Development of a Desiccated Cadaver Delivery System to Apply Entomopathogenic Nematodes for Control of Soil Pests

Abstract

Entomopathogenic nematodes may be more capable of controlling soil pests when they are harbored by desiccated cadavers. A small-scale system was developed from a modified crop seed planter to effectively deliver desiccated nematode-infected cadavers into the soil. The system mainly consists of a metering unit, an air pressure source, a cadaver scraper, a custom-designed cadaver container, tension adjustment devices, double disk soil opener, a discharge tube, a packer wheel, and a press-drive wheel. The metering unit intermittently discharges a cadaver to the discharge tube at a constant rate. The double disk opener creates a narrow 7.5-cm deep slot for the placement of the discharged cadavers. The packer wheel then covers the cadavers with loose and somewhat moist soil. The spring tension device and the press-drive wheel control the slot depth. The number of cells on the metering plate controls the cadaver delivery rate regardless of the travel speed. The metering unit with modified double bean plates has delivery accuracy between 79% and 94% at 500-Pa air pressure. A slower travel speed and fewer cells on the metering plate improved the accuracy of delivery. When the travel speed was 4.8 km/h or slower, the desiccated cadaver delivery system performed satisfactorily in both laboratory and field tests, and delivered the cadavers at a rate of 1.6, 3.3, or 6.6 cadavers/m length in the soil.