Within-field Pathogenic Diversity of Phytophthora sojae in Commercial Soybean Fields in Iowa

2009 ◽  
Vol 10 (1) ◽  
pp. 8 ◽  
Author(s):  
Alison E. Robertson ◽  
Silvia R. Cianzio ◽  
Sarah M. Cerra ◽  
Richard O. Pope
Keyword(s):  
The United States ◽  
Phytophthora Sojae ◽  
Soil Samples ◽  
Soybean Plant ◽  
North Central Region ◽  
North Central ◽  
The North ◽  
History Of ◽  
The Many ◽  
Pathogenic Diversity

Phytophthora root and stem rot (PRR), caused by the oomycete Phytophthora sojae, is an economically important soybean disease in the north central region of the United States, including Iowa. Previous surveys of the pathogenic diversity of P. sojae in Iowa did not investigate whether multiple pathotypes of the pathogen existed in individual fields. Considering the many pathotypes of P. sojae that have been reported in Iowa, we hypothesized multiple pathotypes could exist within single fields. In the research reported herein, several soil samples were collected systematically from each of two commercial fields with a history of PRR in Iowa, and each soil sample was baited separately for isolates of P. sojae. Numerous pathotypes of P. sojae were detected from both fields. As many as four pathotypes were detected in some soil samples (each consisting of six to eight soil cores), which suggests that a single soybean plant could be subjected to infection by more than one pathotype. This possibility presents important implications in breeding resistant cultivars and in the management of PRR. Accepted for publication 14 July 2009. Published 8 September 2009.

scholarly journals Characteristics of Xanthomonas cucurbitae Isolates from Pumpkins and Survival of the Bacterium in Pumpkin Seeds

Plant Disease ◽  
2018 ◽  
Vol 102 (9) ◽  
pp. 1779-1784 ◽  
Author(s):  
X. Zhang ◽  
M. Babadoost
Keyword(s):  
The United States ◽  
Culture Collection ◽  
Colony Development ◽  
North Central Region ◽  
North Central ◽  
The North ◽  
Significant Difference ◽  
Optimum Ph ◽  
Pumpkin Seeds ◽  
Maximum Temperatures

This study was conducted to determine characteristics of Xanthomonas cucurbitae, the causal agent of bacterial spot of pumpkin, and survival of the bacterium in pumpkin seeds. Fourteen X. cucurbitae isolates from the north central region of the United States, along with the X. cucurbitae strain 23378 from the American Type Culture Collection, were included in this study. The range of minimum, optimum, and maximum temperatures for colony development of X. cucurbitae were 4 to 6°C, 24 to 30°C, and 34 to 36°C, respectively. Optimum pH for colony development ranged from 6.5 to 8.0. Leaves of 3-week-old pumpkins ‘Howden’ and ‘Dickinson’ were inoculated with X. cucurbitae isolates (108 CFU/ml). There was a significant difference in the postinoculation periods for appearance of bacterial lesions on the leaves among the isolates; however, there was no significant difference in diameters of the lesions on each of the pumpkin cultivar 7 days after inoculation. Four of the isolates caused significantly larger lesions on ‘Dickinson’ leaves than ‘Howden’ leaves. Naturally infected ‘Howden’ pumpkin and inoculated ‘Dickinson’ pumpkin seeds with X. cucurbitae were stored at 4 and 22°C. X. cucurbitae was isolated from both naturally infected and inoculated seeds 24 months after storage at both 4 and 22°C, and the isolated bacteria were pathogenic.

scholarly journals Community Composition, Abundance, and Phenology of Stink Bugs (Hemiptera: Pentatomidae) in Soybean in the North Central Region of the United States

2019 ◽  
Vol 112 (4) ◽  
pp. 1722-1731 ◽  
Author(s):  
Daniela T Pezzini ◽  
Christina D DiFonzo ◽  
Deborah L Finke ◽  
Thomas E Hunt ◽  
Janet J Knodel ◽  
...  
Keyword(s):  
United States ◽  
Central Region ◽  
The United States ◽  
Growth Stages ◽  
Stink Bug ◽  
North Central Region ◽  
Stink Bugs ◽  
North Central ◽  
The North

Abstract Stink bugs (Hemiptera: Pentatomidae) are an increasing threat to soybean (Fabales: Fabaceae) production in the North Central Region of the United States, which accounts for 80% of the country’s total soybean production. Characterization of the stink bug community is essential for development of management programs for these pests. However, the composition of the stink bug community in the region is not well defined. This study aimed to address this gap with a 2-yr, 9-state survey. Specifically, we characterized the relative abundance, richness, and diversity of taxa in this community, and assessed phenological differences in abundance of herbivorous and predatory stink bugs. Overall, the stink bug community was dominated by Euschistus spp. (Hemiptera: Pentatomidae) and Chinavia hilaris (Say) (Hemiptera: Pentatomidae). Euschistus variolarius (Palisot de Beauvois) (Hemiptera: Pentatomidae), C. hilaris and Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) were more abundant in the northwestern, southeastern and eastern parts, respectively, of the North Central Region of the United States. Economically significant infestations of herbivorous species occurred in fields in southern parts of the region. Species richness differed across states, while diversity was the same across the region. Herbivorous and predatory species were more abundant during later soybean growth stages. Our results represent the first regional characterization of the stink bug community in soybean fields and will be fundamental for the development of state- and region-specific management programs for these pests in the North Central Region of the United States.

Interannual variability of crop residue potential in the north central region of the United States

2013 ◽  
Vol 49 ◽  
pp. 231-238 ◽  
Author(s):  
Rajesh Chintala ◽  
Michael C. Wimberly ◽  
Gemechis D. Djira ◽  
Mirela G. Tulbure
Keyword(s):  
United States ◽  
Interannual Variability ◽  
Central Region ◽  
Crop Residue ◽  
The United States ◽  
North Central Region ◽  
North Central ◽  
The North

scholarly journals Occurrence of Bacterial Spot on Pumpkin and Squash Fruit in the North Central Region of the United States and Bacteria Associated with the Spots

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2377-2382 ◽  
Author(s):  
Qiong Liu ◽  
Abbasali Ravanlou ◽  
Mohammad Babadoost
Keyword(s):  
United States ◽  
Central Region ◽  
The United States ◽  
Antagonistic Activity ◽  
Polymerase Chain Reaction Test ◽  
Polymorphism Analysis ◽  
North Central Region ◽  
Bacterial Spot ◽  
North Central ◽  
The North

Since 2006, a bacterial spot disease has been widely observed on pumpkin and squash fruit in the North Central region (NCR) of the United States. Surveys were conducted during 2011 to 2013 to determine the occurrence of the disease on pumpkin and winter squash in the NCR. In each state, at least five commercial pumpkin and squash fields were visited each year within 3 weeks of harvest, and 60 fruit were inspected in each field. In nine states surveyed, 217 of 245 fields had fruit with bacterial spot. The average incidence of the symptomatic fruit in all pumpkin fields surveyed was 27.1, 30.3, and 25.3% in 2011, 2012, and 2013, respectively. The average incidence of fruit with bacterial spot in all squash fields surveyed was 20.2% in 2012 and 16.9% in 2013. The incidence of symptomatic fruit was more than 90% in some fields. Xanthomonas cucurbitae and non-X. cucurbitae bacteria were isolated from all of the symptomatic fruit collected. X. cucurbitae was identified based on colony characteristics on yeast extract-dextrose-CaCO3 agar, a polymerase chain reaction test using primers RST2 and RST3, and pathogenicity on pumpkin leaves. All X. cucurbitae isolates tested were pathogenic on ‘Howden’ pumpkin. In total, 312 non-X. cucurbitae isolates were identified into 10 genera based on the restriction fragment length polymorphism analysis. None of the non-X. cucurbitae isolates was pathogenic on Howden. In vitro studies of interactions between non-X. cucurbitae and X. cucurbitae showed that Pantoea isolates had antagonistic activity against X. cucurbitae. Identified Pantoea agglomerans showed the highest antagonistic activity against X. cucurbitae.

Incidence of Alfalfa mosaic virus, Bean pod mottle virus, and Soybean mosaic virus in Nebraska Soybean Fields

2006 ◽  
Vol 7 (1) ◽  
pp. 37 ◽  
Author(s):  
Loren J. Giesler ◽  
Amy D. Ziems
Keyword(s):  
Mosaic Virus ◽  
Soybean Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
The United States ◽  
Planting Date ◽  
Mottle Virus ◽  
North Central Region ◽  
Bean Pod Mottle Virus ◽  
North Central ◽  
The North

The incidence of soybean viruses is increasing across the North Central Region of the United States as indicated by survey efforts and grower reports from several states. To determine the level of virus infection in Nebraska, we surveyed soybean fields for two consecutive years. Alfalfa mosaic virus (AMV) was detected in 52% of the fields in 2001 and in 56% of fields in 2002. The incidence of Bean pod mottle virus (BPMV) varied more, with 54% of fields testing positive in 2001 and 91% testing positive in 2002. Soybean mosaic virus (SMV) was not detected in 2001, but it was detected in 31% of fields in 2002. The widespread distribution of detected SMV in 2002 is suggestive of introduction with seed. The incidence of BPMV was significantly higher in fields planted earlier than the recommended optimum planting date in one of the two years studied. The widespread incidence of AMV and BPMV and the irregular occurrence of SMV indicate that further studies of soybean viral diseases in Nebraska are warranted. Accepted for publication 13 March 2006. Published 24 April 2006.

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