G07-1678 The Relationship of Dry Bean and Sugar Beet Pathogens with Common Weeds in Nebraska Production Fields

Certain weeds in the Nebraska Panhandle can serve as hosts for pathogens that cause disease in dry edible beans and sugar beets. Properly managing weed populations and rotating with nonhost crops can help control the spread of disease. This 2007 NebGuide discusses the symptoms, results and control of these pathogens

G07-1678 The Relationship of Dry Bean and Sugar Beet Pathogens with Common Weeds in Nebraska Production Fields

Certain weeds in the Nebraska Panhandle can serve as hosts for pathogens that cause disease in dry edible beans and sugar beets. Properly managing weed populations and rotating with nonhost crops can help control the spread of disease. This 2007 NebGuide discusses the symptoms, results and control of these pathogens

NF00-426 Rhizopus Head Rot of Sunflower

This NebFact discusses the increase in sunflower production and the potential for diseases

Evaluating chickpea lines for disease resistance in western Nebraska

Chickpeas (Cicer arietinum) are a newly emerging alternative crop for western Nebraska. Interest in this crop is increasing with approximately 4,000 hectares cropped per year over the last 5 seasons. Several disease problems have been identified that will limit optimal production success if left unchecked. These diseases include Ascochyta blight, caused by A. rabiei, and a root disease complex consisting of Rhizoctonia solani, Fusarium spp., and Pythium spp. Thus trials were conducted at multiple locations (2003–2004) throughout the Nebraska Panhandle for testing chickpea lines and cultivars for yield potential and tolerance to both types of diseases under both dryland and irrigated conditions. Differences were observed between entries and their yield response to the different irrigation systems. In general, those entries with better root disease tolerance tended to yield better from irrigated production, while those more susceptible to disease performed better under dryland conditions. Identification of better sources of resistance is encouraging for the new chickpea industry in Nebraska and this process will continue as interest and production expands

Dry Edible Bean Disease Diagnostic Series

Root Diseases Fusarium root rot...................................PP1820-1 Pythium diseases..................................PP1820-2 Rhizoctonia root rot...............................PP1820-3 Soybean cyst nematode (SCN).............PP1820-4 Soybean cyst nematode sampling.........PP1820-5 Stem and Wilt Diseases Bacterial wilt..........................................PP1820-6 Fusarium yellows (wilt)..........................PP1820-7 Stem rot.................................................PP1820-8 White mold.............................................PP1820-9 Foliar Diseases Anthracnose........................................PP1820-10 Bacterial brown spot............................PP1820-11 Bean common mosaic virus................PP1820-12 Common bean rust..............................PP1820-13 Common bacterial blight .....................PP1820-14 Halo blight............................................PP1820-1

Bacterial Wilt of Dry Beans in Western Nebraska

Bacterial wilt of dry beans has reappeared in Nebraska dry bean fields. This NebGuide addresses symptoms and identification, life cycle, and management of bacterial wilt in dry beans. Bacterial wilt of dry beans, caused by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), has been a sporadic — but often serious — production problem in dry beans throughout the irrigated High Plains since first being reported in South Dakota in 1922. It was first observed in western Nebraskadry bean production fields in the earlymid 1950s, and continued to be an endemic, economically important problem throughout the 1960s and early 1970s. The disease then only periodically appeared in seed, but had little detectable effect on yields after the implementation of crop rotation and seed sanitation practices The pathogen was again identified in 2003 for the first time in this area in almost 25 years. Over the last seven to eight years, it has fully re-emerged in the Central High Plains (Nebraska, Colorado, and Wyoming) and has now been identified from more than 400 fields. Affected fields were planted with dry beans from multiple market classes and seed sources, including yellows, great northern, pintos, kidneys, cranberries, blacks, navies, pinks, and small reds. Disease incidence in these fields has varied from trace levels to \u3e90 percent

Identification of \u3ci\u3eErwinia rhapontici\u3c/i\u3e as the Causal Agent of Crown and Shoot Rot and Pink Seed of Pea in Nebraska

Over the last five years, the production of dry yellow peas (Pisum sativum L.) has been increasing in Nebraska and other areas of the Central High Plains, according to a USDA report (Jasa 2013). Dry pea is a short-season crop with a low water requirement, making it a good rotational crop for the high plains. We have noted bacterial pathogens, potentially a disease complex, that may negatively impact the production of pea in this region, and one of the emerging pathogens is Erwinia rhapontici. This pathogen is a gram-negative bacterium that has been reported from soil, seed, and different plant tissues, causing pink seed, crown rot, shoot and stem rot, blossom rot, or soft rot on more than 20 plant hosts, including pea (Huang et al. 2003). The disease was first reported on pea in the United States from Montana in 2002 and was later found in North Dakota in 2006 (Wise et al. 2008). Erwinia rhapontici belongs to the carotovora subgroup of Erwinia. Unlike many members of the soft rot carotovora subgroup that produces pectolytic enzyme, E. rhapontici does not degrade pectate. The organism is capable of fermenting glucose, fructose, maltose, and sucrose. Also, it produces a diffusible pink pigment on sucrose-peptone agar but not on potato dextrose agar nor nutrient agar. However, it has been shown that some strains may not produce pink pigments regardless of the type of media used (Huang et al. 2003). Proferrosamine A has been identified in the pink pigment produced, it is associated with iron deficiency in plants, and was suspected by Huang et al. (2003) as partly a pathogenicity determinant and virulence factor of E. rhapontici

Abiotic Diseases of Dry Beans

The environment plays a major role in the process of infection and disease development in plants by providing the conditions necessary for pathogens to cause disease. However, adverse environmental conditions or genetic abnormalities also may be responsible for plant damage. This type of damage often is referred to as abiotic disease or stresses. Many of the symptoms of these “diseases” may be confused with true dry bean diseases, thus this publication is designed to educate those working with dry bean on how to recognize abiotic problems and avoid unnecessary disease treatments. Genetic Disorders The genetic abnormalities leading to changes in color in dry beans include chimeras, leaf spotting, yellowing. or production of albino plants or seedlings. Chimeras are among the most common genetic disorders. These aberrations, which may be inherited, result from a single site (point) cell mutation or from outcrossing during seed production. They may occur any time in the season. In leaf tissues, they cause a loss of chlorophyll, giving the leaf a white to yellow variegation (Figure 1). General chlorosis or yellowing traits (Figure 2) also may be inherited and are not likely to cause significant damage. However, the albino seedlings that may be observed early in the season, usually do not survive due to a deficiency of chlorophyll (Figure 3)

Improving Root Health and Yield of Dry Beans in the Nebraska Panhandle with a New Technique for Reducing Soil Compaction

A field study conducted during the 2001 and 2002 growing seasons investigated the integration of fungicide applications and tillage methods for reducing root health problems in dry bean (Phaseolus vulgaris) plants by alleviating soil compaction and its potential exacerbation of root disease. Several cultural practices were combined with applications of the strobilurin fungicide azoxystrobin. Soil compaction was created artificially throughout the entire plot area. Six treatments, consisting of four tillage treatments and two combinations of tillage or applications of azoxystrobin, were tested to alleviate the compaction and enhance root health. Tillage treatments included a compacted control with no additional tillage, formation of beds approximately 10 cm above soil surface, zone tillage with an implement using in-row shanks, and both zone tillage and bedding combined. Fungicide treatments utilized the combination of both zone tillage and bedding with fungicide applications, and a fungicide treatment singly. Effects of compaction on plant vigor and disease development and severity were evaluated 67 and 83 days after planting in 2001 and 2002, respectively, by a visual estimation of plot vigor and by destructively sampling and making root and hypocotyl disease ratings on dry bean plants from nonharvest rows. Soil resistance and moisture were measured in plots 80 and 104 days after planting in 2001 and 2002, respectively, to estimate degree of compaction. In both years, Fusarium root rot, caused by Fusarium solani f. sp. phaseoli, was determined to be the main root disease impacting plant health in studies. All measured variables (root disease index, plant vigor ratings, total seed yield, seed size, and soil resistance) were significantly improved by any treatment that included zone tillage prior to planting. No added advantages were observed for decreasing disease or improving root health and plant performance with the use of azoxystrobin or by planting on raised beds. This is the first study to evaluate zone tillage as a method of reducing plant stress and root disease in dry bean plants

Common Stalk Rot Diseases of Corn

Extension Circular 1898 (EC1898) Stalk rot diseases of corn are common, occurring in every field to some extent. Each year stalk rot diseases cause about 5 percent yield loss. Under some conditions, losses can exceed 10–20 percent, and in isolated areas losses have been as high as 100 percent. Stalk rot diseases reduce yield both directly and indirectly. Plants with prematurely rotted stalks produce lightweight, poorly filled ears because of the plant’s limited access to carbohydrates during grain fill. Infected stalks are converted from sturdy, solid rods to hollow tubes as the stalk pith pulls away from the outer rind, compromising stalk strength. Rotted, weakened stalks are prone to lodging, particularly if decay occurs below the ear. Stalk rot diseases tend to be more common in higher yielding hybrids that produce large, heavy ears. During times of stress, such as when foliar diseases cause substantial loss of leaf area, these large ears may cannibalize carbohydrates from the stalk and weaken it. Large, heavy ears also can predispose the stalk to lodging with the added weight supported above weakened lower stalk tissue. Lodging indirectly reduces yield through harvest complications and ear loss. Stalk rot diseases can be caused by many fungi and bacteria. Most of these pathogens occur commonly in the field and behave opportunistically by primarily infecting senescing, injured, or stressed plants. A single plant often may be infected by multiple stalk rot pathogens which cause other diseases of corn and other crops. Each pathogen is favored by particular environmental conditions