Potato Early Dying Research Articles

Linking the Laboratory and the Field in Potato Early Dying Detection: From Spectral Signatures to Vegetation Indices Obtained with Multispectral Cameras Coupled to Drones

Linking the Laboratory and the Field in Potato Early Dying Detection: From Spectral Signatures to Vegetation Indices Obtained with Multispectral Cameras Coupled to Drones

Potato early dying – agents, causes and symptoms

Climate changes observed for many years adversely affect the development of crops, but also create conditions for the development of individual diseases or their complexes, which so far have not found favorable conditions fot their development. One of such complexes is potato early dying (PED). The fungus Verticillium dahliae is considered to be the main culprit of this disease, but other culprits of PED include Colletotrichum coccodes (Wallr.) Hughes, Verticillium albo-atrum Reinke & Berthold and Fusarium spp. and pectynolytic bacteria Pectobacterium carotovorum subsp. carotovorum. Nematodes Paratylenchus penetrans (Cobb) Sher and Allen play an important role in stimulating the disease and increasing losses. The disease is common in potato-growing areas, causing losses of up to 50%. Due to large amount of infectious material and the possibility of long-term survival in the soil and the wide range of hosts, combating its harmfulness requires the use of all available methods.

Potato Early Dying and Yield Responses to Compost, Green Manures, Seed Meal and Chemical Treatments

Verticillium dahliae Kleb. is a soilborne fungal pathogen of many crops. In potato, it is the major causal agent of Early Dying. In Manitoba, potato fields planted with cv. Russet Burbank are infested with highly pathogenic V. dahliae isolates, which can produce up to 90 % disease severity. The objective of the study was to evaluate selected compost, green manure, and seed-meal treatments, in comparison with the soil fumigant Vapam, for their ability to reduce propagule density of V. dahliae in soil and decrease disease, and to enhance potato yield. Select green manure crops (oriental and white mustard, Canada milk vetch, sorghum-sudangrass, rye, alfalfa, oat/pea mixture), organic amendments (composted cattle manure and mustard seed-meal), and Vapam, and crop sequences that contribute to the suppression of Verticillium, or the improvement of potato yield were used in a 3-year field study initiated in 2006. Survival in soil of microsclerotia was evaluated as a measure of treatments’ success in potentially reducing Early Dying. Compost and seed-meal treatments, compared to an untreated control, reduced incidence to 30 and 40 %, respectively, but only seed-meal reduced V. dahliae propagule density. Overall, green manures over 1 or 2-years were ineffective in reducing propagule density or improving potato yield. Vapam was partially effective in reducing the propagule density only at the beginning of the potato season, but it did not reduce disease incidence compared to the control. Compost and seed-meal are promising as alternative control of V. dahliae. Only compost reduced disease and increased potato yield, which was associated with improved nutrient availability (phosphorus and sulfate) in soil.

Role of co‐infection by Pectobacterium and Verticillium dahliae in the development of early dying and aerial stem rot of Russet Burbank potato

Potato early dying (PED) is a disease complex primarily caused by the fungus Verticillium dahliae. Pectolytic bacteria in the genus Pectobacterium can also cause PED symptoms as well as aerial stem rot (ASR) of potato. Both pathogens can be present in potato production settings, but it is not entirely clear if additive or synergistic interactions occur during co‐infection of potato. The objective of this study was to determine if co‐infection by V. dahliae and Pectobacterium results in greater PED or ASR severity using a greenhouse assay and quantitative real‐time PCR to quantify pathogen levels in planta. PED symptoms caused by Pectobacterium carotovorum subsp. carotovorum isolate Ec101 or V. dahliae isolate 653 alone included wilt, chlorosis and senescence and were nearly indistinguishable. Pectobacterium wasabiae isolate PwO405 caused ASR symptoms including water‐soaked lesions and necrosis. Greater Pectobacterium levels were detected in plants inoculated with PwO405 compared to Ec101, suggesting that ASR can result in high Pectobacterium populations in potato stems. Significant additive or synergistic effects were not observed following co‐inoculation with these strains of V. dahliae and Pectobacterium. However, infection coefficients of V. dahliae and Ec101 were higher and premature senescence was greater in plants co‐inoculated with both pathogens compared to either pathogen alone in both trials, and V. dahliae levels were greater in basal stems of plants co‐inoculated with either Pectobacterium isolate. Overall, these results indicate that although co‐infection by Pectobacterium and V. dahliae does not always result in significant additive or synergistic interactions in potato, co‐infection can increase PED severity.

A knowledge-based prediction model of Verticillium wilt on potato and its use for rational crop rotation

Verticillium dahliae is the major causal agent of potato early dying (PED) syndrome, characterized by stunting, chlorosis and wilting, premature senescence and early plant dying. It is a common practice to reduce the risk of Verticillium wilt (VW) by applying a rational crop rotation. A knowledge based prediction model for VW was developed and validated. It was based on experimental data and practical management experience, and utilized a knowledge-based approach to acquire the expert knowledge. The potential contribution of this approach was demonstrated in the process of knowledge acquisition and in the model development. The experts identified eight major factors that affect disease development (in descending order of importance): inoculum level in the soil, cultivar susceptibility, fumigation history, frequency of susceptible crops within a crop rotation, growing season, fallow seasons within a crop rotation, infection level in the tubers and soil type. The procedure used for selecting the factors and the method used for extracting their relative weights (pairwise comparison) was proved to be useful as the factor and their relative weights replicated the conclusions of studies from other sites. Additionally, the prediction model was found to be 80% accurate. The prediction model was integrated in a spatial decision support system (SDSS), built under ArcGIS 10, that advises the farmer on plot allocation for potato growing with minimal risk of VW. The SDSS interface and its outputs are presented using real-world data. Effective use of the SDSS by farmers requires the construction of a historical database that includes values of the abovementioned factors and a user-friendly interface for routine updating.

Prevalence and species identification of Pratylenchus spp. in Manitoba potato fields and host suitability of ‘Russet Burbank’

The objectives of this study were to determine the occurence and identity of Pratylenchus species in Manitoba potato (Solanum tuberosum) fields with a history of Potato Early Dying disease using both morphometric and molecular techniques. In addition, suitability of the most widely used potato cultivar in Manitoba, ‘Russet Burbank’, as a host for Pratylenchus spp. was determined. During the summer of 2004 and 2005, 283 soil samples were collected from 31 potato fields with a history of occurrence of Potato Early Dying encompassing the major potato growing areas in Manitoba. Pratylenchus spp. were detected in 39% of the fields and densities in soil samples ranged from 45 to 631 nematodes kg−1 fresh soil with a median density of 125 nematodes kg−1 fresh soil. Morphometrics of female nematodes and molecular analysis (polymerase chain reaction followed by sequencing and comparison of sequence data to the GenBank BLAST database) showed that the species of Pratylenchus in potato fields was P. neglectus. Further, the near absence of male Pratylenchus in the soil samples is consistent with the parthenogenic nature of P. neglectus. Potato 'Russet Burbank' was a poor host to populations of Pratylenchus sp. present in two fields. We suggest that the presence of suitable host plants, cereals and canola, in rotation with potato in Manitoba and soil texture have favoured P. neglectus rather than P. penetrans, the most widespread Pratylenchus species found in soil regularly cropped to potato in the Eastern United States and Canada. More studies are warranted to determine whether Pratylenchus spp. such as P. neglectus in Manitoba are causing damage to crops in rotation with potato and if they play a role in the Potato Early Dying disease complex.

Colonization Dynamics and Spatial Progression of Verticillium dahliae in Individual Stems of Two Potato Cultivars with Differing Responses to Potato Early Dying.

Potato early dying (PED), caused by Verticillium dahliae, is a chronic yield-limiting disease of potato (Solanum tuberosum). In this study, we describe the colonization dynamics of V. dahliae in two potato cultivars with varying responses to PED. We utilized a quantitative real-time polymerase chain reaction (Q-PCR) assay to assess the colonization and spatial progression of V. dahliae in cvs. Ranger Russet (moderately resistant) and Russet Norkotah (highly susceptible). Ninety plants per cultivar were inoculated with a conidial suspension in the greenhouse. Every 2 weeks until week 10, we collected basal samples from 15 plants, and repeatedly sampled the growing apices of another 15 plants. The mean infection coefficient (IC) values in the basal and apical samples were significantly lower in cv. Ranger Russet at all five sampling dates. The pathogen was detected in basal samples of both cultivars by week 2, and in apical samples of cv. Russet Norkotah at week 4 and of cv. Ranger Russet at week 6. Colonization of cv. Russet Norkotah consistently increased in apical and basal samples during the 10 weeks, while it plateaued after week 6 in cv. Ranger Russet. Differences in response to PED appear associated with the speed of colonization and the establishment of a higher population density by V. dahliae in the plant.

Multiplex Real-Time Quantitative PCR to Detect and Quantify Verticillium dahliae Colonization in Potato Lines that Differ in Response to Verticillium Wilt

ABSTRACT Potato early dying (PED), also known as Verticillium wilt, caused by Verticillium dahliae, is a seasonal yield-limiting disease of potato worldwide, and PED-resistant cultivars currently represent only a small percentage of potato production. In this study, we developed a real-time quantitative polymerase chain reaction (Q-PCR) approach to detect and quantify V. dahliae. The efficiency of the designed primer pair VertBt-F/VertBt-R, derived from the sequence of the beta-tubulin gene, was greater than 95% in monoplex Q-PCR and duplex (using Plexor technology) procedures with primers PotAct-F/PotAct-R, obtained from the sequence of the actin gene, designed for potato. As few as 148 fg of V. dahliae DNA were detected and quantified, which is equivalent to five nuclei. Q-PCR detected V. dahliae in naturally infected air-dried potato stems and fresh stems of inoculated plants. Spearman correlations indicated a high correlation (upward of 80%) between V. dahliae quantifications using Q-PCR and the currently used plating assays. Moreover, Q-PCR substantially reduced the variability compared with that observed in the plating assay, and allowed for the detection of V. dahliae in 10% of stem samples found to be pathogen free on the culture medium. The described Q-PCR approach should provide breeders with a more sensitive and less variable alternative to time-consuming plating assays to distinguish response of breeding lines to colonization by V. dahliae.

Soil Water Pressure Affects Population Dynamics of Biocontrol Agents of Verticillium dahliae, the Cause of Potato Early Dying

Soil Water Pressure Affects Population Dynamics of Biocontrol Agents of Verticillium dahliae, the Cause of Potato Early Dying

Comments on the Feature "Potato Early Dying: Management Challenges in a Changing Production Environment".

Comments on the Feature "Potato Early Dying: Management Challenges in a Changing Production Environment".

Authors' Response to the Letter from Davis and Huisman Commenting on "Potato Early Dying: Management Challenges in a Changing Production Environment".

Authors' Response to the Letter from Davis and Huisman Commenting on "Potato Early Dying: Management Challenges in a Changing Production Environment".

Potato Early Dying: Management Challenges in a Changing Production Environment.

The potato (Solanum tuberosum L.) had its start in the Andean highlands of South America, where archeological evidence indicates it has been cultivated for at least 8,000 years (72). Today it is grown on all continents except Antarctica. Serving as a primary food source to indigenous people when the Spanish explorers arrived in Peru in the mid-1500s, the potato traveled the globe as a valuable staple, fueling armies, improving diets, and changing economies (Fig. 1). The importance of the potato goes beyond the feeding of nations, however. Today potato starch is used in the production of paper, adhesive, and textile goods, and in edible binding agents and low-fat food additives. The potato yields up a highly absorbent biodegradable material for use in disposable diapers. It provides starch products to keep oil well drilling bits smooth and to hold together the ingredients in lipsticks and cosmetic creams, and it provides a substance that works as a flocculation agent in water purification systems, replacing petroleumbased chemicals (33). China is the world’s largest producer of potatoes, followed by the Russian Federation (33). It is the most important vegetable crop in North America, where in 2000, nearly 690,000 ha were grown, with an average yield of 32.6 metric tons/ha and a farm gate value of over $2.7 billion. The potato is subject to several diseases caused by root-infecting pathogens. Two of particular significance are the soilborne fungi Verticillium dahliae and V. alboatrum. The potato root is also a host to the root-lesion nematode Pratylenchus penetrans. The two fungal pathogens alone, or in conjunction with P. penetrans, cause a disease called potato early dying (PED), also known as early die, early maturity wilt, and Verticillium wilt (64). This disease is endemic in many potato production areas of the United States, particularly in the Midwest and Pacific Northwest. In fields with a long history of potato production, it is a consistent yield constraint that requires intensive management. On land new to potato production, it may be absent in the first few years the crop is grown, but it almost invariably develops over time, requiring implementation of control measures to maintain high yields. In the last decade, the North American potato industry has undergone considerable changes. Production is increasingly being

Effect of coinoculation by Verticillium dahliae and Colletotrichum coccodes on disease symptoms and fungal colonization in four potato cultivars

Interactions between Verticillium dahliae and Colletotrichum coccodes, major causal agents of potato early dying (PED) syndrome, were studied in four potato cultivars that differ in their susceptibility to these pathogens. Aseptic plantlets of Nicola, Desiree, Alpha and Cara were inoculated with identical concentrations of each pathogen or with a mixture of the pathogens, and grown for 4 weeks in a monitored growth chamber. Coinoculation of Nicola with both pathogens caused more severe foliar disease symptoms and crown rot and greater C. coccodes colonization, than inoculation with each pathogen separately. Significant reductions in weight and height were also observed in plants coinoculated with both pathogens, as compared with plants inoculated with each pathogen separately or noninoculated plants. In Desiree, more roots were covered with C. coccodes sclerotia and disease symptoms were significantly more severe in plants inoculated with both pathogens together. However, plant weight and height were similar to those of plants inoculated with C. coccodes only. In Alpha, disease symptoms and levels of sclerotia in the roots were not affected by simultaneous inoculation with both pathogens. Weight and height of all plants were similar, whether inoculated with each pathogen separately or with both pathogens together. In Cara, plants inoculated with the mixture or either pathogen alone were smaller than the noninoculated control. Disease symptoms and occurrence of sclerotia were similar in plants inoculated with the combination and with a single pathogen. Compared with the effects of inoculation with either pathogen, simultaneous inoculation with both pathogens can, in some cultivars, increase the incidence of PED syndrome and thus severely decrease yields.

Molecular Characterization of Vegetative Compatibility Group 4A and 4B Isolates of Verticillium dahliae Associated with Potato Early Dying.

Forty isolates of Verticillium dahliae, collected from potato seed tubers and potato plants from various regions in North America and previously assigned to vegetative compatibility groups (VCGs) 4A or 4B, were characterized using molecular markers. The VCG 4A isolates were previously shown to be a highly virulent pathotype of potato and to interact synergistically with the root-lesion nematode Pratylenchus penetrans to cause potato early dying. All but one of the VCG 4A isolates characterized in this study lacked the subspecies-specific repetitive DNA sequence E18 and could be differentiated from the remaining isolates by restriction fragment length polymorphisms (RFLPs) in the nuclear rDNA and Trp1 loci. The E18 RFLP patterns of several VCG 4B isolates from Maine and New York were highly similar to those of VCG 4B isolates previously collected from potato and tomato fields in Ontario. The data presented here suggest that the molecular markers will be useful for the detection and classification of isolates of V. dahliae associated with potato early dying.

Effect of Compost Amendment or Straw Mulch on Potato Early Dying Disease.

Single potato plants (Solanum tuberosum) cv. Superior were grown in field microplots to evaluate the effects of spent mushroom compost or straw mulch on early dying of potato caused by Verticillium dahliae and/or Pratylenchus penetrans. Prior to planting, soil was fumigated, placed in field microplots, and then infested with pathogens. Area under the senescence progress curve (AUSPC) was greater for plots infested with V. dahliae and/or P. penetrans than for noninfested plots. Plants grown in soil infested with both pathogens developed symptoms earlier than plants grown in soil infested with a single pathogen. Both V. dahliae and P. penetrans reduced yields; the combination of pathogens reduced marketable tuber yields by 22 to 44% (A- and B-sized tubers). Although the total number of tubers of all sizes was not affected by cultural or pathogen treatments, the addition of compost increased marketable tuber weight and decreased AUSPC. Soil amendment with spent mushroom compost may be a means of reducing the effects of potato early dying and increasing tuber yield when one or both pathogens are present.

Assessment of Irrigation as a Method of Managing Potato Early Dying

Pre- and posttuber initiation irrigation treatments were evaluated for their impact on development of potato early dying symptoms in Russet Burbank potatoes grown in field microplots in northcentral Oregon. Irrigation treatments were in a factorial arrangement of three pre- and three posttuber initiation regimes across six inoculum densities of Verticillium dahliae. Microplots were drip-irrigated to provide deficit, moderate, or excessive amounts of irrigation water prior to tuber initiation, followed by all nine possible posttuber initiation combinations. Moderate irrigation was approximately equal to estimated consumptive use (ECU) by the plant; the deficit and excessive regimes were 50 and 150% of ECU, respectively [...]

Development of Potato Early Dying in Response to Infection by Two Pathotypes ofVerticillium dahliaeand Co-infection byPratylenchus penetrans

Verticillium dahliae isolates assigned to subgroups A and B of vegetative compatibility group 4 (VCG 4A and 4B) were tested for virulence to potato and ability to interact with the root-lesion nematode Pratylenchus penetrans in field microplot and greenhouse experiments. Microsclerotial inocula and the Verticillium-susceptible potato cultivar Superior were used. No differences in virulence were found between isolates from VCG 4A and 4B when plants were grown in soil infested with V. dahliae only. In contrast, plants grown in soil infested with V. dahliae isolates from VCG 4A plus P. penetrans exhibited higher disease severity and had lower tuber yields than plants grown in soil infested with V. dahliae isolates from VCG 4B plus P. penetrans [...]

Expression of a pea disease resistance response gene in the potato cultivar Shepody

The coding sequence from the pea disease resistance response gene 49 (DRR49 gene), was transferred into the potato (Solanum tuberosum L.) cultivar Shepody viaAgrobacterium co-cultivation. Potato leaf explants were co-cultivated withAgrobacterium tumefaciens harboring a binary vector containing the coding sequence from the DRR49 gene under the control of the 35S promoter from cauliflower mosaic virus (CaMV). Transformed potato plants were selected by their resistance to kanamycin. The insertion of foreign DNAs was detected by polymerase chain reaction (PCR) and Southern blot analysis. The expression of DRR49 coding sequence was confirmed via the detection of the corresponding mRNA in northern blot analysis. Field pathogenicity tests indicated that transgenic plants expressing the pea DRR49 mRNA have higher tuber yields than the control plants when grown in PED (potato early dying) infested soil.

Biology and Management of Early Dying of Potatoes

Premature vine death and declining yields are a long-standing problem in many areas where potatoes have been in production for several years. This syndrome, called potato early dying (PED), occurs in both nonirrigated and irrigated production areas of the United States. It is especially important in irrigated areas of the central, southern, and western states (53, 57, 72, 75, 77). Common synonyms for this disease include early maturity wilt, early die, and verticillium wilt. In long-established potato production areas, especially in the north-central states, the Red River Valley of North Dakota and Minnesota, and in Idaho, PED has developed slowly over many years. Growers often do not realize that their yield expectations are low and consider early maturity a normal situation on their land. The recognition of PED in long-established production areas has been complicated by the trend over the last 10-20 years of increasing yields due to improved cultivars, cultural practices, and pest controls. In many

Influence of Irrigation on Severity of Potato Early Dying and Tuber Yield

The effects of three different irrigation regimes on potato early dying and associated yield loss were assessed in potato cultivar Russet Burbank grown in field microplots at two environmentally distinct locations in Oregon. Fumigated soil was either noninfested or infested with 5, 10, or 25 colony-forming units of Verticillium dahliae per gram of soil (cfu). Microplots were drip-irrigated to provide deficit, moderate, or excessive amounts of irrigation water. Moderate irrigation was approximately equal to estimated consumptive use (ECU); the deficit and excessive regimes were 50 and 150% of ECU in 1987 and 50 and 200% of ECU in 1988, respectively []