Project Number: 3607-21620-006-11
Project Type: Specific Cooperative Agreement

Start Date: Aug 02, 2005
End Date: Jul 31, 2008

Objective:
(1)To develop a custom-designed, five-port, aira-assist sprayer to improve spray penetration into dense nursery canopies while minimizing off-target loss, and (2)to determine optimal sprayer characteristics such as air-velocity and nozzle height to provide sufficient spray deposition for effective pest control within dense canopies.

Approach:
The hypothesis of the new sprayer design is that spray penetration into dense nursery crops can be improved by dividing a conventional large diameter air jet to several small diameter air jets arranged in a flat fan shape. Small air jets due to high speed can inject spray droplets into deeper dense canopies and at the same time the adjacent air jets will create eddies to spread out droplets in surrounding areas within canopies. Small air jets due to their flat fan pattern arrangement can cover much wider spray width than a conventional large diameter air jet. In contrast, using a conventional large diameter air jet may easily damage canopies due to high air volume and speed. In cooperation with the ARS Application Technology Research Unit, Wooster, OH, this research will include the following: An improved air assisted sprayer with five-port nozzles will be developed and modified to discharge sufficient spray droplets into dense nursery canopies. Spray droplet size and spray pattern uniformity at various distance from nozzle orifice will be measured with a particle imaging size and velocity analyzer. Field tests will be conducted to investigate spray deposition and air velocity distribution at various levels within several dense canopies, various nozzle heights, and application rates to evaluate new and improved sprayer performance. Several dense nursery crops will be selected for field experiments. Correlations between deposition and air velocity within canopies will be determined under field conditions. Reliability and durability of new sprayers will be continuously tested under field production conditions for three years.