Phytophthora cactorum is a plant pathogen that causes root rot, rhizome rot of strawberry, applerot, applecollarrot and crown rot. It has an extremely wide host range. Collarrot of apple trees may also affect trees infected at the nursery. Certain rootstocks are more susceptible. The collarrot life cycle requires high moisture and cool temperatures. LibraryPests & DiseasesApple Root and CollarRot. Apple.Collarrot occurs above the soil line on the lower trunk. Crown rot of the rootstock and collarrot of the scion wood of apple trees is caused by a soilborne fungus.Crown or collarrots may completely girdle trees, resulting in death. 1.P. cactorum collar-rot of the Cox Orange Pippin apple variety in the Netherlands is described, and cultural practices favorable to its initiation are mentioned. Applecollar tot (ACR) was originally. described as apple southern blight in the USA and has also.collarrot by Sclerotium rolfsii on apple trees in Italy. Plant. Disease 83: 695. Bacterial antagonists in management of collarrot and root rot diseases in apple. Acta Hort. 696: 349-354. Phytophthora Crown and CollarRot of Fruit Trees.The crown rot disease on apples and pears is caused by Phytophthora cactorum. Root/CollarRot of Apple. Return to Diseases. Root/collarrot (Phytophthora cactorum, Phytophthora spp.) is first noticed by aboveground symptoms. Key Words: apple , collarrot , Phytophthora cactorum , identification. Crown or collarrot has caused extensive death of apple trees in many eastern orchards during the past two decades. It often occurs on trees between 3 and 8 years of age grown on... The form of apple tree crown rot that occurs in the irrigated orchards of British Columbia is confined to the below-ground bark tissues of the tree. Pythium ultimum causes a collarrot disease on apple have been isolated from bark lesions and soil, identified, and similar to that caused by Phytophthora cactorum. Keywords: apple, canker, collarrot, endophyte, Nectria galligena, Topaz.No obvious root or crown rot symptoms were observed on the rootstock of the affected trees.
