{"id":1431,"date":"2024-03-14T11:00:11","date_gmt":"2024-03-14T18:00:11","guid":{"rendered":"http:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/?p=1431"},"modified":"2024-04-15T11:30:29","modified_gmt":"2024-04-15T18:30:29","slug":"drone-pesticide-application-the-second-take","status":"publish","type":"post","link":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/2024\/03\/14\/drone-pesticide-application-the-second-take\/","title":{"rendered":"Drone Pesticide Application: the second take"},"content":{"rendered":"

Contributed by Joel Felix, Oregon State University and Clarke Alder, Amalgamated Sugar<\/p>\n

The era of using drones to apply agricultural pesticides is upon us. Recently, I was invited to speak at a pesticide license recertification course and among the attendees were individuals seeking drone spray license recertification credits! Drone spraying helps to infuse technology in agricultural operations that does not require someone to sit in a tractor for hours spraying large fields or flying in a small plane! Drone spraying is cool! Once the spray route is programed, the drone could be autonomously operated with the operator watching while seated outside the field, save for the periodic refilling of the spray tank. So, maybe, just maybe, this could help to steer the youngsters back to the farms to take over farming from older farmers who are contemplating retirement.<\/p><\/div>\n

In the blog titled \u201cNeed Aerial Pesticide Spray? Call the Drone Guy\u201d<\/a> published on September 28, 2023, I concluded with the observation that \u201cdrone pesticide spray is convenient and probably suited for much more forgiving pesticides, for example, insecticides and fungicides, but risky for herbicides, particularly if there are sensitive crops nearby\u201d. I also promised to write a follow up article, which is what you are reading now.<\/p>\n

Drones used to spray agricultural pesticides are fitted with 5 to 10 gallon tanks, a boom, or nozzles (actually \u2013 atomized disc spray system) underneath the propellers as is the case with DJI AGRAS T40 (link opens in new tab)<\/a>. The spray volume is 2 to 3 gallon per acre, which calls for repeated refills that take a minute or so turn around! The proprietor I visited was operating the drone at 10 ft above the crop canopy while delivering a swath of about 30 ft wide! So, all things being equal (they teach that in economic 101) drones could be used to spray all types of agricultural pesticides. But as we know, things are seldomly equal, and mother nature throws curveballs during spray season. Our contention is that in some geographic areas drone spray is better suited to pesticides other than herbicides. For example, in areas where a single crop dominates the landscape, e.g. wheat in eastern Washington or eastern Oregon, one could venture into spraying herbicides using a drone knowing that stray product would land on a neighboring wheat field and most likely cause no harm. But in regions with multiple crops interspersed in adjacent fields, e.g. in the Treasure Valley of south eastern Oregon and southwestern Idaho, the risk of herbicide drift to non-target crops is much higher and is probably a risky operation!<\/p><\/div>\n<\/div>\n<\/div><\/div>\n

Let us take a case of herbicide drift we happened on during spring\/summer 2023. A drone was used to spray Affinity\u00ae herbicide to control weeds in a winter wheat field. All went well, except the operator did not realize at the time that fine herbicide droplets had strayed onto sugar beet plants growing in a field across the road separating the two fields (Figure 1).<\/p><\/div>\n

\n\t\t\"Damaged \n\t<\/div>\n

Figure 1. Herbicide drift into a sugar beet field (left of the road) in the Oregon Slope area near Ontario, Oregon. Note part of the target wheat field on the top right corner. Photograph by Joel Felix, Oregon State University, June 22, 2023.<\/p><\/div>\n

<\/p><\/div>\nSugar beet plants were severely injured or completely killed (Figure 2). Injury severity at the entry point depended on plant size, with smaller plants killed while relatively older plants exhibited typical ALS herbicide injury (Figure 2, top right). Plants exhibited injury characterized by leaf deformities and chlorosis as far as 800 yds deep into the field.<\/p><\/div>\n<\/div>\n<\/div><\/div>\n

\n\t\t\"Damaged \n\t<\/div>\n<\/div>\n
\n\t\t\"Damaged \n\t<\/div>\n

<\/p><\/div>\n

\n\t\t\"Damaged \n\t<\/div>\n<\/div>\n<\/div><\/div>\n

<\/p><\/div>\nFigure 2. Sugar beet plant injury from suspected Affinity\u00ae herbicide drift intended for the wheat field across the road in the Oregon Slope near Ontario, OR June 2023. Photographs by Joel Felix, Oregon State University, June 22, 2023.<\/p><\/div>\n

<\/p><\/div>\n

<\/p><\/div>\nBecause of contractual agreements for sugar beet cooperative members to satisfy their quota, the grower continued tending to the field as if nothing had happened. Largely due to sugar beet crop\u2019s ability to compensate for stand loss by growing bigger roots, a follow up photograph taken on August 11, 2023 suggested full canopy closure (Figure 3).<\/p><\/div>\n<\/div>\n<\/div><\/div>\n

\n\t\t\"Sugar \n\t<\/div>\n<\/div>\n
\n\t\t\"Sugar \n\t<\/div>\n<\/div>\n<\/div><\/div>\n

Figure 3. Suspected Affinity\u00ae herbicide drift on sugar beet in the Oregon Slope area near Ontario OR, June 22, 2023 (left photo) and the same field on August 11, 2023 (right). Photograph by Joel Felix, Oregon State University, 11-08-2023.<\/p><\/div>\n

<\/p><\/div>\nSo, what about sugar beet root yield and quality? True, the beets in figure 3 certainly look well enough to produce a crop – and for the most part they did, producing 30.4 t\/A and about 17.5% sugar content. Not what you\u2019d call a \u201ctotal crop loss\u201d by any means, but about 10 t\/A short of what the company average was for Crop Year 23. What the casual observer may not see, however, is what happened to the beets that did survive the application. Aside from the lost yield due to missing plants, the actual quality of the beets working to recover throughout the remainder of the season diminished greatly.<\/p><\/div>\n

Figure 4 shows how the beets looked at harvest. The shriveled \u201cdriftwood\u201d look of the beets is quite the contrast to the normal smooth outer layer of a \u201cnormal\u201d sugar beet. When cut open, many beets still exhibit remnants of dark rings in the vascular tissue indicating chronic damage from the herbicide.<\/p><\/div>\n<\/div>\n<\/div><\/div>\n

<\/p><\/div>\n

\n\t\t\"Shriveled \n\t<\/div>\n<\/div>\n

<\/p><\/div>\n

\n\t\t\"Sugar \n\t<\/div>\n<\/div>\n

<\/p><\/div>\n

\n\t\t\"Shriveled \n\t<\/div>\n<\/div>\n

<\/p><\/div>\n

\n\t\t\"Sugar \n\t<\/div>\n<\/div>\n<\/div><\/div>\n

Figure 4. \u201cPetrified\u201d look at harvest of beets suffering from group 2 herbicide damage. Dark rings in the vascular tissue still reside even after 5 months of healing and repair. Photos by Clarke Alder, Amalgamated Sugar, Taken 2 November, 2023<\/p><\/div>\n

<\/p><\/div>\nThough these beets may have made it through the season, some of the biggest challenges lie ahead for the cooperative. First, beets of this nature will not store long-term. At best, the cooperative has inside of 7 days to process these beets before they become unusable due to excess deterioration as the plants respire while trying to repair themselves from the damage of four months prior. Secondly, when these beets make it to the factory, they can be difficult to slice as many of them quickly become \u201crubbery\u201d instead of staying crisp after harvest. Further into the process, they can cause issues in the filtration process as they deteriorate and perform much like rotten\/discard beets producing compounds that commonly plug up filters in the factory. Small amounts of these beets must be blended with \u201cgood\u201d beets in order to keep the factory slicing at capacity. To make a long story short, there\u2019s more than meets the eye with a sugar beet crop when it comes to herbicide drift. Because the roots are what is used, the tops may not always indicate a usable quality crop.<\/p>\n

To the original point about drones and pesticide safety. Well, there\u2019s much research still to be done, but it stands to reason that instances like this would like to be avoided by all parties. That said, following the label helps to avoid many mistakes regardless of the application method. It may be that this could have just as easily happened with a ground rig with a breeze strong enough to move small droplets or while spraying during an inversion. So, in terms of the level of safety in applying herbicides with drones, we\u2019ll let you decide. But as we stated at the beginning of this post, the era is upon us \u2013 And we hope we\u2019re ready.<\/p><\/div>\n<\/div>\n<\/div><\/div>\n<\/p>\n","protected":false},"excerpt":{"rendered":"

This article shares the dangers of drone-applied pesticide drift on nearby crops.<\/p>\n","protected":false},"author":4524,"featured_media":1441,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[8],"tags":[],"_links":{"self":[{"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/posts\/1431"}],"collection":[{"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/users\/4524"}],"replies":[{"embeddable":true,"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/comments?post=1431"}],"version-history":[{"count":32,"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/posts\/1431\/revisions"}],"predecessor-version":[{"id":1500,"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/posts\/1431\/revisions\/1500"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/media\/1441"}],"wp:attachment":[{"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/media?parent=1431"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/categories?post=1431"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/smallgrains.wsu.edu\/weeders-of-the-west\/wp-json\/wp\/v2\/tags?post=1431"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}