Skip to main content Accessibility help

Effect of Moisture Stress on Wild Oat (Avena fatua) Response to Diclofop

  • William C. Akey (a1) and Ian N. Morrison (a1)


The effect of moderate moisture stress on the activity of the methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} applied to wild oat (Avena fatua L.) and the influence of morphological and physiological factors on the activity of the herbicide on stressed plants were investigated in growth-room experiments. Wild oat was grown in very fine sandy loam brought to a gravimetric soil moisture content (SMC) of 20% (water potential of -0.3 bars) or 10% (-6.5 bars) prior to herbicide treatment. The activity of diclofop on wild oat was slightly, but significantly, reduced when the SMC was increased from 10 to 20% immediately after spraying. Maintaining the SMC at 10% after spraying further reduced the activity of the herbicide. Wild oat plants grown at 20% SMC had 22% greater leaf area and retained 23% more herbicide than plants grown at 10% SMC. Penetration of the methyl ester of 14C-diclofop into wild oat grown at 20 or 10% SMC did not differ significantly 12, 24, or 48 h after application. Stressed and unstressed plants did not differ significantly in the metabolism of the methyl ester of 14C-diclofop. However, growth at a low SMC prior to treatment decreased the proportion of the radiolabeled herbicide recovered in the apex, third leaf, and tillers of wild oat. This may partially account for the reduced activity of this herbicide on wild oat subjected to moisture stress.



Hide All
1. Acevedo, E., Hsiao, T. C., and Henderson, D. W. 1971. Immediate and subsequent growth responses of maize leaves to changes in water status. Plant Physiol. 48:631636.
2. Ahmadi, M. S., Haderlie, L. C., and Wicks, G. A. 1980. Effect of growth stage and water stress on barnyardgrass (Echinochloa crus-galli) control and on glyphosate absorption and translocation. Weed Sci. 28:277282.
3. Basler, E., Todd, G. W., and Meyer, R. E. 1961. Effects of moisture stress on absorption, translocation, and distribution of 2,4-dichlorophenoxyacetic acid in bean plants. Plant Physiol. 36:573576.
4. Chow, P.N.P. and Dorrell, D. G. 1979. Response of wild oat (Avena fatua), flax (Linum usitatissimum), and rapeseed (Brassica campestris and B. napus) to diclofop-methyl. Weed Sci. 27:212215.
5. Crafts, A. S. and Crisp, C. E. 1971. Phloem Transport in Plants. W. H. Freeman and Co., San Francisco. 481.
6. Davis, F. S., Merkle, M. G., and Bovey, R. W. 1968. Effect of moisture stress on the absorption and transport of herbicides in woody plants. Bot. Gaz. 129:183189.
7. Dortenzio, W. A. and Norris, R. F. 1980. The influence of soil moisture on the foliar activity of diclofop. Weed Sci. 28:534539.
8. Hibbit, C. J. 1969. Growth and spray retention of wild oat and flax in relation to herbicidal selectivity. Weed Res. 9:95107.
9. Hoerauf, R. A. and Shimabukuro, R. H. 1979. The response of resistant and susceptible plants to diclofop-methyl. Weed Res. 19:293299.
10. Jeffcoat, B. and Harries, W. N. 1975. Selectivity and mode of action of flamprop-isopropyl, isopropyl ($pM)-2-[N-(3-chloro-4-fluorophenyl)benzamido] propionate, in the control of Avena fatua in barley. Pestic. Sci. 6:283296.
11. Jeffcoat, B., Harries, W. N., and Thomas, B. W. 1977. Factors affecting the choice of flamprop-methyl, methyl ($pM)-2-[N-(3-chloro-4-fluorophenyl)benzamido] propionate, for the control of Avena species in wheat. Pestic. Sci. 8:112.
12. Kocher, H. 1981. Diclofop-methyl and its mode of action. Proc. 6th Aust. Weed Conf. 1:5154.
13. McCree, K. T. and Davis, S. D. 1974. Effect of water stress and temperature on leaf size and on size and number of epidermal cells in grain sorghum. Crop Sci. 14:751755.
14. McWhorter, C. G., Jordan, T. N., and Wills, G. D. 1980. Translocation of 14C-glyphosate in soybeans (Glycine max) and Johnsongrass (Sorghum halepense). Weed Sci. 28:113118.
15. Merkle, M. G. and Davis, F. S. 1967. Effect of moisture stress on absorption and movement of picloram and 2,4,5-T in beans. Weeds 15:1012.
16. Miller, S. D., Nalewaja, J. D., Pudelko, J., and Adamczewski, K. A. 1978. Difenzoquat for wild oat (Avena fatua) control. Weed Sci. 26:571576.
17. Morrison, I. N. and Cohen, A. S. 1980. Plant uptake, transport and metabolism (of xenobiotics). Pages 193214 in Hutzinger, O., ed. Handbook of Environmental Chemistry. Vol. II, Part A. Springer-Verlag, Heidelberg.
18. Morrison, I. N., Owino, M. G., and Stobbe, E. H. 1981. Effects of diclofop on growth, mitotic index, and structure of wheat (Triticum aestivum) and wild oat (Avena fatua) adventitious roots. Weed Sci. 29:426432.
19. Pallas, J. E. Jr. and Williams, G. G. 1962. Foliar absorption and translocation of P32 and 2,4-dichlorophenoxyacetic acid as affected by soil moisture tension. Bot. Gaz. 123:175180.
20. Robertson, M. M. and Kirkwood, R. C. 1970. The mode of action of foliage-applied translocated herbicides with particular reference to the phenoxyacid compounds. II. The mechanism and factors influencing translocation, metabolism and biochemical inhibition. Weed Res. 10:94120.
21. Sharma, M. P., McBeath, D. K., and Vanden Born, W. H. 1977. Studies on the biology of wild oat. II. Growth. Can. J. Plant Sci. 57:811817.
22. Sharma, M. P., Vanden Born, W. H., and McBeath, D. K. 1978. Spray retention, foliar penetration, translocation and selectivity of asulam in wild oat and flax. Weed Res. 18:169173.
23. Shimabukuro, R. H., Walsh, W. C., and Hoerauf, R. A. 1979. Metabolism and selectivity of diclofop-methyl in wild oat and wheat. J. Agric. Food Chem. 27:615623.
24. Schultz, M. E. and Burnside, O. C. 1980. Effect of lanolin or lanolin and starch rings on absorption and translocation of 2,4-D or glyphosate in hemp dogbane (Apocynum cannabinum). Weed Sci. 28:149151.
25. Terry, N., Waldron, J., and Ulrich, A. 1971. Effects of moisture stress on the multiplication and expansion of cells in leaves of sugar beet. Planta 97:281289.
26. Todd, B. G. and Stobbe, E. H. 1977. Selectivity of diclofop-methyl among wheat, barley, wild oat (Avena fatua) and green foxtail (Setaria viridis). Weed Sci. 25:382385.
27. Todd, B. G. and Stobbe, E. H. 1980. The basis of the antagonistic effect of 2,4-D on diclofop-methyl toxicity to wild oat (Avena fatua). Weed Sci. 28:371377.
28. West, L. D., Dawson, J. H., and Appleby, A. P. 1980. Factors influencing barnyardgrass (Echinochloa crus-galli) control with diclofop. Weed Sci. 28:366371.


Effect of Moisture Stress on Wild Oat (Avena fatua) Response to Diclofop

  • William C. Akey (a1) and Ian N. Morrison (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed