72 



a rake or li arrow and cattle or pigs allowed access to them. Turning- 

 pigs loose in the fields after only the marketable tubers have been 

 gathered is useless as they will not eat the badly infested tubers and 

 thus the principal danger remains. 



Agee (H. p.) & SwEZEY (0. H.). Director's Report. — Rep. Com- 

 mittee in Charge Expt. Sta., Hawaiian Sugar Plant. Assoc., for 

 Year ending 30th September 1919, Honolulu, 1919, pp. 7-49. 



The reduction in the numbers of the leaf-hopper [Perkinsiella 

 saccharicida] noticed during 1918 [R.A.E., A, vii, 412] has continued 

 except for a few scattered outbreaks. In the upper lands at Olaa 

 the pest has persisted throughout the summer, probably owino; to 

 the excessively heavy rains in the winter which destroyed its parasites 

 in great numbers and allowed it to gain an ascendency that it main- 

 tains for a long period. The Formosan species of Ootetrastichus, 

 introduced as a parasite in 1916, has become very generally established 

 throughout the Islands. 



A visit was made early in 1919 to North Queensland to study the 

 leaf-hopper parasites there, and a number of beneficial insects have 

 been brought to Hawaii in good condition. These include 136 

 individuals of Drypta spp., including D. australis, and allied beetles 

 that should be of great importance when they have become sufficiently 

 numerous, and 31 Staphylinid beetles, which should increase with 

 even greater rapidity. These are all predaceous on the leaf-hoppers. 

 Other insects imported were beetles of the genus Chlaenius predaceous 

 on army- worms ; Coccinella arcudta and C. repanda predaceous on 

 Aphids ; and Syrphid flies, that were liberated in Aphid-infested 

 sugar-cane, together with Hemerobiids that were reared en route. 



Anomala orientalis is now fully controlled by the Philippine wasp, 

 Scolia manilae, which was first introduced into the Islands in 1915- 

 1916. This is considered a remarkable example of the control of 

 an insect pest by an introduced parasite. The parasites maintain 

 their existence in regions previously infested by Anomala by breeding 

 on Adoretus umbrosus (Japanese rose beetle). The distribution of 

 this parasite is discussed. The cane-borer [Rhabdocnemis obscura] 

 continues to be controlled by the imported Tachinid [Ceromasia 

 sphenophort]. 



BovELL (J. R.) & d'Albuquekque (J. p.). Parts i and ii. Manurial 

 Experiments with Sugar Cane. — Barbados Dept. Agric, Rept. 

 Sugar-Cane Expts., 1917-1919; 1919, pp. 4-19. 



In the course of manurial experiments with sugar-cane in Barbados, 

 some statistics have been gathered regarding the numbers of Diaprepes 

 abbreviatus, L. (root-borer) and Phy talus smithi, Arrow (brown hard- 

 back), on sugar-cane and the losses caused by these beetles. On 

 one estate examined the loss from these two beetles was 4*36 tons 

 of canes per acre, the minimum monetary loss being nearly £8 per 

 acre. From a series of experiments on three estates the loss due to 

 Diatraea saccharalis, F. (moth borer) was found to be an average of 

 6*25 tons of canes per acre with a monetary loss of about £12 106', 

 per acre, while in the factory the loss was reckoned at an average 

 of 585 lb. of saccharose per acre with an equivalent value of £6 5s. 



