Full TGIF Record # 15210
Item 1 of 1
Publication Type:
Content Type:Abstract or Summary only
Author(s):Jones, Keith R.
Author Affiliation:Central Illinois Public Service Company, Springfield, Illinois.
Title:Low Volume Application of Picloram as a Soil Treatment on Utility Rights-of-Way.
Meeting Info.:Held: December 13-15, 1988, Minneapolis, MN.
Source:Proceedings of the North Central Weed Control Conference. Vol. 43, December 1988, p. 122.
Publishing Information:Omaha, NB: North Central Weed Control Conference
Keywords:TIC Keywords: Picloram; Roadside turf; Application methods
Abstract/Contents:"In Central and Southern Illinois on some 10,000 acres of brush infested rights-of-way, the management of brush through the use of conventional high volume foliage, LV basal, and certain soil-applied methods has proven to be less than ideal due to the geological and land-use characteristics prevalent in this part of the country. Rights-of-way are consistently fragmented into multiple land uses, e.g., pasture, corn/beans, and roads. Additionally, accessibility is complicated by ditches, fences, lanes, and gullies. For this reason, conventional application methods employing spray trucks, off-road equipment and the like have proven to be very time consuming and labor intensive in addition to environmentally unsound, i.e., foliage spray next to crops. The search for a spray method and chemical was initiated several years ago which would feature the following characteristics: 1. Less than 50 gallons-per-acre volume, preferably much lower. 2. Reduced risk from drift. 3. Reduced labor for application. 4. Greater ease for traversing obstacles such as ditches, fences, around crops, etc. 5. Effective and safe brush control with minimal non-target vegetation damage such as grass, low-growing species of the brush and the like. Picloram has turned out to be the product best suited to fitting the above criteria for us. Having seen a tendency for applicator error in years past with TORDON 10k pellets, we were concerned with movement in soil and root uptake by non-target trees. We made demonstration applications initially beginning in 1982, gradually introducing liquid delivery of picloram with backpack sprayers to field crews. Under more and more varied conditions, as our observation of the results increased, our confidence in the effectiveness and safety of the methods was established. For treatment of hydroaxed cut stubble, broadcast application of 2 lb a.i.a. proved very effective. The challenge became reducing the volume of carrier to a practical minimum. Applications ranged from 80 GPA down to 4 GPA maintaining the 2 lb a.i.a. herbicide rate. The high end of the volume necessitated either large equipment, a holding tank, or unacceptable time in retrieving water. The low volume was too difficult to apply evenly and uniformly, and seemed to have a tendency to hang up on surface debris, thus reducing efficacy and having a tendency to move with physical movement of chips during heavy rains. The 16 GPA and 32 GPA total volume rates have become the optimum rates for our crews reducing the disadvantages of the extremes above. The decision of 16 vs. 32 GPA is a field decision depending on the site characteristics and the availability of water in the vicinity. Standing brush is also controllable with the above methods but requires, normally, from 4-8 lbs a.i.a. To overcome the difficulty with the labelled maximum of 2 lb a.i.a., ceilings on brush densities per acre are maintained. About 1200 stems of contiguous brush can be treated assuming 36 sq.ft. root area/stem and the 2 lb a.i.a. rate. At the 16 GPA rate, this roughly equates to about 1 second of spray time per stem using the 1 GPM SOLO 425 non-powered backpack. Larger brush requires more active ingredient to achieve effective control. As the size of brush increases, we proportionally increase the amount of picloram per stem. We also proportionally reduce the allowable treated stems per acre to insure not exceeding the 2 lb a.i.a. The maximum amount of picloram per stem would equate to a maximum density of 300 stems per acre. Safety with liquid-delivered soil-applied picloram has proven to be much more reliable and stable than similar applications of picloram as TORDON 10k pellets. Stability of picloram in the soil is excellent. Based upon field observations in our service territory (characterized by soils of high clay and organic matter) relative to root uptake, even vertical movement is limited. Picloram can be safely applied at the 2 lb a.i.a. rate right up to the edge of mature Illinois forest. The slides shown accompanying this report illustrate the results of picloram application under various conditions, including safe application next to mature trees. Grass bleaching is possible with the higher concentrations of picloram. As a result, the methods of application have been modified from a 'snake' band to a large droplet arc delivered at a 45 degree angle to the vertical making a loose droplet pattern over the rootzone of target brush. This change in method has substantially reduced the suppression of grass at the higher delivery rates. Application equipment is a non-powered SOLO 425 backpack sprayer with a Spray Systems .0020 straight-stream non-adjustable nozzle which delivers 1 GPM at about 20psi. There is a tendency to see some resprouting of Shingle Oak and White Ash with rootzone application of picloram. We are beginning to look at the addition of small amounts of tebuthiuron, bromacil, or imazapyr to improve activity without undue suppression of grasses. Finally, the use of a 2-cycle motorized centrificial pump backpack appears to show promise. Rates of application are more consistent and the fatigue factor is reduced. In the end, this reduces application costs. SOLO recently introduced a Model 415 2-cycle powered backpack and MARUYAMA has a model designated as MS 045 which we will be testing in the near future. ARMITZU also has a similar unit. All of these units are capable of delivering much more than the 1.5 GPM at 20-40 psi which is the range applicable to our delivery methods described above."
Note:This item is an abstract only!
ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Jones, K. R. 1988. Low Volume Application of Picloram as a Soil Treatment on Utility Rights-of-Way.. Proc. North Cent. Weed Sci. Soc. 43:p. 122.
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