756 EXPEEIMENT STATION RECORD. 



tlirougliout the State lead them to believe that a standard miscible oil, applied 

 just before the buds open in the spring, is the best treatment for the terrapin 

 scale. " The solution should be diluted at the rate of 1 part to 15 parts 

 water. Treatment applied as late in the spring as jiossible before the buds open 

 is less likely to prove injurious to buds or twigs. There is no doubt that treat- 

 ing peach trees with any of the oil sprays may at any time be attended by 

 injury, either to buds or twigs, or both. Nevertheless, this is the only treatment 

 that seems available, and even if some injury to the tree is occasioned, it is 

 better to run the ri.sk than allow the terrapin scale to continue to develop in 

 the orchard." 



The purple scale (Lepidosaphes beckii), H. J. Quayle {California Sta. Bui. 

 226, pp. 319-3JiO, figs. 12). — This important scale was first described by New- 

 man in 1SG9 in England as Coccus beckii and the following year by Packard in 

 this country as Aspidiotus citricola. In 1876 Glover reported that it had been 

 found in 1857 in Jacksonville, Fla.. on imported lemons. It ai)pears to have 

 been introduced into California directly from Florida in 1888 or 1889. It is 

 stated that at the present time the purple scale occurs in California in the 

 counties of San Diego, Los Angeles, Orange, Ventura, and Santa Barbara. In 

 addition to Florida and California, it is known to occur in this country in Lou- 

 isiana and Colorado. 



Next to the black and red or yellow scales, it is the most important scale 

 occurring in the southern California citrus belt. " Its distribution is not so 

 general as that of either the black, red or yellow, but where it does occur it is 

 the most serious of them all, because it yields less readily to treatment. Where 

 this scale occurs among others, fumigation work is directed primarily against 

 the purple, and usually successful treatment against it readily controls the red 

 or black scales. The purple scale infests leaf, branch, and fruit, often becoming 

 completely incrusted upon these, but it is usually only a portion of the tree 

 that becomes thus infested. The lower side or interior of the tree is where the 

 insect thrives best, and here it is that the injury is most evident. . . . The 

 scale causes a marked yellowing of the leaves and there is consequently a heavy 

 dropping so that many of the branches will be completely denuded. 



"The injury is due directly to the feeding, as is the case with the red scale, 

 since no honeydew is excreted. The scales on the ripening fruit often have a 

 tendency to delay the coloring, and a marked green spot will be seen about the 

 scale while the rest of the surface is yellow. On account of their firm attach- 

 ment to the fruit they are with great difliculty removed therefrom, so that the 

 ordinary brushing or washing of the packing-house has little effect upon them. 



" The economic status of this scale is due largely to its resistance to such 

 treatments as fumigation or spraying. It is not a particularly prolific insect 

 for the maximum number of eggs will not exceed SO, and there are not more 

 than 3, or at most 4, generations a year. It is in the egg stage that it is most 

 resistant to fumigation. This must be largely on account of the very complete 

 protection afforded the eggs by the secretion of the ventral scale, which together 

 with the dorsal scale completely envelops them. The only opening is at the 

 posterior tip where the young upon hatching emerge." 



" The complete list of food plants from which L. 'beckii has been recorded is 

 as follows : Orange, lemon, citron, grapefruit, fig, olive, croton, oak, Elseagnus, 

 Banksia integrifolia, Taxus cuspidata, Cercidiphyllum japonicum, Pomaderris 

 apetala." 



Technical descriptions are given of its stages, together with an account of 

 its life history and habits. " The time required for the life cycle, from young 

 to young, during the summer months is about 3 months and in winter may be 

 prolonged a mouth or more longer. . . , During May, and also in June, young 



