The basal bark method (Figure 9) is primarily used during the dormant season to apply a mixture of the herbicide in a diesel fuel or kerosene carrier to the lowest 18 to 24 inches of stems and crown of plants. This carrier also acts as a penetrant to help move the herbicide into the cambium. Most low pressure hand sprayers are suitable for basal treatments when fitted with a single-nozzle spray wand. Where possible, treat rose bushes from more than one side. Adding a wand extension is helpful when working near thorny multiflora rose plants. Use of an adjustable cone nozzle is recommended.
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| Figure 9 |
Basal bark treatments use lighter, less costly, and more portable spray equipment than required for foliar applications. This equipment is well adapted for use on steeper terrain where multiflora rose frequently occurs. If a light covering of snow is present, footprints can assist in identifying treated plants. Follow individual herbicide labels; applications are generally permitted when ground is frozen, provided there is not excessive snow or surface water or ice to prevent proper application to plant stems and crown. Do not apply in a manner that will directly contaminate water courses. The basal bark method, compared with foliar, requires less spray volume, which is targeted only to the lower portion of bushes. This procedure reduces the potential for off-site herbicide movement. Also, sensitive crops are not present in adjacent areas in the wintertime.
Table 3 shows information concerning formulations and mean effectiveness ratings for four herbicides labeled for dormant basal bark applications. Banvel and Crossbow are labeled for use in pastures. This table lists the amount of product to mix with approximately one gallon of #2 Diesel or Kerosene carrier. Banvel also can be formulated at lower cost as an oil-in-water emulsion with water and nonionic surfactant substituted for about 85% of the petroleum carrier. See Table 4 for formulas to mix various quantities of Banvel Lo-Oil basal spray. (Banvel data in Table 3 is also from trials using the Lo-Oil mixture.)
| Table 3. Herbicides for dormant basal bark application using #2 diesel fuel or kerosene carrier | ||||||
|---|---|---|---|---|---|---|
| Product | Use rate (%) | Pasture label | Product needed for 1 gallon solution | Mean plant kill (BRR 1-4)1 | Number of trials | |
| Ounces | Milliliters | |||||
| Acme SBK | 5 | No | 6.4 | 189 | 1.4 | 12 |
| Banvel | 6.6 | Yes | 8.4 | 250 | 1.4 (Lo-Oil) | 17 |
| Brushmaster | 5 | No | 6.4 | 189 | 1.2 | 6 |
| Crossbow | 4 | Yes | 5.1 | 151 | 1.4 | 8 |
| 1. BRR (basal resprout rating) where: 1 = none, 2 = slight, 3 = moderate, and 4 = extensive basal regrowth 8 to 15 months after application. | ||||||
| Table 4. Mixing various quantities of Banvel Lo-Oil basal bark solution | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Spray solution | Banvel (4 DMA) | Surfactant1 | Kerosene or #2 Diesel | Water | |||||||
| English or metric | English or metric | English or metric | English or metric | ||||||||
| (gal) | (oz) | (pt/qt) | (ml) | (oz) | (ml) | (oz) | (qt) | (ml) | (oz) | (qt/gal) | (ml) |
| 1 | 8 | = 0.5 pt | = 237 | 0.5 | = 15 | 20 | = 0.6 | = 592 | 100 | = 3.12 qt | = 2960 |
| 2 | 16 | = 1 pt | = 474 | 1 | = 30 | 40 | = 1.2 | = 1183 | 200 | = 6.25 qt | = 5920 |
| 5 | 40 | = 1.2 qt | = 1184 | 2.5 | = 74 | 100 | = 3.12 | = 2960 | 500 | = 3.9 gal | = 14800 |
| 10 | 80 | = 2.5 qt | = 2368 | 5 | = 148 | 200 | = 6.25 | = 5920 | 1000 | = 7.8 gal | = 29600 |
| 1. Acutrol emulsifier or nonionic surfactant. | |||||||||||
No differences in effectiveness were apparent during the December 20 to April 10 dormant season during which these experiments were conducted in southern Ohio. All four herbicides provided similar and quite effective multiflora rose control. In more than 50% of the experiments, complete plant kill occurred. All of these herbicides except Banvel contain the phenoxy herbicides 2,4-D and/or 2,4-DP. Clearly, phenoxy-containing herbicides control multiflora rose in Ohio more consistently and effectively when applied by basal bark dormant, compared with their use as foliar sprays. While overall dormant basal bark results were very acceptable, a few unexplained instances of less than acceptable plant kill were encountered with the most extensively tested products.
Important Note: It is very difficult to properly clean any hand sprayer used for basal bark applications for later applications of any pesticide to tobacco, vegetable, ornamental, or other sensitive crops.
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