Search results for "root rot"

Infection and spread of root rot caused byHeterobasidionspp. inPinus contortaplantations in Northern Europe: three case studies

2019

This study investigated the origins and spread patterns of Heterobasidion root disease in three Pinus contorta Dougl. ex Loudon plantations established on forest and agricultural land and subjected to three different management scenarios. Trees with decline symptoms and stumps remaining from the previous rotation were sampled for fungal isolations. Ten isolates of Heterobasidion parviporum Niemelä & Korhonen and 425 of Heterobasidion annosum (Fr.) Bref. were tested for clonality through somatic compatibility tests. The following conclusions were reached: (i) P. contorta is highly susceptible to H. annosum and H. parviporum and both pathogens cause dieback of P. contorta; (ii) H. annosum…

Blight of English Ivy (Hedera helix) caused by Sclerotium rolfsii in Sicily

2007

English ivy, Hedera helix L. (Araliaceae), an evergreen climbing vine is widely cultivated as an ornamental and foliage plant. In the summer of 2005, a severe blight of ivy plants trained as topiaries and grown in an open field was observed in a nursery near Giarre (eastern Sicily). Foliage of infected plants appeared lighter green and progressively turned bronze and withered. Eventually, the entire plant collapsed. Foliar symptoms were associated with basal stem and root rot. White, cottony mycelium and numerous sclerotia developed externally on the lower stem and on the soil around the affected plants. The disease was randomly distributed, affecting approximately 5% of plants in a stock …

First report of root and crown rot of sage caused by Phytophthora cryptogea in Italy

2019

Sages are cultivated as aromatic and ornamental plants in Italy and represent the common name of certain species of Salvia and Phlomis (family Lamiaceae). In Sicily (southern Italy) during the summer of 2001, ≈40% of 1,400 2-year-old landscape plants of S. leucantha Cav. (Mexican bush sage or velvet sage) showed symptoms of stunting, chlorosis, and gradual dieback or sudden wilt, which are associated with root and crown rot. Plants were supplied by a commercial nursery, transplanted from pots in the spring, and irrigated using a trickle system. Phytophthora was isolated consistently from roots and basal stems of symptomatic plants on a BNPRAH medium (2). The species was identified as P. cr…

Collar and root rot of olive trees caused by Phytophthora megasperma in Sicily

2019

Olive (Olea europea L.) is grown on about 154,000 ha in Sicily (southern Italy). In the summer of 1999, a few 3-year-old olive trees with decline symptoms were observed in a recently planted commercial orchard in the Enna province (Sicily). The trees were propagated on wild olive (O. europea L. var. sylvestris Brot.) rootstock. Aerial symptoms, consisting of leaf chlorosis, wilting, defoliation, and twig dieback followed in most cases by plant death, were associated with root rot and basal stem cankers. A Phytophthora sp. was consistently isolated from rotted rootlets and trunk cankers using the BNPRAH (benomyl, nystatin, pentachloronitrobenzene, rifampicin, ampicillin, and hymexazol) sele…

First Report of Phytophthora spp. as Pathogens of Pandorea jasminoides in Italy

2019

In the summer of 2005, approximately 5% of a nursery stock of 12-month-old potted plants of bower vine (Pandorea jasminoides (Lindl.) K. Schum.) in Sicily (Italy) showed wilt, leaf chlorosis, defoliation, root rot, and collapse of the entire plant. Three Phytophthora spp. (20, 50, and 30% of the isolations of the first, second, and third species, respectively) were isolated from rotted roots on BNPRAH selective medium (2). Single-hypha isolates of the first species formed petaloid colonies on potato dextrose agar (PDA) and had an optimum growth temperature of 25°C (9.3 mm/day); on V8 juice agar, they produced uni- and bipapillate, ovoid to limoniform sporangia with mean dimensions of 45 × …

Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe

2021

Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates…

Root rot pathogens on Calamondin grafted on Volkameriana lemon, in Sicily

2010

Pea root rot diseases : characterization and biocontrol of the disease complex including Aphanomyces euteiches.

2021

Root rots in peas are a major concern in most growing regions around the world. The disease is caused by a parasitic complex made up of many species of soil-borne fungi and oomycetes. In France, the main pathogen involved until recently was the oomycete Aphanomyces euteiches. The identity of the other components of the parasitic complex and their respective contributions to the disease have not been investigated. No control method is currently available to effectively control the disease, apart from a predictive biological test questioned by some users. However, this test allows the avoidance of infested plots, which furthermore limits the multiplication in soils of A. euteiches, i.e. the m…

Root rot of pea: characterization and biocontrol of the soil-borne disease complex including Aphanomyces euteiches

2018

Pea root rot is an increasing constraint in most of intensive pea cropping areas across the globe. The pathogenic complex responsible for the disease is composed of soil-borne fungal and oomycete pathogens such as Fusarium solani, F.oxysporum, F. avenaceum, F. culmorum, Rhizoctonia solani, Thielaviopsis basicola, Ascochyta pinodella, Pythium spp., Aphanomyces euteiches and probably others not yet identified. The diversity of their ecological and pathogenic properties can explain the worldwide dispersion of the disease and the absence of chemical, agricultural or genetic control tools. My research program aims at characterizing the parasitic consortium occurring in the North of France and at…

Root rot of pea : characterization and biocontrol of the soil-borne disease complex including Aphanomyces euteiches

2018

Pea root rot is an increasing constraint in most of intensive pea cropping areas across the globe. The pathogenic complex responsible for the disease is composed of soil-borne fungal and oomycete pathogens such as Fusarium solani, F.oxysporum, F. avenaceum, F. culmorum, Rhizoctonia solani, Thielaviopsis basicola, Ascochyta pinodella, Pythium spp., Aphanomyces euteiches and probably others not yet identified. The diversity of their ecological and pathogenic properties can explain the worldwide dispersion of the disease and the absence of chemical, agricultural or genetic control tools. My research program aims at characterizing the parasitic consortium occurring in the North of France and at…