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Invert Emulsion Droplet Size and Mycoherbicidal Activity of Colletotrichum truncatum

Published online by Cambridge University Press:  12 June 2017

Grant H. Egley ,
James E. Hanks  and
C. Douglas Boyette
Grant H. Egley
Affiliation:
South. Weed Sci. Lab., Agric. Eng., Applic. Tech. Res. Unit., Stoneville, MS 38776
James E. Hanks
Affiliation:
Agric. Res. Serv., U.S. Dep. Agric., Stoneville, MS 38776
C. Douglas Boyette
Affiliation:
Agric. Res. Serv., U.S. Dep. Agric., Stoneville, MS 38776
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Abstract

When formulated and sprayed in an invert emulsion (IE), conidia of the mycoherbicide, Colletotrichum truncatum, controlled hemp sesbania in the absence of dew. To optimize hemp sesbania control, formulation droplet size influence upon the pathogen's germination and pathogenicity was investigated. Conidia germination in manually produced IE droplets decreased from 46% to 5% as droplet diameter decreased from 2700 to 900 μm. Droplet size did not affect appressoria formation. On a per conidium basis, 900-μm droplets were more pathogenic to detached hemp sesbania leaves than were 2100-μm droplets. An air-assist spray system produced droplet spectra with volume median diameters of 421 and 104 μm, respectively. The spectrum of smaller droplets covered the target better than did that of larger droplets. When applied to whole hemp sesbania plants in greenhouse trials, conidia in the smaller and larger droplet spectra gave 90 and 94% control, respectively. Sufficient conidia germinated in IE droplets of a variety of sizes to control hemp sesbania excellently.

Keywords

Hemp sesbania (Sesbania exaltata (Rydb) ex. A. W. Hill # SEBEX), Colletotrichum truncatum (Schw.) Andrus and MooreBiocontrolfungal pathogenhemp sesbaniaspray formulationair-assist sprayerSesbania exaltataSEBEX
Type
Research
Information
Weed Technology , Volume 7 , Issue 2 , June 1993 , pp. 417 - 424
Copyright
Copyright © 1993 Weed Science Society of America 

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References

Literature Cited

1. Amsellem, Z., Sharon, A., Gressel, J., and Quimby, P. C. Jr. 1990. Complete abolition of high inoculum threshold of two mycoherbicides (Alternaria cassiae and A. crassa) when applied in invert emulsion. Phytopathology 80:925–929.Google Scholar
2. Barry, J. W., Ekblad, R. B. Markin, G. P., and Trostle, G. C. 1978. Methods for sampling and assessing deposits of insecticidal sprays released over forests. USDA Tech. Bull. 1596. U.S. Gov. Printing Office, Washington, DC. 162 p.Google Scholar
3. Boyette, C. D. 1991. Host range and virulence of Colletotrichum truncatum, a potential mycoherbicide for hemp sesbania (Sesbania exaltata). Plant Dis. 75:62–64.CrossRefGoogle Scholar
4. Boyette, C. D. 1991. Control of hemp sesbania with a fungal pathogen, Colletotrichum truncatum. U.S. Patent No. 5,034,328.Google Scholar
5. Boyette, C. D., Quimby, P. C. Jr., Connick, W. E., Daigle, D. J., and Fulgham, F. E. 1990. The biocontrol efficacy of Colletotrichum truncatum (Schw.) Andrus and Moore for control of hemp sesbania [Sesbania exaltata (Raf.) Cory.] is improved with an emulsifiable invert formulation. Abstr. Weed Sci. Soc. Am. 30:50.Google Scholar
6. Bryson, C. T. 1987. Interference of hemp sesbania (Sesbania exaltata) with cotton (Gossypium hirsutum). Weed Sci. 35:314–318.CrossRefGoogle Scholar
7. Bryson, C. T., Wills, G. D., and Quimby, P. C. 1990. Low volume invert emulsions for purple nutsedge (Cyperus rotundus) control. Weed Technol. 4:907–909.Google Scholar
8. Connick, W. J. Jr., Daigle, D. J., and Quimby, P. C. Jr. 1991. An improved invert emulsion with high water retention for mycoherbicide delivery. Weed Technol. 5:442–444.CrossRefGoogle Scholar
9. Daigle, D. J., Connick, W. J. Jr., Quimby, P. C. Jr., Evans, J., Trask-Morrell, B., and Fulgham, F. E. 1990. Invert emulsions: carrier and water source for the mycoherbicide, Alternaria cassiae . Weed Technol. 4:327–331.CrossRefGoogle Scholar
10. Dickinson, S. 1971. Studies in the physiology of obligate parasitism, VIII. An analysis of fungal responses to thigmotropic stimuli Phytopathology Zeit. 70:62–70.Google Scholar
11. Greaves, M. P. and Macqueen, M. D. 1988. Progress and prospect for mycoherbicides. Aspects Appl. Biol. 17:417–424.Google Scholar
12. Hanks, J. E. and McWhorter, C. G. 1991. Variables affecting the use of positive displacement pumps to apply herbicides in ultralow volume Weed Technol. 5:111–116.Google Scholar
13. McWhorter, C. G. and Anderson, J. M. 1979. Hemp sesbania (Sesbania exaltata) competition in soybeans (Glycine max). Weed Sci. 27:58–63.Google Scholar
14. McWhorter, C. G., Fulgham, F. E., and Barrentine, W. L. 1988. An air-assist spray nozzle for applying herbicides in ultra-low-volume. Weed Sci. 36:118–121.CrossRefGoogle Scholar
15. Quimby, P. C. Jr., Fulgham, F. E., Boyette, C. D., and Connick, W. J. Jr. 1989. An invert emulsion replaces dew in biocontrol of sicklepod—a preliminary study. p. 264–270 in Hovde, D. A. and Beestman, G. B., eds. Pesticide Formulations and Application Systems, Vol. 8, ASTM-STP 980. American Society for Testing Materials., Philadelphia, PA 19103.Google Scholar
16. Staples, R. C., Laccetti, L., and Yaniv, Z. 1976. Appressorium formation and nuclear division in Colletotrichum truncatum . Arch. Microbiol. 109:75–84.Google Scholar