Farm Budget Implications of Dicamba Ruling

The use of dicamba herbicides for controlling weeds in cotton and soybeans has been widely debated for several years due to potential drift concerns with their use. However, dicamba has proven to be effective in controlling Palmer amaranth, which has become resistant to herbicides such as glyphosate. The ruling by the Ninth Circuit Court of Appeals in June 2020 to vacate the registrations of three herbicides—Xtendimax, Engenia, and FeXapan, which are labeled for use in XtendFlex® cotton and Xtend® soybeans—has led to concerns about the herbicide options available to control herbicide-resistant weeds. There is also a need to determine how this ruling may affect the financial outlook of farmers growing dicamba-resistant crops.

The Mississippi State University Department of Agricultural Economics has created budgets that would demonstrate the changes in revenue and expenses incurred if farmers move to different herbicide options. For all budgets, direct expenses represent variable expenses that are incurred only through crop production. Fixed expenses represent costs that are incurred even if no crops are grown, such as tractor and implement costs. Total specified expenses include all direct and fixed expenses.

Tables 1–3 are representative budgets of a farm growing soybeans using furrow irrigation in the Delta area of Mississippi. Table 1 is a budget with approved dicamba formulations. Table 2 represents an alternative budget where PPO (Protoporphyrinogen Oxidase) herbicides such as fomesafen are used for postemergence weed control instead of dicamba. The trade name for the fomesafen herbicide used in this publication is Prefix. However, Palmer amaranth is becoming resistant to several herbicides, especially glyphosate. Therefore, Table 3 examines a growing situation with no postemergence herbicide options for controlling Palmer amaranth. In this scenario, Palmer amaranth control is provided by various preemergent herbicides such as dimethenamid-P. The trade name for the dimethenamid-P herbicide used in this publication is Outlook.

Table 1, which includes approved dicamba formulations, shows lower returns than the alternative budget with no dicamba application (Table 2) by $8.54 per acre. Table 3, which covers the absence of postemergence control of Palmer amaranth, has the lowest returns of all the soybean budgets. Returns in this scenario were $29.30 per acre less than the approved dicamba formulations (Table 1), and $38.03 per acre less than the alternative budget that used fomesafen for weed control (Table 2). The budgets assume that there are no yield differences between different herbicide options since Norsworthy et al. (2008) and Barkely et al. (2016) found that Palmer amaranth can be effectively controlled by fomesafen. Sarangi and Jhala (2019) also note that the use of dimethenamid-P alongside other herbicides is effective in controlling Palmer amaranth and various other weeds in soybeans. However, if Palmer amaranth is not sufficiently controlled, or it builds resistance to fomesafen, then yield losses could occur. For all growing situations, returns above total specified expenses are negative due to the estimated prices received for each crop.

The difference in returns between the three budget situations is primarily due to herbicide costs. The herbicides used and the respective estimated costs for each situation is presented in Table 4. The lowest herbicide expenses are incurred with soybeans with no approved dicamba formulations, at a cost of $87.90 per acre. Herbicide expenses with approved dicamba formulations are slightly higher at $96.44 per acre. The herbicide Engenia was considered to be the favored herbicide used according to Extension specialists, and its higher cost compared to other herbicides is the main driver for the higher expenses incurred for this growing situation. The highest herbicide expenses are seen when there are no postemergence options for controlling Palmer amaranth. In this scenario, herbicide costs would be $121.50 per acre. These budgets are only an estimate of the costs, so costs may vary from producer to producer.

Table 5 and Table 6 are representative budgets of a farm growing cotton using furrow irrigation in the Delta area of Mississippi. Table 5 represents a growing situation with approved dicamba formulations, whereas Table 6 represents a situation in which glufosinate is used in place of dicamba. Table 5 has slightly higher returns above total specified expenses when compared to Table 6, but the difference is miniscule. Yield estimates of each table are the same since Barnett et al. (2013) and Cahoon et al. (2015) note that effective control of Palmer amaranth can be achieved by the use of glufosinate. However, both the soybean and cotton budgets are representative, so an individual farmer’s situation may vary from what is found here.

Table 7 depicts the changes in herbicides used and their respective estimated costs for each cotton budget. In contrast with soybean production, cotton production that uses dicamba had lower herbicide costs than production with no dicamba application. However, the differences in herbicide expenses are small; cotton grown using glufosinate instead of dicamba have herbicide expenses $0.66 more per acre than cotton grown with dicamba applications.

Although the registrations for certain dicamba herbicides have been vacated, options for growing cotton and soybeans are still available. The budgets presented show that changes in herbicides used have a minimal effect on the estimated returns of each crop, with some growing situations offering a higher return when compared to using approved dicamba herbicides. However, if herbicide resistance in Palmer amaranth continues to increase, then herbicide costs will increase significantly, and returns will be severely impacted. Yield losses in this scenario would compound this issue leading to a further decrease in returns.

¹Full season, RR2X, stale seedbed, 12R 30”, furrow irrigated 9 acre inches.

¹Full season, RR2X, stale seedbed, 12R 30”, furrow irrigated 9 acre inches.

¹Full season, RR2X, stale seedbed, 12R 30”, furrow irrigated 9 acre inches.

¹12R-38” solid, conservation tillage, furrow irrigation for B3XF/W3FE variety at 10.5 acre inches.

¹12R-38” solid, conservation tillage, furrow irrigation for B3XF/W3FE variety at 10.5 acre inches.

References

Barkley, S. L., Chaudhari, S., Jennings, K. M., Schultheis, J. R., Meyers, S. L., and Monks, D. W. (2016). Fomesafen programs for Palmer amaranth (Amaranthus palmeri) control in sweetpotato. Weed Technology, 506-515.

Barnett, K. A., Culpepper, A. S., York, A. C., and Steckel, L. E. (2013). Palmer amaranth (Amaranthus palmeri) control by glufosinate plus fluometuron applied postemergence to WideStrike® cotton. Weed Technology, 27(2), 291-297.

Cahoon, C. W., York, A. C., Jordan, D. L., Everman, W. J., Seagroves, R. W., Culpepper, A. S., and Eure, P. M. (2015). Palmer amaranth (Amaranthus palmeri) management in dicamba-resistant cotton. Weed Technology, 29(4), 758-770.

Norsworthy, J. K., Griffith, G. M., Scott, R. C., Smith, K. L., and Oliver, L. R. (2008). Confirmation and control of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in Arkansas. Weed Technology, 22(1), 108-113.

Sarangi, D., and Jhala, A. J. (2019). Palmer amaranth (Amaranthus palmeri) and velvetleaf (Abutilon theophrasti) control in no-tillage conventional (non–genetically engineered) soybean using overlapping residual herbicide programs. Weed Technology, 33(1), 95-105.

Publication 3507 (POD-8-20)

By Brian Mills, PhD, Assistant Professor, Delta Research and Extension Center; Evan Gregory, Extension Associate I, Agricultural Economics; Trent Irby, PhD, Associate Extension Professor, Plant and Soil Sciences; and Jason Bond, PhD, Extension/Research Professor, Delta Research and Extension Center.

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Produced by Agricultural Communications.

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Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. GARY B. JACKSON, Director