Final Report for LS05-169
A team of researchers and farmers in Georgia and the Carolinas conducted three years of controlled experiments and on-farm trials to develop a system for organic peanut production in the Southeast, focusing on pest management. Insects could be controlled through irrigation, with thrips requiring foliar sprays of spinosad at times. Post-establishment disease could be managed via resistance and perhaps copper sprays for leaf spot. The overwhelming limitation was weed control, which depended on rapid establishment of a dense stand, itself a formidable problem. However, through careful timing and frequent cultivation with proper equipment, 3,000 lb/a organic peanuts can be produced.
1. Address specific problem areas of organic pest management in controlled, replicated trials. Specific techniques will be applied alone and in combination in multifactorial experiments the first year of study, and the best performing combinations evaluated over the two subsequent years. To efficiently assess controls for all pests, an Area of Concentration (AOC) will pertain to each of the three collaborating research locations reflecting the expertise at each location.
2. Implement and assess rational management plans for organic peanuts on farms in the region. Experience, prior information, and results from Objective 1 (after the first year) will contribute to a management plan to include organic peanut production at a number of certified organic farms throughout the Southeast. Pests will be repeatedly monitored at each site and the efficacy of control techniques re-evaluated and updated each season.
3. Develop a decision-making template as an aid to incorporating organic peanut production into particular farms. A computer- and paper-based tool which integrates extensive information on successful methods, and an algorithm to consider and compile them into a customized peanut management scheme, will be built, tested, and made available to growers and extension agents through a variety of entry points.
4. Disseminate findings to growers in the southern region, Both traditional and novel outreach strategies will be used, including a publication, an internet site for Objective 3, and a traveling exhibit targeted to large gatherings of growers.
There is a high demand for organic peanuts, but production is confined almost entirely to the Southwest, with >99% of certified acreage (48,55). Yet southeastern farmers manage 74% of the nation’s peanut acreage, and arguably have advantages from a sustainability standpoint because they do not rely upon strained or depleted water supplies, and enjoy proximity to major Eastern population centers, reducing fuel use and concomitant pollution. Yet with only one certified (and successful) organic grower in Alabama, they are missing out on the potential of organic peanuts, in terms of both market share and value in a rotation (34,41,48). The market continues to grow, with organic processors unable to obtain sufficient peanut stocks, themselves currently limited to the small-seeded Valencia market-type which can be produced in the Southwest (1,19). There are indications that large mainstream processors will add organic peanut products to their lines, mirroring the rapid growth in organic retail sales of 20%/year, and the increasing presence of organic foods among the offerings of major food companies and supermarket chains (12,19). Premiums are high for organic peanuts, with $600/ton (.30/lb) paid in New Mexico, compared with the current national average of $384/ton (.192/lb) for conventional peanuts (49,55). Peanut hay, a very desirable, high-quality forage, cannot legally be fed if it has been treated with most conventional fungicides, thus representing an unexploited market for organic producers. Market types used for direct consumption or as ingredients in candy, and those used green for boiled peanuts (a market largely limited to the South), are virtually unavailable in organic form. (It is notable that a small Georgia grower surveyed sells organic boiled peanuts to regional whole-food stores and directly to consumers for $3.33/lb) (1,19). The dearth of these otherwise dominant peanut types in organic form is a direct consequence of the absence of production in the Southeast.
Why haven’t farmers capitalized on this largely unsatisfied, lucrative market? For peanuts in the Southeast, hurdles unique to organic production are less likely to be related to fertility or water than to pest control (6,36,55). Indeed, a survey of the small number of Southeastern producers with experience in organic peanuts identifies pests—primarily weeds and to a lesser extent disease—as the limiting factor in organic production, features which are less problematic in the arid Southwest (1,19). In addition, the low adoption of organic practices generally in the Southeast, and the lack of model farm systems which include organic peanuts, may explain why conventional peanut growers have not attempted organic production (12,9,16). A quota system that severely restricted the addition of peanuts on existing farms of any type, though abolished by the 2002 farm bill, may have accounted for the historical unwillingness of organic farmers to include peanuts in their rotations (41,48). The continuing reluctance may be exacerbated by limited awareness of existing and emerging pest control strategies and methods for their integration into an holistic design (55).
The time is ripe for organic peanuts in the Southeast. Peanut acreages are shifting rapidly in the wake of the quota removal, as long-time peanut farmers abandon the crop for economic reasons (would they if there was awareness of an organic market?), and growers in new areas capitalize on regional advantages due to soil, climate, low pest background, etc. (South Carolina acreage increased 40% from 2002 to 2003) (34). The opening of new land for peanuts allows better and longer rotations, an excellent prospect for organic production. Against this dynamic background, the increasing demand in the organic sector dovetails with the arrival of new varieties and practices amenable to such a system, making the organic option not only viable but potentially highly rewarding.
The key to taking advantage of this opportunity is methodical research to integrate the available techniques, refinement of successful practices thus discovered in the context of working farms, and traditional and novel outreach activities to make growers aware of the possibilities. Farmer adoption should be encouraged realistically and where appropriate, and the transition to organic peanuts should be facilitated for those who choose the option. These are precisely the objectives of our proposed program. We will elaborate on each objective after first identifying recent advances in pest management applicable to organic peanuts in the Southeast.
In order for an organic peanut grower to be successful, an annual battle against weeds must be fought, arguably the greatest challenge to organic producers in the Southeast (19). The top problem weeds in peanut in the region include: pigweeds, perennial nutsedges, annual morning glories, Florida beggarweed, Texas panicum, southern crabgrass, and sicklepod (50,51). As conventional systems are heavily dependent on herbicides, a well-planned integrated system combining mechanical controls (cultivation and hand-weeding) and cultural controls (crop rotations, stale seedbeds, and cover crops) is crucial in an organic system. Thermal weed control and herbicides approved by the Organic Materials Review Institute (OMRI) also may assist in weed management in peanut.
Mechanical weed control is a critical component in organic crop production. Wilson et al. (53) found that fall harrowing improved control of tap-rooted weed species, while harrowing in the spring was effective on weakly rooted weeds. Stale seedbeds, in which weeds are allowed to germinate then killed with multiple shallow tillage, have been effective in organic peanuts in Georgia (19,22, 24,25). A sweep cultivator is the tool of choice for peanuts, because it does not throw soil onto the crown, which exacerbates disease.
Crop rotation can effectively control weeds, especially when rotation species are judiciously chosen (18, 23, 28, 30, 46). Hauser et al. (18) showed that with intensive weed management in a 3 year cotton-corn-peanut rotation, numbers of yellow nutsedge tubers were reduced by 97 to 99% relative to continuous peanuts. Other cultural controls for weeds include narrow rows, which are more competitive with weeds and have been effective in peanuts (4,7,9,17,52), and conservation tillage, particularly strip tillage into a cover crop. Conservation tillage has increased recently in peanuts (43), and in addition to erosion and soil quality benefits, the cover crops have been shown to suppress weed emergence (3, 31,39).
Novel weed control methods include propane flaming, which can be as effective as glyphosate on stale seedbeds (5) and has performed well on peanuts in preliminary trials at Tifton (W. C. Johnson, III, unpublished), and OMRI-approved herbicides, though cost may limit use of the latter.
The Southeast favors a number of diseases, particularly early and late leaf spot (yield reductions of 50% or more), Sclerotinia blight, Cylindrocladium black rot (CBR), stem rot, Rhizoctonia limb rot, tomato spotted wilt virus (TSWV), and root-knot nematode damage (27,34). The heaviest fungicide use occurs for leaf spot control, and for this organic farmers must rely on resistant cultivars, cultural controls, biocontrol, and OMRI-approved fungicides.
Disease resistance has been the primary tool for southeastern organic peanut growers (19,55,54), primarily with respect to leaf spot. The picture should improve with new resistant cultivars (e.g. DP-1, Georgia 01-R, Perry) and breeding lines (e.g. C 11-2-39, N96076L, N03075FT). In 2-year tests, runner C 11-2-39 showed very little yield response to chlorothalonil sprays under heavy disease pressure, and in 2003 performed successfully on an organic farm (Culbreath, unpublished). Some new Virginia-type breeding lines have high yield potential and also have field resistance to TSWV and Sclerotinia blight (Shew, unpublished).
Cultural practices are a staple in disease management. Bailey (34, p. 61) stated that “. . . a long rotation is the single most powerful disease management tool available to peanut growers,” effective for CBR, Rhizoctonia limb rot, stem rot, and nematodes (27). Conservation tillage also suppresses leaf spot epidemics, allowing 42% spray reductions in one study, and has been shown to reduce TSWV, Sclerotinia blight, and CBR (26,). Planting date can affect leaf spot occurrence (44), and small grain cover crops, mulches, and addition of cereal stubble may also reduce some diseases (32,42,15,39).
In North Carolina, strip intercropping of a susceptible peanut cultivar with corn or cotton suppressed leaf spot epidemics (13,14, Shew and Boudreau, unpublished), largely by delaying epidemic onset. This delay was achieved by avoiding commercial production areas (equivalent to a long rotation) or by applying two fungicidal sprays early in the growing season under high leaf spot pressure, and demonstrates the necessity and potential of multiple control measures in organic systems.
Finally, biological control shows promise for organic peanuts. Bacillus subtilus (e.g. Serenade®) may be effective as a seed treatment (47), and in four years of tests at Tifton, Serenade® applied with a copper fungicide has provided leaf spot suppression comparable to chlorothalonil (Culbreath, unpublished). Other OMRI-approved fungicides could utilize weather advisories to optimize performance (2).
Insect pest management:
Peanut is attacked by a complex of arthropods in the Southeast, including tobacco thrips (causing direct loss and vectoring TSWV), corn earworm, fall armyworm, granulate cutworm, velvetbean caterpillar, two-spotted spider mite, lesser cornstalk borer (LCB), wireworms, southern corn rootworm, and peanut burrower bug (34,20). Though insects have been less problematic than weeds and disease for organic production (1,19,55), it is notable that in conventional systems insecticides are used to control thrips on virtually 100% of the acreage and are routinely applied to suppress soil insects. Furthermore, insecticides may increase the need for acaricides (34,20).
Perhaps the major challenge in organic peanut insect management is thrips suppression, for which insecticides on conventional farms can afford more than 1000 lb/ac yield responses. (20). The efficacy of an integrated program of resistance, planting date, increased plant population, reduced tillage, and twin-row planting in suppressing thrips/TSWV is well documented (C3,26). However, the efficacy of organic insecticides used in combination with these cultural practices is unknown.
Canopy-feeding lepidotera are relatively exposed and therefore would be susceptible to organically acceptable alternatives (e. g. Bacillus thuringiensis). Cultural practices such as reduced tillage are also effective in suppressing lepidopterous populations in peanut (8).
Peanut can be grown successfully in the Southeast without soil insect treatments. As an example, over the past two years South Carolina produced 55,000 acres of peanut, 98% with no soil insecticide besides in-furrow thrips treatments. Very high yields, often >5,000 lb/ac, were obtained with minimal soil insect injury, primarily attributed to adequate rainfall. Increased soil moisture is known to exacerbate southern corn rootworm injury on poorly drained soils (21), but these soils can be avoided by organic producers. Drought stress greatly increases the risk of LCB injury (29), however the effect of irrigation and adequate soil moisture on other soil insect pests and canopy feeding Lepidoptera is not documented on peanut. Therefore there is a crucial need to evaluate irrigation as a means for insect suppression in peanut production systems.
Encouraging organic peanut production in the Southeast both diversifies existing organic farms, and retains or regenerates the economic competitiveness of a social foundation of the rural South, the small owner-operated family farm which has historically raised peanuts. The health of the farmers, the quality of soil and water, and the diversity of wildlife are particularly preserved with organic peanuts, because 90% of the conventional acreage is treated with some of the most toxic systemic granular insecticides (e.g. aldicarb) and relies heavily on herbicide application (34,35,36). Although some costs for organic peanut production (certification fees, labor for cultivation) are higher than those in conventional systems, considerable savings will result from eliminating pesticide application, which may represent 30% of the cost of production in high-yielding systems (33,34). Yields and prices vary, but Luke Green, Alabama organic peanut producer, routinely exceeds county average yields (41), and this is coupled with premiums of 200% or more even without adding value (55). This economic benefit may be achieved more easily with peanuts than with many specialty market niches, such as medicinal herbs, entailing fewer logistical changes. In the process, a highly nutritious food staple is produced which reinforces a regional food production system by displacing organic peanuts “imported” from New Mexico, allowing area growers to gain a share in a remunerative market for a product which, indeed, is identified with the South.
The preceding section described some of the specific contributions of the proposed project to the sustainability of agriculture in the South and wherever peanuts are grown under similar conditions. By developing and demonstrating the viability of organic peanuts in the Southeast from a very practical production standpoint, and making it straightforward for individual farmers to determine if organic peanuts are right for them and, if so, how they could be incorporated into their particular situation, the project addresses each of the three elements of sustainability: economic viability, environmental soundness, and social justice. Economic viability, because substantial price premiums and an additional, high-quality option in a rotation await exploitation as peanut acreage adjusts to the post-quota setting. Environmental soundness, because of the soil-building, low-input nature of peanuts from a fertility perspective, and recent developments, built upon by the work proposed herein, that allow elimination of chemical dependence from a pest-control perspective. Finally, the social justice issue is addressed by simply providing another means for the rural and often poor southern planters to be competitive by capitalizing on an already-familiar crop, but in a new way that should not be limited to growers on arid lands and far from eastern markets.
This work would build on past SARE projects which have established the value of particular rotations for controlling root-know nematodes in peanuts in Alabama and Florida, studied cover crops to encourage beneficial insects, and demonstrated the need for information to transition to more sustainable peanut production methods in North Carolina (11,16,33,41,38).
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Research trials were primarily conducted on plots at research stations in standard multifactorial designs, typically randomized complete blocks with 3-5 replicate plots. The following sites were used over the study period:
Coastal Plains Experiment Station, Tifton, GA
Southwest Research and Education Center, Plains, GA
Attapulgus Research Farm, Attapulgus, GA
Edisto Research and Education Center, Blackville, SC
Peanut Belt Research Station, Lewiston-Woodville, NC
Upper Coastal Plains Research Station, Rocky Mount, NC
Because of the large number of researchers involved in this project, each evaluating different techniques for different aspects of peanut pest management over a period of 3-4 seasons, details of plot sizes, planting patterns and dates, and treatments are numerous and the reader is referred to specific publications below for this information.
On-farm trials were conducted not as replicated and controlled experiments but simply were attempts, at each site, to integrate the information from the experiments to successfully grow organic peanuts under the local conditions. Six farms participated over the study period in Colquitt, Screven, and Sumter Counties in Georgia, Calhoun County in South Carolina, and Halifax County in North Carolina. However, only Relinda Walker Farm in Screven Co. and Koinonia Community in Sumter Co. participated in more than one year. Again, the practices and acreage varied from farm to farm and year to year.
Objective 1. Research station trials were generally consistent through the study for the most part. Copper sprays and to a lesser extent sulfur provided sufficient control of leaf spot in conjunction with resistance afforded by cultivars such as Georganic and GA-05E in Georgia and NC-343 in North Carolina. Organic seed treatments and their interactions with cover crops, cultivars, and seed processing, evaluated in microplot and greenhouse studies, showed promise for improving stand establishment.
Frequent mechanical cultivation appears to be the primary reliable means of weed control. A flex-tine cultivator utilized at cracking and repeatedly at 5-6 day intervals until canopy lapping, supplemented with a sweep cultivation for between-row broadleaves, appears to be ideal. In trials at Tifton, strip-tillage failed due to in-row weeds, and no-till into a clover cover suppressed weeds early in the season but required hand-weeding later. Commercial products such as Matran® and Groundforce® , flame weeding, and hydro-mulch offered little control in trials to date and can be quite costly. A rotary brush cultivator may be effective if properly adjusted.
Objective 2. Each year of the on-farm trials reminded us of the difficulty of organic peanut production, and most participating farmers gave up after one year, invariably overrun by weeds. Only in 2007 did one of our growers, Relinda Walker, produce an excellent, clean stand of peanuts that was successfully harvested and yielded 3,000 lbs/acre. Because of the absence of organic shelling facilities, Relinda packaged the peanuts herself and was able to sell them through retail and wholesale outlets in the region. However, in 2008 a late planting resulted in a dug crop ruined by frost.
Our experience indicated that the limiting factors for organic peanut production were primarily stand establishment and weed control. Weeds could only be managed through early and frequent cultivations with a tine cultivator, and this was only effective if environmental and management factors allowed planting at precisely the right time. If the ideal planting window is missed, many aspects of production may fail, including poor and uneven germination, weeds rapidly colonizing gaps and poorly-competing peanuts, and slow maturity or freezing damage at the end of the season.
Objective 3. The unanticipated difficulties in delineating a viable organic peanut production system has delayed the creation of a computer-based decision tool for growers. We were naive in proposing this aspect of the project at such an early stage. However, because the project continues through a second round of funding until 2010, we intend to complete this task despite the delay.
Objective 4. The many publications, presentations, and outreach activities associated with this project are indicated in the section below. Powerpoint presentations summarizing what we know about organic peanut production at this point, and what to think about as a farmer considering organic peanuts, are available at Hebert Green Agroecology’s website. ATTRA has produced an organic peanut production which can also be accessed through this site.
Educational & Outreach Activities
Cantonwine, E.G., A.K. Culbreath, B.B. Shew, and M.A. Boudreau. 2008. Efficacy of Organically Acceptable Fungicides for Management of Early and Late Leaf Spot of Peanut. Online. Plant Health Progress doi:10.1094/PHP-2008-0317-03-RS.
Johnson, W.C. III, B.G. Mullinix Jr., and M.A. Boudreau. 2008. Peanut response to naturally-derived herbicides used in organic crop production. Peanut Science 35:73-75.
Johnson, W.C. III and B.G. Mullinix Jr. 2008. Potential weed management systems for organic peanut production. Peanut Science 35:67-72.
Boudreau, M.A., E.G. Cantonwine, J.W. Chapin, A.K. Culbreath, W.C. Johnson III, and B.B. Shew. 2008. Organic Peanut Production Strategies for the Southeast. American Society of Agronomy Annual Meetings, Oct. 6, Houston. http://a-c-s.confex.com/crops/2008am/webprogram/Paper46017.html. (abstract)
Johnson, W.C. III, N.B. Smith, D.A. Keiser, and M.A. Boudreau. 2008. Cultivation Strategies for Weed Control in Organic Peanut Production. Proc. Amer. Peanut Res. Edu. Soc. 40:65-66. (abstract)
Keiser, D.A., N.B. Smith, W.C. Johnson, and R.S. Tubbs. 2008. Economic Feasibility Analysis of Transitioning to Organically Grown Peanuts. Proc. Amer. Peanut Res. Edu. Soc. 40:25-26. (abstract)
Ruark, S.J., and B.B. Shew. 2008. Evaluation of Biological and Other Novel Seed Treatments for Use in Organic Peanut Production. Proc. Amer. Peanut Res. Edu. Soc. 40:20-21. (abstract)
Organic Peanut Symposia were held at the annual meeting of the American Peanut Research and Education Society, July 10-13, 2007 in Birmingham, AL, and July 11-14, in Savannah, GA. The scientists, farmers, and research work funded by this grant were represented significantly in both these events. Specific abstract citations are below.
Cantonwine, E.G., Culbreath, A.K., and Boudreau, M.A. 2007. Evaluation of organically acceptable fungicides for management of leaf spots in Georgia. Proc. Amer. Peanut Res. Edu. Soc. 39:72. (abstract)
Gremillion, S.K., E.G. Cantonwine, N.B. Smith, and M.C. Lamb. 2007. Developing Enterprise Budgets for Organic Peanut Production. Proc. Amer. Peanut Res. Edu. Soc. 39:72-73. (abstract)
Johnson, W.C. III. 2007. Progress Report: Weed Management in Organic Peanut Production. Proc. Amer. Peanut Res. Edu. Soc. 38:90. (abstract)
Chapin, J.W., and J.S. Thomas. 2007. Efficacy of Organic (OMRI-Approved) Foliar Insecticides and Mulching for Thrips and Spotted Wilt Suppression on Peanut. Proc. Amer. Peanut Res. Edu. Soc. 38:91-92. (abstract)
Walker, R. 2007. Organic Peanut Production in the US: A Grower's Perspective. Proc. Amer. Peanut Res. Edu. Soc. 38:92. (abstract)
Shew. B.B., Cantonwine, E.G., Culbreath, A.K., and Boudreau, M.A. 2007. Disease control for organic peanuts. Proc. Amer. Peanut Res. Edu. Soc. 38:90. (abstract)
Ruark, S. J. 2008. Evaluation of Biological and Other Novel Seed Treatments for Organic Peanut Production. M.Sc. thesis, NC State Univ.
Boudreau, M. A. 2007. Producing Organic Peanuts in the Southeast. http://www.greenagroecology.com/presentations/organicpeanuts.shtm
Shew, B. B., Jordan, D., and Reberg-Horton, C. 2008. A New Look at Organic Peanuts. Virginia-Carolina Peanut News, Summer 2008, p. 7.
Field day on organic peanuts held at Walker Farms, July 2007.
Talk at Georgia Peanut Tour on organic production by Emily Cantonwine, 2006.
Displays on organic peanut production at Southern Sustainable Agriculture Working Group annual conference, Chattanooga, TN, Feb 2009; and Georgia Organics annual conference, Decatur, GA, Mar 2009.
The demand for organic peanuts continues to be pronounced, but again production is not occurring in the Southeast to meet that demand. Interest among farmers continues, but this is dampened by the lack of an organic shelling facility in the region, the escalating prices of competing crops in recent years, and the difficulties and risks of successful production that our study has truly brought home.
Our success in 2007 with Relinda Walker’s crop, which yielded well by any standard, gave us confidence that it is indeed possible to grow organic peanuts in the Southeast. That same year Chad Heard, a large conventional grower in Southwest Georgia, produced equivalent yields on acreage he is converting to organic. He is now formally part of our team as we enter a second round of this grant, in which we hope to repeat the success of ’07 and be clear to all interested farmers about what they need to consider and how well they’re positioned to make an attempt at this promising, if difficult, crop.
We are aware of a total of nine farmers in the region who attempted to grow peanuts organically over the period of the project, including those who were formal collaborators. Only two of these produced a successful crop, both in 2007, and not surprisingly only three of the nine attempted this risky enterprise more than one year. Low production volumes currently preclude shellers from becoming organic certified in the Southeast, so the need to market directly or ship to the Southwest for processing currently discourage growers from trying more than small areas of organic peanuts. However, we reached dozens of growers through the outreach activities cited above, and informed them of the prospects and risks associated with this enterprise. The high premiums for organic peanuts and the crop’s potential as a good rotational element keep interest high, but the success of this project and independent efforts by others to grow organic peanuts over the next few years will ultimately determine how many adopt the practice.
Areas needing additional study
Over the initial three years of SARE funding our team of scientists and farmers has made great progress in overcoming the limitations to organic peanut production in the region, yet we also have been humbled by the enormity of the task. Insects and post-emergence diseases can be managed organically with success, but initial stand establishment and weed control remain major challenges. Building on our studies so far, rigorous experiments in stand establishment and weed control at multiple sites need to be performed, and these and other practices integrated in on-farm trials in multiple states.
Probably the most productive work that we could recommend would be integration of peanuts into long-term organic systems trials at research sites such as the Center for Environmental Farming Systems in North Carolina. The work we did was a necessary first step to (1) evaluate specific techniques for isolated problems at research station trials, coupled with (2) heroic efforts by farmers which underscored the challenges of organic peanuts in the real world. Some of this type of work needs to continue, but it suffers from the limited applicability of (1) under farm conditions, and the lack of replication, good data collection, and different priorities affecting management decisions in (2). This may be possible under a different funding program in the future. Confident that good production protocols are at hand for organic peanuts, it is important to also evaluate the economics of production as well and facilitate marketing options for growers, perhaps the greatest hurdle for growers at this point in time.