 

 the antennas and less are dusky. The entire body and wings are 

 covered with a very fine white powder which entirely hides all of the 

 markings except two small dark spots on each fore wing and one on 

 each hind wing. When the wings are folded they overlap so that there 

 appears to be but one dark spot on each forewing. The length is 

 nearly 1-25 inch. The eggs are very minute, oblong and attached at 

 one end by a very short stipe. The color is first lemon yellow but 

 becomes almost dark purple before hatching. The young larva? are 

 elliptical, light yellow with a white marginal fringe which gradually 

 disappears as they grow older. Full-grown larva? are light yellow or 

 dusky, flat, naked or slightly covered with white powder. The eye spots 

 show red. The length averages about ?. inch. The pupa 1 are broadly 

 elliptical, light yellow or dusky, sparsely covered with white powder, 

 cm nvex. much higher than the larva? and somewhat longer. 



Life History. — The life history is practically the same as for the 

 greenhouse white fly. 



Nature of Work. — The young feed upon the foliage and are often 

 so abundant as to stunt the plants and cause the foliage to turn yellow 

 besides the smutting because of the honey-dew. 



Distribution. 113 llt — This species has quite a wide distribution, hav- 

 ing been reported from the following counties: Alameda, Los Angeles, 

 Santa Clara, San Francisco and Santa Cruz. 



Food Plants.— The following food plants are recorded by Quain- 

 tance 113 and Bemis 114 : Agoseris sp., black twinberry, buckeye, dahlia, 

 fuchsia, iris, malva (M. rotundifolia) , morning-glory (Convolvulus 

 occidentalis) , nightshade (8. douglasii), nine bark, plantain, Cherokee 

 rose, common sow thistle and tree tobacco. 



It has become a very serious pest of the common iris in Berkeley and 

 Oakland during the past years and is also common on sow thistle. 



11 Quaintance, A. L., Tech. Ser. No. 8, Bur. Ent. U. S. Dept. Agric, p. 38, 1900. 

 . Florence E., Proc. U. S. Nat. Mus., XXVII, p. 532, 1904. 



