THE BIOLOGICAL CONTROL OF INSECT PESTS AND INJURIOUS PLANTS IN THE HAWAIIAN ISLANDS
Authors: IMMS A. D. 
Published: February 2008

Insect pests in the Hawaiian Islands are, with few exceptions, immigrant species from other countries. Their control by biological methods dates from 1890, when A. Koebele introduced Novius cardinalis for repressing the cottony cushion scale, Icerya personas, and the experiment was completely successful.

The sugar cane leafhopper, Perkinsiella saccharicida, has been suppressed by the combined activities of several imported species of Chalcid egg‐parasites, followed by the introduction of the predaceous Capsid, Cyrtorhinus mundulus, from Fiji and Queensland.

Satisfactory control of the sugar cane borer, Rhabocnemis obscura has been achieved in most infested areas by the Tachinid Ceromasia sphenophori, introduced from New Guinea. In certain districts, under bad climatic conditions, outbreaks still occur and efforts are being made to meet the situation by introducing other beneficial insects.

Efficient control of the beetle, Anomala orientalis has been obtained by the introduction of the wasp, Scolia maniliae from the Philippines. This pest has not since increased to its former destructive proportions.

The Avocardo mealy bug, Pseudococcus nipae, affords one of the most recent examples of biological control. Since the importation of the Chalcid parasite Pseudaphycus utilis from Mexico in 1922 this pest has been difficult to find in many districts.

The indigenous Pyralid leaf‐rollers Omiodes accepta and O. blackburni are no longer pests of serious consequence. They are controlled by several enemies, chief among them being the Braconid, Macrodyctium omiodivorum and the Chalcid, Chalcis obscurata: both parasites were originally obtained from Japan.

Satisfactory repression of the Mediterranean fruit fly, Ceratitis capitata, has yet to be achieved. The importation of parasites from Africa and Australia has markedly decreased the infestation, but their efficiency appears to be partly neutralised by the species competing against one another and supra‐parasitism is prevalent.

The Australian fern weevil Syagrius fulvitarsis no longer occasions damage to tree ferns to its former extent. The recent introduction of the Braconid Ischiogonus syagrii from Australia has brought about this result.

Early introductions of various Coccinellidae, more particularly of Cryptolaemus montrouzieri and Coelophora inaequalis, resulted in the complete subjugation of certain coccids and aphides.

Promising results are being obtained against army worms and cutworms by the recent introduction of the Chalcid Euplectrus platyhypenae from Mexico. The breeding and liberation of this parasite are still being carried out.

Control of wireworms and the horn fly has not, so far, met with success.

The colonisation of a number of species of insect enemies of Lantana, from Mexico, afford the first example of pest plant control by this method. The restraint which they have exercised, more especially by prevention of seeding, has checked that plant reinfesting areas previously cleared.

The repression of nut grass (Cyperus rotundatus) by the introduction of insect enemies from the Philippines is being carried out as a preliminary experiment and a survey of the possibility of controlling Pamakani (Eupatorium glandulosum) has been made in its Mexican habitat.