314 



Smith (H. S.). Report of the Bureau of Pest Control.— M//j/v. 

 Bull. Cal. Dept. Agric, Sacramento, x, no. 11-12, November- 

 December 1921, pp. 570-597, 10 figs. [Received 12th April 

 1922.] 



The organisation and activities of the Bureau of Pest Control are 

 discussed, and the general remedial measures employed in certain 

 cases, such as against the codling moth [Cydia pomonella] in walnuts. 

 Phylloxera in rooted grape-vines, insects in dried fruit, and 

 potato tuber moth \Phthortmaea opercnlella] in potatoes, are des- 

 cribed, with the methods of disinfecting nursery stock, fumigation of 

 Citrus, etc. 



Field work included dealing with an infestation of Otiorrhynchus 

 rugifrons (strawberry weevil) over about 30 acres. The ground was 

 deeply ploughed during late August and allowed to dry in order to kill 

 both plants and larvae. A narrow strip of plants was allowed to remain 

 on the outskirts to act as a trap to check the migration of adult weevils 

 that might have survived the treatment ; this will be ploughed during 

 the next larval period of the insect. Complete eradication appears to 

 have been effected by these methods. Work has also been done against 

 Typophorus {Paria) canellus (strawberry leaf weevil) by spraying with 

 arsenicals, and will be reported upon. Taeniothrips inconsequens 

 [Euthrips pyri) (pear thrips) continues to be destructive in many 

 locahties. Pseudococciis marithmis (pear mealy-bug) greatly lessens 

 the value of pears by the honeydew deposited while the pears are just 

 ripening. Winter appHcations of crude oil, miscible oils and distillate 

 oil emulsion aid in keeping dowoi infestation, but do not destroy egg- 

 masses and active stages of the mealy-bugs that are deeply hidden 

 under the rough bark of old trees. Centipedes in asparagus beds 

 are doing considerable damage, in some cases destroying the roots. 

 Anarsia lineatella (peach moth) was unusually abundant in several 

 localities, and damaged many late peaches. Tetranychus telarins 

 (red spider) caused defoliation of many fruit trees during the growing 

 season. 



The biological method as used against certain pests of Citrus is 

 reported upon, and an account is given of the use of Aphycus 

 lounsburyi against the black scale [Saissetia oleae] [R. A.E., A, ix, 191] ; 

 of Cryptolaemus montrouzieri against citrus-feeding mealy-bugs ; and of 

 Tanaomastix ahnormis against Pseudococcus citri [R. A.E., A, ix, 190]. 

 Some difficulty is being experienced in maintaining supplies of the 

 Coccinellid, Novius [Vedalia] cardinalis, against the cottony cushion 

 scale [I eery a purchasi], as it sur\'ives the north Californian winter 

 with difficulty, and field collections have to be resorted to. Tests 

 are being made to determine which are the most efficient enemies of 

 the red scale [Chrysomphahis aurantii], trials being made with Orcus 

 chalyhaeus, Rhizobius lophantae and Chilocortts bivulnerus, while 

 observation is being kept on the small golden Chalcid, Aphelinus 

 diaspidis, an external parasite, which is present on nearly all of the 

 plots being tested. The numbers of various predators and parasites 

 that have been reared at the laboratory or collected in the field durhig 

 the period under consideration are shown in a table. In addition 

 to those mentioned above are Scutellista cyanea, Rhizobius ventralis, 

 Axion plagiatus and Coccophagus lunidatus against Saissetia oleae ; and 

 Sympherobius barberi, Scymnus sordidus, Hyperaspis lateralis, Leucopts 

 bella and Pauridia peregrina against mealy-bugs. 



