Vegetarian, 05-08 / August 2005

Can We Rely on SOS when our Plants are in Trouble? (Snake Oil Science)
E.H. Simonne, Horticultural Sciences Department, Gainesville

Vegetables need water, mineral elements, oxygen, carbon dioxide, light and time to complete their life cycle and produce economical yields. Vegetables also need to be protected from biotic (disease, pests, nematodes, mammals) and abiotic (heat, drought, flood, wind) stresses. Hence, vegetable production requires the use of a wide range of products (also called “production inputs”) which include water, fertilizers, fungicides, insecticides, and soil fumigants. The composition of these products is well defined and they have a clear role in vegetable production, as well as a clear mode of action. In contrast, a wide array of production inputs has less defined roles and modes of action. Typically, these production inputs are “stimulators” or “growth enhancers” of some sorts (Table 1). These production inputs are affectionately referred to as “snake oils” although “biostimulant” should be used. The objectives of this paper are to (1) highlight the origins of the “snake oils”, (2) identify warning signs, (3) provide guidelines for conducting on-farm trials to test efficacy of biostimulants, and (4) provide a brief summary of biostimulant research in Florida.

The term “snake oil” was originally used to describe a type of 19th century patent medicine sold in the United States that claimed to contain snake fat, supposedly an American Native remedy for various ailments. Clark Stansley’s snake oil tested by the federal government in 1917 was found to contain mineral oil, 1% fatty oil (presumed from beef), red pepper, turpentine, and camphor. This product did not contain snake parts, but its formulation resembles that of modern-day capsaicin-based liniments. “Snake oil” became rapidly a synonym of “quack” or fraudulent medicine, and was used to describe a worthless preparation fraudulently peddled as a cure for many ills. In this historical context, labeling a product as a “snake oil” implied an intention to deceive. By extension, “snake oil” is used today to describe products that have no clear use or that can be easily replaced in areas as diverse as computer cryptography, medicine, insurance, or engine treatment products. This term has also found its way into the agricultural vocabulary. The conventional wisdom defines “snake oil” as a product that may help crop production. In this paper, the term “snake oil” is used only to describe a class of products, and does not imply any intention by any party involved to engage in a deceptive practice.

While defining biostimulant is difficult, “snake oils” share common characteristics: they seldom hurt plants, they usually don’t help, they cost money, and they always make the user feel better. When growers consider using a production input, the two most important points they consider first are price and efficacy. The old motto “you get what you pay for” often helps justify a hefty price and creates the willingness to buy almost any product. Warning signs that a product may be a “snake oil” include (1) sales language that states or implies “Trust us, we know what we are doing”, (2) the impossibility to know what is in the product under the pretext of “old proven secret recipe”, (3) the abundant use of invented terms (technobabble), obscure jargon, or trademarked terms that confuse rather than explain, (4) claims of “revolutionary breakthrough”, or (5) most important, unsubstantiated claims.

So if the warning signs are so easily recognizable, how did “snake oils” get associated with agriculture and vegetable production? Some reasons may include (1) the perennial attractiveness of what is “new” and “improved”, even at the expense of proven efficiency; (2) failure of proven practices that trigger an immediate and desperate search for alternatives; (3) decision based on emotions rather than on facts; and, (4) the fear of a customer to show ignorance by not understanding an obscure, complex lingo used to describe a product and its benefits. Clearly, the best remedy against disappointment is information and education.

Products that (1) have been tested by not-for-profit organizations such as public universities, (2) have an established mode of action, (3) are efficient over a defined range of circumstances, and (4) are reasonably priced, may not be “snake oils” and may be worth using (Trenholm, 2003). In the absence of reliable information, the best alternative to test a biostimulant’s efficacy is to try it under the conditions of its intended use: in the field, with a crop. Field trials should be well defined, large enough, representative, and fair. The purpose of a field trial should be well defined. Doing so will help develop a valid protocol that really puts the product to the test. Moreover, a clear purpose will help assess the mode of action. Trials involving few plants may no reflect field variability, thereby yielding erroneous conclusions. Trials should include areas where product are tested and a control area. Having a control helps isolate the effect of that product alone, since the only difference between the treated area and the control is the application of the product tested. Ideally, trials should replicated. Trials should be conducted in a “real” field, not in an area of the farm where growing conditions are less than optimal. Areas such as row ends, low spots, and shady areas should be avoided. Data collected should be simple, and relevant to the set objectives. Identifying before the trial begins where/how/when the trial will be conducted will help ensure the trial is valid, and the conclusions are reliable. Results of well-conducted on-farm trials will yield trustworthy information about the efficacy, but at times will not reveal the composition - and therefore the mode of action - of the product. As the conventional wisdom admits “ if yo do not know how a product works, you won’t find out why it does not work”.

Biostimulant research with vegetables has a long history in Florida (see additional resources section). Most products evaluated were foliar or soil-applied fertilizers. Their intended effect on vegetable crops is typically to promote plant growth of high-value crops such as tomato (Lycopersicon esculentum), pepper (Capsicum annuum) or strawberry (Fragaria x Annassassa). Collectively, research results can be summarized as inconsistent from year to year, better performance under stressful conditions, and generally too expensive for regular use. In contrast, soil applications of humate-based products did not increase root length of red maple (Acer rubrum L.), but they increased sap flow (Kelting et al., 1998). In a pot experiments, green bean (Phaseolus vulgaris) mean pod fresh weight responded to algal treatment (Russo and Berlyn,1992). Overall, the literature contains a few isolated reports of positive effects of biostimulants. It is unfortunate that the vast majority of research conducted on biostimulants aims at testing the efficacy of a formulation (sometimes undisclosed). The projects aim at finding out if the product works, or if it does not. In either case, few attempts are made to understand the reasons why the products worked or did not. Hence, current work on biostilmulant is somewhat like short-term product testing. An alternative approach would be to start with a formulation, optimize it, and develop an understanding of the role of each ingredient. Unfortunately, this long-term, costly approach is not commonly used. Until then, we’ll have to expect miracles from SOS.

Literature Cited and Additional Readings

Brunings, A.M., L.E. Datnoff, and E.H. Simonne. 2005. Phosphorous acid: When all P are not equal, EDIS, HS1010, http://edis.ifas.ufl.edu/HS254.

Castro, B.F., S.J. Locascio, and S.M. Olson. 1988. Tomato response to foliar nutrient and biostimulant applications. Proc. Fla. State Hort. Soc. 101:350-353.

Csizinski, A.A. 1996. Yield response of bell pepper cultivars to filiar-applied ‘Atonik’ biostimulant, EDIS HS819, http://edis.ifas.ufl.edu/HS113.

Csizinszky, A. A. 1986. Response of tomatoes to foliar biostimulant sprays. Proc. Fla. State Hort. Soc. 99:353-358.

Csizinszky, A. A. 1988. Yield response of green peppers to biostimulants. Florida Pepper Institute 1988. Univ. of Fla., IFAS, Veg. Crops Extension Report SSVEC-802.

Csizinszki, A.A. Yield response of tomato, cv. Agriset 761, to seaweed spray, micronutrient, and N and K rates. Proc. Fla. State Hort. Soc. 107:139-142.

Csizinszky, A. A. 1990. Response of two bell pepper (Capsicum annuum L.) cultivars to foliar- and soil-applied biostimulants. Soil and Crop Sci. Soc. Fla. Proc. 49:199-203.

Csizinski, A.A., C.D. Stanley, and G.A. Clark. 1991. Foliar and soil-applied biostimulant studies with microirrigated pepper and tomato. Proc. Fla. State Hort. Soc. 103:113-117.

Csizinszky, A. A. 1994. Yield response of Jupiter bell pepper to foliar biostimulant spray. Bradenton GCREC Research Report BRA-1994-4.

Csizinszky, A. A., C. D. Stanley, and G. A. Clark. 1990. Foliar and soil-applied biostimulant studies with microirrigated pepper and tomato. Proc. Fla. State Hort. Soc. 103:113-117.

Kelting, M., J.R. Harris and L. Fanelli. 1998. Humate based biostimulants affect early post transplant root growth and sap flow of balled and burlapped red maple. HortScience 33(2):342-344.

Malerbo-Souza, D.T., R.H. Nogeira-Couto, and L.A. Couto. 2004. Honey bee attractants and pollination in sweet orange, Citrus sinensis (L.) Osbeck, var. Pea-Rio. J. Venom. Anim. Toxin. 10(2):144-153.

Russo, R.O. and G.P Berlyn. 1992. Vitamin-humic-algal root biostimulant increases yield of green bean. HortScience 27(7):847.

Sanford, M.T.1992 . Beekeeping: Watermelon pollination. EDIS, RF-AA091, http://edis.ifas.ufl.edu/AA091.

Stamps, R.H. 1990. Biostimulant and high fertilizer rates do not affect leatherleaf fern frond development, yield or vase life. Proc. Fla. State Hort. Soc. 102:274-276.

Tew, J.A. and D.C. Ferree. The influence of a synthetic foraging attractant, Bee-ScentTM, on the number of honey bees visiting apple blossoms and on subsequent fruit production. Ohio State Res. Bull. 299-99, http://ohioline.osu.edu/rc299/rc299_2.html.

Trenholm, L.E. 2003. Organic lawn care. EDIS, EHS883, http://edis.ifas.ufl.edu/EP140.

Vavrina, C.S. 2001. Chemical stimulation of plant growth of vegetables in Florida, EDIS HS816, http://edis.ifas.ufl.edu/HS110.

Table 1. Claimed benefits, composition, and mode of action of selected biostimulants.^z