First Report of Sclerotinia minor on Sida spinosa in North Carolina

The soilborne fungus Sclerotinia minor Jagger is a major pathogen of peanut (Arachis hypogaea L.) in North Carolina, Virginia, Oklahoma, and Texas. The pathogen attacks several winter annual weed species (1). Economic crops that are hosts to S. minor are seldom grown in rotation with peanut; therefore, its pathogenicity on weed species is of importance in understanding how inoculum densities are maintained between peanut crops. During September 2004, signs of fluffy, white mycelium, small, black sclerotia, and symptoms of bleached leaves and stems were observed on prickly sida (Sida spinosa L.) in a peanut field in Bertie County, NC. Plants of prickly sida with similar signs and symptoms were observed previously in a Chowan County, NC peanut field. Prickly sida is one of several weed species commonly found in peanut fields and rotational crops in agricultural areas of northeastern North Carolina. Cultivation and herbicides usually keep prickly sida under control in the early part of the growing season, but as the summer progresses into early fall, it can become prevalent, as was true in the two fields reported here. Symptomatic tissues were excised into 1- to 2-cm sections, rinsed in tap water, blotted dry, and placed on potato dextrose agar (PDA). The pure cultures with small, black irregular-shaped sclerotia (<2 mm) scattered abundantly over the culture surface were distinctive of S. minor. Pathogenicity was determined by inoculating stems of two symptom-free prickly sida plants with 2-day-old fungal mycelium. Mycelial agar plugs, 4 mm in diameter, were held in place with self-sticking bandaging gauze. Plants were misted, enclosed in plastic bags, and incubated at ambient temperature (24°C) on the laboratory countertop. Fluffy mycelium developed on the stems in 2 days and water-soaked leaves and bleached lesions formed within 6 days after inoculation. Following the incubation period, S. minor was reisolated from the inoculated plants. Two plants treated similarly with plugs of pure PDA remained healthy over the incubation period. The performance of Koch's postulates confirmed that prickly sida is a host of S. minor. To our knowledge, this report of S. minor on prickly sida is also the first report of a plant in the family Malvaceae as a host of S. minor (2). Reference: (1) J. E. Hollowell et al. Plant Dis. 87:197, 2003. (2) M. S. Melzer et al. Can. J. Plant Pathol. 19:272, 1997.

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First Report of Stem and Leaf Blight Caused by Sclerotinia minor on Geranium carolinianum in North Carolina

Plant Disease ◽

10.1094/pdis.2004.88.3.312b ◽

2004 ◽

Vol 88 (3) ◽

pp. 312-312

Author(s):

J. E. Hollowell ◽

B. B. Shew

Keyword(s):

North Carolina ◽

Tap Water ◽

Signs And Symptoms ◽

Fungal Mycelium ◽

Weed Species ◽

Sclerotinia Minor ◽

First Report ◽

Plastic Bags ◽

Pure Cultures ◽

Winter Annual

The soilborne fungus Sclerotinia minor Jagger is a major pathogen of peanut (Arachis hypogaea L.) in North Carolina and overwinters in soil, on crop debris, or on winter annual weed species (1). Bleached stems and small, black sclerotia are typically seen on peanut plants infected by S. minor. Carolina geranium (Geranium carolinianum L.) is one of several winter annual weed species found during winter fallow in peanut production areas of northeastern North Carolina. During a March 2002 survey of previously harvested peanut fields, plants of Carolina geranium were observed with typical signs and symptoms of infection caused by S. minor. Symptomatic plants with bleached stems and signs of small, black sclerotia were collected in the field and returned to the laboratory. Pathogen isolation and fungal identification were performed from the symptomatic tissues by placing 1- to 2-cm sections of stems on potato dextrose agar after rinsing with tap water and towel drying. Pure cultures of S. minor were obtained and observed to have white, fluffy mycelium and small, black irregular-shaped sclerotia (<2 mm) produced abundantly and scattered over the culture surface. Pathogenicity was tested by inoculating stems of three symptom-free Carolina geranium plants with 2-day-old fungal mycelium from pure isolation. Mycelial agar plugs, 4 mm in diameter, were held in place with self-sticking bandaging gauze. Plants were misted, enclosed in plastic bags, and incubated at ambient temperature (24°C) on the laboratory counter top. Bleached water-soaked lesions developed on the stems, and leaves became chlorotic after 8 days. Following 8 days of incubation, S. minor was reisolated from all inoculated plants. Three noninoculated plants remained healthy over the incubation period. The performance of Koch's postulates confirmed that Carolina geranium is a host of S. minor. To our knowledge, this is the first report of S. minor on G. carolinianum. These results indicate that G. carolinianum is a potential overwintering host for S. minor in peanut fields. Infected weed hosts allow reproduction of the fungus in the winter, potentially resulting in more disease on peanut planted in the spring. Reference: (1) J. E. Hollowell et al. Plant Dis. 87:197, 2003.

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First Report of Sclerotium rolfsii on Common Chickweed in North Carolina

Plant Disease ◽

10.1094/pdis.2004.88.4.426b ◽

2004 ◽

Vol 88 (4) ◽

pp. 426-426

Author(s):

J. E. Hollowell ◽

B. B. Shew

Keyword(s):

North Carolina ◽

Tap Water ◽

Sclerotium Rolfsii ◽

Control Treatment ◽

Fungal Mycelium ◽

Weed Species ◽

Stellaria Media ◽

Crop Species ◽

First Report ◽

Pure Cultures

Common chickweed (Stellaria media (L.) Cyrillo) is a common weed species found in agricultural fields of northeastern North Carolina. Symptomatic plants of common chickweed were observed during a March 2001 survey of winter annual weed species in Perquimans County, NC. The plants were growing in a harvested peanut field with a known history of southern stem rot caused by Sclerotium rolfsii Sacc. Water-soaked, bleached stems and chlorotic leaves were collected from plants and brought to the laboratory for isolation. Small portions (1 to 2 cm) of symptomatic stems and entire leaves were rinsed with tap water and placed on potato dextrose agar (PDA). Developing colonies were transferred to obtain pure cultures. The rapidly growing cultures had coarse, white mycelium typical of S. rolfsii and produced abundant, small, round, brown sclerotia approximately 2.0 mm in diameter on the surface of the culture. Clamp connections were observed with microscopic examination of mycelia. Pathogenicity of isolates was tested by placing 4-mm-diameter agar plugs of 2-day-old fungal mycelium on stems of three mature, nonsymptomatic chickweed plants. Agar plugs without fungal mycelium were used for the control treatment. Plugs were held in place with self-sticking bandage gauze. Plants were misted with water, enclosed in plastic bags, and incubated on a laboratory counter top at ambient temperature (24°C). Abundant mycelia developed, and water-soaked lesions and necrotic stems were observed. Noninoculated plants remained healthy and free of signs and symptoms during the incubation period. The fungus was reisolated on PDA, and pure cultures of S. rolfsii were obtained. Koch's postulates confirmed common chickweed was a host of S. rolfsii. To our knowledge, this is the first report of common chickweed as a host of S. rolfsii. Crop species commonly used in peanut rotations (corn, small grains, sorghum, and cotton) do not support populations of S. rolfsii. Many dicotyledonous weed species have been reported as hosts of S. rolfsii, but our observation of active disease on a winter weed species was unexpected. Colonization of winter weed, if prevalent, may enhance survival of S. rolfsii between crops of susceptible hosts such as peanut.

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First Report of Sclerotinia minor on Allium vineale in North Carolina

Plant Disease ◽

10.1094/pd-89-0908c ◽

2005 ◽

Vol 89 (8) ◽

pp. 908-908

Author(s):

J. E. Hollowell ◽

B. B. Shew

Keyword(s):

North Carolina ◽

Incubation Period ◽

Tap Water ◽

Early Spring ◽

Fungal Mycelium ◽

Isolation And Identification ◽

Sclerotinia Minor ◽

Fungal Isolation ◽

Pure Cultures ◽

Wild Garlic

Allium vineale L. (wild garlic) is a bulbous perennial that emerges in early spring in many agricultural fields. The soilborne fungus Sclerotinia minor Jagger is a major pathogen found in many peanut (Arachis hypogaea L.) production areas of northeastern North Carolina. During September 2002, symptoms of bleached, water-soaked foliage and wilting were observed on several wild garlic plants growing in a 0.8-ha (2-acre) peanut research plot in Perquimans County, NC. We had previously observed similar symptoms on wild garlic at another location. Two symptomatic wild garlic plants were collected from the field. In the laboratory, symptomatic tissues were excised into 1- to 2-cm sections, rinsed in tap water, towel dried, and placed on potato dextrose agar (PDA) for fungal isolation and identification. Pure cultures with small, black, irregular-shaped sclerotia (<2 mm) scattered abundantly over the culture surface were distinctive of S. minor. Pathogenicity of isolates was tested by inoculating leaf blades near the leaf axils of two symptom-free wild garlic plants (vegetative stage, 4 cm high) with fungal mycelium from 2-day-old cultures. Mycelial agar plugs (4 mm in diameter) were held in place with self-sticking bandaging gauze. Plants were misted, enclosed in plastic bags, and incubated at an ambient temperature (24°C) on the laboratory countertop. Fluffy mycelium developed on leaves within 2 days. Plants wilted and bleached water-soaked lesions formed within 6 days after inoculation. Sclerotia were produced on leaf blades after approximately 14 days. Following the incubation period, S. minor was reisolated from the inoculated plants. Two plants treated similarly with plugs of pure PDA remained healthy over the incubation period. The performance of Koch's postulates confirmed that wild garlic is a host of S. minor. Although few monocots have been reported as hosts of S. minor, the fungus has been reported on two other species of Allium (A. cepa and A. satium), Gladiolus spp., and Cyperus esculentus (1,2). Weed hosts may support populations of S. minor during rotations to nonhosts, serve as reservoirs of inoculum, or act as infection bridges in peanut fields. References: (1) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. On-line publication. ARS, USDA, 2005. (2) M. S. Melzer et al. Can. J. Plant Pathol. 19:272, 1997.

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First Report of Sclerotinia minor Infecting Ipomoea hederacea and I. coccinea in Texas

Plant Disease ◽

10.1094/pdis-92-3-0482c ◽

2008 ◽

Vol 92 (3) ◽

pp. 482-482 ◽

Cited By ~ 3

Author(s):

J. E. Woodward ◽

M. A. Batla ◽

P. A. Dotray ◽

T. A. Wheeler ◽

T. A. Baughman

Keyword(s):

Weed Management ◽

Tap Water ◽

The United States ◽

Plant Diseases ◽

Weed Species ◽

Sclerotinia Minor ◽

Ipomoea Hederacea ◽

First Report ◽

Sclerotinia Blight ◽

Pathogenicity Tests

Sclerotinia blight, caused by the soilborne fungus Sclerotinia minor Jagger, is a major disease of peanut (Arachis hypogaea L.) in parts of west Texas. Previous reports have indicated that annual weed species may serve as collateral hosts for S. minor (2). Several Ipomoea spp. are commonly found in peanut fields throughout the region. In September of 2007, Ipomoea hederacea and I. coccinea plants with bleached, shredded stems, and signs of black sclerotia were collected from a field known to be infested with S. minor. Symptomatic stem sections were rinsed in tap water, surface disinfested in 0.5% sodium hypochlorite for 1 min, air dried, and plated on potato dextrose agar (PDA). Pure cultures of S. minor consisting of white, fluffy mycelia and small (<2 mm), black, irregular sclerotia were consistently recovered. Pathogenicity tests were conducted by wound-inoculating healthy I. hederacea and I. coccinea transplants (n = 3) with agar plugs obtained from the edges of actively growing S. minor cultures. Plants were incubated in a dew chamber at 20°C and 95% relative humidity for 5 days. Plants inoculated with sterile PDA plugs served as controls (n = 3). A similar test was conducted using the susceptible peanut cultivar Flavorunner 458. Characteristic symptoms of Sclerotinia blight (3) were observed on all inoculated weed and peanut plants; whereas, the controls remained healthy. Pathogenicity tests were repeated with similar results. Cultures of S. minor were obtained from all symptomatic tissues, fulfilling Koch's postulates. These results indicate that I. hederacea and I. coccinea are additional hosts of S. minor and that sclerotia produced on infected plants can significantly augment soil inoculum. S. minor has been observed to infect I. batatas seedlings in New Jersey (1); however, this to our knowledge is the first report of S. minor infecting Ipomoea spp. in Texas. Therefore, weed management should inevitability be a part of disease management strategies for the control of Sclerotinia blight in peanut. References: (1) Anonymous. Index of Plant Diseases in the United States. USDA Handb. No. 165, 1960. (2) J. E. Hollowell et al. Plant Dis. 87:197, 2003. (3) D. M. Porter and H. A. Melouk. Sclerotinia blight. Page 34 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathologicial Society, St. Paul, MN, 1997.

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Weed management in bromoxynil-resistantGossypium hirsutum

Weed Science ◽

10.1017/s0043174500092328 ◽

1999 ◽

Vol 47 (5) ◽

pp. 596-601 ◽

Cited By ~ 16

Author(s):

Mary D. Paulsgrove ◽

John W. Wilcut

Keyword(s):

North Carolina ◽

Gossypium Hirsutum ◽

Weed Management ◽

Chenopodium Album ◽

Conventional Tillage ◽

Cassia Occidentalis ◽

Common Lambsquarters ◽

Sida Spinosa ◽

Prickly Sida ◽

Anoda Cristata

An experiment was conducted at two locations in Georgia and two locations in North Carolina during 1994 and 1995 to evaluate weed management in conventional-tillage bromoxynil-resistantGossypium hirsutumL. (cotton). The weed management systems evaluated included different combinations of fluometuron preemergence (PRE), bromoxynil or bromoxynil plus MSMA early postemergence (EPOST), bromoxynil postemergence (POST), and cyanazine plus MSMA late post-directed (LAYBY). Fluometuron PRE improved control ofAcanthospermum hisptdiumDC. (bristly starbur),Cassia occidentalisL. (coffee senna),Chenopodium albumL. (common lambsquarters),Desmodium tortuosum(Sw.) DC. (Florida beggarweed),Sida spinosaL. (prickly sida),Jacquemontia tamnifolia(L.) Griseb. (smallflower morningglory), andAnoda cristata(L.) Schlecht. (spurred anoda), compared to system that did not use fluometuron PRE. It also improvedG. hirsutumyields at three four locations. Bromoxynil-containing systems provided better weed control and higherG. hirsutumyields than systems without bromoxynil. Bromoxynil EPOST controlledA. hispidium, C. occidentalis, C. album, D. tortuosum, S. spinosa, J. tamnifolia, andA. cristata.Control of these species was frequently improved by a second application of bromoxynil POST. Bromoxynil EPOST, POST, or EPOST plus POST did not controlSenna obtusifolia(L.) Irwin and Barneby (sicklepod), but the addition of MSMA to bromoxynil EPOST improvedS. obtusifoliacontrol. Control of all dicotyledonous weeds was improved by a LAYBY treatment of cyanazine plus MSMA, and yields were improved at three of four locations with this treatment.Gossypium hirsutumwas not injured by POST treatments of bromoxynil, and only temporary injury resulted from POST treatments of MSMA.

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Fusarium lateritium: A Pathogen of Spurred Anoda (Anoda cristata), Prickly Sida (Sida spinosa), and Velvetleaf (Abutilon theophrasti)

Weed Science ◽

10.1017/s0043174500040170 ◽

1981 ◽

Vol 29 (6) ◽

pp. 629-631 ◽

Cited By ~ 21

Author(s):

H. Lynn Walker

Keyword(s):

Abutilon Theophrasti ◽

Weed Species ◽

Disease Symptoms ◽

Naturally Occurring ◽

Fusarium Lateritium ◽

Hibiscus Trionum ◽

Sida Spinosa ◽

Stem Lesions ◽

Prickly Sida ◽

Anoda Cristata

An isolate ofFusarium lateritium(Nees) emend. Snyder and Hansen was associated with naturally occurring disease of spurred anoda [Anoda cristata(L.) Schlecht.] and prickly sida (Sida spinosaL.) plants. In greenhouse inoculation studies, theFusariumisolate was pathogenic to healthy spurred anoda and prickly sida plants. The disease symptoms were characterized by leaf, stem, and root lesions. The stem lesions enlarged with time and formed cankers that often girdled the stems and killed inoculated plants. In host-range studies, velvetleaf (Abutilon theophrastiMedic.), Venice mallow (Hibiscus trionumL.), okra [Abelmoschus esculentus(L.) Moench], and hollyhock [Althaea rosea(L.) Cav.] were also susceptible to the pathogen. This is the first report of these six species as hosts for this pathogen. Corn (Zea maysL.), cotton (Gossypium hirsutumL. andG. barbadenseL.), soybean [Glycine max(L.) Merr.], and 18 other representative crop and weed species in eight families were resistant to the pathogen.F. lateritiummay be a useful biological herbicide for susceptible malvaceous weeds.

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Weed management with CGA-362622 in transgenic and nontransgenic cotton

Weed Science ◽

10.1614/p2002-014 ◽

2003 ◽

Vol 51 (6) ◽

pp. 1002-1009 ◽

Cited By ~ 19

Author(s):

Dunk Porterfield ◽

John W. Wilcut ◽

Jerry W. Wells ◽

Scott B. Clewis

Keyword(s):

North Carolina ◽

Weed Control ◽

Weed Management ◽

Field Studies ◽

Palmer Amaranth ◽

Management Systems ◽

Weed Species ◽

Crop Tolerance ◽

Prickly Sida ◽

Smooth Pigweed

Field studies conducted at three locations in North Carolina in 1998 and 1999 evaluated crop tolerance, weed control, and yield with CGA-362622 alone and in combination with various weed management systems in transgenic and nontransgenic cotton systems. The herbicide systems used bromoxynil, CGA-362622, glyphosate, and pyrithiobac applied alone early postemergence (EPOST) or mixtures of CGA-362622 plus bromoxynil, glyphosate, or pyrithiobac applied EPOST. Trifluralin preplant incorporated followed by (fb) fluometuron preemergence (PRE) alone or fb a late POST–directed (LAYBY) treatment of prometryn plus MSMA controlled all the weed species present less than 90%. Herbicide systems that included soil-applied and LAYBY herbicides plus glyphosate EPOST or mixtures of CGA-362622 EPOST plus bromoxynil, glyphosate, or pyrithiobac controlled broadleaf signalgrass, entireleaf morningglory, large crabgrass, Palmer amaranth, prickly sida, sicklepod, and smooth pigweed at least 90%. Only cotton treated with these herbicide systems yielded equivalent to the weed-free check for each cultivar. Bromoxynil systems did not control Palmer amaranth and sicklepod, pyrithiobac systems did not control sicklepod, and CGA-362622 systems did not control prickly sida.

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Glyphosate and Paraquat Effects on Weed Seed Germination and Seedling Emergence

Weed Science ◽

10.1017/s004317450004981x ◽

1978 ◽

Vol 26 (3) ◽

pp. 249-251 ◽

Cited By ~ 26

Author(s):

G. H. Egley ◽

R. D. Williams

Keyword(s):

Seedling Emergence ◽

Soil Surface ◽

Amaranthus Retroflexus ◽

Sorghum Halepense ◽

Weed Species ◽

Sida Spinosa ◽

Broadleaf Species ◽

Prickly Sida ◽

Grass Weed ◽

Weed Emergence

Glyphosate [N-(phosphonomethyl)glycine] (30, 125, 250 mg/L) in petri dishes had no effect on germination of prickly sida(Sida spinosaL.), velvetleaf(Abutilon theophrastiMedic), barnyardgrass [Echinocloa crus-galli(L.) Beauv.] and johnsongrass [Sorghum halepense(L.) Pers.] seeds, but additional experimentation indicated that glyphosate stimulated germination of redroot pigweed(Amaranthus retroflexusL.) seeds. Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) (30, 125, 250 mg/L) did not affect germination of the three broadleaf species, but inhibited johnsongrass and barnyardgrass germination. In the greenhouse, soil surface applications of glyphosate (1.1, 2.2, 9.0 kg/ha) did not significantly affect emergence of these five weed species when they were on or beneath the soil surface at time of treatment. Paraquat (same rates) did not affect broadleaf weed emergence but some rates inhibited grass weed emergence when the seeds were treated while on the soil surface. It is unlikely that normal field use rates of glyphosate will influence weed emergence; whereas paraquat may inhibit the emergence of some grass weeds if the herbicide contacts seeds on the soil surface.

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Influence of Time of Planting and Distance from the Cotton (Gossypium hirsutum) Row of Pitted Morningglory (Ipomoea lacunosa), Prickly Sida (Sida spinosa), and Redroot Pigweed (Amaranthus retroflexus) on Competitiveness with Cotton

Weed Science ◽

10.1017/s0043174500061245 ◽

1980 ◽

Vol 28 (5) ◽

pp. 568-572 ◽

Cited By ~ 8

Author(s):

G. A. Buchanan ◽

J. E. Street ◽

R. H. Crowley

Keyword(s):

Gossypium Hirsutum ◽

Amaranthus Retroflexus ◽

Fresh Weight ◽

Weed Species ◽

Ipomoea Lacunosa ◽

Redroot Pigweed ◽

Weed Growth ◽

Pitted Morningglory ◽

Sida Spinosa ◽

Prickly Sida

Influence of time of planting and distance from the cotton row of pitted morningglory (Ipomoea lacunosaL.), prickly sida (Sida spinosaL.), and redroot pigweed (Amaranthus retroflexusL.) on yield of seed cotton (Gossypium hirsutumL. ‘Stoneville 213’) was determined on Decatur clay loam during 1975 through 1978. Weed growth was measured in 1977 and 1978. Seeds of the three weed species were planted 15, 30, or 45 cm from the cotton row at time of planting cotton or 4 weeks later. Weeds planted 4 weeks after planting cotton grew significantly less than did weeds planted at the same time as cotton. When planted with cotton, redroot pigweed produced over twice as much fresh weight as did prickly sida or pitted morningglory. The distance that weeds were planted from the cotton row did not affect weed growth in 1978, but did in 1977. The distance that weeds were planted from the cotton row did not affect their competitiveness in any year as measured by yield of cotton. However, in each year, yields of cotton were reduced to a greater extent by weeds planted with cotton than when planted 4 weeks later. In 3 of 4 yr, there were significant differences in competitiveness of each of the three weed species with cotton.

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Weed Seed Germination Under Simulated Drought

Weed Science ◽

10.1017/s0043174500027090 ◽

1973 ◽

Vol 21 (4) ◽

pp. 322-324 ◽

Cited By ~ 26

Author(s):

C. S. Hoveland ◽

G. A. Buchanan

Keyword(s):

Weed Seed ◽

Weed Species ◽

Pennisetum Typhoides ◽

Ipomoea Lacunosa ◽

Sesbania Exaltata ◽

Simulated Drought ◽

Sorghum Sudangrass ◽

Sida Spinosa ◽

Prickly Sida ◽

Better Than

Seeds of five crop and 17 weed species were germinated with 0, 3, 6, and 10-bar water solutions of polyethylene glycol to simulate drought. With simulated drought, most weed species germinated better than soybeans (Glycine maxL. ‘Hampton 266A’) but were not equal to pearlmillet [Pennisetum typhoides(Burm.) Stapf. and C. E. Hubb ‘Millex 23’] or sorghum-sudangrass [Sorghum bicolor(L.) Moench xS. sudanense(Piper) ‘SX-16’]. Prickly sida (Sida spinosaL,), sicklepod (Cassia obtusifoliaL.), andIpomoea lacunosaL. were the most tolerant weed species to simulated drought. Four species were intermediate in tolerance and four species germinated poorly under simulated drought. Hemp sesbania [Sesbania exaltata(Raf.) Cory] was the least tolerant and was similar to soybean.

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