G07-1753 Cercospora Leaf Spot of Sugar Beet

The symptoms, factors favoring infection, prediction and control measures for Cercospora leaf spot of sugar beet is described in this 2007 NebGuide

G07-1753 Cercospora Leaf Spot of Sugar Beet

The symptoms, factors favoring infection, prediction and control measures for Cercospora leaf spot of sugar beet is described in this 2007 NebGuide

Identification of Sources of Bacterial Wilt Resistance in Common Bean (\u3ci\u3ePhaseolus vulgaris\u3c/i\u3e)

Over the last decade, bacterial wilt, caused by Curtobacterium flaccumfaciens pv. flaccumfaciens, has reemerged in the Central High Plains (Nebraska, Colorado, and Wyoming) and has been identified in almost 500 fields. Affected fields were planted with bean (Phaseolus vulgaris) from multiple market classes and seed sources, including yellow, great northern, pinto, kidney, cranberry, black, navy, pink, and small red, and incidence varied from trace levels to \u3e90%. One wiltresistant bean, ‘Emerson’, is available today but it is grown on a limited basis as a specialized cultivar for targeted markets in Europe and cannot be grown in all fields where the disease has recently been identified. Thus, we are faced with an emerging problem that must be addressed by utilizing newly developed resistant cultivars. This study was initiated to evaluate the Phaseolus National Plant Germplasm System (NPGS) bean collection for resistance to C. flaccumfaciens pv. flaccumfaciens in the ongoing effort to develop a new wilt-resistant cultivar adapted to this region. In total, 467 entries, including accessions from the NPGS, several commercial great northern and pinto cultivars, and University of Nebraska experimental lines, were screened with a highly virulent orange strain of C. flaccumfaciens pv. flaccumfaciens previously recovered from an infected great northern bean plant in Nebraska. Bacterial wilt severity ratings were 1.0 to 9.0 (0 to 90% incidence). Of the 427 accessions from the NPGS, only 1 showed resistance (0.23%), 19 showed intermediate resistances (4.45%), and the remainder were susceptible (95.34%). PI 325691 was identified as a source of bacterial wilt resistance. It was screened against six additional C. flaccumfaciens pv. flaccumfaciens strains and still produced resistant reactions. PI 325691 is a wild common bean (P. vulgaris) collected 8 miles South of Tzitzio, Michoacán, Mexico; however, it has a small seed size (5.3 g 100–1 seeds) that is commercially unacceptable. It will take several backcrosses to transfer this resistance to bacterial wilt and recover the seed size into a cultivated bean

Evaluation of Rhizoctonia zeae as a potential biological control option for fungal root diseases of sugar beet

Several common root diseases routinely damage sugar beet in Nebraska and other production areas of the Central High Plains, and it is becoming more common to find fields infested simultaneously with multiple pathogens. Owing to the shortage of available fungicides for economic management of soilborne diseases, alternative techniques such as biological control are increasingly being sought for disease management. Over the last several years, unidentified, sterile fungi have been isolated in conjunction with pathogens from infected sugar beet roots and seedlings. At least two promising isolates have been identified from in vitro assays that inhibit the radial growth of multiple sugar beet root pathogens, including Rhizoctonia solani, Fusarium oxysporum f. sp. betae, Phoma betae and Pythium aphanidermatum. Based on morphological and molecular characterisation, two isolates, ‘Hall’ and ‘R47’, were putatively identified as Rhizoctonia zeae. In vitro pathogenicity testing indicated that these isolates were not pathogens of sugar beet. Both isolates were compared with the well-established biological control fungus Laetisaria arvalis and tested as potential treatments in a field naturally infested with multiple sugar beet root diseases. Data indicated that these fungi provided some level of protection against a complex of soilborne diseases and suggest that these isolates could have a potential fit in an integrative management strategy for several sugar beet root diseases

New Outbreaks of Bacterial Wilt of Dry Bean in Nebraska Observed from Field Infections

Bacterial wilt caused by Curtobacterium flaccumfaciens pv. flaccumfaciens was one of the more problematic diseases of dry bean (Phaseolus vulgaris L.) throughout the irrigated High Plains (Colorado, Nebraska, and Wyoming) in the 1960s and early 1970s, but has not been observed since that time. However, in August of 2003, plants exhibiting wilting and irregular, interveinal necrotic foliar lesions surrounded by a bright yellow border were found in three dry bean fields (market class Great Northern) in Scotts Bluff County, Nebraska. During 2004, plants exhibiting identical symptoms were additionally found occurring in more than 40 dry bean fields in western Nebraska. Affected fields were planted with dry bean from multiple market classes and seed sources, including yellow bean, Great Northern bean, and pinto bean, and incidence varied from trace levels to 80 to 90%. Isolations were made from leaf and stem tissues and seeds collected after harvest from infected plants, and all yielded slow-growing, creamy yellow or orange, fluidal colonies on nutrient broth-yeast extract medium. The bacterium was identified as C. flaccumfaciens pv. flaccumfaciens based on cell morphology (coryneform-shaped motile rods), positive Gram stain and KOH reactions, fatty acid profiles, and BIOLOG (Hayward, CA) identifications. Great Northern (cv. Orion) plants were inoculated by bacterial suspensions (5 × 107 CFU/ml) injected into leaf axils adjacent to the first fully expanded trifoliolate and were incubated in the greenhouse under ambient conditions fluctuating between 24 and 35°C. Wilting symptoms developed 7 days after inoculation with foliar necrosis and yellowing symptoms appearing after 24 days. Identical bacterial colonies were reisolated from inoculated tissues, completing Koch\u27s postulates. Although recent reports of wilt have been made in North Dakota (2) and western Canada (1) in 1995 and 2002, respectively, they were based only on the presence of discolored seeds observed in dockage from processing plants after harvest. To our knowledge, this report represents the first widespread observations of bacterial wilt from field infections in Nebraska in more than 30 years

Development an edge-computing sensing unit for continuous measurement of canopy cover percentage of dry edible beans

Canopy cover (CC) is an important indicator for crop development. Currently, CC can be estimated indirectly by measuring leaf area index (LAI), using commercially available hand-held meters. However, it does not capture the dynamics of CC. Continuous CC monitoring is essential for dry edible beans production since it can affect crop water use, weed, and disease control. It also helps growers to closely monitor “yellowness”, or senescence of dry beans to decide proper irrigation cutoff to allow the crop to dry down for harvest. The goal of this study was to develop a device – CanopyCAM, containing software and hardware that can monitor dry bean CC continuously. CanopyCAM utilized an in-house developed image-based algorithm, edge-computing, and Internet of Things (IoT) telemetry to transmit and report CC in real-time. In the 2021 growing season, six CanopyCAMs were developed with three installed in fully irrigated dry edible beans research plots and three installed at commercial farms. CC measurements were recorded at 15 min interval from 7:00 am to 7:00 pm each day. Initially, the overall trend of CC development increased over time but there were many fluctuations in daily readings due to lighting conditions which caused some overexposed images. A simple filtering algorithm was developed to remove the “noisy images”. CanopyCAM measured CC (CCCanopyCAM) were compared with CC obtained from a Li-COR Plant Canopy Analyzer (CCLAI). The average error between CCCanopyCAM and CCLAI was 2.3%, and RMSE and R2 were 2.95% and 0.99, respectively. In addition, maximum CC (CCmax) and duration of the maximum CC (tmax_canopy) were identified at each installation location using the generalized reduced gradient (CRG) algorithm with nonlinear optimization. An improvement of correlation was found between dry bean yield and combination of CCmax and tmax_canopy (R2 = 0.77, Adjusted R2 = 0.62) as compared to yield vs. CCmax (R2 = 0.58) or yield vs. tmax_canopy (R2 = 0.45). This edge-computing, IoT enabled capability of CanopyCAM, provided accurate CC readings which could be used by growers and researchers for different purpose

EC04-183 Chickpea Production in the High Plains

Chickpea (Cicer arietinum L.) is an annual grainlegume or “pulse crop” that is used extensively for human consumption. The seed of this plant, when dried, is commonly used in soup. Its primary use in the United States is for salad bars, while in the Middle East and India it is more frequently cooked and blended with rice dishes. Major chickpea producers include India, Pakistan, Mexico, Turkey, Canada, and Australia. Chickpea makes up more than 20 percent of world pulse production, behind dry bean and pea. Currently, the United States imports more than 80 percent of its domestic chickpea needs. Since the 1980s, chickpea production has increased rapidly in the northwestern United States. Meanwhile, due to agronomic, processing, and marketing constraints, production in the High Plains has been sporadic and often short-lived. During the past few years, the development of new varieties and the potential for chickpea production under dryland and limited irrigation conditions has generated renewed interest among High Plains producers. With this in mind, the purpose of this publication is to provide information to enhance the potential for successful chickpea production

EC04-183 Chickpea Production in the High Plains

Chickpea (Cicer arietinum L.) is an annual grainlegume or “pulse crop” that is used extensively for human consumption. The seed of this plant, when dried, is commonly used in soup. Its primary use in the United States is for salad bars, while in the Middle East and India it is more frequently cooked and blended with rice dishes. Major chickpea producers include India, Pakistan, Mexico, Turkey, Canada, and Australia. Chickpea makes up more than 20 percent of world pulse production, behind dry bean and pea. Currently, the United States imports more than 80 percent of its domestic chickpea needs. Since the 1980s, chickpea production has increased rapidly in the northwestern United States. Meanwhile, due to agronomic, processing, and marketing constraints, production in the High Plains has been sporadic and often short-lived. During the past few years, the development of new varieties and the potential for chickpea production under dryland and limited irrigation conditions has generated renewed interest among High Plains producers. With this in mind, the purpose of this publication is to provide information to enhance the potential for successful chickpea production