ARS | Publication request: Reduced use of pesticides for effective controls of arthropod pests and plant diseases

Submitted to: Journal of Environmental Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 30, 2011
Publication Date: September 1, 2011
Citation: Zhu, H., Zondag, R.H., Krause, C.R., Merrick, J., Daley, J. 2011. Reduced use of pesticides for effective controls of arthropod pests and plant diseases. Journal of Environmental Horticulture. 29(3):143-151.

Interpretive Summary: Pesticide applications that meet stringent market requirements are critical to ensure healthy, unblemished ornamental nursery plants. However, conventional spray application practices only suggest for the modification of carrier volume for preparations of spray mixtures, but not the amount of active ingredients per unit area. Quality spray applications with half the conventionally recommended volume of carrier and dosage of active ingredients were tested to achieve effective pest and disease control under commercial nursery production conditions. This research demonstrated that growers could use their existing spray equipment to reduce pesticide and water use by 50% with properly changing spray nozzles at no extra cost and still achieve the effective pest and disease control. This equates to doubling the pesticide application efficiency with reduced pesticide costs, reduced health risk to applicators, and diminished adverse impact to the environment. Other benefits accrued with this approach included increased operational efficiency (the area sprayed is doubled, the frequency and travel time required for the tank refilling times are reduced), decreased labor costs, and reduced costs for energy consumption for new equipment, as well as reduced risks of pesticide exposure of workers.

Technical Abstract: Current label recommendations of pesticides for arthropod pests and plant diseases in the nursery and green industry are vague and frequently result in excessive pesticide use. The objective of this research was to demonstrate that modifications of spray application techniques with existing spray equipment in ornamental nursery production could reduce pesticide use. The efficacy of half rates and full rates of both active ingredients and carrier was investigated in commercial nurseries with air-assisted sprayers in two tests and a State inspector survey for the control of arthropod pests and plant diseases. Sprayers were optimized with properly sized nozzles and properly calibrated operating parameters. In Test 1, treatments were conducted in approximately 0.5 ha plot each in three commercial nurseries for control of arthropod pests and diseases, and in Test 2, the same treatment for aphid control was evaluated in a Birch tree plot. The survey was a compilation of the pests and diseases that were diagnosed by State inspectors in over 2,800 plant varieties and species from two commercial nursery fields (total about 280 hectares) after the spray treatments in six growing seasons. Crop damage by 49 insects and 40 diseases were surveyed for different application rates. The studies revealed that insect and disease control using 50% of the label rates was as effective as full rates when quality spray coverage on targets was achieved, resulting in real cost benefits to producers, consumers and environment.