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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #223965
Title: A susceptible weed host can compromise suppression of Meloidogyne incognita by resistant cotton

Author
item Davis, Richard
item Webster, Theodore

Submitted to: International Congress of Nematology
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2008
Publication Date: 7/24/2008
Citation: Davis, R.F.; Webster, T.M. 2008. A susceptible weed host can compromise suppression of Meloidogyne incognita by resistant cotton. Proceedings of the Fifth International Congress of Nematology, Brisbane, Australia, July 13-18, 2008:309-310

Interpretive Summary:

Technical Abstract: Weeds can support nematode reproduction when a non-host or resistant host crop is grown. Meloidogyne incognita, the dominant nematode pathogen of cotton in many areas in the US, reproduces well on prickly sida (Sida spinosa), which is a significant weed in some cotton-producing areas. The development and use of Meloidogyne-resistant cotton in the future seems likely, so microplot experiments were conducted in 2006 and 2007 to study the extent to which infestation of cotton fields with prickly sida would affect the nematode-suppressive effects of growing Meloidogyne-resistant cotton. A single row (76 cm) of seven cotton plants (cv. M-120 RNR) was grown per microplot. A factorial arrangement of treatments with five replications was used: prickly sida seedlings were transplanted at 0, 1, 2, or 8 plants per microplot, and M. incognita eggs were either added (2,000 eggs to each cotton and prickly sida plant) or not added. Root-galling (0 to 10 scale) on prickly sida following cotton harvest in 2007 averaged 1.7 in non-inoculated plots and 5.5 in inoculated plots. Years were pooled for a combined analysis of variance, and nematode counts (juveniles/150 cm3 soil) at cotton harvest increased with prickly sida density: mean counts in inoculated plots were 122, 299, 699, and 974 for 0, 1, 2, and 8 prickly sida, respectively. In non-inoculated plots, counts did not differ (P = 0.10) but generally increased numerically with prickly sida density: mean counts ranged from 1 for 0 prickly sida to 147 for 8 prickly sida. Prickly sida, and any other equally susceptible weed, will greatly reduce the nematode-suppressive effect of growing nematode-resistant cotton, so weed control must be a component of nematode management.