134 INSECTS OF ECONOMIC IMPORTANCE 



The ciiRYSANTin>:AiUM midge ^^ {DiartJiromyia 



Jiypogcra) 



Order — Diptera 



The chrysanthemum midge is a late comer to 

 America and is ah-eady causing considerable in- 

 jury; the small mosquito-like adult fly lays its tiny 

 eggs among the hairs on a leaf where it hatches in 

 about 24 hours; the maggots cause galls on the 

 leaves, petioles, or buds ; the galls may be so abun- 

 dant as to cause malformation of plants, check 

 growth, and prevent blooming. 



Control — A majority of the adult flies seem to 

 issue after midnight ; therefore fumigation with nic- 

 otine should be commenced at midnight and carried 

 on every other night for 2 or 3 weeks; spraying 

 with nicotine sulphate, i pint to 500 pints of water 

 with an ounce of soap to each gallon, has proven 

 effective; an application should be made every 

 fourth or fifth day for a month. 



Scale insects and mealy bugs ^^ 

 There are many species of scale insects that are 

 injurious in greenhouses. The soft scale (Coccus 

 hcspcridiim) that infests palms, croton, ficus, et al. ; 

 the hemispherical scale (Saissctia hcmisphccrica) 

 that occurs on palms, orchids, croton and other 

 plants; the oleander scale (Aspidiofus hcdcrcu), the 

 fern scale (Hcmichionaspis aspidistrcu) and the 

 white pineapple scale (Diaspis hromclUcc) are some 

 of the more common ones. There are also two 

 common species of mealy bugs that occur in green- 

 houses on palms, coleus, umbrella plants, et al. 

 These are Pscudococcus adonidmn and Psciidocciis 

 citri. 



Control of scale insects — Whale-oil soap, i 



10 Guyton— Jr. Ec. Ent., Vol. 12, p. 162. 



11 Davis— 27th Kept. 111. State Ent., p. 122. 



