The viscosity of vegetable oil-pesticide mixtures is much higher than that of water-pesticide mixtures, especially at low temperatures. Flow rates of soybean oil through regular flat fan nozzles are similar to those of water, while flow rates through flooding nozzles decreased dramatically when soybean oil was sprayed. Soybean oil increased the flow rate through hollow cone nozzles as compared to water with a decreased flow as temperature increased from 25 to 40°C for the TX4 and TX6 nozzles. In field applications grass control decreased as oil was added to water as a carrier, especially at the 50% concentration. There was very little difference in weed control when using either water or soybean oil as the carrier for low-volume application of foliar herbicides. Trends indicate improved grass control and decreased broadleaved weed control when using soybean oil as a carrier as compared to water.

Evaluations of the spray characteristics of a new atomizer (Micromax) indicate that rotary atomizers used on tractor-mounted sprayers have the potential to apply agricultural pesticides effectively. Operating the units at the spacing, height, and tilt angle that provides double to triple overlap of the spray output results in acceptable distribution patterns over a range of disk speeds and flow rates. The droplet spectrum produced by the Micromax is much narrower than the spectrum produced by conventional hydraulic nozzles, and the median size generated is related to the speed of the disk. Spray droplets from the Micromax tend to move off the swath and deposit in the first few metres downwind much more than those from flat fan sprays. At distances greater than 10 to 20 m downwind, the deposits were no different from those from a flat fan spray.

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Lime was applied at rates from 0 to 5.0 t ha-1 at 4 sites in southern and central New South Wales. A root and crown disease characterised by basal stem blackening affected up to 60% of wheat plants and 80% of triticale plants when the soil pH in 0.01 mol L-1 CaCl2 was above 5.0 at all 4 sites. Below pH 4.8, incidence was less than 5%. The take-all fungus, Gaeumannomyces graminis var. tritici, was consistently associated with this symptom. Losses in grain yield from the disease ranged from 26 to 77% depending on site. Regression analysis indicates that each 10% increase in plants with basal stem blackening decreased yield by 0.76%. These results demonstrate that the disease can reverse the expected increase in yield after liming, and that progressive acidification of the soils in the region may have caused the present reduced amount of take-all.

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