First Report of Sydowia polyspora on Aleppo Pine (Pinus halepensis) in Italy.

Pinus halepensis Mill. is a pine native to the Mediterranean region that is generally located from sea level up to an altitude of 200 meters. In July 2012, extensive leaf yellowing and scorching were observed on the foliage of two specimens of P. halepensis in a public park of Alassio municipality, Liguria region (northern Italy). Diseased needles showed chlorotic and reddish brown colored areas that were randomly distributed among healthy needles. In order to isolate the potential pathogen, diseased needle tissues were surface sterilized for 1 min in 1% NaOCl and plated onto potato dextrose agar (PDA) amended with 100 ppm of streptomycin sulfate. After 7 to 10 days, a brown to dark green mycelium slowly developed on the PDA. From the mycelium, single cell conidia averaging 7.0 (4.7 to 12.2) × 2.9 (2.4 to 5.4) µm (n = 50) were produced. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS1f/ITS4 and sequenced. A BLAST (1) search yielded 100% of maximum identity with Sydowia polyspora (Bref. & Tav.) E. Müller for ITS1f and ITS4. Pathogenicity was confirmed by inoculating 15 3-year-old plants (approximately 5 months after bud break) of P. halepensis grown singly in 8-cm diameter pots and maintained in greenhouse. Twelve of 15 plants were wounded by gently rubbing needles together. Five non-inoculated plants, with wounded and non-wounded branches, were kept as controls. Inoculations were carried out at 16.5 to 18.5°C. A suspension of S. polyspora conidia was made by adding 1 to 2 ml sterile water to the spore mass on 1-month-old PDA cultures in 9-cm petri dishes. Inoculum (107 spores/ml) was applied on the needles with a soft paint brush. After inoculation plants were covered with polythene bags for 5 days, kept at temperatures ranging from 5.5 to 26.4°C (average 14.5°C), and watered as needed. The inoculation trial was repeated once. All inoculated plants, both wounded and non-wounded, developed leaf yellowing and browning since the fifth day after inoculation in both inoculation tests, while control plants remained symptomless. After 15 days from first symptom appearance, S. polyspora was re-isolated from the needles of inoculated plants according to the procedure already described. S. polyspora is associated with current season needle necrosis (CSNN) on various conifer species. P. halepensis was reported in Spain to be a susceptible host (2) and S. polyspora has been isolated from infected tissues of fir (Abies spp.) (3). To our knowledge, this is the first report of S. polyspora on P. halepensis in Italy. Control of the pathogen with fungicides was ineffective on fir species, while application of very high rates of calcium chloride during shoot elongation was able to reduce the severity of CSNN (3). In forest areas, municipality gardens, and parks, effective management strategies have not yet been developed. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) L. Botella et al. Fungal Diversity 40:1, 2010. (3) V. Talgø et al. Fungal Biol. 114:545, 2010.

First Report of Sclerotinia sclerotiorum on Lantana camara in Italy.

Lantana camara L. is grown as an ornamental potted plant in Liguria (northern Italy) and is widely used in private and public gardens in central and southern Italy. In some countries, this plant is considered a noxious weed. In the winter of 2007, a sudden wilt was observed on 22-month-old potted plants grown in a commercial greenhouse. Affected plants showed stem necrosis and watery and necrotic leaf tissues. As stem and foliar necrosis progressed, infected plants died. Some plants wilted unilaterally. Infected plants were characterized by the presence of whitish and cottony mycelium. Dark sclerotia were rapidly and abundantly produced on the mycelium. The diseased stem tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (2) was consistently recovered from infected stem pieces. Typical-sized sclerotia were produced on PDA and measured 1.4 to 7.3 × 1.9 to 8.1 (average 3.6 × 4.5) mm. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 506-bp segment showed a 100% homology with the sequence of S. sclerotiorum. The nucleotide sequence has been assigned GenBank Accession No. EU 627006. Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 10 15-month-old plants grown singly in 14-cm-diameter pots. Mycelium plugs, 1 cm2, were excised from a 10-day-old PDA culture of each isolate and were placed on the soil surface around the base of each plant. Ten noninoculated plants served as controls. Plants were maintained in a greenhouse under shade at temperatures ranging between 10 and 26°C (average 17°C) and relative humidity >85%. The inoculation trial was carried out twice. All inoculated plants developed leaf yellowing by 10 days after inoculation. White, cottony mycelium and black sclerotia developed on stems and at the base of all inoculated plants. Eventually, the infected plants wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. To our knowledge, this is the first report of L. camara as a host of S. sclerotiorum in Italy as well as worldwide. The economic importance of this disease is currently limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) N. F. Buchwald. Kongl. Veterisk Landb. Aarssk. 75, 1949.

Pathogenicity and Host-Parasite Relationships of Meloidogyne arenaria in Sweet Basil.

Stunted growth of sweet basil (cv. Genovese) associated with large patches and severe soil infestations by the root-knot nematode Meloidogyne arenaria race 2 were observed in open fields at the end of the crop-growing season in Albenga, province of Savona, Northern Italy by early September 2007. Observed morphological traits of nematode life stages and results of analysis of isozyme electrophoretic patterns and differential host tests were used for nematode species and race identification. Nematode-induced mature galls (either in naturally infected plants or in artificially inoculated root tissues) were spherical or ellipsoidal and confluent along the root axis, containing usually several females, males, and egg-masses with eggs. Feeding sites were characterized by the development of giant cells that contained several hypertrophied nuclei and nucleoli. Giant cell cytoplasm was aggregated along the thickened cell walls. Vascular elements within galls appeared disorganized and disrupted. Due to the heavy damage observed, the relationships between the initial population density and growth of basil plants was also tested in a greenhouse experiment in which inoculum levels varied from 0 to 512 eggs and juveniles/cm3 of soil. Height and top fresh weight data of the inoculated and control plants was fitted to Seinhorst's model. Tolerance limits with respect to plant height and fresh top weight of basil cv. Genovese plants to M. arenaria race 2 were estimated as 0.15 eggs and juveniles/cm3 of soil. The minimum relative values (m) for plant height and top fresh weight were 0.39 and 0.19 at initial nematode population density (Pi) ≥16 eggs and juveniles/cm3 of soil, respectively. The maximum nematode reproduction rate (Pf/Pi) was 448.7 times at an initial population density of 4 eggs and second-stage juveniles/cm3 of soil.

Powdery Mildew Caused by Golovinomyces cichoracearum on Paris Daisy (Argyranthemum frutescens) in Italy.

Paris daisy (Argyranthemum frutescens), also known as Marguerite daisy, is an economically important crop in the Riviera Ligure (northern Italy) where approximately 18 million potted plants per year are produced for export. During the fall and winter of 2007, Paris daisy 'Bright Carmen' plants, started in a greenhouse and growing outside in a commercial nursery at Albenga, showed a previously unknown powdery mildew. Young stems, particularly in the interior portions of the plant, were covered with a white mycelium. As the disease progressed, leaves became covered with the mycelium, resulting in smaller, chlorotic leaves. Conidia were hyaline, cylindrical, borne in chains (two to three conidia per chain) and measured 30 × 12 µm (20 to 34 × 10 to 15 µm). Conidia were generated by conidiophores represented by a foot cell measuring 55 to 101 × 11 to 12 µm followed by two shorter cells measuring 19 to 29 × 11 to 14 and 24 to 33 × 12 to 14 µm. Fibrosin bodies were absent. Chasmothecia were not observed in the collected samples. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 441 bp showed a 100% homology with the sequence of Golovinomyces cichoracearum (= Erysiphe cichoracearum) (3). The nucleotide sequence has been assigned GenBank Accession No. EU486992. Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of healthy Paris daisy plants of cvs. Blazer Rose, Bright Carmine, Cherry Harmony, Crowned Rose, Fulvia, Sole Mio, Stella 2000, Summit Pink, and Sun Light. Three plants per cultivar were inoculated, while the same number served as noninoculated controls. The pathogenicity test was carried out twice. Plants were maintained in a greenhouse at temperatures ranging from 15 to 21°C. Fifteen days after inoculation, typical symptoms of powdery mildew developed on inoculated plants of all cultivars, with the exception of Stella 2000. The fungus observed on inoculated plants was morphologically identical to that originally observed. Noninoculated plants did not show symptoms. To our knowledge, this is the first report of powdery mildew on A. frutescens in Italy. G. cichoracearum has been reported on Chrysanthemum frutescens in Switzerland (2). The economic impact of this disease is limited but can easily increase because of the intensive cultivation of this crop. The availability of resistant or partially resistant cultivars will help reduce the impact of this new disease. Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) A. Bolay, Cryptogam. Helv. 20:1, 2005. (3) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000.

First Report of Sclerotinia sclerotiorum on Calceolaria integrifolia in Italy.

Calceolaria integrifolia L. is an ornamental species grown as a potted plant in Liguria, northern Italy. In the winter of 2006, extensive chlorosis was observed on approximately 10% of the 10-month-old potted plants in a commercial greenhouse. Initial symptoms included stem necrosis and darkening of leaves. As stem and foliar necrosis progressed, infected plants wilted and died. Wilt occurred on young plants within a few days after the initial appearance of symptoms. Infected plants were characterized by the presence of soft, watery tissues that became covered with white mycelium and dark sclerotia. The diseased stem tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (3) was consistently recovered from infected stem pieces. Sclerotia observed on infected plants measured 0.7 to 1.0 × 2.8 to 4.4 mm (average 1.6 to 2.1 mm). Sclerotia produced on PDA measured 1.0 to 1.1 × 3.0 to 4.2 mm (average 1.7 to 2.3 mm). The internal transcribed spacer (ITS) region of rDNA was amplified with primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 522-bp amplicon resulted in 100% homology with the sequence of S. sclerotiorum. The nucleotide sequence has been assigned GenBank Accession No. EU 627004. Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 10 120-day-old plants grown in individual 14-cm-diameter pots maintained in a greenhouse under partial shade. Inoculum consisted of 1 cm2 of mycelial plugs excised from a 10-day-old PDA culture of each isolate. Plants were inoculated by placing a mycelial plug on the soil surface around the base of each plant. Ten plants were inoculated per isolate and an equal number of noninoculated plants served as controls. The trial was repeated once. All plants were kept at temperatures ranging between 8 and 17°C (average 12.5°C) and watered as needed. All inoculated plants developed leaf yellowing within 8 days after inoculation, soon followed by the appearance of white mycelium and sclerotia, and then by wilt. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. S. sclerotiorum was reported previously on a Calceolaria sp. in the United States (2). To our knowledge, this is the first report of white mold on C. integrifolia in Italy. The economic importance of this disease is currently limited. References (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) Anonymous. USDA Agric. Handb. 165:441, 1960. (3) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift 75, 1949.

Fusarium Wilt of Gerbera Caused by a Fusarium sp. in Brazil.

In 2006, gerbera (Gerbera jamesonii) plants, cvs. Basic, Xena, and Olimpia grown for cut flower production in two greenhouse farms in the region of Guarapuava, Paraná, Brazil, exhibited symptoms of a wilt disease. Affected plants (approximately 20, 60, and 50% on cvs. Basic, Xena, and Olimpia, respectively) were stunted and developed yellow leaves unilaterally with initially brown and eventually black streaks in the vascular system. The first symptoms occurred 2 months after transplanting during the hottest period of the summer with an average air temperature of 27°C. Vascular streaks in the yellow leaves were continuous with a brown discoloration in the vascular system of the crown and upper taproot. Occasionally, the leaves of affected plants turned red. A Fusarium sp. was consistently and readily isolated onto a Fusarium-selective medium from symptomatic vascular tissue sampled from the crown of infected plants. Colonies were identified as Fusarium oxysporum on the basis of colony and conidia morphology (1) after subculturing on potato dextrose agar. Since F. oxysporum f. sp. chrysanthemi has been previously reported on Chrysanthemum morifolium, Argyranthemum frutescens, and gerbera (4), pathogenicity tests were carried out by using one monoconidial isolate obtained from wilted plants and one Italian isolate (F. oxysporum f. sp. chrysanthemi MASS 6). The isolates of F. oxysporum were grown in casein hydrolysate in shake culture (90 rpm) for 10 days at 25°C with 12 h of fluorescent light per day. Healthy rooted plants of 30-, 20-, and 45-day-old C. morifolium (cv. Captiva), A. frutescens (cv. Stella 2000), and gerbera (cvs. Jaska, Dalma, and Excellence), respectively, were inoculated by separately dipping roots into a conidial suspension (5 × 107 conidia/ml) of the two isolates of F. oxysporum. Plants were transplanted (one plant per pot) into pots (3.5 liter vol). Noninoculated plants served as control treatments. Plants (15 per treatment) were grown in a glasshouse at an average day temperature of 32°C and night temperature of 23°C (minimum 21°C and maximum 43°C). Wilt symptoms and discoloration of the vascular system in roots, crown, and petioles developed within 29 days on C. morifolium, 26 days on A. frutescens, and 14 days on gerbera. Noninoculated plants remained healthy. F. oxysporum was consistently reisolated from infected plants. The pathogenicity test was carried out twice. Gerbera wilt caused by F. oxysporum f. sp. chrysanthemi was recently reported in Italy (2) and Spain (3). Currently, the wilt of gerbera in the area of Paraná is limited to two farms. To our knowledge, this is the first report of the disease in Brazil as well as in South America. References: (1) C. Booth. Fusarium. CMI, Kew, UK, 1977. (2) A. Garibaldi et al. Plant Dis. 88:311, 2004. (3) A. Garibaldi et al. Plant Dis. 91:638, 2007. (4) A. Minuto et al. J. Phytopathol. 155:373, 2007.

First Report of Powdery Mildew Caused by Golovinomyces cichoracearum on English Daisy (Bellis perennis) in Italy.

Bellis perennis (English daisy) is a flowering plant belonging to the Asteraceae and is increasingly grown as a potted plant in Liguria (northern Italy). In February 2007, severe outbreaks of a previously unknown powdery mildew were observed on plants in commercial farms at Albenga (northern Italy). Both surfaces of leaves of affected plants were covered with white mycelia and conidia. As the disease progressed, infected leaves turned yellow. Mycelia and conidia also were observed on stems and flower calyxes. Conidia were hyaline, ellipsoid, borne in chains (as many as three conidia per chain), and measured 27.7 × 16.9 (15.0 to 45.0 × 10.0 to 30.0) µm. Conidiophores measured 114.0 × 12.0 (109.0 to 117.0 × 11.0 to 13.0) µm and showed a foot cell measuring 78.0 × 11.0 (72.0 to 80.0 × 11.0 to 12.0) µm followed by two shorter cells. Fibrosin bodies were absent. Chasmothecia were not observed in the collected samples. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 415 bp obtained showed an E-value of 7e-155 with Golovinomyces cichoracearum (3). The nucleotide sequence has been assigned the GenBank Accession No. AB077627.1 Pathogenicity was confirmed through inoculations by gently pressing diseased leaves onto leaves of healthy B. perennis plants. Twenty plants were inoculated. Fifteen noninoculated plants served as a control. Plants were maintained in a greenhouse at temperatures ranging from 10 to 30°C. Seven days after inoculation, typical symptoms of powdery mildew developed on inoculated plants. The fungus observed on inoculated plants was morphologically identical to that originally observed. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. To our knowledge, this is the first report of powdery mildew on B. perennis in Italy. The disease was already reported in other European countries (2). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) U. Braun The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena, Germany, 1995. (3) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000.

First Report of Sclerotinia sclerotiorum on African Daisy (Osteospermum sp.) in Italy.

African daisy (Osteospermum sp.) is an ornamental plant grown in the winter as a potted plant in Liguria (northern Italy) and is generally marketed in early-to-late spring in Italy and central and northern Europe. In the winter of 2006, stem lesions, general chlorosis, wilt, and plant death occurred in a greenhouse nursery. Affected plants were characterized by the presence of soft, watery tissues. Necrotic tissues were covered with a white, cottony mycelium. During periods of high humidity, black sclerotia differentiated within the mycelium. To recover the pathogen, diseased stem tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (2) was consistently isolated from affected tissue. Sclerotia produced on PDA measured 1.3 to 3.1 × 1.5 to 3.5 mm in diameter. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and then sequenced. BLASTn analysis (1) of the 633 bp showed a 100% identity with S. sclerotiorum. The nucleotide sequence was assigned GenBank Accession No. EU 556701. Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 10 80-day-old plants grown in 14-cm-diameter pots. Inoculum consisted of 1 cm2 of mycelium excised from a 10-day-old PDA culture of each isolate and placed on the soil surface around the base of each plant. Ten plants were inoculated with each isolate and 10 noninoculated plants served as controls. Plants were maintained in a greenhouse under shade at temperatures of 10 to 22°C (average 19°C), in high relative humidity (>90%), and were watered as needed. The trial was conducted twice. All inoculated plants developed leaf yellowing within 12 days of inoculation. White, cottony mycelium and black sclerotia developed on stems and at the base of all inoculated plants, which eventually wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. This disease has been reported on an Osteospermum sp. in the United States (3) and Argentina (4). To our knowledge, this is the first report of white mold on an Osteospermum sp. in Italy as well as in Europe. Currently, the economic importance of this disease is limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift. 75, 1949. (3) H. S. Gill. Plant Dis. Rep. 59:82, 1975. (4) E. R. Wright et al. Plant Dis. 89:1014, 2005.

First Report of White Mold Caused by Sclerotinia sclerotiorum on Oreganum vulgare and Taraxacum officinale in Italy.

Oreganum vulgare (wild marjoram) and Taraxacum officinale (dandelion) plants with culinary and medicinal uses are grown in the field and as potted plants in Liguria in northern Italy. In the spring of 2006, extensive chlorosis was observed on both crops on commercial farms. Economic losses were low. Symptoms included foliar necrosis and a watery decay of the stem at the soil level. Necrotic tissues became covered with a whitish mycelium that produced dark sclerotia. Eventually, affected plants wilted and died. Samples of diseased stem tissue were surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (1) was consistently recovered from diseased stem pieces. Sclerotia from infected O. vulgare plants measured 1.8 to 3.4 × 1.8 to 6.1 (average 2.5 to 3.6) mm. Sclerotia from these isolates measured 1.3 to 4.7 × 1.6 to 6.1 (average 2.7 to 3.4) mm on PDA. Sclerotia from infected T. officinale plants measured 1.8 to 3.4 × 1.8 to 6.1 (average 2.5 to 3.6) mm. Sclerotia from these isolates measured 1.7 to 5.2 × 2.0 to 5.7 (average 3.3 to 3.8) mm on PDA. Pathogenicity of three isolates obtained from O. vulgare and three isolates from T. officinale was confirmed on each host. Inoculum consisted of 1 cm2 of mycelial plugs excised from a 10-day-old PDA culture of each isolate. Plants were inoculated by placing a mycelial plug on the soil surface around the base of each plant. Ten plants were inoculated per isolate and an equal number of noninoculated plants served as controls. Plants were incubated at 10 to 27°C (average 18°C) and watered as needed. Pathogenicity tests were repeated once. All inoculated plants developed chlorosis within 12 to 18 days, followed by the appearance of white mycelium and sclerotia, and eventually wilt. Control plants remained symptomless. S. sclerotiorum was reisolated from inoculated plants of both hosts. To our knowledge, this is the first report of white mold on O. vulgare in Italy as well as worldwide and the first report of white mold on T. officinale in Italy. S. sclerotiorum is a well known pathogen of T. officinale (2) and its use as a mycoherbicide has been proposed (3). References: (1) N. F. Buchwald. Page 75. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 1949. (2) D. M. McLean. Plant Dis. Rep. 35:162, 1951 (3) G. E. Riddle et al. Weed Sci. 39:109, 1991.

Fusarium Wilt of Gerbera in Spain in Soilless Crops.

In 2004, gerbera (Gerbera jamesonii cv. Excellence) plants, grown for cut flowers, were observed in a soilless cultivation system (coconut fiber substrate) in one farm in the Cadiz area (southwestern Spain) exhibiting symptoms of a wilt disease. Gerbera represents a relevant crop for the industry in the region, after rose and carnation. Affected plants were stunted and developed yellow leaves with initially brown and eventually black streaks in the vascular system. The vascular streaks in the yellow leaves were continuous with a brown discoloration in the vascular system of the crown and upper taproot. In some cases, the leaves of affected plants turned red. Fusarium spp. was consistently and readily isolated from symptomatic vascular tissue of infected plants onto a Fusarium-selective medium (3). Colonies were identified as F. oxysporum after subculturing on potato dextrose agar on the basis of morphological observations. Pathogenicity tests were carried out by using two monoconidial isolates, compared with an Italian one, obtained from wilted gerbera plants. Each isolate of F. oxysporum was grown in shake culture (90 rpm) for 10 days on casein hydrolysate at 25°C with 12 h of fluorescent light per day. Healthy rooted 30-day-old plants (cv. Jaska), were inoculated by dipping roots into a conidial suspension (5 × 107 conidia/ml) in one of the three test isolates of F. oxysporum. Plants were transplanted (1 plant per pot) into pots (3.5 liter vol.) containing rockwool-based substrate. Noninoculated plants served as control treatments. Plants (15 per treatment) were grown in a glasshouse at an average day temperature of 30°C and night temperature of 24°C (minimum of 22°C and maximum of 41°C). Wilt symptoms and vascular discoloration in the roots, crown, and veins developed within 30 days on each inoculated plant, while noninoculated plants remained healthy. F. oxysporum was consistently reisolated from infected plants. The pathogenicity test was conducted twice. A wilt of gerbera was described in the Netherlands in 1952 (1) but its presence was not confirmed in further observations (4). Gerbera wilt was recently reported in Italy (2) and identified as F. oxysporum f. sp. chrysanthemi (A. Garibaldi, personal communication). Currently, the wilt of gerbera in Spain is limited to a few farms and a very limited percent (2 to 3%) of plants. References: (1) J. Arx and J. A. von Tijdschr. PlZiekt. 58:5, 1952. (2) A. Garibaldi et al. Plant Dis. 88:311, 2004. (3) H. Komada. Rev. Plant Prot. Res. 8:114, 1975. (4) G. Scholten. Neth. J. Plant Pathol. 76:212, 1970.

First Report of Syringae Leaf Spot Caused by Pseudomonas syringae pv. syringae on Tomato in Italy.

In the spring of 2006 and 2007, grafted and nongrafted tomato plants (scion cv. Cuore di Bue, rootstock Lycopersicon lycopersicum × L. hirsutum cv. Beaufort) displaying stem and petiole necrosis were observed in many commercial greenhouses in the Piedmont of northern Italy. Initial symptoms that developed 2 to 10 days after transplanting consisted of water-soaked circular lesions (2 to 3 mm in diameter) on stems and petioles. These lesions eventually coalesced into brown-to-black areas as much as 1 cm in diameter. In some cases, necrotic areas progressed from stem petioles to leaf tissues. Thereafter, plants wilted and died within a few days. In some greenhouses, more than 80% of young plants exhibited symptoms and production was severely reduced. Two to three sections of symptomatic tissue from stems and petioles from 20 affected plants were surface disinfested in 0.5% NaOCl for 1 min and repeatedly washed in sterile deionized water. Samples were macerated in nutrient yeast dextrose broth, streaked onto nutrient yeast dextrose agar (NYDA), and incubated at 22 ± 1°C for 48 h. Light yellow colonies typical of Pseudomonas spp. were consistently isolated on NYDA. All colonies fluoresced under UV light when grown on King's B medium (3). Colonies were levan positive, oxidase negative, potato soft rot negative, arginine dihydrase negative, and tobacco hypersensitivity positive (LOPAT test; group Ia). In addition, all isolates were positive for arbutin and aesculin hydrolysis and utilized erythitol, but not adonitol, l(+)-tartrate or dl-homoserine as a carbon source. The isolates also caused severe necrotic lesions on lemon fruits and lilac leaves (4). The bacterial colonies were identified as Pseudomonas syringae pv. syringae (1). Also, repetitive-sequence PCR using the BOXA1R primer indicated that the isolates belong to pattern 4 of P. syringae pv. syringae (4). The pathogenicity of three isolates was tested twice by growing the bacterium in nutrient broth shake cultures for 48 h, pelleting the suspension, resuspending the cell pellet in sterile water to a concentration of 106 CFU/ml, and spraying 35-day-old healthy tomato plants (cv. Cuore di Bue) with the inoculum. Ten grafted and 10 nongrafted plants were inoculated, and the same number of plants was sprayed with sterile nutrient broth as a control. After inoculation, plants were covered with plastic bags for 48 h and placed in the greenhouse at 22 ± 1°C. Six days postinoculation, stem lesions, similar to those seen in the field, and leaf spots were observed on all bacteria-inoculated plants, but not on the controls. Leaf tissues did not develop symptoms. Isolations were made from the lesion margins and the resulting bacterial colonies were again identified as P. syringae pv. syringae. To our knowledge, this is the first report of Syringae leaf spot caused by P. syringae pv. syringae in Italy as well as in Europe. A bacterial spot of tomato caused by P. syringae pv. syringae has been reported in the United States (2). References: (1) A. Braun-Kiewnick and D. C. Sands. Pseudomonas. Page 84 in: Laboratory Guide for the Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. The American Phytopathological Society, St. Paul, MN, 2001. (2) J. B. Jones et al. Phytopathology, 71:1281, 1981. (3) E. O. King et al. J. Lab. Clinic. Med. 44:301, 1954. (4) M. Scortichini et al. Plant Pathol. 52:277, 2003.

First Report of White Mold Caused by Sclerotinia sclerotiorum on Iberis sempervirens in Italy.

Iberis sempervirens (candytuft) is an ornamental plant that thrives in cool conditions, and its growth as a potted plant has been increasing in Liguria (northern Italy). In the spring of 2004, extensive chlorosis was observed on 10-month-old potted plants of I. sempervirens grown in a plastichouse on a commercial farm near Albenga in northern Italy. Initial symptoms included stem necrosis at the soil level and darkening of leaves. As stem and foliar necrosis progressed, infected plants wilted and died. Wilt occurred within a few days on young plants, characterized by the presence of soft, watery tissues, particularly on affected leaves. Symptomatic plants were found on many farms, with an average disease incidence of 5 to 10%. Necrotic tissues became covered with a whitish mycelium that produced dark sclerotia. The diseased stem tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (1) was consistently recovered from infected stem pieces. Sclerotia observed on infected plants measured 1.4 to 3.2 × 2.1 to 4.1 mm (average 2.1 to 2.7 mm). Sclerotia produced on PDA measured 1.2 to 4.2 × 1.4 to 6.1 mm (average 2.5 to 3.1 mm). Pathogenicity of three isolates obtained from infected plants and used in a mixture was confirmed by inoculating 10 single-potted 120-day-old plants grown in 18-cm diameter pots maintained outside under shade. Inoculum that consisted of 1 cm2 of mycelium excised from a 10-day-old PDA culture plate of each isolate was placed on the soil surface around the base of each plant. Ten noninoculated plants served as control. The inoculation trial was repeated once. All plants were kept at temperatures ranging between 8 and 17°C (average 12.5°C) and watered as needed. All inoculated plants developed symptoms of leaf yellowing within 18 days, soon followed by the appearance of white mycelium and sclerotia, and then eventual wilt. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. S. sclerotiorum has been previously reported only on I. umbellata (2). To our knowledge, this is the first report of white mold on I. sempervirens in Italy as well as worldwide. The economic importance of this disease can be considered low at the moment in the case of field-grown plants. References: (1) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift 75, 1949. (2) J. M. Waterston. Report of the Plant Pathologist, 1946. Dep. Agric. Bermuda, 1947.

First Report of Downy Mildew Caused by Peronospora parasitica on Iberis sempervirens in Italy.

Iberis sempervirens (evergreen candytuft) is a garden species belonging to the Brassicaceae family. During June 2004, a damaging foliar disease was observed in several commercial farms near Albenga (northern Italy) on I. sempervirens plants grown outdoors in containers. More than 30% of the plants were affected. Symptoms appeared on both sides of leaves, buds, flowers, and fruits. Initially, leaves were slightly chlorotic, but within 5 to 7 days a characteristic whitish furry growth developed on the lower and upper leaf surfaces. The efflorescence was particularly evident on the lower surfaces of leaves and consisted of sporangiophores and sporangia. The appearance and severity of the disease increased because of overhead sprinkler irrigation. Microscopic observations revealed dichotomously branched sporangiophores with slender curved tips. Sporangiophores with a length of 115 to 410 µm (average 295 µm) ended with sterigmata bearing single sporangia. Sporangia were ovoid and measured 18 to 28 × 25 to 45 µm (average 22 × 35 µm). The pathogen was identified as Peronospora parasitica on the basis of its morphological characteristics (3). Pathogenicity was confirmed by inoculating leaves of 10 45-day-old healthy plants grown in 14-cm-diameter pots with a sporangial suspension (1 × 103 conidia/ml). Ten noninoculated plants served as controls. Plants were maintained outdoors at 50% light intensity with temperatures ranging between 16 and 25°C (average 18°C) and 85 to 100% relative humidity. The pathogenicity test was carried out twice. After 18 days, typical symptoms of downy mildew developed on the inoculated plants and P. parasitica was observed on the leaves. Noninoculated plants did not show symptoms. To our knowledge, this is the first report of P. parasitica on evergreen candytuft in Italy. P. parasitica was previously reported on I. sempervirens in the United Kingdom (1) and on I. amara in California (2). Voucher specimens are available at the AGROINNOVA Collection, University of Torino, Italy. References: (1) S. Francis and G. Waterhouse. Trans. Br. Mycol. Soc. 91:1, 1988. (2) P. R. Muller et al. Index of Plant Diseases in the United States. USDA Handbook No. 165, 1960. (3) D. M. Spencer. The Downy Mildews. Academic Press, New York, 1981.

First Report of Powdery Mildew Caused by Leveillula clavata on Poinsettia (Euphorbia pulcherrima) in Italy.

Euphorbia pulcherrima (poinsettia) is a winter-flowering plant grown primarily for Christmas sales. During the fall of 2005, severe outbreaks of a previously unknown powdery mildew were observed on cv. Gala in a commercial greenhouse located in Albenga (northern Italy). The abaxial surfaces of green leaves were irregularly covered with white mycelia and conidia, while the adaxial surfaces only showed slight chlorotic round lesions. As the disease progressed, mycelium turned from rose to reddish. Symptoms and signs were never observed on red bracts. Conidia were clavate (55 to 95 × 20 to 40 µm, average 70 × 23 µm) and borne singly on conidiophores that emerged through stomata. On the basis of host, morphological characteristics, and microscopic observations of the intercellular colonization of mesophyll cells, the pathogen was identified as a species of Oidiopsis. Although chasmothecia were not observed, the causal agent based on the literature is believed to be Leveillula clavata Nour (2). Pathogenicity was confirmed by inoculating young leaves of three 4-month-old E. pulcherrima plants, cv. Gala, with a conidial suspension (3 × 105 conidia/ml). Three noninoculated plants sprayed with deionized water served as control. After inoculation, plants were maintained in a growth chamber at 18°C with relative humidity ranging from 56 to 100%. After 20 days, powdery mildew symptoms were observed on leaves of inoculated plants. Noninoculated plants remained healthy. The pathogenicity test was carried out twice. To our knowledge, this is the first report of L. clavata on poinsettia in Italy and probably in Europe. It presently is restricted to a few commercial farms. L. clavata previously has been observed on poinsettia in Kenya (1,2). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) M. L. Daughtrey et al. Powdery Mildew Diseases. Pages 39-42 in: Compendium of Flowering Potted Plant Diseases. The American Phytopathological Society, St. Paul, MN, 1995. (2) M. A. Nour. Trans. Brit. Mycol. Soc. 40:477, 1957.

First Report of Sclerotinia Stem Rot and Watery Soft Rot Caused by Sclerotinia sclerotiorum on Sand Rocket (Diplotaxis tenuifolia) in Italy.

Several species of Diplotaxis (D. tenuifolia, D. erucoides, and D. muralis), known as wild or sand rocket, are widely cultivated in Italy. Rocket is used in Mediterranean cuisine as salad, a component of packaged salad products, and as a garnish for food. In winter 2003, a severe disease was observed on D. tenuifolia grown in unheated glasshouses on commercial farms near Albenga in northern Italy. Initial symptoms included stem necrosis at the soil level and darkening of leaves. As stem necrosis progressed, infected plants wilted and died. Wilt, characterized by the presence of soft and watery tissues, occurred within a few days on young plants. The disease was extremely severe in the presence of high relative humidity and mild temperature (15°C). Necrotic tissues became covered with white mycelium that produced dark sclerotia. Diseased stem tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm streptomycin sulfate. Sclerotinia sclerotiorum (1) was consistently recovered from infected stem pieces. Sclerotia observed on infected plants measured 1.23 to 3.00 × 1.40 to 5.38 mm (average 2.10 × 2.85 mm). Sclerotia produced on PDA measured 1.00 to 4.28 × 1.00 to 6.01 mm (average 2.38 × 3.23 mm). Pathogenicity of three isolates obtained from infected plants was confirmed by inoculating 30-day-old plants of D. tenuifolia grown in 18-cm-diameter pots in a glasshouse. Inoculum, 2 g per pot of wheat kernels infested with mycelium and sclerotia of each isolate, was placed on the soil surface around the base of each plant. Three replicates of five pots each were used per isolate. Noninoculated plants served as controls. The inoculation trial was repeated once. All plants were kept at temperatures ranging between 10 and 26°C (average 15°C) with an average relative humidity of 80% and were watered as needed. Inoculated plants developed symptoms of leaf yellowing within 12 days, soon followed by the appearance of white mycelium and sclerotia, and eventually wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from inoculated plants. To our knowledge, this is the first report of infection of D. tenuifolia by S. sclerotiorum in Italy as well as worldwide. The disease currently has been observed in the Liguria Region but not yet in other areas where sand rocket is cultivated. The economic importance of this disease for the crop can be considered medium at the moment, but is expected to increase in the future. Reference: (1) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 75, 1949.

Leaf Spot Caused by Alternaria sp. on Iberis sempervirens in Italy.

Iberis sempervirens (candytuft) is increasingly grown in Liguria (northern Italy) as a potted plant for ornamental purposes, particularly under cool-weather conditions. At the end of the summer of 2003, extensive necrosis was observed on leaves and young stems of 4-month-old plants grown in 14-cm diameter pots outdoors at a commercial farm. In many cases, on the upper side of the leaves, necrotic spots were surrounded by a chlorotic halo that turned progressively black. The necrotic areas often coalesced, generating larger and irregularly shaped spots. On the lower side of the leaves, no chlorotic areas were observed. Severely affected plants were defoliated. Infected plants rarely died, but the presence of lesions on mature plants decreased aesthetic quality and subsequently market value. The disease occurred on 40% of plants at each of the two farms. Leaf spots contained dark brown, multicellular pear-shaped conidia. Conidia were 22.5 to 50.0 µm (average 32.8 µm) long and 7.5 to 15.0 µm (average 12.3 µm) wide, with 5 to 7 longitudinal cross walls and an average of 6 to 7 single cells. From infected leaves, a fungus identified on the basis of its morphological characteristics as Alternaria sp. was consistently isolated on potato dextrose agar. Pathogenicity tests were performed by spraying leaves of healthy 12-month-old potted I. sempervirens plants with a spore and mycelial suspension (105 CFU/ml). Plants without inoculation served as control. Ten plants were used for each treatment. Plants were covered with plastic bags for 10 days after inoculation and kept outdoors for 60 days at temperatures ranging from 0 to 32°C (average 12°C). The first lesions developed on leaves 45 days after inoculation, while control plants remained healthy. From such lesions, Alternaria sp. was consistently reisolated. The pathogenicity test was carried out twice. The presence of A. brassicae was reported in Tanganica on Iberis sp., I. umbellata in Denmark (2), and I. amara in the United States (4); A. matthiolae was observed on seeds of I. amara and I. umbellata (3). A leaf spot incited by Alternaria sp. on I. amara was observed in Florida (1). This is, to our knowledge, the first report of Alternaria sp. on I. sempervirens in Italy as well as worldwide. References: (1) S. A. Alfieri et al. Index of Plant Diseases in Florida. Bull. 11, 1984. (2) P. Neergaard. Rev. Appl. Micol. 18:572, 1939. (3) P. Neergaard. Rev. Appl. Micol. 25:382, 1946). (4) R. D. Raabe. Comb. Proc. Int. Plant Propagators Soc. 40:160, 1991.

First Report of White Mold Caused by Sclerotinia sclerotiorum on Rosmarinus officinalis 'Prostratus' in Italy.

Rosmarinus officinalis L. 'Prostratus' is an evergreen shrub that is native to the Mediterranean Region in southern Europe and grown as a potted plant in Italy. This cultivar is widely used in gardens and landscapes. During the winter of 2002, extensive chlorosis was observed on 8-month-old potted plants of R. officinalis L. 'Prostratus' grown outdoors in commercial farms near Albenga in northern Italy. Initial symptoms included stem necrosis at the soil level and darkening of leaves. As stem necrosis progressed, infected plants wilted and died. Wilt, characterized by the presence of soft and watery tissues, occurred within a few days on young plants. The disease infected 15% of the plants. Necrotic tissues became covered with a whitish mycelium that produced dark sclerotia. The diseased stem tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm of streptomycin sulfate. Sclerotinia sclerotiorum (1) was consistently recovered from infected stem pieces. Sclerotia observed on infected plants measured 0.30 to 3.33 × 1.00 to 4.23 mm (average 1.31 × 1.88 mm). Sclerotia produced on PDA measured 0.09 to 3.08 × 0.38 to 4.05 mm (average 1.94 × 2.43 mm). Pathogenicity of three isolates obtained from infected plants and used in mixture was confirmed by inoculating 60-day-old plants grown in 14-cm-diameter pots in a glasshouse. Inoculum (wheat kernels infested with mycelium and sclerotia) for each isolate was placed on the soil surface around the base of each plant. Pathogenicity tests included three inoculated plants grown in separate pots per isolate. Three noninoculated plants grown in three pots served as controls. The inoculation trial was conducted twice. All plants were kept at temperatures ranging between 8 and 34°C (average 18°C) and watered as needed. Plants were covered with plastic for 96 h after inoculation to increase the moisture level. All inoculated plants developed symptoms of leaf yellowing within 30 days, soon followed by the appearance of white mycelium and sclerotia, and eventual wilt. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. To our knowledge, this is the first report of white mold of R. officinalis L. 'Prostratus' in Italy and in Europe. S. sclerotiorum has been previously reported on R. officinalis in India (2) and the United States (3). The economic importance of this disease for the crop in Italy can be considered low at the moment. References: (1) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 32:75, 1949. (2) L. Mohan. Indian Phytopathol. 47:443, 1994. (3) M. L. Putnam. Plant Pathol. 53:252, 2004.

Verticillium Wilt Incited by Verticillium dahliae in Eggplant Grafted on Solanum torvum in Italy.

Eggplant cultivars grafted on rootstocks resistant to root-knot nematodes (Meloidogyne spp.) are increasingly grown in Italy to reduce nematode infection. During the winter of 2003-2004, eggplants (cv Black Bell and Mirabell) grafted on the nematode-resistant rootstock Solanum torvum were observed with symptoms of a wilt disease in several greenhouses in Sicily (southern Italy). The vascular tissue in stems of affected plants appeared brown. These plants were stunted and developed yellow leaves with brown or black streaks in the vascular tissue. The wilt appeared in several greenhouses at a very low incidence (0.01 to 0.05%). Later, during the fall of 2004, disease incidence was approximately ten times greater in the same greenhouses on new crops. Verticillium dahliae was consistently and readily isolated from symptomatic vascular tissue of the rootstock (S. torvum) and the scion (cv Black bell) when cultured on potato dextrose agar (PDA) (1). Healthy, 50-day-old plants of S. torvum and eggplant (cv. Black Bell) were separately inoculated by root dip with a conidial suspension (1 × 107 CFU/ml) of two isolates of V. dahliae obtained from the rootstock and the scion of the infected grafted plants and with a known pathogenic isolate of V. dahliae from nongrafted eggplant. Noninoculated S. torvum and eggplant served as control treatments. Plants (30 per treatment) were grown in a glasshouse at temperatures ranging between 12 and 41°C (weekly average 15 to 36°C) and relative humidity ranging between 36 and 99% (weekly average 54 to 95%). The first wilt symptoms and vascular discoloration in the roots, crowns, and veins developed 26 and 21 days after inoculation on S. torvum and eggplant, respectively. Seventy-two days after inoculation, 20, 26, and 27% of S. torvum plants and 97, 100, and 87% of the eggplants showed symptoms caused by V. dahliae isolates obtained from the scion of diseased grafted plants, the rootstock of diseased grafted plants, and nongrafted eggplants, respectively. Noninoculated plants remained healthy. To our knowledge, this is the first report in Italy of Verticillium wilt on eggplant grafted on S. torvum rootstocks under commercial conditions. Use of eggplant grafted on the nematode-resistant rootstock of S. torvum presents an interesting opportunity to control the root-knot nematode but has to be carefully considered when dealing with soils severely infested by V. dahliae. Reference: (1) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002.

First Report of Southern blight Incited by Sclerotium rolfsii on Dichondra repens in Italy.

Kidney weed (Dichondra repens) is increasingly used for low maintenance turf in Italy, particularly for gardens and parks in areas characterized by mild climate. During September 2003, on the D. repens turf of a private garden located near Imperia (northern Italy), yellow, circular areas as much as 60 cm in diameter appeared with the grass becoming chlorotic and thin. A ring of the patch at its periphery exhibited a reddish brown color and eventually died. An area of green grass remained in the center of the patch. Rings of dead grass enlarged rapidly during hot, humid weather. In the presence of abundant moisture, a white mycelium occurred on the dying grass at the periphery of the ring. White or light-to-dark brown sclerotia (1 to 3 mm in diameter) developed from mycelium on the dead grass. The diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with 100 mg/l of streptomycin sulphate. Sclerotium rolfsii was consistently isolated from infected plants. Pathogenicity of three isolates obtained from infected plants was confirmed by inoculating healthy D. repens turf (1 m2 plots and three replicates). Inoculum that consisted of wheat kernels infested with mycelium and sclerotia of each isolate was placed on the soil surface. Noninoculated plots served as controls. The inoculation trial was repeated once. Turf was covered with a plastic film for 7 days, kept at temperatures ranging between 22 and 25°C, and watered as needed. Inoculated plants developed symptoms of leaf yellowing within 11 days, soon followed by the appearance of white mycelium and sclerotia, and then eventually wilted. Control plants remained symptomless. Sclerotium rolfsii was re-isolated from inoculated plants. To our knowledge, this is the first report of S. rolfsii on D. repens in Italy. This disease has been reported on kidney weed in several countries such as the United States (3), Brazil (1), and India (2). References: (1) M. Menezes and J. A. A. Lima. Fitossanidade 1:18, 1974. (2) K. Ranganathan and N. Shanmugam. Indian Phytopathol, 27:113, 1974. (3) J. D. Smith et al. Fungal Diseases of Amenity Turf Grasses. E & F.N. Spon, London, 1989.

First Report of Downy Mildew Caused by Peronospora sp. on Basil (Ocimum basilicum) in France.

Sweet basil (Ocimum basilicum) is an economically important herb in several Mediterranean countries. Approximately 30 ha are grown annually in France for fresh and processed consumption. During the spring and fall of 2004, a damaging foliar disease was observed in some crops near Saint Tropez in the French Riviera Region. More than 50% of plants were affected in an organically produced field-grown crop at an altitude of 250 m. Leaves of infected plants were initially slightly chlorotic, especially near the central vein. Within 2 to 3 days, a characteristic gray, furry growth was evident on the lower leaf surface and sometimes on the upper leaf surface. The appearance and severity of the disease was affected by overhead sprinkler irrigation. Basal leaves were severely affected. Microscopic observations revealed sporangiophores branching two to seven times. Sporangiophores, with a length of 250 to 500 µm (average 350 µm), ended with sterigmata bearing single sporangia. Sporangia measured 15 to 25 × 20 to 35 µm (average 22 × 28 µm), were elliptical and grayish in mass. The pathogen was identified as Peronospora sp. on the basis of its morphological characteristics (4). Pathogenicity was confirmed by inoculating leaves of 40-day-old healthy plants with a sporangial suspension (1 × 105 conidia/ml). Three containers with 150 plants each of O. basilicum cv Genovese gigante were used as replicates. Noninoculated plants served as controls. Plants were maintained in a growth chamber at 20°C (12 h of light per day) and 90 to 95% relative humidity. The pathogenicity test was carried out twice. After 6 days, typical symptoms of downy mildew developed on the inoculated plants, and Peronospora sp. was observed on the leaves. Noninoculated plants did not show symptoms. To our knowledge, this is the first report of Peronospora sp. on basil in France. Peronospora sp. was previously reported on sweet basil in Italy (1) and P. lamii on sweet basil in Uganda (3). Seed transmission (2) is suspected as the reason for recent outbreaks in Europe. References: (1) A. Garibaldi et al. Plant Dis. 88:312, 2004. (2) A. Garibaldi et al. Z. Pflanzenkr. Pflanzenschutz 111:465, 2004 (3) C. G. Hansford. Rev. Appl. Mycol. 12:421, 1933. (4) D. M. Spencer. The Downy Mildews. Academic Press, NY, 1981.