Spot-application of fungicide for wild blueberry using an automated prototype variable rate sprayer
- 2.1k Downloads
Wild blueberry producers apply fungicide uniformly without considering significant bare spots in the field. The wrong or over use of fungicide in bare spots results in an increased cost of production and threatens the environment. An automated prototype variable rate (VR) sprayer was used for spot-application (SA) of Chlorothalonil (Bravo®) fungicide in a wild blueberry field. Eighteen 6.1 m wide test tracks were selected in the field and bare spots were mapped using a real-time kinematics-global positioning system (RTK-GPS). Six plots were selected randomly for three different application rates. Water sensitive papers (WSP) were placed in foliage and bare spots in SA and uniform-application (UA) tracks. The percent area coverage (PAC) of WSP with both SA and UA in foliage and bare spot areas were calculated. Plant growth parameters were measured from all 108 randomly selected plots in SA, UA and control (CN) tracks for comparison. Plant images were taken over six selected plots in each of the 18 tracks. Images were analyzed using custom developed software to calculate the percentage of green pixels (PGP) for determining the effect of Bravo® on plant health. Fruit yield parameters were also measured from selected plots for comparison. Non-significance of the t test for SA versus UA plant targets’ PAC indicated that there was no significant bias in the SA with saving (9.90–51.22 %) and SA was accurate. Bravo® did not show any significant difference on plant growth parameters among SA, UA and CN. However, PGP, floral bud and harvestable yield of SA and UA were significantly increased over CN. Therefore, a VR sprayer could be used for SA of fungicides in wild blueberry cropping system to reduce chemical usage and maintain crop productivity.
KeywordsAgrochemicals Precision agriculture Color camera Bare spot detection Real-time Spot-application
This work was supported by Oxford Frozen Foods Limited, Wild Blueberry Producers Association of Nova Scotia, Agri-Futures Nova Scotia and the Nova Scotia Department of Agriculture Technology Development Program. The authors would like to thank Gary Brown and Doug Wyllie (farm managers Bragg Lumber Company) and Scott Read for their assistance during the experiment. Also special thanks to the graduate students and summer students that assisted with data collection.
- Esau, T. (2012). Development and evaluation of a prototype variable rate sprayer for spot—Application of agrochemicals in wild blueberry fields. M.Sc. Thesis. Dalhousie University, Halifax, NS, Canada.Google Scholar
- McIsaac, D. (1997). Growing wild lowbush blueberries in Nova Scotia. Department of Agriculture and Marketing. Retrieved January 23, 2012 from http://nsac.ca/wildblue/facts/grow.asp.
- Michaud, M., Watts, K. C., Percival, D. C., & Wilkie, K. I. (2008). Precision pesticide delivery based on aerial spectral imaging. Canadian Journal of Biosystems Engineering, 50, 9–15.Google Scholar
- National Climate Data and Information Archive. (2010). Environment Canada. Retrieved January 25, 2012 from http://www.climate.weatheroffice.gc.ca.
- Pariseau, J., Saint-Louis, R., Delaporte, M., Khair, M., McKenna, P., Tremblay, R., et al. (2009). Potential link between exposure to fungicides chlorothalonil and mancozeb and haemic neoplasia development in the soft-shell clam. Marine Pollution Bulletin, 58, 503–514.Google Scholar
- Percival, D., & Dawson, J. (2009). Foliar disease impact and possible control strategies in wild blueberry production. Acta Horticulturae (ISHA), 810, 345–354.Google Scholar
- Schumann, A. W., & Hostler, K. H. (2009). Computerized automatic variable rate controller for application of agrochemicals in orchards. U.S. patent 8260507 issued on September 4, 2012.Google Scholar
- Schumann, A. W., Miller, W. M., Zaman, Q. U., Hostler, K. H., Buchanon, S., & Cugati, S. (2006). Variable rate granular fertilization of citrus groves: Spreader performance with single-tree prescription zones. Applied Engineering in Agriculture, 22(1), 19–24.Google Scholar
- Wild Blueberry Factsheet. (2009). New Brunswick Department of Agriculture and Aquaculture. Retrieved December 15, 2011 from http://www.gnb.ca/0171/10/0171100029-e.pdf.
- Yarborough, D. E. (2009). Wild blueberry. Orono, Maine: University of Maine Cooperative Extension. Retrieved January 26, 2012 from www.wildblueberries.maine.edu/.
- Zaman, Q. U., Esau, T., Schumann, A. W., Percival, D. C., Chang, Y., Read, S., et al. (2011). Development of a prototype automated variable rate sprayer for real-time spot-application of agrochemicals in wild blueberry fields. Computers and Electronics in Agriculture, 76(2), 175–182.Google Scholar
- Zaman, Q. U., Swain, K. C., Schumann, A. W., & Percival, D. C. (2010). Automated, low- cost yield mapping of wild blueberry fruit. Applied Engineering in Agriculture, 26(2), 225–232.Google Scholar