191 



Aphycus loimshuryi, introduced from South x\frica and Australia, 

 has been successfully established in California, and it is hoped to 

 colonise it this year in all districts where scale conditions are favourable. 

 It is necessar}^, however, to make some provision for maintaining 

 it throughout all periods ; in the interior districts particularly it is 

 reduced to insignificant numbers by the continually recurring periods 

 when the scale is not present in a suitable form for food. At these 

 periods it is necessary to supplement its numbers by insectary work 

 or by finding an auxiliary food-supply. In the latter connection 

 it is remarked that at the time when A. lounshiiryi is dying out for 

 lack of food there is an abundant supply of suitable-sized scales on 

 pepper trees and a few ornamental shrubs. If in the summer months 

 a supply of the parasite could be taken from the citrus orchards and 

 placed on the pepper trees, they could thus be maintained, and re- 

 transferred to Citrus when the scales were large enough on them. 

 Satisfactory natural control is only maintained by destroying 

 practically all the scales of each generation. 



Other beneficial insects used in this work are a Hymenopteron, 

 Scutellista cyanea, of which the larvae are predaceous on the eggs of 

 S. oleae, and Rhizohius vcntralis, a Coccinellid introduced from 

 Australia. 



The working of the chief insectaries is briefly described. 



Maskew (F.). Report of the Plant Quarantine Service, 1919-20. 



— Mthly. Bull. Cal. Dept. Agric, Sacramento, ix, no. 10-11, 

 October-November 1920, pp. 459-467, 3 figs. [Received 10th 

 February 1921.] 



The work of the Plant Quarantine Service of the Department of 

 Agriculture during the year ended 30th June 1920 is reviewed, and 

 reports from the various stations are included. 



NouGARET (R. L.). Report of the Viticultural Service, 1919-20. — 



Mthly. Bull. Cal. Dept. Agric., Sacramento, ix, no. 10-11, October- 

 November 1920, pp. 487-501, 5 figs. [Received 10th February 

 1921.] 



Only those insect pests of the vine that are a serious menace to 

 Californian vineyards, and that cause damage for which no practical 

 control is known, are here mentioned. Phylloxera was introduced 

 into California about 1858, and made much slower progress than in 

 France, some vineyards being infested for as long as twenty years 

 before their cultivation became unprofitable. Very little has yet 

 been done to guard against the pest. The progress of infestation 

 varies largely in accordance with climatic conditions, and a deficient 

 rainfall during the past two or three seasons has been the cause of 

 further weakening of the xdtality and resistance of the vines. 



If California is to maintain her grape industry, it is clear that resistant 

 stocks only must be planted on soils susceptible to Phylloxera, and it 

 is always these soils that are the best for vine-growing. A survey 

 has been made of the chief vine-growing counties, which demonstrates 

 the susceptibility and immunity of certain kinds of soils and shows 

 the infested localities. Experiments have been carried out over 

 a number of years to test resistant varieties and their adapability 

 to Californian soils. Both propagators and purchasers of rooted vines 



