An experiment designed to assess the usefulness of a male attractant, 4-(p-acetoxypheny1)butan-2-one, for the control of relatively isolated populations of the Queensland fruit fly, is described. Traps baited with the lure and an insecticide were distributed at fairly high density throughout a small town and its immediate surroundings, while a similar town nearby was left untreated for purposes of comparison. The numbers of males killed each week in the treated town were estimated, and in both towns regular measurements were made of: (i) ratios of males to females; (ii) rates of insemination of mature females; and (iii) rates of infestation of fruit. The results show that there was a clear effect of the treatment in the early part of the season, but that this diminished as the season progressed until finally there was little difference between the populations. We conclude that this male attractant, used alone, is unlikely to provide effective control of the Queensland fruit fly, except perhaps when used against thoroughly isolated populations. It may, however, be more useful if used in combination with other methods which provide some protection against inseminated females.

This is the second paper in a series describing experiments designed to investigate the potential usefulness of chemical lures for the suppression of isolated populations of the Queensland fruit fly. The experiments reported here were done in two consecutive years and involved 12 country towns in central and north-central New South Wales. Three of the towns were treated with a male-attractant plus an insecticide; three were treated with a general lure plus an insecticide; three others received a combination of both treatments; and the remaining three were left untreated for comparison. In the first year neither single treatment had any significant effects on the populations, while the double treatment achieved an acceptable level of control. In the second year the performances of both single treatments improved greatly, while the combined treatment gave excellent control. It is shown that isolated populations of fruit fly can be suppressed by these means.The implications of these results for future large-scale control of the Queensland fruit fly are discussed briefly. More complete discussion must await publication of further developments of this work, which will be reported in later papers in this series.