WAR ON INSECT PESTS

Nelson Evening Mail, Volume LXVI, 12 July 1932, Page 6

WAR ON INSECT PESTS

MARSHALLING PARASITES CAMPAIGN IN THE SPRING In one of Palmerston North's bestknown Streets stands an unpretentious 1 dwelling, wHerein is a refrigerator which is the home of thousands of insects, each colony swarming in little .box sanctuaries, awaiting the advent of spring, comments a Manawatu paper. Some bf these have been brought from the other side of the world, from the Imperial Institute of Entomology, and 'jjave been pampered in many curious ways in order to keep them ali\ e foi the time when they will be marshalled and released in waves to light many of the pests which to-day threaten some of the Dominion’s best crops. The special work of rearing these parasites for the checking or extermination of the enimies of plant life is undertaken at the Plant Research Station under the direction of Mr J. Muggcfidge, B.Se., the Government entomologist. Next spring an insect war, organised by the scientists attached to the Plant Research Station, will be waged in various parts of New Zealand on the white butterfly, whose ravages among the cruciferous crops has directed attention to its remarkable capacity for destruction unless its activities aic rigorously curtailed. Preparations are <2 being made for the release of an insect enemy of the butterfly. The parasite has the formidable name of Apanteles glomeratus, and was imported to this country some months ago. A generation of these has been successfully reared by Mr Muggcridge, and they are now being held alive in cold storage. A • second, generation is now being raised, and the work generally being carried out is regarded as a triumph from the scientific point of yiSSv, and will probably prove to be of considerable eco-

nomic significance. ' The possibility of the parasite, which is to take the offensive against the white butterfly being attacked in turn by a hyper-parasite, has been eliminated. An unknown species of the latter Was discovered among them when they /arrived, and was speedily isolated. Most plants are susceptible to insect attacks, but it was considered that the humble garden carrot was comparatively immune until the appearance of a new insect in the Gisborne district recently; a pest that is causing much damage. It is believed that this insect came originally from Australia some ’years ago. Being slow to distribute its ■species, however, it probably remained unnoticed until it manifested itself recently, and it may not become of serious "economic consequence for several years yet, but it is reported to be well established in the Gisborne district. This carrot pest is known scientifically as Listrodcrcs costirostris, and lias" also been called the tomato weevil. It attacks tomatoes and practically anything green. A watch is being kept on" the depredations of this pest, and, should ruthless war become necessary, doubtless other battalions of parasites will be sought and another series of battles carried out in the affected / areas. ' i Of importance to orchardists is the completion by Mr W. Cottier, M.Sc., assistant entomologist at the Plant Research Station, of the history of the red mite, the orchard pest which establishes its home mainly in New Zealand apples. It has been determined at exactly what period summer and winter eggs are laid by the mite, and that the former 1 are more susceptible to the effects of the oil spray. The study of the fed mite’s history is expected to prove of some significance because it will enable the pdst to be attacked by man-made methods at the weakest stage of its development. This will mean much more effective control.