Mazel tov! It’s nozzle talk!

I recently finished writing up a study about the use of different nozzle types and water rates for dollar spot in putting greens. When working on a presentation about this awhile back, I noticed that “nozzle talk” sounded like “Mazel tov!” and so that was a running joke in my house for a few days.

I worked with a colleague in our Biological and Agricultural Engineering Department, Dr. Bob Wolf. Bob has done a lot of work with nozzles and spray technology in field crops such as corn, but he also works with turf. We also had some valuable discussions with Matt Giese from Syngenta as we were selecting nozzles and working out the protocol. We did the studies in 2007 and 2008. Other researchers have examined nozzles and water volume previously, and I won’t get into that for the moment. That might be a good topic for a winter/off-season discussion. John has done a fair amount of work in this area with Mike Fidanza, for example, and others have too. I’ll just describe our KSU study. It is published in the online journal Applied Turfgrass Science.

We did the work on an A4 creeping bentgrass green that was maintained at 0.156 in. We looked at 5 nozzle types, and each nozzle was used with 0.5, 1.0, and 2.0 gal/1000. We used Daconil Ultrex at 1.8 oz/1000. This is the low rate and was used so that there was enough disease pressure to allow us to see some differences. That is, with a high rate we may not have seen enough disease to tease apart differences.




The nozzle types we used were:

*TurfJet
*Extended range flat-fan (XR)
*Air Induction
*Turbo Twin Jet
*Turbo Drop Twin Fan

Each nozzle was used in 02, 04, and 08 flow rates to give 0.5, 1.0, or 2.0 gal/1000. The flow rate is usually printed on the nozzle (as shown in the next photo) and represents gal/minute at 40 PSI. 02 = 0.2 gal/minute for example. The Turbo Twin Jet is not available in 08 orifice size, and therefore a Turbo Duo adapted with two Turbo Twin Jet 04 nozzles (TT11004) orifices was substituted. (Basically, we used two Turbo Twin Jet 04’s stuck together).




The TurfJet nozzle produces coarse droplet sizes and usually has less complete coverage, and in some previous studies it has provided less disease control than others. The XR is commonly thought to provide very complete coverage and is widely used and thus was selected as the comparison “standard.” The Air Induction nozzle is designed for drift control. In air induction nozzles, air is drawn into the nozzle body and combined with the spray solution to form large, drift-resistant “bubbles” which explode upon contact with the plant. The Turbo Twin Jet (with a pre-orifice design to reduce drift) and TurboDrop Twin Fan (another air induction design) are recently-developed nozzles used more in field crops that have not been tested for disease control in turfgrass systems. They produce a “twin stream” of water as is shown in the photos.

In our studies, the 0.5, 1.0, and 2.0 gal/1000 water rates all performed similarly with few significant differences. That is, for most nozzles on most rating dates, all water rates performed equivalently. In addition, for the most part all the NOZZLES performed similarly except for the TurfJet nozzles which had poorer disease control on some rating dates.










The images below show how we collected some spray coverage data. Bob then scanned the water-sensitive papers and ran them through an analysis program.