Departmental Activities, 501 



but iioi very seriously, the efficiency of lead arsenate. Until this is 

 further investigated, fruit "-rowers should not use less than 2i lb. paste 

 or 1| ll>. pov^^der lead ai'senate in 40 imperial gallons of liordeaux. 

 Probably the normal efficiency of lead arsenate in bordeaux Avill be 

 maintained by increasing slightly the amount of lead arsenate in 

 every 40 gallons cf water. 



5. Arsenite of soda rc/su.^ lead arsenate in codling control. 

 Williams and Benrre Hardy trees sprayed with ] lb. sodium 



arsenite in 40 gallons of bordeaux or in 40 gallons of water, to which 

 was added 3 lb. of stone lime, i)roduced respectively 57 per cent, and 

 83 per cent, clean fruit in comi)arison with 84.1 per cent, and 91.5 

 per cent, non-infested fruit for the lead arsenate sprayed trees. The 

 inefficiency of the killing capacity of the sodium arsenite, a mucli 

 cheaper arsenical than lead arsenate, together with the severe burn- 

 ing of the foliage and fruit which resulted, discourages tbe use of this 

 insecticide in orchard spraying. 



6. The efficiency of conct-iitrated lime sulphur in the cf)ntro1 of 

 red scale. 



Xiefter pear trees sprayed with Capex (concentrated lime sulidiur) 

 diluted at the rate of 1-10, shortly before buds had opened in spring, 

 and with no foliage spray of lime sulphur applied later, produced 

 45 per cent, of fruit infested with scale, in comparison with 5 per 

 cent, infestation for trees sprayed at the same time with 1-10 lime 

 sulphur and later with the foliage 1-40 dilution of lime sulphur 

 during the first two codling applications of lead arsenate. Beurre 

 Hardy and Duchesse pear trees sprayed with Capex, 1-20, in late 

 winter before buds had burst, and with no foliage sprays, produced 

 respectively 3.3 per cent, and 44 per cent, scale-infested fruits in 

 comparison with nine-tenths of 1 per cent, and 9 per cent, for trees 

 sprayed at the same time with 1-20 lime sulphur, and later twice wdth 

 a foliage spray dilution of 1-40 during the first two applications of 

 lead arsenate spray for codling control. Results indicate that red 

 scale cannot be effectively controlled by one df)rmant spray of 

 lime sulphur at a dilution of 1-10 (4.5 to 5 degrees Beaume), but 

 that in addition to the winter application two foliage sprays of a 1-40 

 (or 1 degree Beaume) dilution will much more eft'ectively control this 

 pest. If this proves to be so in seasons of normally warm springs, 

 fruit growers of the coastal regions of the Cape should consider the 

 substitution of lime sulphur foliage sprays for bordeaux in the 

 contiol of fusicladium, as the former would assist greatly in the 

 control of young migrating scale insects, as well as prevent the 

 fungus disease. Inland fruit growers, wdiere the spring is dry and 

 hot, should use concentrated lime sulphur as a foliage spray with 

 caution, as it is likely to produce burning. 



7. Ten unsprayed trees in the oichard ])r()duced an average of 

 68 per cent, wormy fruit. 



{Note. — Most of the above experiments should be repeated and 

 extended before the jonclusions are put into practice by the fruit 

 grower. The orchardist should depend on established methods of 

 insect control, starting new ideas at first only on a small scale, if at 

 all, until they are well established by experiment and demonstration 

 by the expert.) 



