73 



BUG VS. BUG. -^ 



infested \\ itb San Jose scale when received. Throughout this region the San Jose 

 scale was found scatteringly in all orchards and in all gardens. In Aomori and 

 vicinity it is doing no very great damage in any of the orchards, but in some of the 

 small gardens and especially in one or two neglected ones in the city of Aomori, it 

 was as abundant on particular trees as it often is in America. At the first investi- 

 gation no evidence of parasitism was seen, but from later collections two of the 

 parasites which attack the scale insect in America were raised in great numbers from 

 infested branches collected at Aomori. These as determined by Dr. Howard are 

 Aphelinus fuscipennis, How., and Aspidiotophagus dtrinus, Craw, the latter being 

 the more numerous. 



This latter parasite is the true internal parasite of the Japanese 

 yellow orange scale. The San Jose scale is not a native of Japan, so it 

 is evident that this little parasite adapts itself to the introduced variety, 

 which is a near relative of the yellow scale upon which it is generally 

 found. 



So effective has this work of introducing beneficial insects and encour- 

 aging native parasites been, that we have practically reduced all the 

 worst of our scale pests and very many other destructive insects below 

 the danger line. Among the many beneficial insects which are now at 

 work in our State, and the pests which they are at work upon, and most 

 of which they keep in control, we name the following: 



COCClNELLIDiE. 

 Vedalia eardinalis, Mulsant. (Plate 1, Figs. 4, 4a, 4ft.) This is 

 commonly known as the "Australian ladybird," from the fact that it 

 was imported from Australia in order to work upon the cottony cushion 

 scale (Jcerya purchasi, Maskell). As stated above, this pest had 

 obtained such a foothold in our orange orchards that the citrus industry 

 of California was threatened. The fact that the cottony cushion scale 

 came from Australia, where it was not a pest, was sufficient proof that 

 there was some very efficient check at work upon it there, and investiga- 

 tion by Albert Koebele discovered this little beetle. The orange-growers 

 of Los Angeles County, especially, had a very expensive experience with 

 this scale. As it had spread into the wild bushes and trees, extermina- 

 tion by artificial means was out of the question. Now the scale is no 

 longer a pest. When it appears in an orchard the owner is supplied 

 with a colony of Vedalia. During the summer the transformations of 

 this ladybird are very rapid. From the egg, through the larva and 

 chrysalis, to the perfect beetle, takes only twenty-one days. Of course, 

 the larvae are the most active feeders. When short of feed, the larvae 

 will attack each other, but no matter how hungry they are they will not 

 eat any other species than the cottony cushion scale. This ladybird 

 breeds throughout the year. 



Novius koebelei, Olliff (Koebele's ladybird). (Plate I, Figs. 1, la, 

 1&. lc.) This is another effective enemy of the cottony cushion scale 



2— BH 



