Cowpea seed treatment with carbosulfan: potential for control of seedling pests

Results from three field trials and a screenhouse study conducted in 1985 and 1986 using carbosulfan (Marshal 25 ST) insecticide dust formulation at 0, 10, 20, 30 and 40 g/kg cowpea seed indicated that infestation and/or damage by aphids, foliage beetles and leafhoppers was satisfactorily reduced with treatment levels above 20 g carbosulfan/kg seed. The period of activity of the different treatments ranged from 15 to 23 days for various pests in the screenhouse, and slightly longer in field trials. Post-flowering pests were, however, not controlled at any of the rates tested. The ease of application and high dermal LD₅₀ (> 2000 mg/kg rabbit) make Marshal 25 ST a very attractive option for use by small-scale farmers as a component of an integrated pest management strategy in locations where these pests are important and adequate levels of genetic resistance are not available.     

Nitrogen inputs and outputs in a small agricultural catchment in the eastern part of the United Kingdom

Abstract. Nitrate concentrations measured in an ephemeral stream draining a 170 ha clay catchment in eastern England, with about 23% arable land, were greater than 11.3 mg N 1–¹ on the resumption of flow each autumn but then declined. There was also a spring peak in two years out of seven, 1978–1984, which depend on the length of time soils was at field capacity in the preceding winter. Mean annual load measured in rain was 19 kg N ha^-1 and loss of nitrate in the stream 34 kg N ha^-1. A catchment nitrogen balance suggested that inputs, which averaged 130 kg N ha yr^-1, were generally more than outputs, average 108 kg N ha yr^-1', but gaseous losses were not taken into account.     

Overview of field studies for the application of remote sensing to the study of malaria transmission in Tapachula, Mexico

A National Aeronautics and Space Administration (NASA) sponsored project to use remote sensing technology in a predictive model of vector population dynamics and malaria transmission potential for the coastal plain of Chiapas, Mexico, is described. Included are the results of recent studies to characterize vector habitats and an assessment of the kinds of information that will be required for developing the predictive model within a geographic information system.