“Speedbox” as an effective mini gas generator for phosphine fumigation
Abstract: Phosphine based fumigants are mainly used today for stored product insect pest control. However, some limitations, such as low temperatures and relatively long exposure time, limit their uses. In order to overcome these difficulties, a special device, called “speedbox” was developed by Detia Degesch GmbH, Germany. The Speedbox is consigned exclusively for the use of Degesch Plates®. The Speedbox is a small waterproof aluminium box containing a heater and a ventilator that injects and recirculates the phosphine gas in and out of the fumigated space. This technology was compaered with traditional phosphine formulations, such as aluminium phosphide tablets and magnesium phosphide tablets and plates. At the rate of 4 g/m3, using the Speedbox, phosphine concentrations of 200 ppm and 830 ppm were reached 2 h and 8 h, respectively, following the fumigation, compared with 35-102 ppm and 200-520 ppm with the other technologies. The accumulative phosphine concentrations using Speedbox were much higher during 72 h of the fumigation compared with the non-speedbox technologies. As a consequence of using the Speedbox a high phosphine concentration was reached practically at the beginning of the fumigation, 100% mortality of all tested insects at all developmental stages were recorded after only 48 h treatment at the rate of 6 g/m3 or 72 h at 4 g/m3. The Speedbox enables us to control all developmental stages of the major stored product insects by shortening the time of phosphine treatment from 7-10 days to 2-3 days. The Speedbox as a mini gas generator demonstrates a high efficacy and other advantages compared with the common phosphine fumigation technologies for stored product insect pest control.