| Studies conducted in a wind tunnel compared the double nozzle to fine and coarse nozzles. At a 2 m/s wind speed, drift from the double nozzle was minimal, with less than 40% of the spray susceptible to drift. This compares favorable with the coarse nozzle at 4 m/s, but is about twice the drift of the coarse nozzle at the same wind speed, but is half that of the fine nozzle at the same speed. Because the amount of spray drifting from the double nozzle (at any wind speed) was approximately double that of the coarse and the field rate was half, the total amount of AI drifting is approximately the same as for the coarse nozzle. Thus, at 50% AI reduction there is no increase in drift. Drift is correspondingly reduced at AI rates below 50%. For example, at a field rate of 30%, drift is reduced by 40%. |
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| The dose-response curve for glyphosate through the double nozzle is very similar to that of the fine nozzle at low rates, and is intermediate between the coarse and fine nozzles at higher rates. |
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| Glyphosate was applied to a field of Roundup Ready â soybeans through the double nozzle at rates of 33, 50, 75 and 100% label rate, and through a conventional sprayer at 80% label rate. Weed mortality with the double nozzle was higher than with the conventional sprayer at all rates. |
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| A comparison was made of the double nozzle sprayer with a conventional sprayer using glyphosate at 4 rates. This trial to kill fallow (principally foxtail and smartweeds) prior to sowing rye as a winter cover crop resulted in near 100% mortality of the annual weeds with the double nozzle at rates down to 25% the lowest label rate. The conventional sprayer obtained equivalent results at 75% lowest label rate. Mortality of perennials will be assessed Spring 1999. |
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| A field trial with paraquat on quack grass and other weeds showed slightly lower burn down after 48 hr. using rates 50-80% label rate with the double nozzle, relative to label rate through a conventional sprayer. After 72 hr no differences were discernable between the double nozzle (all concentrations) and the coarse nozzle. |
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| Glufosinate was applied to weeds in Liberty-link canola at 2.5 l/ha through different combinations of coarse and fine nozzles. Best results were obtained with all AI delivered through the fine nozzle and water through the coarse nozzle. The effective mortality 17 days post treatment was about 15% higher with the double nozzle than with a coarse nozzle sprayer. |
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| Kelthane through the double nozzle is as effective against mites as through a fine nozzle at rates up to 33% label. At 100% label rate, Kelthane through the double nozzle is more effective against mites than through a fine nozzle. The double nozzle is more effective than a coarse nozzle at all rates. |
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| Colorado potato beetles have become resistant to permethrin in many parts of the country, including NE Ohio. Thus, the expected performance of permethrin against Colorado potato beetle is very poor (~35% mortality). In a double nozzle sprayer trial using permethrin, 80% mortality was obtained at rates down to 25% and 100% mortality using label rate. |
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| A tank mix of Imidacloprid and Thiodan was used against aphids on pre-harvest lettuce in a field trial in Arizona. Pest pressure was very high but the Double Nozzle successfully reduced the aphid populations at rates down to 33% label rate. Both the conventional and the Double Nozzle achieved acceptable control of aphids on the wrapper leaves, but only the Double Nozzle penetrated the head leaves for adequate aphid control. |
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| A tank mix of Spinosad and Metasystox R was used against diamondback moth caterpillars on cabbage in a field trial in Arizona. Pest pressure was moderately high. Over a 7 day period the Double Nozzle virtually eliminated diamondback at rates down to 33% label rate. Even at 90% label rate, the conventional system performed poorly compared to the Double Nozzle at 33%. |
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