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During December 1999, root and stem rot was observed on greenhouse-grown cucumber (cvs. Albatros, Brunex, Acapulco, and Cerrucho) plants in Almería, Spain, using rock wool cultures. The disease caused severe damage, estimated at a loss of up to 75% of the plants, in the first greenhouse affected; afterward, the disease was found in eight additional greenhouses (14 ha) in 1999 and 2000. Stem lesions extended up to 10 to 12 cm above the crown in mature plants, although no fruit damage was observed. In the advanced stages, abundant development of orange sporodochia was evident on crown and stem lesions, without vascular discoloration. Root, crown, and stem pieces that were placed on potato dextrose agar (PDA) after surface-disinfection with 5% sodium hypochlorite, rinsed, and dried resulted in pure fungal colonies. Based on morphological characteristics of conidia, phialides, and chlamydospores from the isolations, the fungus was identified as Fusarium oxysporum Schlechtend.:Fr. Pathogenicity tests were conducted on cucumber (cvs. Marketmore 76 and Cerrucho [F1 hybrid]), melon (cvs. Amarillo oro, Perlita, Piboule, Tania, and Nipper [F1]), watermelon (cvs. Sugar Baby, Sweet Marvel, Jubilee, and Pata Negra and hybrid Crimson sweet), Cucurbita maxima × Cucurbita moschata, zucchini (cv. Senator), and loofah (Luffa aegyptiaca) at several stages: (i) pregermination; (ii) 1 or 2 true leaves; and (iii) more than 10 true leaves. Five fungal isolates were grown on PDA or shaken potato dextrose broth at 25°C for 8 days. Inoculation was performed in pots (10 seeds or plants of each cultivar or hybrid and isolate) by drenching with 100 ml of a fungal suspension (104 to 106 CFU/ml). Sterile water was applied to noninoculated control plants. Tests were repeated in growth chambers at 25°C (night) and 28°C (day) with a 16-h photoperiod. Fifteen to fifty days after inoculation, cucumber and melon plants at all three stages developed symptoms of root and crown rot in 100% of inoculated plants, with no observed vascular discoloration. Fifty days after inoculation, all three stages of C. maxima × C. moschata and zucchini remained symptomless. Loofah and watermelon germinated poorly or not at all when inoculated at the pregermination stage. Fifteen to fifty days after inoculation, 100% of inoculated cucumber and melon plants developed symptoms. Watermelon plants inoculated at the 10 or more true-leaf stage did not develop disease symptoms. No symptoms developed on noninoculated control plants. F. oxysporum was reisolated from infected roots, crowns, and stems of inoculated plants, confirming Koch's postulates. The main symptoms on cucumber infected by F. oxysporum f. sp. cucumerinum are wilt, yellowing, and vascular discoloration. In contrast, based on inoculation of the host differentials and the resulting disease symptoms found in this study, the fungus was identified as F. oxysporum f. sp. radicis-cucumerinum (1). To our knowledge, this is the first report of F. oxysporum f. sp. radicis-cucumerinum causing root and crown rot in cucumber in Spain. Reference: (1) D. J. Vakalounakis. Plant Dis. 80:313, 1996.

Recently, sweet basil (Ocimum basilicum L.) grown in greenhouses was introduced in Almería, Spain. It is typically cultivated in soil or perlite soilless culture. During the last 6 years, the following symptoms were observed sequentially in basil cultivation: yellowing and wilting of apical tips, wilting and necrosis of leaves and petioles, stunting, black lines along stems and petioles, and discoloration and necrosis of the xylem. Symptoms began at the apex and progressed to the plant base. Within 4 months of planting, symptoms developed in more than 14% of soil-cultivated plants, and in more than 13% of perlite-cultivated plants. Isolations from diseased xylem revealed the presence of Fusarium oxysporum. Inoculations were performed with a fungal suspension (104 CFU/ml) on basil cv. Genovesa, by drenching plants grown in sterile substrate or dipping the roots and transplanting plants into sterile substrate. Of 30 isolates, 80% were pathogenic and resulted in symptoms of the disease described above. The pathogen was reisolated from all inoculated plants. Inoculating Melissa officinalis L., Salvia officinalis L., Origanum majorana L., Mentha piperita L., Satureja hortensis L., and Thymus vulgaris L tested specificity of F. oxysporum. This test utilized the same methods used for basil. None of these species developed symptoms. Results indicated that symptoms of the disease on basil were caused by F. oxysporum f. sp. basilici. Since cultivation of basil is relatively new to Almería, it was necessary to determine the source of the inoculum. Accordingly, 3,200 seeds from Germany and Italy, the primary source of seed in Almería, were analyzed. F. oxysporum was isolated from 0.5% of the seeds. Following methods used earlier, all isolates were inoculated on basil. Fifty percent of the isolates reproduced the disease symptoms. The results suggest that the seeds from Germany and Italy were the source of the inoculum, and to our knowledge, introduced the disease into the growing basil cultures of Almería.

In autumn 1999, crown and root rot along with wilting of cucumber (Cucumis sativus L.) were observed in greenhouses in southeastern Spain (Granada). Symptoms appeared again during the 2000 to 2001 growing season. In spring 2001, root and crown symptoms were observed also on melon (Cucumis melo L.) in greenhouses in another area of southeastern Spain (Almeria). Isolates from diseased plants from both locations were identified as Phytophthora capsici (Leonian). Isolates produced papillate sporangia of variable shape, some of them with two or three papilla. Sporangia were caducous with pedicels of variable lengths that could be longer than the sporangia. Three isolates were crossed with P. capsici strains of known mating type. All isolates produced amphigynous antheridia and were mating type A1. Isolates grew well at 35°C and did not produce chlamydospores. Pathogenicity was examined for one isolate from cucumber and one from melon. Cucumber and melon plants at the four-leaf stage and pumpkin (Cucurbita maxima × C. moschata) plants at the five-leaf stage were inoculated with a mycelium suspension. Both isolates caused wilting and death of plants on the three host species tested. The pathogen was reisolated from roots and stems of diseased plants. To our knowledge, this is the first time P. capsici has been found on cucumber in Spain. It is also the first time P. capsici has been found on melon in the greenhouses of southeastern Spain, and the first time it has been reported to cause root and crown rot of melon. Previously, P. capsici has been reported to cause disease of field-grown melon (2) and greenhouse-grown pepper (Capsicum annum) (1) in eastern and southeastern Spain, respectively. References: (1) J. C Tello. Comun. INIA 22, 1984. (2) J. J. Tuset Barrachina. An. INIA 7:11, 1977.

During October and November 2001, four nurseries reported severe losses in production of pepper seedlings (Capsicum annuum). Plants were affected with the following symptoms: chlorotic spots on upper leaf surfaces along with a dark brown felt and violet reflections on the undersurface of leaves. Spots became necrotic and expanded to include almost the entire blade prompting defoliation that made the plants worthless. These disease symptoms had not been observed in Spain previously. At least four pepper seedbeds were affected and 1.6 million plants (>40% total production) suffered severe defoliation. California type cultivars that produce yellow fruit (Capino, Vélea, and Fiesta) exhibited more severe symptoms compared with cultivars that produce red fruit (Orlando, Haban, Barbadillo, Ribera, and Requena). Lamuyo type cultivars were not severely diseased. Identification of the parasitic fungus from leaves revealed that Peronospora tabacina was the causal agent of downy mildew in pepper, the same pathogen known as the causal agent of tobacco blue mold. Sexual reproductive structures were not found on pepper leaves. Sporangia and sporangiophores corresponded with those described for P. tabacina (synonym P. hyoscyami f. sp. tabacina) (3). The shape of sporangia was spherical in the youngest sporangia and oval to elliptical in mature sporangia (23 × 16 μm). Sporangia were borne on dendritic, dichotomously branched sporangiophores that branched four to eight times and terminated in curved, acute apices. Sporangiophores occurred singly or in small groups. Pathogenicity tests were conducted on California and Lamuyo type pepper cultivars. An inoculum suspension prepared by washing leaves with distilled water was sprayed on seedlings with four true leaves. Inoculated seedlings were maintained at temperatures of 15 to 25°C (night/day). P. tabacina exhibiting the same morphological features as those described above was observed 15 days later on pepper leaves. This disease on pepper was described first in the United States (1,2) and subsequently reported in Greece and Australia (2). The fungus caused disease in nurseries producing pepper seedlings following production of tobacco seedlings or close to other tobacco plants (1). In Murcia, this downy mildew in pepper appeared in pepper nurseries with supplemental heating and did not appear in those without heating. However, the disease spread when diseased pepper seedlings were moved to nonheated nurseries greenhouses. The inoculum may originate from tobacco plants introduced in the greenhouses for the purpose of propagating parasites of whitefly (Bemisia tabaci). Otherwise, tobacco is not cultivated in the Murcia region. References: (1) G. M. Armstrong and W. B. Albert. Plant Dis. Rep. 17:37, 1933. (2) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory, On-line publication. http://nt.ars-grin.gov/fungaldatabases/databaseframe.cfm. August 2, 2002. (3) G. Hall. Peronospora hyoscyami f. sp. tabacina. No. 975 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1989.

During the winters of 2002 and 2003, a wilt occurred in melons cultivated on 1,500 ha in Colima State, Mexico. Yield losses reached 25% of final production, despite soil disinfestation with 60% methyl bromide and 40% chloropicrin. On the basis of the observation of plants with necrotic xylem, yellowing, and wilting of leaves, this disease was identified provisionally as Fusarium wilt. During February 2003, four soil samples from affected fields were plated onto a Fusarium-selective medium (1), which resulted in the detection of 2,260 ± 357, 179 ± 76, 668 ± 357, and 1,391 ± 256 CFU/g of F. oxysporum (3). Thirty-one randomly chosen isolates were used to inoculate differential cultivars of melon as described by Risser et al. (4). The cultivars were Amarillo Canario (susceptible to all races), Diana (resistant to races 0 and 2), Tango (resistant to races 0 and 1), and Vulcano (resistant to races 0, 1, and 2) (2). Ten plants of each cultivar, grown on sterilized vermiculite, were inoculated at the first true-leaf stage by drenching with 200 ml of a conidial suspension (1 × 105 CFU/ml) of each isolate. Noninoculated plants of each cultivar served as controls. Plants were maintained in a growth chamber with a 16-h photoperiod (18 × 103 lux) and temperatures at 23 to 25°C. Yellowing, wilt, and vascular discoloration symptoms developed on cvs. Amarillo Canario and Diana following inoculation with each of the 31 isolates, while noninoculated plants remained symptomless. F. oxysporum was consistently reisolated on potato dextrose agar from the affected plants. On the basis of the combination of affected cultivars, all isolates were identified as F. oxysporum f. sp. melonis race 1. To our knowledge, this is the first report of F. oxysporum f. sp. melonis race 1 in Colima State, Mexico. References: (1) H. Komada. Rev. Plant Prot. Res. 8:114, 1975. (2) J. Marín Rodríquez. Portagrano 2004. Vadmecum de Variedades Hortícolas. Agrobook, Spain. 2004. (3) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, 1983. (4) G. Risser et al. Phytopathology 66:1105, 1976.