Crown Rot of Zucchini Squash Caused by Fusarium solani f. sp. cucurbitae in Almería Province, Spain

Abstract

Cucumber, melon, watermelon, and zucchini are intensively cropped in the southern part of Spain where approximately 20,000 ha of the crops are grown in greenhouses. In the spring of 2007, zucchini plants (Cucurbita pepo) at the fruit-bearing stage in three commercial plastichouses in Almería exhibited necrosis on the basal stem, wilt, and death. The incidence of dead plants was 20 to 30%. Fusarium solani was consistently isolated from the basal stems of symptomatic plants on potato dextrose agar (PDA). Cultures of six single-hyphal transfers were identified on the basis of molecular sequences and morphological characteristics (2). Sequences of ribosomal DNA from ITS1 region, 5.8S rDNA, and ITS2 were identical for all six isolates of F. solani. The rDNA sequence of isolate Fscl-3 of F. solani was deposited as GenBank Accession No. AM940070. The pathogenicity of these six isolates of F. solani was tested in two experiments conducted in one plastichouse in Almería. Pregerminated seeds of zucchini cv. Consul were sown in 1-liter containers filled with vermiculite on 21 May and 22 June, 2007 (experiments 1 and 2, respectively). Plants at the one- to two-true-leaf stage or younger were inoculated with a soil drench of 2.0 to 8.4 × 105 propagules per ml). One colonized PDA petri plate of each isolate was blended and homogenized in 500 ml of distilled water. Inoculum (50 ml per plant) was poured around the stem of zucchini plants growing in vermiculite. The experimental design was a randomized complete block with three replicates with each plot comprising four plants (one plant per container). In both experiments, 12 uninoculated plants of the same cultivar served as controls. Plants were maintained for 1 month following inoculation in a greenhouse with mean temperatures ranging between 20.7 and 24.6°C and 23.3 to 29.8°C for experiments 1 and 2, respectively. Wilting first occurred 9 days after inoculation, and 14 days later, all plants inoculated with the F. solani isolates died. Inoculated plants exhibited lesions on the stem base without rot of secondary roots. At the end of the experiment, the uninoculated plants remained asymptomatic. Results of experiment 2, with higher temperatures, were similar. The pathogen was consistently recovered from symptomatic plants in both experiments, fulfilling Koch's postulates. Although F. solani f. sp. cucurbitae race 1 was reported in field squash (C. maxima) in the province of Valencia of east-central Spain (1), to our knowledge, this is the first report of F. solani as the causal agent of crown rot of zucchini plants in plastichouses in the Almería Province of Spain, one of the world's largest concentrations of greenhouses. References: (1) J. García-Jiménez et al. Plant Dis. 81:1216, 1997. (2) C. M. Messiaen and R. Cassini. Taxonomy of Fusarium. Page 427 in: Fusarium: Diseases, Biology, and Taxonomy. P. E. Nelson et al., eds. Pennsylvania State University, University Park, 1981.

Fungal Endophytes as Biocontrol Agents against the Main Soil-Borne Diseases of Melon and Watermelon in Spain

“…Hansen (Fsc) (actually included in genus Neocosmospora). The first one (Fon), with four pathogenic races (race 0, 1, 2, and 3), specifically affects watermelon [11], while Fom, with four pathogenic races (0, 1, 2, and 1.2) [12], is reported to be associated with melon. The third mentioned species, Fsc, is associated with cucurbit species like watermelon, melon, squash, or pumpkin.…”

“…Fu) Sand.-Den. and Crous, respectively, both cited at the national level [7,8,12]. In addition, the other two species, N. falciformis (Carrión) L. Lombard and Crous (=F.…”

Tolerance Screening for Phytophthora capsici and Fusarium solani f. sp. cucurbitae in Cucurbita spp. and Gene Expression Responses in Mutant Families

“…Phytophthora capsici (MI0211, GenBank MG012233) [6] and Fsc race 1 (Fs511, GenBank AM940070) isolates [35], obtained from infected plants in greenhouses in Almería province (Spain) were morphologically and molecularly described in previous studies [6,35]. Both pathogens were preserved in the IFAPA-La Mojonera laboratories and subsequently inoculated on C. pepo, and re-isolated and identified again from dead plants prior to inoculation.…”

Fusarium annulatum causes Fusarium rot of cantaloupe melons in Spain

“…Regarding the Fusarium species affecting cucurbits in Spain, the following species have become particularly important: F. oxysporum (Martínez et al, 2003), and F. solani f. sp. cucurbitae Snyder & Hansen on watermelon grafted to pumpkin (Armengol et al, 2000), zucchini (Gómez et al, 2008) and melon (Gómez et al, 2014). In many studies only Fusarium rots caused by Fusarium sp.…”