THE MONTHLY BULLETIN. 



91 



Avhite oak. flowering almond, pecan, potato, nightshade, Amaranthus, 

 CJi€ no podium, Bermnda grass. 



Control. — Artificial control by 

 sprays and fumigation are never 

 practiced because of the efficiency 

 of natural enemies. This is the 

 one case where nature controls per- 

 fectly a serious pest. 



Predaceous Enemies. — The com- 

 mon Vedalia {Xoviiis cardiualis) 

 and the Koebele's ladybird {Novius 

 ka'helei) are the ladybird beetles 

 which keep the cottony cushion 

 scale in complete subjection. In 

 many localities the former is the 

 most efficient, but in some places, 

 and especially in Ventura County, 

 the writer found the latter doing 

 most of the control work. 



While these ladybirds are usu- 

 ally present in limited numbers in 

 most sections, yet at times they 

 completely disappear and the cot- 

 tony cushion scale increases so as 

 to cause considerable damage be- 

 fore the beetles can again be 

 established. It is always well to 

 keep a close watch of this pest, and 

 if it appears without being accom- 

 panied by the larvti? of the Vedal- 

 ias, adults of the latter should be 

 obtained and liberated as soon as 

 possible. 



True Parasites. — There are two 

 true parasites which also prey upon 

 this coccid : the hymenopterous 

 enemy, Ophelosia crawfordi, and 

 the dipterous parasite, CryptocJice- 

 fioii {Lesiophonus) iceryce Will. 

 The latter is often responsible for 

 as much effective work as are the 



Fig. 70. — Cottony cu-shion scale Vprlfllifl« thnno-li +liio -Fa/i+ ic n/^+ 



ilcerya purchasi Mask.) on ovange Veaaiias, tnougll tlllS tdCtlSUOt 



twig. (Cai. Hort. Com.) generally known. 



