Lee HL, Antonietta PE, Seleena P and Chiang YF
Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia
CITATION: Lee HL, Antonietta PE, Seleena P, Chiang YF. Simultaneous ultra-low-volume application of adulticide (malathion) and larvicide (Bacillus thuringiensis H-14) for the control of dengue vectors. International Medical Research Journal. 1997 Jun;1(1):13–9.
ABSTRACT
The evaluation of the effectiveness of ultra-low-volume fogging with a mixture of bioinsecticide Bacillus thuringiensis H-14 and malathion for the control of dengue vectors was conducted in a residential area. The effectiveness was measured using four different indicators: larval mortality, adult mortality, Bti enumeration and droplet analysis. The fogging formulation which was a mixture of 9 parts VECTOBAC 12AS® and 1 part 96% technical grade malathion was dispersed using a Dynafog Maxi Pro4® ULV generator with a 18 horse power engine. The flowrate which was 0.25 L/min was able to effectively deliver sufficient Bti toxins and malathion up to a distance of 19.7 m (65 ft) from the generator. The amount discharged was also sufficient to effect complete residual activity in Aedes mosquito larvae for a minimum of 14 days post ULV. Malathion does not affect the activity of larvicidal toxin of Bti since 100 % larval mortality was obtained in the test samples. On the other hand, VECTOBAC 12ASR too did not exert any negative effect on malathion as 100 % adult mortality was obtained in the Aedes mosquito species. Bti fogged at a dosage of 0.25 Umin had good coverage of the target area and penetration of dwellings, these being attributed to satisfactory droplet profiles. Based on the results of this study, it can be concluded that VECTOBAC 12AS®, an aqueous suspension formulation of Bti, dispersed simultaneously with malathion, a chemical insecticide, using ULV fogging at a discharge rate of 0.25 L/min, was very effective in controlling Aedes mosquitoes.
KEYWORDS: Bacillus thuringiensis H-14, Malathion, Dengue vector control
