LOUISIANA CIRCULAR No. 4. 11 



A grayish, scurfy appearance of a peach, plum or apple tree 

 should at once excite suspicion. In the case of badly infested 

 trees the scales frequently occur in such great numbers upon the 

 medium-sized limbs that the bark itself is invisible. When an 

 infestation reaches this stage the tree is commonly referred to as- 

 * ' incrusted. " During summer the immature stages of the 

 insect are found along with the adult scales, and at this time also 

 the larvae, minute yellow lice, may be found crawling about in 

 abundance over the twigs and limbs. The half-grown female 

 scales are usually almost jet-black in color and are quite different 

 from the partially-matured scales of closely related species. 



If the finger-nail, or a knife-blade, be rubbed over a badly 

 infested limb upon which the insects are alive, their bodies will 

 be crushed and the body fluids exuding will not only be visible 

 to the naked eye but will give a smooth, greasy appearance and 

 feeling to the portion rubbed. 



Another feature, while by no means characteristic of this 

 scale, which is of considerable assistance in identification, is the 

 reddish cast given to the cambium (sapwood) of the affected 

 twigs and limbs. Where isolated insects occur, the scale, espe< 

 cially upon peach and plum, is surrounded by a reddish area, and 

 if the bark be trimmed from a thoroughly-infested limb the wood 

 just below the bark will be found mottled with red blotches and 

 spots. 



While the San Jose scale rarely gets upon the fruit of peach 

 trees, the downy covering of the peach being objectionable to the 

 young lice, the insects do often occur in abundance upon the fruit 

 of plum, apple and pear trees. On fruit the red discoloration 

 is very evident, and we have seen many apples and pears that 

 were so thickly infested that they had become deformed and 

 knotty. In infested peach orchards, the young lice crawl onto the 

 peach leaves in great numbers and establish themselves there, 

 either on the upper or lower surface, usually right next to the 

 mid-rib of the leaf. Red spots quickly follow the attack of the 

 scale upon the peach leaf, and a sprinkling of red spots over the 

 leaves often indicates the presence of the pest even when the 

 infestation upon the limbs and trunk is not sufficient to attract 

 casual attention. In our Southern climate, peach trees attacked 



