Search results for "Root rot"
showing 8 items of 18 documents
Les pourritures racinaires du pois potager, caractérisation et biocontrôle du complexe parasitaire d’origine tellurique incluant Aphanomyces euteiches
2021
Pea root rots are a major concern for pea growing regions around the world. The disease is caused by a parasitic complex composed of many species of fungi and oomycetes of soil origin. In France, the main pathogen is the oomycete Aphanomyces euteiches. The identity of the other components of the parasitic complex and their respective contributions to the disease have never been investigated. No means of control is currently available to effectively control the disease except for a predictive bioassay that is questioned by some users. However, this test allows the avoidance of infested plots, which limits the multiplication of the major pathogen A. euteiches in the soil. In this context, the…
First report of Phytophthora palmivora on Coronilla valentina subsp. glauca in Italy
2019
The genus Coronilla L. (family Fabaceae), which includes several species native to central and southern Europe, such as C. varia L. (axseed or crown-vetch), C. emerus (scorpion senna), and C. valentina L., is used in Italy as a landscape shrub or potted ornamental plant. During the summer of 2001, 80% of approximately 10,000 1-year-old plants of C. valentina subsp. glauca (L.) Batt. used to landscape an industrial area in the Caltanissetta Province (Sicily) showed symptoms of dieback associated with basal stem and root rot. Plants had been transplanted from pots in April and watered using a trickle irrigation system. A species of Phytophthora was isolated consistently from rotted roots and…
Root and Basal Stem Rot of Rose Caused by Phytophthora citrophthora in Italy
2011
Approximately 800 ha of cut flower roses are cultivated for commercial production in Italy. During autumn of 2004 in an experimental greenhouse in western Sicily (southern Italy), 60% of 2-year-old plants of rose cv. Red France on Rosa indica cv. Major rootstock grown in soil showed leaf chlorosis and wilt. A dark brown lesion lined by a water-soaked area was noticeable at the stem base near the soil surface. Root rot was found consistently associated with aboveground symptoms and plants collapsed within 4 months after the appearance of the first symptoms. The same symptoms were observed sporadically on rose plants of the same cultivar during the last 6 years in commercial nurseries in wes…
Phytophthora species causing crown and root rot of tomato in southern Italy
2000
Phytophthora capsici, Phytophthora cryptogea and Phytophthora nicotianae were isolated from tomato plants with symptoms of crown and root rot in plastic-house crops in Sicilia and Calabria (southern Italy). The species were identified primarily on the basis of morphological and cultural characteristics. The identification was confirmed using molecular methods, polyacrylamide gel electrophoresis (PAGE) of mycelial proteins and polymorphism of DNA sequences amplified by polymerase chain reaction using random primers (RAPD-PCR). P. capsici caused significant losses in tomato crops that had succeeded capsicum crops. P. cryptogea was found to be the most frequent species causing basal stem rot o…
First report of Phytophthora palmivora as a pathogen of olive in Italy
2000
Olive (Olea europea L.) is an economically important crop in Italy and is planted on about 1 million ha. The Apulia, Calabria, and Sicily regions of Southern Italy account for about 70% of the production. Many new plantations have been established during the last 10 years. In summer 1999, 1- to 2-year-old olive trees (cv. Carolea) with decline symptoms were observed in new plantations in Catanzaro Province (Calabria). The symptoms associated with the root rot were leaf chlorosis, defoliation, wilting, twig dieback, and eventual plant collapse. In some cases, more than 40% of the trees were affected. A Phytophthora sp. was isolated consistently from rotted rootlets of diseased trees using a…
Resistance of Phytophthora capsici to metalaxyl in plastic-house capsicum crops in southern Italy
2000
In Calabria (southern Italy), control of crown and root rot of capsicum caused by Phytophthora capsici has relied primarily on soil drenches of metalaxyl. However, severe outbreaks occur every year in glasshouse crops, in which the practice of using plastic mulch and furrow irrigation favours the disease. Single-hypha isolates of P. capsici collected in Calabria in 1992/1998 were tested in vitro for their level of sensitivity to metalaxyl. Isolates of other species of Phytophthora were used as reference. Fungicide sensitivity was determined by plating mycelial plugs onto potato dextrose agar amended with metalaxyl, at final concentrations ranging from 0.1 to 1000μg mL−1 a.s. Inhibition of r…
Phytophthora palmivora a New Pathogen of Lavender in Italy
2019
Root rot caused by Phytophthora nicotianae is considered the most serious disease of lavender in commercial cultivations in Italy. In summer 2001, in the Gela area (Sicily), ≈60% of 34,000 2-year-old landscape shrubs of English lavender (L. angustifolia) grown in a clay loam soil showed symptoms of dieback associated with root rot. Plants had been transplanted from pots in May and watered using a trickle irrigation system. A species of Phytophthora was isolated consistently from roots of symptomatic plants using potato dextrose agar (PDA) containing benomyl, nystatin, pentachloronitrobenzene, rifampicin, ampicillin, and hymexazol. The species was identified as P. palmivora on the basis of …
Differentiation of the Disease Caused by Aphanomyces cochlioides and Girth Scab on Sugar Beet Roots – a Review
2017
Severe symptoms of root rot on sugar beet have been observed in Poland and Germany since 2001. The symptom classification suggested girth scab as it was mistakenly classified on the basis of current classification, e.g. in LIZ. However, the cause of the disease was Aphanomyces cochlioides infection, not Streptomyces spp. According to these findings we cannot call the symptoms caused by A. cochlioides as ‘girth scab’. The typical scab (girth scab) symptoms can be promoted by A. cochlioides infections. In many cases, A. cochlioides developed at the beginning of the season, during the seedling stage. Its further development was due to rainfall and was not routinely recognised in disease-change…