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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #324840
Title: Evidence for a disease complex between Pythium aphanidermatum and root-knot nematodes in cucumber

Author
item MORRIS, KELLY - University Of Georgia
item LANGSTON, DAVID - University Of Georgia
item DUTTA, BHABESH - University Of Georgia
item Davis, Richard
item Timper, Patricia - Patty
item NOE, JAMES - University Of Georgia
item DICKSON, DONALD - University Of Florida

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2016
Publication Date: 9/8/2016
Citation: Morris, K.A., Langston, D.B., Dutta, B., Davis, R.F., Timper, P., Noe, J.P., Dickson, D.W. 2016. Evidence for a disease complex between Pythium aphanidermatum and root-knot nematodes in cucumber. Plant Health Progress. 17:200-201. doi:10.l094/PHP-BR-16-0036.

Interpretive Summary: A field trial in 2012 indicated a possible disease complex between Pythium and the southern root-knot nematode (RKN) in cucumber. Two growth chamber trials were conducted to investigate this potential disease complex. Treatments included inoculating nine-day-old cucumber seedlings with Pythium alone, RKN alone, Pythium + RKN, and an untreated control. Inoculated “cone-tainers” (5 cm x 25 cm) received 1500 RKN and/or 100 g of sand-corn meal mix containing Pythium. Once inoculated, cucumbers were placed in a growth chamber with high humidity. Plants were monitored daily for 3 weeks for symptoms of Pythium infection. In both trials of the experiment, there was a synergistic interaction between RKN and Pythium on damping-off. Plants inoculated with both pathogens had 9- to 28-fold more plant death than plants inoculated with only one pathogen. These results indicate that control of RKN may be important for managing Pythium damping-off in cucumber.

Technical Abstract: A field trial in 2012 indicated a possible disease complex between Pythium aphanidermatum and the root-knot nematode (RKN) Meloidogyne incognita in cucumber. Two growth chamber trials were conducted to investigate this potential disease complex. Treatments included inoculating nine-day-old cucumber seedlings with Pythium alone, RKN alone, Pythium + RKN, and an untreated control. Inoculated “cone-tainers” (5 cm x 25 cm) received 1500 juveniles of M. incognita and/or 100 g of sand-corn meal mix containing P. aphanidermatum. Once inoculated, cucumbers were placed in a growth chamber at 28oC, 12 h photoperiod, and 75 % relative humidity. Plants were monitored daily for 3 weeks for symptoms of Pythium infection. In both trials of the experiment, there was interaction between RKN and Pythium on damping-off (P = 0.015 for Trial 1 and P= 0.0002 for Trial 2). Plants inoculated with both pathogens had 9- to 28-fold more plant death than plants inoculated with only one pathogen. These results indicate that control of RKN may be important for managing Pythium damping-off in cucumber.