Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 29-30. (Budapest, 1997)

The proper formulation of mosquito and fly larvicidal agents is an important factor for the success of treatments. In co-operation with Stockhausen Company, Germany, a world-wide expert of absorbent polymers, Bábolna Bioenvironmental Centre is now in possession of special granule formulations that have proven suitable and advantageous to incorporate BTI or methoprene (or both together) for practical application. These types of granule, having great versatility in composition and physical properties, are a variety of the Culigel pellets used previously in mosquito control. They consist of a hydrophilic superabsorbent polymer matrix based on polyacrylic acid and special polysaccharides. The protection of the active ingredients from adverse environmental effects and the slow, timed release are the most significant features of these novel granule formulations. Our new preparations, BTI B 5 GR and BIOPREN BM 5 GR formulations are now being tested in the laboratory and field. Some of these results have already been reported in brief elsewhere (Varjas et al. 1995; Varjas et al. 1996; Hedicke et al. 1996). In the present paper we give further information on these studies performed recently with the new granule formulations at different laboratories, both in Hungary and abroad. MATERIALS AND METHODS Test insects For laboratory studies on mosquitoes at CHINOIN Agrochem Business Unit (Budapest) a colony of a susceptible WHO standard strain of the yellow-fever mosquito (Aedes aegypti) was maintained at 25 ± 2 °C and a photoperiod of LD 17:7. Females were given the opportunity to feed on mice three times per week. Eggs were deposited onto pieces of filter paper standing partially in water. Following a 5-day incubation at 96% relative humidity, eggs were stored at 15 °C. Young larvae were fed with yeast powder (30 mg/litre) but from day 2 they received powdered dry blood (60 mg/litre). At ORSTOM Laboratories (Montpellier, France) larvae of the same species were fed with sterilised, crushed cat feeding pellets. In experiments of KABS (Waldsee, Germany), larvae of the wood mosquito (Aedes cantans) collected from their natural breeding habitats in the Upper Rhine Valley were used. In laboratory tests and field trials performed by Veterinorg Ltd., University of Veterinary Science (Budapest), larvae of the house fly (Musca domestica) were used. An insecticide-sensitive strain (WHO-SRS) was reared for this purpose on fresh pig manure as larval breeding medium. Preparations tested BTI B 5 GR slow-release granules as a new bacterial preparation was studied. It contained 5% active ingredient consisting of parasporal protein crystals (+ spores and dead cells) of Bacillus thuringiensis subsp. israelensis (BTI) having a specific activity of 10,000 ITU/mg. BIOPREN BM 5 GR was the other bioactive preparation investigated. In these granules, the 5% methoprene (isopropyl-/E,E/-/7R,S/-l l-methoxy-3,7,11-trimethyl-dodeca-2,4 dienoate) active ingredient was incorporated. The juvenoid active ingredient was produced in high purity, i. e. the active stereoisomer content was over 90%>. Otherwise, it was a racemic compound. As a reference preparation, Altosid Pellets containing 10%> methoprene were also used.