506 



of adults in the orchard trees and in other trees growing within 

 300-600 feet of the orchard, subsequent infestation has been reduced 

 73 6 per cent. 



The borers have few insect enemies, but woodpeckers play an 

 important part in holding them in check. 



No easier and cheaper method of control has been found than the 

 old one of worming the trees. This should be done as soon as possible 

 after the last eggs of the season have hatched, and should be repeated 

 in the spring follo%ving the blossoming time of apple trees. Paints 

 and other kinds of tree protectors were useds^ to prevent o\aposition 

 on the bark. Nothing of this nature has been found that surpasses 

 common white-lead paint in cheapness, ease of application, and 

 effectiveness. Young apple trees painted once annually for from four 

 to six years showed no injury, and the treatment gave a control 

 efl&ciency of 7J:'3 per cent. 



Various attempts to kill borers were made by applying penetrating 

 liquids of a poisonous or irritating nature to the bark of infested trees. 

 Nicotine sulphate, kerosene, kerosene emulsion, sodium arsenate in 

 a miscible-oil carrier, and linseed oil, were among the materials tested. 

 None of these was effective on large borers that\^d penetrated deep 

 into the tree, but most of them killed a considerltble perc entage of 

 young individuals that were still feeding in shallow burrows. Some 

 of the hquids, particularly kerosene, injured the trees. Carbon 

 bisulphide can be injected with good results into deep burrows, though 

 it injures the bark. 



The beetles feed rather freely on the leaves and the bark of twigs, 

 and it is possible to kill them by spraying with arsenicals. Sprays 

 for this purpose should be applied to young orchards within ten days 

 after the apple blossoms have disappeared. In bearing orchards 

 what is known as the first codhng-moth spray will be effective also 

 against the adults of S. Candida. 



Smith (H. S.) & Compere (H.). The Life-History and successful 

 Introduction into California of the Black Scale Parasite, Aphycus 

 lounsburi/i. How. — Mthlij. Bull. Cal. State Dept. Agric, Sacramento, 

 ix, no. 8, August 1920, pp. 310-320, 5 figs., 1 plate. 



Aphycus lounsburyi has become firmly established in the citrus 

 orchards of California. The various stages of this Chalcid and its 

 method of oviposition are described. This parasite of the black scale, 

 Saissetia oleae, Bern., was first liberated in September, and further 

 liberations were made throughout the mnter. Colonies of the 

 Coccinellids Scutellista cyanea and Rhizobi us ventralis were also liberated 

 in order to form a combination that would insure a natural control. 

 So far, 30,000 individuals of A. lounsburyi have been liberated in 

 various plots. 



As this experiment proved successful, a new area, comprising 10,000 

 trees, has been set aside to form a propagating ground for A. lounsburyi 

 on a commercial scale. This parasite does not spread very rapidly, 

 but if present in sufficient numbers it will attack practically every 

 scale in the area of its abundance. The life-cycle from egg to adult 

 varies according to climatic conditions from 28 davs to 3 months. 



