WHITE BUTTERFLY

Auckland Star, Volume LXXV, Issue 252, 24 October 1944, Page 2

WHITE BUTTERFLY

CONTROL OF PEST

PARASITES' ESTABLISHMENT

(0.C.) CHRISTCHURCH, this day. White butterflies, which have worried home and commercial gardeners for several years, have made an early appearance round Christchurch this summer. The warm weather has hastened their development and for several weeks they have been attacking cabbages. Home gardeners who had to use quantities of dust or arsenate cf lead last year to keep dozens of butterflies away from their cabbages or cauliflowers are inclined to be sceptical of reports that the pest is being controlled in New Zealand. But considerable progress in this direction has been made* by the entomology division of the Plant .Research Bureau, which has been working on the problem for more than nine years.

The director of the entomology division (Dr. D. Miller) said that the pupal parasite, which attacked the cocoons of the white butterfly, was well established all over New Zealand, and the division was doing its best to get the larval parasite, which attacked the caterpillars, established in the North Island and the South Island. The larval parasite, introduced from North America, had become well established in the Nelson district, where white butterflies were seldom seen. Both the pupal and larval parasites were required to hold the white butterfly down, however, and in other parts of the country, where only the pupal parasite had been established, the butterfly had got out of control and there were temporary epidemics.

Dr. Miller added that the pupal parasite was established in. Canterbury, but the larval parasite had not established itself, as so far there had been only one liberation in North Canterbury. Control of the white butterfly by parasites was more effective under field conditions. Where vegetables were grown for household use it was not possible to obtain 100 per cent control with parasites, and therefore it became necessary to spray or dust. The annual report of the entomology division last year stated that observations throughout the country showed that the white butterfly had generally been held successfully during the year by the pupal parasite. From the limited data available it could be said that the larval parasi/i.' was aiding the pupal parasite in exercising a greater control of the white butterfly in the Nelson district than where control depended solely on the pupal parasite.