Location: Crop Protection and Management Research
Title: Induced resistance to nematodes in cotton: a novel contribution to nematode management. Authors
Submitted to: Nematropica
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2012
Publication Date: December 1, 2012
Citation: Davis, R.F., Aryal, S.K., Stevenson, K.L., Timper, P. 2012. Induced resistance to nematodes in cotton: a novel contribution to nematode management. Nematropica. 42:366. Technical Abstract: Induced resistance against plant-parasitic nematodes has not previously been shown in cotton. We tested whether co-infection of cotton by Meloidogyne incognita and Rotylenchulus reniformis affected population levels of either nematode compared to single-species infection. In split-root experiments, single plants were inoculated with 1) R. reniformis only, 2) M. incognita only, 3) both species, or 4) a non-treated control. Half of the root system of 6-week-old plants was inoculated with R. reniformis on day 0 and the other half with M. incognita on day 0 or day 14 depending on the experiment. Experiments were conducted on DP 0935 B2RF (susceptible to both nematodes) and LONREN-1 (resistant to R. reniformis). Root galling and total nematode levels (vermiform and eggs) were determined from each half of the root system 8 weeks after inoculation with challenge inoculum. When M. incognita was introduced 14 days after R. reniformis, reductions in galling (36 % on DP 0935 and 33 % on LONREN-1) and M. incognita levels (34 % on DP 0935 and 45 % on LONREN-1) occurred compared to plants inoculated only with M. incognita; differences were not seen with simultaneous inoculation. Activities of enzymes (P-peroxidase, G-peroxidase, and catalase) involved in systemic acquired resistance (SAR) were greater (P = 0.05) in leaves of M. incognita, R. reniformis, and acibenzolar-S-methyl (Actigard) treated plants than in the control. These studies documented for the first time that infection of cotton by a nematode can induce SAR against another nematode species. Preliminary studies have found that potassium silicate can reduce M. incognita levels on cotton; ongoing work will determine if this is an SAR response.