MANY KINDS OF BORERS 



477 



the center, lighter at the edges. A full-sized scale has a length of a 

 quarter of an inch, and a width of one-eighth of an inch. This scale 

 attacks nearly all kinds of deciduous fruits, but especially the prune 

 and apricot. It is a very hardy scale, and the remarks about the black 

 scale apply to it also. 



Other Lecaniums. There are several other scales on fruit trees ; 

 The filbert scale (hemisphericum), which is common in greenhouses 

 and occurs to limited extent on citrus trees; the frosted scale (pruino- 

 sum), very large oval and convex, covered with dense, whitish bloom, 

 occurs on deciduous fruit trees. 



Cottony Cushion Scale or Fluted Scale (leery a purchasi). This 

 promised at one time to be the most grievous of all scales in its rapid 

 increase and wide range of food plants, but it was speedily reduced 

 by an Australian ladybird, Novius (Vedalia) cardinalis, introduced 

 by Albert Koebele, with such success that specimens were for a 

 number of years rarely seen, but have recently become abundant in 

 some localities. 



Mealy Bugs. Closely allied to the scales are the mealy bugs 

 (species of dactylopius), soft and of a pale pink color, generally cov- 

 ered with a whitish mealy powder, hence the name. The common 

 species is found in nearly every greenhouse in the world, and in 

 California climate lives in the open air on many kinds of plants, and 

 has at various times proved quite troublesome. Unless checked by 

 natural enemies, the mealy bugs multiply very rapidly, and mass 

 themselves in the corners of the leaves. The plants turn black from 

 the fungus growth growing on the honeydew, and the bush pre- 

 sents the same appearance as a scale-infested plant. With the aid 

 of a magnifier the appearance of the mealy bugs, as different from 

 scales can be readily recognized. Recently they have become very 

 injurious on grape-vines and various fruit trees. 



Remedies for Scale Insects. Though most of the scale insects 

 are attacked by parasitic and predaceous insects, as already stated, 

 these natural agencies have generally not proved rapid enough to 

 cope with the increase of the scales, and insecticides have to be em- 

 ployed to save the fruit and trees. There is a vast number of these 

 washes, many of which will do good work if thoroughly applied, 

 which is usually the secret of success. A few which have proved 

 of special value will be given at the close of this chapter. 



INSECTS BORING IN TWIG, STEM, OR ROOT 



Peach Twig-Borer or Peach Worm. This larva is probably the 

 most serious insect pest that the California peach grower has had to 

 contend with. The creature hibernates as a young larva in burrows 

 in the crotches of the tree. As soon as the tree begins to grow in 

 the spring the larva becomes active, eats its way out of its winter 

 home and bores into the new growing twigs causing them to wither 

 and die. Later generations of the worm attack the fruit and from 



