BUTTERFLY WAR.

Auckland Star, Volume LXVI, Issue 238, 8 October 1935, Page 5

BUTTERFLY WAR.

BREEDING PARASITES.

SCHOOLBOYS' EXPERIMENTS.

CONTROL OF PEST SUCCEEDS. \So successful have been the results of the agricultural section of the Otaliuhu Technical in experimental work against the white butterfly that there are now only small numbers of the pest in the district and this year's research work is hampered by a lack of available chrysalids on which to experiment. Some 18 months ago it was decided to carry out localised experimental work J with the pteromalus puparum parasite, a small insect of the wasp family, and about the size of a sandfly. Under the energetic guidance of Dr. W. S. Hill, head of the agricultural department at the school, a glass'house was built by the boys in the school grounds and the latest * electrically-oontrolled incubator boxes installed. The total cost was only £50, which was defrayed by the Manukau, Papatoetoe, Manurewa, Mount Wellington and Howick local bodies. Dr. Hill said that they had concentrated their attention on the pteromalus parasite because of its success in combating the white butterfly plague in the South of England in 1918. The parasite was easy to breed in an incubator, multiplying tenfold each time it laid. Its greatest advantage was that it attacked nothing but thechrysalid of the white butterfly. When the white butterfly was killed off the parasite automatically followed suit. Last year some 10,000 parasites were liberated in the district supporting the ( work. The success of the work is apparent in the small numbers of white butterflies to be seen in the Otahuhu district at present. Twelve months ago the fields were white with them but now a white butterfly is rather the exception than the rule.. Dr. Hill said this year only about 5000 parasites would' be liberated.