Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2007
Publication Date: 1/31/2008
Citation: Derksen, R.C., Frantz, J., Ranger, C.M., Locke, J.C., Zhu, H., Krause, C.R. 2008. Comparing Greenhouse Handgun Delivery to Poinsettias by Spray Volume and Quality. Transactions of the ASABE. 51(1)27-33.
Interpretive Summary: Between 2004 and 2005, floriculture sales increased 1.5% with the greatest increase in sales in potted plants. Consumers seek high quality ornamental crops with few cosmetic defects which in turn drives aggressive pest management programs. Despite the intensive nature of ornamental pest protection programs, there is little information available to growers on how to most efficaciously apply crop protection materials. A greenhouse trial was established to determine differences in spray retention in a poinsettia canopy between applications using three different spray volumes and three different spray qualities using single nozzle handgun applicators. Foliar samples and artificial targets were collected to assess the fate of spray in the canopy. Results for the fungicide residue and tracer analysis were similar. For the same areas of the canopy, there were few differences in spray deposit between treatments. Fronts and upper areas of the canopy received more deposits than the backs and lower areas of the canopy. The high volume (100 gpa) application produced the highest deposits on artificial targets across all spray qualities. There were no significant differences in overall spray deposit between the low (25 gpa) and medium (50 gpa) volume treatments. Canopy position (front/back and upper/lower), and the operator’s ability to direct spray at each target plant had more influence over deposition in the canopy than spray volume or spray quality in these trials. Greenhouse producers and pest management specialists can use this information to reduce time and the carrier volume needed to make applications.
Technical Abstract: Pesticide labels often lack specific recommendations on the spray volume and spray droplet sizes which will provide the most efficacious pest management of ornamental pest problems. The objective of this research was to determine the effect of spray volume and spray quality on the fate of spray in a mature poinsettia canopy using handgun applications. A greenhouse trial was established to determine differences in spray retention in a poinsettia canopy between single-nozzle, handgun applications made using three different spray volumes(25, 50, and 100 gpa) and three different spray qualities (Very Fine, Medium, Coarse). For the same areas of the canopy (front/back and upper/lower sections), there were few differences in spray deposit between treatments. Canopy position (front/back and upper/lower)was a significant factor in the amount of spray found on foliar and artificial targets. Higher deposits were measured in the fronts and upper areas of the canopy than the backs and lower areas of the canopy. There were no significant differences in recovery of fungicide from leaves between treatments. The high volume application produced the highest deposits on artificial targets across all spray qualities. There were no significant differences in overall spray deposit between the low and medium volume treatments. There was no benefit to treating with small droplet, high volume sprays as commonly used in commercial production systems. The results of this study also demonstrate the importance of knowing the limitations of the equipment in each cropping system to help ensure an efficacious application by a single-nozzle handgun.