This paper addresses the hypothesis that the spray application system used will affect the retention of spray deposits of microbial herbicides on different plant structures. There was greater spray retention on the hypocotyl of 4 to 6-true leaf Amaranthus retroflexus plants (20-31%) sprayed with an aerosol-producing laboratory sprayer than with a hydraulic nozzle (3-5%). Spray deposition and retention from the hydraulic nozzle was increased by 28-42% when the nozzle was used horizontally. Spray droplets generally contained the expected conidial number for the conidial concentration but this was affected by increased inoculum density (size, concentration and mycelial contamination), causing a reduction in the actual number of conidia present, compared to the expected. Up to 40-50% of the conidia in the sprayed suspension could not be accounted for when conidium deposition was on a target. This loss could increase to 90-92% when the weed was sprayed under a crop canopy.

Inclusion of Alternaria alternata conidia in a spray formulation affected the distribution pattern on the target. The dry weight of Amaranthus retroflexus plants was reduced by more than 83% when A. alternata conidia (107 ml -1 ) were applied at 200 L ha -1 or greater and when given a 24 h dew period. At low application volumes (25 or 50 L ha -1 ) plant dry weight was reduced by only 29 or 54%. After 7-8 h dew period, conidial germination on the leaf surface was 11-19%. This increased to 62-91% after 24 h dew period. Counts of conidia on leaves indicated that up to 86% of the conidia sprayed were not retained on the target plant, or did not reach it. This is reflected in lesion numbers per unit area being only 3-5% of the calculated theoretical numbers. The results cast doubt on the suitability of A. alternata as a microbial herbicide for the control of Am. retroflexus .

A Y-adaptor manifold assembly includes a main tubular segment adapted to be coupled to an intravascular catheter. A first, tubular side port is joined to the main tubular segment so as to be in fluid communication with a through passage of the main tubular member. The first side port forms an infusion port for radiopaque dye. A second, tubular side port is joined to the main tubular segment so as to be in fluid communication with a through passage of the main tubular member. The second side port and main tubular segment are adapted to receive dilatation catheters. To prevent backbleeding, the second side port and main tubular segment include passive hemostatic valve mechanisms. Each valve mechanism includes a valve member and a disk valve. The valve member has a normally closed, sealed state, an open state and an in-use sealed state. The valve member has an inherent tendency to move to its normally closed, sealed state or its in-use state (wherein the valve member conforms about the dilatation catheter). Application of a compressive radial force moves the valve member to its open state.

The effects of 10 commercially available tank-mix adjuvants on the retention and coverage of aqueous sprays on foliage were examined quantitatively under track sprayer conditions, following application at their maximum recommended rates. Substantial enhancement of fluorescein retention was observed only on water-repellent barley and peas, but the differences in performance between the additives were considerable. Addition of the water-soluble tallow amine and nonylphenol surfactants gave the largest increases in retention, whereas there was little improvement in efficiency compared with water alone after inclusion of either the latex- or pinolene-based products or ammonium sulphate. Retention enhancement was also achieved using the mineral oil, vegetable oil, methylated vegetable oil and phospholipid ECs and the organosilicone surfactant, but this was often much less than that obtained for the water-soluble surfactants; the best EC was the methylated vegetable oil which also had the highest emulsifier content. Although spray quality was altered significantly in the presence of many of the adjuvants, modifications to this parameter alone could not account for changes observed in deposition efficiency, because retention enhancement was recorded in sprays with volume median diameters both smaller and larger than water. There was a better correlation between retention efficiency and the dynamic surface tension of the corresponding spray liquids, with the exception of the organosilicone, which, as expected from its high surface activity, gave essentially complete spray coverage on leaves. Nevertheless, good coverage could still be achieved by adding the two water-soluble surfactants, as well as the methylated vegetable oil and phospholipid ECs. Coverage performance of the other adjuvants tested was poor in comparison, reflecting, in part, their inferior retention enhancing properties.