410 



Departmental Activities: Entomology. — Jl. Dcpt. Agric. Union 

 S. Afnca, Pretoria, ii, no. 6, June 1921, pp. 492-496. 



It is probable that in the coming season there will be a greater 

 outbreak of locusts over a much larger area. Many swarms of 

 hoppers escaped detection in thinly populated districts, and there lias 

 been an extraordinary prevalence of solitary locusts. 



The larvae of a Coccinellid, Ortalia pallens, Muls., have been found to 

 inhabit the nests of ants, Pheidole punctulata, Meyr., and to prey 

 upon them. 



Weevils of the genus Protosirophus frequently do much damage 

 in plantations. Early this year many transplanted Eucalyptus 

 trees were destroyed by one of these weevils, P. amplicoUis, 

 also known as a pest of maize in certain soils. The injury was restricted 

 to blocks of trees where maize had been previously cultivated. Young 

 trees, including fruit trees, are also often attacked by the wingless 

 weevils of this genus. The attack, confined to newly cultivated 

 lands, is due to the fact that larvae are present in the soil when 

 it is broken up. Weevils of this genus have also defoliated 

 some one-year-old trees of Pinus insignis and also the terminal 

 growtti of young Eucalyptus saligna, the main damage being done 

 early in April ; hand collection has not pro^•ed satisfactory. 



Pettey (F. W.). Codling Moth and Red Scale Control Investigations. 



— //. Dcpt. Agric. Union S. Africa, Pretoria, ii, no. 6, June 

 1921, pp. 500-501. 



These notes are published as a preliminary report on the 1920-21 

 season. 



Experiments in dusting \-ersus spraying for the control of codling 

 moth [Cydia ponwneUa] showed that 20 to 30 per cent, more clean 

 fruit was produced by spraying in six applications with a liquid spray 

 of 2| lb. lead arsenate paste to 40 gals, of water than by dusting with 

 1 5 lb. lead arsenate powder in 85 lb. fine lime. It is considered, however, 

 that the failure of dusting has not been proved until a better quality 

 of lime has been imported into the country for testing. On the other 

 hand, paste or powdered lead arsenate of South African manufacture 

 were found fully as reliable as imported brands. Calcium arsenate, 

 which is cheaper than lead arsenate, and has recently been found 

 efficient in the control of codling moth in North America, is a failure 

 under South African conditions. Its efficiency might be improved 

 by strengthening the solution, but much increase in strength would 

 makes its substitution for lead arsenate no saving in cost. Regarding 

 the use of Bordeaux mixture instead of water in lead arsenate sprays, 

 experiments indicate that it slightly reduces the efficiency of the lead 

 arsenate. Until this is further investigated, fruit growers should not 

 use less than 2\ lb. paste or \\ lb. powder lead arsenate in 40 gals. 

 Bordeaux. Sodium arsenitc proved inefficient in killing capacity and 

 injurious in scorching foliage, and its use in orchards is therefore not 

 recommended. 



Experiments with concentrated lime-sulphur against the red 

 scale [Chrysomphalus aurantii] indicate that it cannot be effectively 

 controlled by one dormant spray of lime-sulphur at a dilution 

 of 1 : 10 (4-5° to 5° Be.), but that in addition to the winter 

 application two foliage sprays of a 1 : 40 (or 1° Be.) dilution would be 

 much more effective. If this proves to be the case in seasons of 

 normally warm springs, fruit-growers of the coastal Cape regions should 



