Bloss plant pathologist emphasis is being placed on studies of the life cycle of phymatotrichum omnivorum, the cause of root rot in cotton, to determine the role of spore mats and the persistence of strands and sclerotia in the soil in perpetuating and spreading the fungus. Phymatotrichum root rot attacks cotton and some 2,000 other plants in the southwestern united states. Symptoms of phymatotrichum root rot occur most often from june through september after soil temperatures reach 82 f. Phymatotrichopsis omnivora article about phymatotrichopsis. Mycopathologia et mycologia applicata 1973, 50 4, 3321. Industrial crops and products an international journal elsev1er industrial crops and products 4 1995 229232 evaluation of six kenaf cultivars for resistance to phymatotrichum omnivorum c.
Physiological studies on phymatotrichum omnivorum x. There was a direct correlation between growth and substrate concentration. Phymatotrichum omnivorum duggar, annals of the missouri botanical garden 3. Pdf molecular systematics of the cotton root rot pathogen. The broad host range of the fungus includes numerous crop plants, such as alfalfa and cotton. Cotton root rot phymatotrichum omnivorum in the low desert. Only rarely was there any doubt as to the identity of the fungus growth, and in such cases the containers were opened at the end of the experi ment and identification checked by microscopic examination of the fungus. Field plot studies were conducted in 19911993 at weslaco, tx in an area naturally infested with p. Six kenaf cultivars were evaluated for disease incidence at four weeks after initial symptoms and. The disease is limited to certain areas in the deserts of southern california palo verde and to a lesser extent the imperial and coachella valleys, texas and arizona. The optimum temperature and ph for growth were 28 c and 5, respectively. Published by the botanical society of america continuously since 1914, the american journal of botany ajb is the societys flagship research journal.
Natalie goldberg, nmsupdc cruciform hyphae of phymatotrichopis omnivorum from chinese pistache photo. The fruits and vegetables manual is a reference manual on diseases which attack fruits including berries, vegetables, and nuts. Phymatotrichum omnivorum was able to utilize different nitrogen sources with the best growth occurring with nh4no3. Physiological studies on phymatotrichum omnivorum physiological studies on phymatotrichum omnivorum gunasekaran, m. This fungus is serious only in black alkaline soilsph 7. Physiological studies on phymatotrichum omnivorum iv. The glycogen content of phymatotrichum sclerotia1 journal. Phymatotrichum root rot new mexico state university.
Phymatotrichum root rot cotton root rot phymatotrichopsis omnivora phymatotrichum omnivorum. Phymatotrichopsis root rot is also called, texas root rot, phymatotrichum root rot, and cotton root rot. The fungus is only active in summer months when air and soil temperatures are high. Hyphal characters of phymatotrichum omnivorum and sistotrema brinkmannii were compared with the aid of an electron. The fungus produces a rootrot disease commonly referred to as phymatotrichum or texas root rot of over 2,300 species of dicotyledonous plants 3,1 1, 12. Natalie goldberg, nmsupdc chinese pistache infected with phymatotrichum root rot photo. The largest free amino acid pool was present in the natural medium and the smallest in the synthetic medium. Gunasekaran division of biology, rust college, holly springs, mississippi 38635 and w. Tamcot luxor was tested extensively throughout texas and oklahoma for resistance to several pathogens causing seedseedling diseases pythium ultimum trow, rhizoctonia solani kuhn, bacterial blight, phymatotrichum root rot phymatotrichum omnivorum duggar, and verticillium wilt verticillium dahliae kleb. Mar 11, 2009 cotton root rot is an important soilborne disease of cotton and numerous dicot plants in the southwestern united states and mexico. The causal fungus has a host range of more than 1800 species of plants. The strands are made up of hyphae, the body of the fungus. Leaves will turn brown and remain attached to the shrub. Physiological studies on phymatotrichum omnivorum, archives.
Influence of assessment methods on selection of fungal antagonists of the sclerotiumforming fungus phymatotrichum omnivorum. Root bark is decayed and brownish, and bronze colored wooly strands of the fungus are frequently apparent on the root surface. Phymatotrichum omnivorum duggar, 1916 texas root rot also known as phymatotrichopsis root rot, phymatotrichum root rot, cotton root rot, or, in the older literature, ozonium root rot is a pathogen fairly common in mexico and the southwestern united states that causes sudden wilt and death of affected plants, usually during the warmer. Phymatotrichum cotton root rot caused by phymatotrichopsis. Although duggar referred to this placement as tentative in 1916, the name remained until 1973, when hennebert synonymized phymatotrichum with botrytis and created the new genus. Cultural practices are commonly recommended for the control of cotton root rot, and fungicides and fumigants that may suppress the disease have also been used.
Fusarium wilt disease, which attacks a wide range of cultivated plants, causes more. Weber department of botany and range science, brigham young university, provo, utah 846o1 with plates 85 to 87 and 2 text. Weber department of botany and range science, brigham young university, provo, utah 846o1 with plates 85 to 87 and 2 textfigures polar lipid. Find out information about phymatotrichopsis omnivora. Cotton root rot, caused by the fungus phymatotrichum omnivorum, also is known by several other names such as phymatotrichum root rot, texas root rot and ozonium root rot. Mullinschadingc 0 usdaars, subtropical agricultural research laboratory, weslaco, tx78596, usa b department of entomology, plant pathology and weed science, new. Phymatotrichum omnivorum duggar name given in 1916, after observations of conidial mats showed conidial formation similar to other phymatotrichum species 4. Effects of auxins and light on growth of the fungus. Physicochemical p r o p e r t i e s of glycogen r guase aran department of botany and range science, brigham young university, prove, utah. Rhizoctonia, phytopthora, fusarium, verticillium, phymatotrichum omnivorum cotton root rot and other root decay fungi. Mycologia, the official journal of the mycological society of america, publishes papers on all aspects of the fungi, including lichens. Effect of ph and the interaction of temperature, minerals and carbon source on growth in vitro. General information about phymatotrichopsis omnivora phmpom name language.
Full text pdf proceedings of the national academy of sciences sep 10, 2014. It causes a root rot of most tap rooted plants and reportedly has parasitized more than 2000 species of dicotyledonous plants 6. Phymatotrichum omnivorum shear duggar is a soilborne fungus indigea nous to the southwestern united states and mexico. Cotton root rot is an important soilborne disease of cotton and numerous dicot plants in the southwestern united states and mexico. Daucus is the genus of plants that includes carrots, wild carrots, and several related plants, including from 22 to 25 species.
Pythium root rot pythium aphanidermatum pythium deliense. Phymatotrichopsis omnivora previously phymatotrichum omnivorum areas affected. It is one of the most destructive plant diseases and attacks more than 2,000 species. Karyogamy, the process of nuclear fusion is required for two haploid gamete nuclei to form a zygote. Saprophytic survival of phymatotrichopsis omnivora. Vertical distribution in soil of and induction of disease by strands of phymatotrichum omnivorum. The influence of ph, and the combined effect of temperature, minerals and carbon source on the vegetative growth of cotton root rot fungus. Phymatotrichum r oot rot, caused by the fungus phymatotrichum omnivorum, is a serious and destructive disease that significantly reduces cotton yield and lowers lint quality. This fungus is unique because it inhabits the soil at depths to 240 cm or greater 40, 42, 71 and has the potential of surviving for many. Phymatotrichum omnivorum article about phymatotrichum. The manual identifies various types of diseases which are known to invade these plants located throughout north, central, and south america.
Chinese pistache showing symptoms of stress caused by phymatotrichum root rot june 14, 20 photo. Phymatotrichum root rot texas cotton root rot phymatotrichum. Lipids and ultrastructure of phymatotrichum omnivorum. Evaluation of six kenaf cultivars for resistance to. From two to four of these bodies are close to each septal pore in electron micrographs. Phymatotrichum cotton or texas root rot is caused by the soilborne fungus phymatotrichopsis omnivora duggar hennebert. Experiences of a west texas cotton farmer with phymatotrichum root rot douglas wilde wall, texas phymatotrichum root rot indigenous soil born fungus occurs in the southwestern us and mexico the fungus invades the cortical tissues of roots and damages the conducting system, induces severe water stress, and causes premature plant death by desiccation.
Phytophthora, phymatotrichum omnivorum cotton root rot, aphanomyces, monosporascus, armillaria, sclerotinia, postia, verticillium, geotrichum, and other rootdecay fungi. The pathogen that causes texas root rot, phymatotrichum omnivorum, is an indigenous soil borne fungus that is found deep in soils. The causal organism, phymatotrichopsis omnivora phymatotrichum omnivorum, is known only as an asexual, holoanamorphic mitosporic fungus, and produces conidia resembling those of botrytis. The leaves of affected plants dry, turn brown, and remain attached to the plant. Field manual of diseases on fruits and vegetables r. Molecular systematics of the cotton root rot pathogen. The active ingredient in this product colonizes the seed and root system protecting them from harmful fungi.
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