First Report of Fusarium solani Causing Stunt on Lisianthus

Abstract

Fusarium solani Mart. (Sacc.) is the causal agent of stem rot and damping-off of lisianthus (Eustoma grandiflorum (Raf.) Shinn.) (1). Since the end of the 1980s, when this flower crop was introduced in Argentina, it has been affected by a basal stem rot (2). A previously undescribed disease was observed in 100% of the greenhouses in the Buenos Aires Province that grow lisianthus. Symptoms that developed after seedlings were transplanted included stunting, shortened internodes with reduced stem diameter, and small narrow leaves that were a dull green color. Some affected plants turned yellow-brownish and died 2 to 3 months after transplanting. Other plants recovered but produced low quality flowers later than normal. A third group of plants remained stunted (5 to 10 cm high) until the last flower harvest (about 8 to 10 months). F. solani was consistently isolated from basal stems and roots of diseased plants. For pathogenicity tests, inoculum was produced by culturing the fungus for 10 days in petri dishes containing sterile moistened rice. Inoculum was air dried, crushed, and mixed with soil that had been autoclaved at 112°C for 40 min on each of two consecutive days. The propagules in the soil were estimated by soil plate dilutions on the Nash & Snyder-PCNB medium at a ratio of about 104 CFU/g soil. Twenty plants of each cultivar Echo White and Echo Blue, whose roots had been pruned, were planted in both infested and noninfested soil. After about 40 days, stunting was observed in 85% of the inoculated plants, while controls remained asymptomatic. F. solani was reisolated from symptomatic plants, thus fulfilling Koch's postulates. A test also was conducted in a commercial greenhouse that produced lisianthus for several years, in which healthy plants were planted in three plots fumigated with methyl bromide and in three nonfumigated plots. The mean cfu/g soil of F. solani in the methyl-bromide treated plots was 5 × 102 and 1.6 × 104 CFU/g in the nontreated plot. After 120 days, the incidence of stunting in the treated plots was 0.6 and about 88% in the control plots. F. solani was recovered from symptomatic plants. Because disinfestation of soil is generally practiced in flower production, stunted plants are limited and can be confused with root problems. This is the first report of F. solani causing stunt on lisianthus. References: (1) J. J. Taubenhaus and W. N. Ezekiel. Phytopathology 24:19, 1934. (2) S. M. Wolcan and G. A. Lori. Invest. Agr. Prot. Veg. 11:465, 1996.

Cultivo hidropônico de lisianto para flor de corte em sistema de fluxo laminar de nutrientes

“…Entre os demais patógenos, destaca-se Phomopsis sp., que causa lesões nas hastes e folhas (Freitas et al, 1996;McGovern et al, 2000;Rivas et al, 2000;Wolcan et al, 2001). Essas doenças vêm limitando a produção da cultura, o que justifica o uso de novas técnicas, como o cultivo hidropônico, que pode proporcionar um meio de controle, principalmente das doenças em que o solo é a principal fonte de inóculo (Jensen, 1997).…”

Enanismo y podredumbre basal de eustoma grandiflorum y su relación con la densidad de fusarium solani en el suelo

“…En el manejo comercial del cultivo de lisianthus, es habitual el tratamiento del suelo antes de la plantación. Como consecuencia de esta práctica, no se observa una incidencia tan elevada de enanismo y esta enfermedad puede pasar inadvertida, ya que los síntomas pueden confundirse con problemas de arraigue de los plantines (Wolcan et al, 2001). Luego de la cosecha se presenta la podredumbre basal, dado que la herida producida por el corte de la flor permite el ingreso del patógeno, más aún cuando el corte se realiza a ras del suelo.…”

“…Sacc. provocando podredumbre del tallo y damping off (Taubenhaus & Ezekiel, 1934) y recientemente enanismo (Wolcan et al, 2001), F. oxysporum Schlecht. f. sp.…”

“…ocasionando podredumbre del tallo y de la corona (Koike et al, 1996). De las especies mencionadas, en la Argentina sólo se observó la presencia de F. solani que provoca importantes pérdidas de la producción a causa de la podredumbre basal (Wolcan y Lori, 1996) y el enanismo (Wolcan et al, 2001).…”

Evaluation of 29 Lisianthus Cultivars (<i>Eustoma grandiflorum</i>) and One Inbred Line of <i>E. exaltatum</i> for Resistance to Two Isolates of <i>Fusarium solani</i> by Using Hydroponic Equipment

“…It occurs commonly in Japan and worldwide and causes serious crop losses. Root infection of lisianthus by F. solani has been described in Argentina (Wolcan et al, 2001), Japan (Chikuo et al, 2003;Tomioka et al, 2002Tomioka et al, , 2011, South Africa (Truter and Wehner, 2004), Korea (Choi et al, 2017), and China (Xiao et al, 2018). Continuous monocropping of lisianthus often leads to serious crop losses, with plants displaying severe symptoms despite soil disinfection with steam or chemicals (Zhou et al, 2019).…”