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Bronze wilt (BW) is a disorder of cotton (Gossypium hirsutum L.) that has reduced yields of susceptible cultivars, and may recur in future cultivar releases. Because BW may impair uptake or translocation of mineral nutrients, soil fertility may affect BW incidence or its impact on growth and development. A 3-year study was conducted to determine effects of N and K fertility and tillage on BW incidence and impact on growth and development of field-grown cotton. Incidence of BW was relatively low and unaffected by N or K fertility in this study with or without tillage. Neither N fertility nor tillage affected growth and development responses to BW, although high N fertility delayed appearance of secondary symptoms by an average of 3.5 days. Plant growth response to K fertility was suppressed by BW. Boll retention was reduced more than vegetative growth by BW, but this response was not mitigated by N or K fertilization. Leaves of BW plants had equivalent K concentration as normal plants, but 30% lower P, indicating that BW impaired P uptake or translocation. Results suggest that N and K fertilization are not useful methods to manage BW, but P nutrition merits further research. Accepted for publication 17 August 2008. Published 17 November 2008. |
