Introduced Fungi: Some Cause Significant Plant Disease Problems

Species of the three groups of fungi characterized here on the basis of their energy source acquisition have differing potentials for becoming problem organisms following introduction as alien fungi new to Iowa. The decomposer group of fungi that obtain an energy supply by action of extracellular enzyme activity on dead plant tissues typically have perennial mycelium, are cosmopolitan in distribution, and are unlikely to become problems even if established. The second group, the mycorrhizal/lichen group are highly specific in their relationships. The mycorrhizal fungus group have a potential for being introduced as mycorrhiza already established with the roots of particular vascular plants. Their potential for survival and establishment would be linked with that of their vascular plant associate. The third large and diverse group of plant parasitic fungi holds great potential for becoming destructive problem fungi on susceptible native plant species. In Iowa, the development of the white pine blister rust fungus Cronartium ribicola Fischer on Pinus strobus L. and Ophiostoma ulmae (Buisman) Nannf. and Ophiostoma nrwo-ulmae Brasier on elms, particularly on Ulmus americana L., are classic examples of the destruction of native plant species by introduced fungi

In Memoriam: George Knaphus

George Knaphus, 75, died Saturday, 20 May 2000, after a two year battle with lymphoma. He was born at McCallsburg, Iowa and resided on a farm near there except during his WWII service years and his undergraduate college years at UNI until moving to Ames in 1998. He graduated from McCallsburg High School in 1942, served in the U.S. Army from 1943-45 in the 112th Infantry 28th division in Europe, and fought in the Battle of the Bulge, receiving the Bronze Star. He graduated with a B.S. in education from Iowa State Teachers College in 1949, earning master and doctorate degrees in plant pathology in 1951 and 1964, respectively, from Iowa State University. He married Marie Gjenvick in August 1947. He farmed and served as teacher and principal at McCallsburg Consolidated School and as a science teacher at NESCO High School prior to returning to Iowa State University to complete his doctoral studies. He joined the faculty at Iowa State University in 1964, eventually serving as a professor in the departments of Botany and of Curriculum and Instruction. He is survived by his wife, Marie, sons Kris and Dan, daughters Debbie and Dawn and nine grandchildren

Further Observations on Claviceps Purpurea

Utilizing techniques which make possible the production of perithecia and ascospores of Claviceps purpurea (Fr.) Tul. in the laboratory ( 9), more detailed observations upon various phases of sclerotial and ascospore germination of this fungus have been made. The ergot bodies (sclerotia) used in these studies were collected from forty-one species of Iowa grasses. (Table I). Collections of C. pusilla Ces. were also made on three Andropogon species

Plant Parasitic Fungi of Ten Tallgrass Prairies of Iowa: Distribution and Prevalence

During the 1980s and 1990s, collections of fungal parasites on above ground parts of prairie plants in Iowa were made throughout the growing seasons. This report presents the fungi recorded from three groups of Iowa tallgrass prairies. The western group was composed of Dinesen, Steele and Stinson Prairie State Preserves, a Loess Hills group of collecting sites in Five Ridge and Runkel Prairie State Preserves and prairies at Waubonsie State Park. 180 species of fungi were collected on 116 hosts from these prairies. A central Iowa group of prairies associated with the Des Moines Lobe landform, Anderson, Doolittle, Kalsow and Ames High (Pohl) Prairie State Preserves, yielded 162 species of fungi from 91 hosts. Two sand prairie state preserves, Cedar Hills and Marietta, provided 78 fungi on 54 hosts. 116 of the species encountered in the current study were not reported in a previous 1990 study of four northern Iowa prairies

Iowa Lichens: An Annotated Listing

The previous listings of Iowa lichens were compiled in the l890\u27s and early 1900\u27s and represented collections primarily from three Iowa counties. In the intervening years, several listings of local lichens have been published. The lichen flora of Iowa as presented here consists of 74 genera with 263 species and is a compilation of previously reported species, of herbarium specimens, and of observations made by the authors. A notation of habitat follows each entry in addition to the general listing of lichens found in similar habits summarized in the discussion

Myxomycetes of Big Bend National Park, Texas

Seventy species of Myxomycetes have been collected directly in the field or observed later in the laboratory from field materials in moist chambers from Big Bend National Park, Texas. Collections were made over a 10 year period, 1989-1997 and 1999, during intensive seven-day fungus collecting trips to Big Bend in late September each year. McGraw (1968) in an earlier study of Texas Myxomycetes had reported 28 species from Big Bend, some of which were also found in this study. A total of 81 species are reported from the park. A variety of environmental conditions occurred during the 10 years with different yearly yields of myxomycetes. The most common species, both in number of years collected, seven, and in incidence per year, was Fuligo megaspora. Thirty-six species were collected only once during the 10 year study reported here

The Plant Rusts (Uredinales) of the Driftless Area of Northeastern Iowa

Several individuals have studied the plant rusts in the driftless area of lowa. Of these, E. W. D. Holway, a Decorah banker, made by far the greatest contribution, having made the initial collection of 120 rusts in Iowa. Alois Kavorik of Spillville was also an early student of the rusts, frequently collecting with Holway. This paper summarizes the collections of these men and others, including our collections. A total of 132 plant rusts have been found in the driftless area. Of these, 28 have been found in Iowa only in the driftless area. In many cases, the host plant(s) for these rusts are found in other parts of the state in similar habitats

A Checklist of Iowa Foliose Lichens

Ninety-one species in 16 genera of foliose lichens are reported from Iowa based on herbarium material from 49 counties and current field collections in 22 counties. Nineteen species are listed as new for the state: Anaptychia obscurata, Lecanora melanophthalma, Parmelia borreri, P. flaventior, P. hypotropa, P. mexicana, P. reticulata, P. recipienda, P. squarrosa, P. ulophyllodes, P. perforata, Peltigera lepidophora, Phaeophyscia sciastra, P. hirtella, P. pusilloides, Physcia caesia, P. melanchra, Pyxine caesiopruinosa, Umbilicaria vellea

The McCormick Effect in Cultures of Diaporthe phaseolorum var. batatatis from Soybeans

One of the problems of the investigator of parasitic fungi is that of obtaining ascospore stages of the organism in cultures derived from diseased plant parts. Such cultures often produce mycelium or mycelium and conidia without the corresponding ascospore stage. With the advent of our knowledge of heterothallism such sexual stages have often been grown artificially by the mating of self-sterile strains. A few cases of heterothallism, in which the sexes are segregated on separate thalli, are also known. Finally, with homothallic fungi that fruit with difficulty in ordinary culture some advance on the problem has been made by students of the nutritional requirements of fungi, particularly under the leadership of Lilly (3). These workers have found that supplementation of of the substrate with vitamins often leads to fruition in cultures that have hitherto been considered sterile or lacking in one or more spore stages

A Preliminary Survey of the Iowa Species of Hypocreaceae and Clavicipitaceae

Recent unusual Iowa collections of members of the Hypocreaceae and Clavicipitaceae are reported. Scoleconectria polythalama (Berk.) Seaver on Syringa and Fraxinus, Nectria coccinea Fr. on Juglans nigra L., Nectria verrucosa (Schw.) Sacc. on Marus alba L., Calonectria diminuta (Berk.) Berl. & Vogl., Hypocrea citrina (Pers.) Fr., Hypocrea patella Cke. and Pk. are reported for the first time. Thyronectrioidea chrysogramma (Ell. and Ev.) Seaver on Ulmus americana L. is the first report of this species on this host from Iowa. In addition observations on the life cycles of Scoleconectria scolecospora (Bref.) Seaver and Cordyceps clavulata Schw. are made