BAD TIME FOR APHIDS.

Hokitika Guardian, 23 November 1925, Page 3

BAD TIME FOR APHIDS.

importation of enemies.

X El, S'OX. November 20. |„ reference to the shipment of lacewing Hies, cabled from Victoria, Dr Til I Hard, Chief Biologist. Cawtliron Institute, says the cablegram refers to the insects known as green lacewings or scientifically chrysopidae. These insects are found in all parts of the world with the exception of small oceanic islands and New /-calami. Their larvae feed voraciously on al kinds of aphids, and they are one of e most valuable groups ot beneficial inseets known. Most of the species inhabit forest trees, and thus then chief value lies in their ability to control outbreaks of aphis on such trees as nine, soruce and oak. In New Zealand, the spruces are beino killed off by a tiny aphis aphis ahietena, for whirl, no remedy has vet been found. Bin,,.- i»s>gms ,s attacked when young by a white aphis, called p’meiis strohi. which may m the course of years develop into a very serious pest, though at present the trees outgrow the attacks. Ibe But--1 ish oak is being badly damaged, and in places like Christchurch and T’imaru practically killed by the combined attacks of the oak scale asteroleeailium varii osiur.. and oak aphis, myzocallus q tie reus.

\ n view of the serious position of the spruce and oak in New Zealand, repeated attempts have been made tithe Cawtliron Institute to introduce chrysopidae. The attempt mentioned in the cablegram is the result of n discussion of the problem between Dr Gibson. Dominion Entomologist ot Can- , ada. and Dr Tillyard. and has heen carried out with the assistance of the entomologists of British Columbia. The laeewings are delicate insects, and. unfortunately. the most valuable species hibernate as adults, hiding in d-eep drifts of fallen leaves in the forest where the majority perish during the Ion" harsh winters, while the race is carried on by the few which survive to the spring. . The problem of carrying such insects across the tropics to New Zealand and 1 then waking them up to a new sum-

mer. six months before it is expected is clearly a most difficult one. and has not vet been satisfactorily solved. If auv appreciable percentage of the present large consignment- reaches Nelson alive, it is hoped to establish them both in the spruces and the oaks.