Petroleum-derived spray oils, commonly referred to as horticultural spray oils, have been used to control insect and fungal pests in horticultural crops since the 1800s (Agnello, 2002). There has been renewed interest in PDSO because these products, when properly refined, have minimal human toxicity and environmental impact (Ebbon, 2002). Although there is debate as to how PDSOs affect plant pests, they can be lethal to plant pests and have the potential to stimulate innate plant defenses (Cortes-Barco et al., 2010a; Northover and Timmer, 2002; Traverner, 2002).
Civitas™ (Suncor Energy, Mississauga, Ontario, Canada) is a novel PDSO that contains a mixture of food-grade isoparaffins (alkanes) ranging in size from 16 to 33 carbons in length and an emulsifier (Hsiang et al., 2013). It is currently produced and marketed by Petro-Canada for disease and insect control in golf turf management. Civitas represents a novel approach to turf pest management because it primes plant defense yet has no fungicidal and limited fungistatic properties (Cortes-Barco et al., 2010a). Specifically, Cortes-Barco et al. (2010a, 2010b) demonstrated that Civitas primed or activated genes involved in induced systemic resistance, including genes involved in the jasmonic acid pathway when applied to both Nicotiana bethamiana and creeping bentgrass (Agrostis stolonifera L.). Consequently, several studies have shown reduced pesticide requirements when using Civitas in a disease management program (Aynardi et al., 2011; Aynardi and Uddin, 2013a, 2013b; McCall and Focht, 2010; Popko et al., 2010; Popko and Jung, 2013).
Acute and chronic phytotoxicity is a known limitation of PDSOs (Hodgkinson et al., 2002). Acute phytotoxicity results from direct damage to plant tissue including leaf lesions, fruit sunburn, and cell membrane disruption (Hodgkinson et al., 2002). Chronic phytotoxicity arises from inhibition of stomatal conductance (gS) causing reductions in transpiration, photosynthesis, and respiration and an increase in photorespiration, photo-oxidation, and oxidative stress (Hodgkinson et al., 2002). For example, a paraffinic PDSO was shown to reduce gS in grapes and altered carbon partitioning (Finger et al., 2002). Similar results have been demonstrated in other horticultural crops (Rethwisch et al., 1992).
Most modern PDSOs are highly paraffinic and are considered safe when mixed with water at concentrations less than 2% by weight (Beattie, 1990). Currently, Civitas is applied at 2.5% to 5% concentrations and can result in turf chlorosis within hours of application. To mask the chlorosis, Civitas is applied with Harmonizer™ (Suncor Energy), which is a green phthalocyanine pigment (Nash, 2011). This type of pigment has been shown to mask injury and mitigate ultraviolet stress (Ervin et al., 2004). The original commercial formulation, Two-Pack, consisted of the Civitas and Harmonizer packaged separately to be mixed on-site. A new pre-mixed single-product formulation, Civitas One™, was introduced in 2013.
The objectives of this project were to characterize the phytotoxic response of a mixed cool-season golf putting surface treated with Civitas, Harmonizer, or their combination in the field and determine how phytotoxicity is elicited in a growth chamber. Our hypothesis was that Civitas causes chronic phytotoxicity as a result of oil persistence and reduced gS.
Agnello, A.M. 2002 Petroleum derived spray oils: Chemistry, history, refining and formulation. p. 2–18. In: Beattie, G.A.C., D.M. Watson, M.L. Stevens, D.J. Rae, and R.N. Spooner-Hart (eds.). Spray oils beyond 2000. University of Western Sydney, Sydney, New South Wales, Australia
Aynardi, B., Rahman, A., Li, Y. & Uddin, W. 2011 Evaluation of fungicides for dollar spot control on a creeping bentgrass fairway, 2010 PDMR: Plant Dis. Mgt. Rpt. 5 15
Aynardi, B. & Uddin, W. 2013b Control of Pythium foliar blight in perennial ryegrass using fungicides, 2012 PDMR: Plant Dis. Mgt. Rpt. 7 T022
Barthlott, W., Neinhuis, C., Cutler, D., Ditsch, F., Meusel, I. & Wilhelmi, H. 1998 Classification and terminology of plant epicuticular waxes J. Linnean Soc. 126 237 260
Beattie, G.A.C. 1990 Citrus petroleum spray oils. Agfact H2.AE.5. NSW Agriculture and Fisheries, Sydney, Australia
Bethea, F.G. 2012 Drought induced morphological and compositional changes in creeping bentgrass (Agrostis stolonifera var. L. palustris) cuticule as it influences foliar nitrogen absorption. MS thesis, Clemson University, Clemson, SC
Bristow, C. III, McElroy, J.S. & Guertal, E.A. 2013 Response of annual bluegrass to zinc in bermudagrass turf. Proc. Crop Sci. Soc. Int. Ann. Meet. Tampa, FL
Cockerham, S.T. & Brinkman, D.J. 1989 A simulator for cleated-shoe sports traffic on turfgrass research plots Calif. Turfgrass Cult. 39 9 10
Cortes-Barco, A.M., Goodwin, P.H. & Hsiang, T. 2010a Comparison of induced resistance activated by benzothiodiazole, (2R, 3R)-butanediol and an isoparaffin mixture against anthracnose of Nicotiana benthamiana Plant Pathol. 59 643 653
Cortes-Barco, A.M., Goodwin, P.H. & Hsiang, T. 2010b Induced systemic resistance against three foliar diseases of Agrostis stolonifera by (2R, 3R)-butanediol or an isoparrafin mixture Ann. Appl. Biol. 157 179 189
Ebbon, G.P. 2002 Environmental and health aspects of agricultural spray oils, p. 323–248. In: Beattie, G.A.C., D.M. Watson, M.L. Stevens, D.J. Rae, and R.N. Spooner-Hart (eds.). Spray oils beyond 2000. University of Western Sydney, Sydney, New South Wales, Australia
Ervin, E.H., Zhang, X. & Fike, J.H. 2004 Ultraviolet-B radiation damage on kentucky bluegrass. I. Antioxidant and colorant effects HortScience 39 1465 1470
Fernandez, V. & Eichert, T. 2009 Uptake of hydrophilic solutes through plant leaves: Current state of knowledge and perspectives of foliar fertilization Crit. Rev. Plant Sci. 28 36 68
Finger, S.A., Wolf, T.K. & Baudoin, A.B. 2002 Effects of horticultural oils on the photosynthesis, fruit maturity, and crop yield of winegrapes Amer. J. Enol. Viticult. 53 116 124
Hay, R.K.M. & Porter, J.R. 2006 The physiology of crop yield. 2nd Ed. Blackwell Publishing Ltd., Oxford, UK
Hodgkinson, M.C., Johnson, D. & Smith, G. 2002 Causes of phytotoxicity induced by petroleum-derived spray oil, p. 170–178. In: Beattie, G.A.C., D.M. Watson, M.L. Stevens, D.J. Rae, and R.N. Spooner-Hart (eds.). Spray oils beyond 2000. University of Western Sydney, Sydney, New South Wales, Australia
Hsiang, T., Goodwin, P.H., Cortes-Barco, A.M., Nash, B.T. & Tung, J. 2013 Activating disease resistance in turfgrasses against fungal pathogens: Civitas and Harmonizer, p. 331–341. In: Imai, R., M. Yoshida, and N. Matsumoto (eds.). Plant and microbe adaptations to cold in a changing world. Springer Science Business Media, New York, NY
Jeffree, C.E. 2006 The fine structure of the plant cuticle, p. 11–110. In: Riederer, M. and C. Muller (eds.). Biology of the plant cuticle. Blackwell Publishing Ltd. Annu. Plant Rev. 23
Jenks, M.A., Andersen, L., Teusink, R.S. & Williams, M.H. 2001 Leaf cuticular waxes of potted rose cultivars as affected by plant development, drought, and paclobutrazol treatments Physiol. Plant. 112 62 70
Jetter, R. & Reiderer, M. 1994 Epicuticular crystals on nonacosan-10-ol: in-vitro reconstitution and factors influencing crystal habits Planta 195 257 270
Kim, K.S., Park, S.H., Kim, D.K. & Jenks, M.A. 2007a Influence of water deficit on cuticular waxes of soybean [Glycine max (L.) MERR.] Intl. J. Plant Sci. 168 307 316
Kim, K.S., Park, S.H. & Jenks, M.A. 2007b Changes in leaf cuticular waxes of sesame (Sesamum indicum L.) plants exposed to water deficit J. Plant Physiol. 164 1134 1143
Koch, K., Hartmann, K.D., Schreiber, L., Barthlott, W. & Neinhuis, C. 2006 Influences of air humidity during the cultivation of plants on wax chemical composition, morphology and leaf surface wettability Environ. Expt. Bot. 56 1 9
Kosma, D.K., Bourdenx, B., Bernard, A., Parsons, E.P., Lu, S., Joubes, J. & Jenks, M.A. 2009 The impact of water deficiency on leaf cuticle lipids of Arabidopsis Plant Physiol. 151 1918 1929
McCall, D.S. & Focht, J.T. 2010 Evaluation of Civitas for control of gray leaf spot in Virginia, 2009 PDMR: Plant Dis. Mgt. Rpt. 4 15
McCarty, L.B., Gann, J.R., Wells, C.E., Bruce, T.F. & Gerard, P.D. 2013 Physiological responses of creeping bentgrass to pigment-containing products Agron. J. 105 1797 1802
Nash, B.T. 2011 Activation of disease resistance and defense gene expression in Agrostis stolonifera and Nicotiana benthamiana by a copper-containing pigment and a benzothiadiazole. MSc thesis, University of Guelph, Guelph, Ontario, Canada
Northover, J. & Timmer, L.W. 2002 Control of plant diseases with petroleum- and plant-derived oils, p. 512–526. In: Beattie, G.A.C., D.M. Watson, M.L. Stevens, D.J. Rae, and R.N. Spooner-Hart (eds.). Spray oils beyond 2000. University of Western Sydney, Sydney, New South Wales, Australia
Popko, J. & Jung, G. 2013 Curative dollar spot control on a creeping bentgrass and annual bluegrass putting green, 2012 PDMR: Plant Dis. Mgt. Rpt. 7 15
Popko, J., Ok, C.-H. & Jung, G. 2010 Evaluation of fungicides for dollar spot control on creeping bentgrass and annual bluegrass putting green [in Korean, with English abstract] Korean Journal of Turfgrass Science 24 161 164
Rethwisch, M.D., McGrady, J., Main, G., Coates, W., Meadows, M., McDaniel, C., Shaw, M. & Thiessen, J. 1992 Effect of oil treatments on head lettuce photosynthesis and growth. Arizona Veg. Rpt., University of Arizona, Tucson, AZ
Skogley, C.R. & Sawyer, C.D. 1992 Field research, p. 596–598. In: D.V. Waddington, R.N. Carrow, and R.C. Sherman (eds.). Turfgrass. Agron. No. 32, Amer. Soc. Agron., Madison, WI
Traverner, P. 2002 Drowning or just waving? A perspective on the ways petroleum-derived oils kill arthropod pests of plants, p. 78–88. In: Beattie, G.A.C., D.M. Watson, M.L. Stevens, D.J. Rae, and R.N. Spooner-Hart (eds.). Spray oils beyond 2000. University of Western Sydney, Sydney, New South Wales, Australia
Yang, Z., Xu, L., Yu, J., DaCosta, M. & Huang, B. 2013 Changes in carbohydrate metabolism in two kentucky bluegrass cultivars during drought stress and recovery J. Amer. Soc. Hort. Sci. 138 24 30
Yoshimitsu, Z., Nakajima, A., Watanabe, T. & Hashimoto, K. 2002 Effects of surface structure of the hydrophobicity and sliding behavior of water droplets Langmuir 18 5818 5822