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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCING PATHOGEN DETECTION AND CROP PROTECTION IN SUGARBEET USING MOLECULAR TECHNOLOGIES

Location: Sugarbeet and Potato Research

Title: Impact of the soybean cyst nematode on seedling diseases of sugarbeet

Authors
item Rudolph, Kurt -
item Nelson, Berlin -
item Bolton, Melvin

Submitted to: Sugarbeet Research and Extension Reports
Publication Type: Proceedings
Publication Acceptance Date: February 14, 2011
Publication Date: March 14, 2011
Citation: Rudolph, K., Nelson, B., Bolton, M.D. 2011. Impact of the soybean cyst nematode on seedling diseases of sugarbeet. 2010 Sugarbeet Research and Extension Reports. 41:236-238. Available: http://www.sbreb.org/research/plant/plant10/RudolphSCNOnSeedlingDisease2010.pdf.

Interpretive Summary: Soybean cyst nematode (SCN; Heterodera glycines) was first reported in North Dakota in 2003. SCN is now well-established in Cass and Richland Counties of North Dakota and Wilkin, Clay, Norman and Red Lake counties in Minnesota, and is likely to continue to progress northward as long as soybean production continues. When sugarbeet is planted into SCN-infested soil, the nematode may attempt to penetrate and establish itself in the sugarbeet roots. Such penetration attempts are likely to create lesions on the root surface. In addition, wounded roots may have an altered production of chemicals secreted by the root. Since wounding of the sugarbeet root is known to increase disease severity for several sugarbeet diseases, the lesions made from entry by SCN might offer convenient entry points for several sugarbeet pathogens. In our past studies, we had shown that SCN can easily penetrate sugarbeet in greenhouse studies. To assess whether this may occur in nature, we set up a microplot experiment under field conditions. Plants were inoculated and checked for the presence of SCN at one, two, and four months after inoculation. SCN was found in all time points. In another study, we wished to assess what sugarbeet growth stage is most susceptible to SCN infection. We found that plants two to four weeks of age had the most SCN larvae in the roots. Interestingly, SBCN-resistant plants had more SCN than SBCN-susceptible plants. Finally, we were interested if pre-infection by SCN increases susceptibility to Rhizoctonia solani, a serious root pathogen of sugarbeet. We found that plants that had pre-infection by SCN had twice the amount of disease as compared to plants inoculated with R. solani alone.

Technical Abstract: Soybean cyst nematode (SCN; Heterodera glycines) is now well-established in Cass and Richland Counties of North Dakota and Wilkin, Clay, Norman and Red Lake counties in Minnesota, and is likely to continue to progress northward as long as soybean production continues. When sugarbeet is planted into SCN-infested soil, the nematode may attempt to penetrate and establish itself in the sugarbeet roots. Such penetration attempts are likely to create lesions on the root surface. In addition, wounded roots may have an altered production of root exudates that attract sugarbeet pathogens. Since wounding of the sugarbeet root is known to increase disease severity for several sugarbeet diseases, the lesions made from entry by SCN might offer convenient entry points for several sugarbeet pathogens. A randomized complete block design was constructed in a microplot under field conditions. Three treatments levels of SCN (10,000 eggs/100cm3, 5,000 eggs/100cm3 and control) were split among three cultivars (ACH 17, SVDH M832224 and SVDH 46519) in a total of 5 replications. We found SCN in inoculated plants at one, two, and four months after inoculation. To determine at what age sugarbeets are most susceptible to SCN penetration, cultivars M832224 and 0957-22 (SESVanderHave) were planted every week in the greenhouse. After 7 weeks, approximately 10,000 SCN eggs were added to the soil of each pot. We found that tissue two to four weeks of age had the greatest amount of SCN in the root tissue. SBCN-resistant plants had more SCN than SBCN-susceptible plants. To determine if pre-infection by SCN increases disease severity from R. solani AG 2-2 IIIB, plants of the cultivar 0957-22 were inoculated with 10,000 SCN eggs. Plants pre-treated with SCN and then inoculated with R. solani had almost twice the necrosis than plants treated with R. solani alone.

Last Modified: 9/20/2014
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