THE SAN JOSE SCALE 275 



THE SAN JOSfi SCALE 



The San Jose Scale — from the many different fruit trees that it 

 infests, the rapidity of its multiplication through its successive 

 broods during the year, and the short time in which it kills the 

 trees that it attacks — is justly regarded as one of our most per- 

 nicious scale-insects. Its character is indicated in the specific name of 

 perniciosus given to it by Professor Comstock when first described 

 by him in 18S0, in the Report of the Commissioner of Agriculture 

 for that year. He has written of it : " It is said to infest all the 

 deciduous fruits grown in California, excepting peach, apricot, and 

 the black Tartarean cherry.* It attacks the bark of the trunk and 

 limbs as well as the leaves and fruit. I have seen many plum and 

 apple trees upon which all the fruit was so badly infested that it 

 was unmarketable. In other instances I have seen the bark of all 

 of the small limbs completely covered by the scales. I think that 

 it is the most pernicious scale-insect known in this country." 



The Los Angeles (Cal.) Horticultural Commission, in their report 

 for 1893, say of it: "This pest, if not speedily destroyed, will 

 utterly ruin the deciduous fruit interests of this coast. It not only 

 checks the growth of the tree, but it covers the tree literally 

 entirely, and the fruit nearly as much so, and, if left unchecked, the 

 tree is killed in three years' time." 



Introduction and Spread 



As with the larger number of our more injurious pests, the San 

 Jose scale is not native to North America. Where it originally 

 occurred is not known. Ifc is frequently found upon plants 

 imported from Japan (Coquillett), and also occurs in Chile and in 

 Australia. It is believed to have been brought into California in or 

 about the year 1870. It first attracted the attention of fruit-grow- 

 ers at San Jose, in Southern California, in 1873. In 1882 it had 

 extended into all the fruit-growing districts of California, and had 

 entered Oregon and "Washington. It is also found in Nevada, but 

 when first observed there is not known. It is reported in one 

 locality in Idaho in 1894 (Alclrich), and as well established at Las 

 Cruces, New Mexico (Cockerel!). 



* It has since been found on the peach, and apricot. 



