PERFORMANCE OF TRIFLUMURON AGAINST BLATTELLA GERMANICA (L.)

Abstract:
The Chitin Synthesis Inhibitor, triflumuron, has great potential for the control of German cockroach, Blattella germanica (L). Field trails were carried out to evaluate its efficacy in combination with a short residual, conventional, insecticide DDVP, and when used alone. The insecticides were applied in Sydney, Australia as sprays to domestic premises which had medium to heavy cockroach infestations. There were eight properties sprayed per treatment and pre and post assessments of population numbers were made using sticky traps. Untreated (control) properties were monitored during the course of study. In the first study, properties were sprayed with DDVP alone (0.6%a.i.), triflumuron alone (0.096% a.i.), and a tank mix DDVP plus triflumuron at the same rates. Post assessments were carried out at one week, one month, two months and four months after spraying. At one week, DDVP alone and the DDVP plus triflumuron gave similar reductions (90% and 85% reduction). The triflumuron alone gave 47% reduction. After four months the triflumuron and DDVP plus triflumuron were providing 90% and 94% population reduction respectively. In the properties treated with DDVP alone the percentage reduction had dropped to 50%. A follow up study examined three rates of triflumuron - the same rate as that used in the first study (0.096% a.i.), and 0.048% a.i. and 0.024% a.i. Post treatment assessments were carried out at two weeks, one month, two months, four months, and thirteen months after spraying. At two weeks the lower rates were giving a similar reduction of about 25'%. The high rate gave 52%) reduction. At four months there was no obvious dose relationship. The high, medium and low rates gave 63%, 64% and 69% population reduction respectively. At thirteen months, control at the low rate properties had dropped to 40% reduction while the other two rates had maintained their four month reduction levels. This study demonstrates that triflumuron is effective and long lasting under difficult field conditions at rates of 0.096'Yo a.i. and 0.048% a.i. Its low initial activity can be overcome by tank mixing with a knockdown insecticide such as DDVP