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Germination, Growth, Development, and Control of Camphorweed (Heterotheca subaxillaris)

Published online by Cambridge University Press:  12 June 2017

M. B. Awang
Affiliation:
Dep. of Hortic. Sci., North Carolina State Univ., Raleigh, NC 27607
T. J. Monaco
Affiliation:
Dep. of Hortic. Sci., North Carolina State Univ., Raleigh, NC 27607

Abstract

Germination studies on camphorweed [Heterotheca subaxillaris (Lam.) Britt. & Rusby] revealed that freshly harvested disk achenes germinated best at 17.5 C (88%) while ray achenes were dormant. Camphorweed seed from disk achenes also germinated at temperatures as low as 3 C. Seedlings grown under long-day conditions at 23 C day and 8 C night temperatures for 144 days elongated at the rate of 0.18 cm/day. Plants grown under short-day conditions at the same temperature regime elongated at the rate of 0.06 cm/day. Total leaf surface area, fresh weight, and dry weight of shoots of plants grown under long days were at least 1.5 times greater than plants grown under short day conditions. Camphorweed, regardless of size and age, survived a 2-h exposure at −5 C. All plants in the rosette stage survived at −15 C in the freezer and an overnight temperature of −11.7 C in the field, whereas larger plants were killed at these temperatures. Stage of growth was an important factor in the herbicidal control of camphorweed. Plants in the rosette stage were generally more susceptible to herbicides than older plants. Simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] at 3.4 kg/ha, paraquat (1,1′-dimethyl-4,4′-bypyridinium ion) at 0.6 kg/ha, methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] at 5.0 kg/ha, and a formulated mix of diuron [3–3,4-dichlorophenyl)-1,1-dimethylurea] and terbacil (3-tert-butyl-5-chloro-6-methyluracil) at 4.5 kg/ha provided adequate control of camphorweed in the rosette stage. Asulam (methyl sulfanilylcarbamate) at 2.2 or 4.5 kg/ha applied alone did not control camphorweed in the rosette form but was more effective on older plants. Various combinations of these herbicides were generally effective at both stages of growth.

Type
Research Article
Copyright
Copyright © 1978 by the Weed Science Society of America 

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References

Literature Cited

1. Aiken, J. B. 1976. Weeds in horticultural crops. Pecan. South. Weed Sci. Soc. Res. Rep. 29:129.Google Scholar
2. Arnold, C. E. 1976. Weeds in horticultural crops. Pecan. South. Weed Sci. Res. Rep. 29:133.Google Scholar
3. Ashton, F. M. and Crafts, A. S. 1973. Mode of action of herbicides. John Wiley & Sons, Inc., New York. 504 pp.Google Scholar
4. Burk, C. J. 1966. Rainfall periodicity as a major factor in the formation of flowering races of camphorweed (H. subaxillaris) . Am. J. Bot. 53:933936.Google Scholar
5. Burk, C. J. and Nah, C. H. 1966. Environmental control of a taxonomic character separating Heterothecas from chrysopsis. Rhodora 68:406408.Google Scholar
6. Catchpole, A. H. and Hibbitt, C. J. 1972. Studies on the retention, penetration and translocation of asulam in some perennial weed species. Proc. Brit. Weed Control Conf. 11:7783.Google Scholar
7. Coble, H. D. and Slife, F. W. 1970. Development and control of honeyvine milkweed. Weed Sci. 18:352356.CrossRefGoogle Scholar
8. Keever, C. 1955. Heterotheca latifolia, a new and aggressive exotic dominant in piedmont old field succession. Ecology 36:732739.CrossRefGoogle Scholar
9. Monaco, T. J. and Cumbo, E. L. 1972. Growth and development of curly dock and broadleaf dock. Weed Sci. 20:6467.Google Scholar
10. Rom, R. C. 1976. Weeds in horticultural crops. Peach. South Weed Sci. Soc. Res. Rep. 29:127.Google Scholar
11. Rom, R. C. 1976. Weeds in horticultural crops. Pear. South Weed Sci. Soc. Res. Rep. 29:132.Google Scholar
12. Skroch, W. A. 1975. Weeds in horticultural crops. Apples. South. Weed Sci. Soc. Res. Rep. 28:157.Google Scholar
13. Skroch, W. A. 1975. Weeds in horticultural crops. Peaches. South. Weed Sci. Soc. Res. Rep. 28:159.Google Scholar
14. Toole, V. K. 1963. Light control of seed germination. Proc. Assoc. Seed Anal. 53:124143.Google Scholar
15. Worsham, A. D., Soots, R. F., and Parnel, J. F. 1974. Herbicides for vegetation management in restoring dredge islands as nesting sites for coastal nesting birds. Proc. South. Weed Sci. Soc. 27:298.Google Scholar