412 



Arsenic at the rate of 10 lb. per acre was tried without success, 

 both as a spray and in the form of dust at the time of ploughing. 

 A marked difference was however noticed between the fields where — 

 owing to late planting — cultivation had continued throughout the flight 

 of the beetles and those where these measures had not been taken. 



Owing to the attraction that meatworks manure has for the grubs 

 it was mixed with 10 lb. of white arsenic per acre : this considerably 

 reduced the injury, and on plots where 20 lb. of arsenic was used 

 with 5 cwt.. of manure per acre the grubs have so far not appeared 

 at all. 



Agee (H. p.) & SwEZEY (0. H.). Director's Report. — Proc. 3Sth 

 Ann. Meeting Hawaiian Sugar Planters^ Assoc, HonohiJu, 

 December 2, 3 and 4, 1918 ; 1919, pp. 153-216. 



The conditions in Hawaii in 1918 with regard to insect pests were 

 more favourable than during the previous years. This was chiefly 

 due to the effectiveness of imported parasites, of which Scolia manilae 

 is now well established in the fields and has considerably checked 

 the ravages of the larvae of Anomala. Three colonies numbering a 

 total of 19,833 adults of this parasite have been liberated during 

 the year. The species of Tiphia, Prosena and Dexia liberated in 1916 

 and 1917 do not show any signs of becoming established, and the 

 same may be said of a large Carabid beetle from Japan and of Tiphia 

 lucida from the Philippines. Dolichunts stantoni, of which about 

 a dozen pairs were liberated in July and September 1917 to destroy 

 cockroaches, is now found in abundance on cane trash and it is 

 thought to be breeding on Phyllodromia Jiieroglyphica and Loboptera 

 extranea. 



With the exception of a few plantations the damage from 

 leaf-hoppers [Perkinsiella saccharicida] has also been greatly 

 reduced. Observations were made to estimate the percentage of 

 parasitism in different regions, and the results were very variable 

 A high percentage of parasitism does not necessarily mean 

 successful control of the pest, as it usually occurs w^hen, owing to 

 favourable conditions, the numbers of eggs laid by the leaf-hoppers is 

 greatly increased. The artificial distribution of Paranagrus [optabilis] 

 and the Formosan species of Ootetrastichus is being continued on a large 

 scale, amounting during the year to 78 colonies with a total of 29,010 

 adults of the latter. Owing to the establishment of OotetrasticJms 

 in the field, rearing of this egg-parasite in cages has been discontinued. 

 Other leaf -hopper enemies include a fungus, Entomopthora sp., which 

 is responsible for the destruction of great numbers, but is unfortunately 

 very difficult to handle in culture, and attem])ts to grow it artificially 

 have failed. 



In the course of the discussion following the reading of this report, 

 it was stated that the cultivation of the variety of sugar-cane known 

 as H109 is largely replacing that of other varieties on the Island, but its 

 chief disadvantage is the attraction it has for leaf -hoppers, although 

 these insects do not cause serious damage unless their attack is 

 combined with eye-spot disease. To increase the resisting power 

 of the cane, Mr. Swezey suggested planting as early as July, and it 

 is probable that fertilisers are better withheld during the first summer, 

 especially if early planting has not been possible. 



