Author
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Derksen, Richard |
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Submitted to: Mid-Atlantic Fruit and Vegetable Convention
Publication Type: Proceedings Publication Acceptance Date: 1/25/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Traditionally, contact insecticides and fungicides are applied through broadcast sprayers and nozzles that produce relatively small droplets. Little is known about how effective low-drift and other new technologies are for managing pest problems in the field. A field experiment was conducted to compare traditional fungicide application techniques with drift reduction nozzles and technologies that may aid in delivery and deposition of small droplets. Treatments included conventional flat fan, disc core and low-drift nozzles. Other deposition aids evaluated included air-assist treatments and spray water treated with copper ions. Drought conditions in 1998 and 1999 somewhat limited levels of foliar disease between treatments. Those treatments where fungicides were applied were slightly more effective than no spray treatments, including the low-drift nozzle treatment. There were generally no differences in the healthy red tomato yield between treatments. Imaging technology and colorimetry techniques were used to quantify deposit quality and quantity. One air-assist treatment produced higher foliar deposits and spray coverage on the underside surfaces of leaves than conventional nozzles. Another air-assist treatment did not perform significantly better than conventional nozzle treatments. The addition of copper ions to the spray water did not increase foliar spray deposits but slightly increased underside leaf coverage. At another field where drought conditions were not as severe, plots treated with low pressure nozzles had similar yields to those treated with traditional, high pressure nozzles. Additional experiments are being planned to correlate coverage and deposition measurements with biological and yield assessments. |
