BAD TIME FOR APHIDS.

Press, Volume LXI, Issue 18545, 21 November 1925, Page 3

BAD TIME FOR APHIDS.

IMPORTATION OF ENEMIES. (arxcuL to "the rsxss.^ NKUSON, November 90. In reference to the shipment of laceflies, cabled from Victoria, Dr. Tillyard, Chief Biologist, Cawthron Institute, says the cablegram refers to the insects known as green laccwings or scientifically chrysopidae. These insects are found in all parts of the world with the exception of small oceanic islands and New Zealand. Their larvae feed voraciously on all kinds of aphids, and they are one of the most valuable groups of beneficial insects knov Most of the species inhabit forest trees, and thus their chief value kes in their .ability to control outbreaks of aphis on such trees as pine, spruce, and oak. In New Zealand, the spruces are being killed off by a tiny aphis, aphis abietena, for which no remedy has yet been found. Pinus insignis is attacked when young bv a white aphis called pineus strobi, which may in the course of _ years develop into "a very serious pest, though at present the trees outgrow the attacks. Th& British oak is being badly damaged, and in places like Christchurch and Timaru practically killed by the combined attacks of the oak scale, asterolecamum variolosum, and oak aphis, mvzocallus quercus. In view of the serious position of the spruce and oak in New Zealand, repeated attempts have been made by the Cawthron Institute to introduce chrysopidae. The attempt mentioned in the cablegram is the result of a discussion of the problem between Dr. Gibson, Dominion Entomologist of Canada, and Dr. Tillyard, and has been carried out with the assistance of the entomologists of British Columbia. The lacewings are delicate insects and t , unfortunately, the most valuable species hibernate as adults, hiding in deep drifts of fallen leaves in the forest where the majority perish during the long harsh winters, while the race is carried on by the few which survive to the spring. The problem of carrving such insects across the tropics to New Zealand and then waking them up to" a new summer sis months before it is expected is clearly a most difficult one, a»d has not yet been satisfactorily solved. If any appreciable percentage of the present large consignment reaches Nelson alive, it is hoped to establish them both on the spruces and the oaks.