Research on the population genetics of microbial organisms requires the use of specialized analyses designed for clonal organisms to avoid violating the assumptions of traditional population genetic models. The tools necessary for performing these analyses existed as a set of unrelated software with non-overlapping capabilities and did not cover all...
Results from approximately 400 fungus-host pure culture
inoculations indicate that specificity of ectomycorrhizal associations
is a complex phenomenon and cannot be based solely on field observations
of sporocarp-host associations. Of the numerous sporocarp-host
specific fungi tested, most formed ectomycorrhizae with one or more
unexpected, non-associated hosts. These results conclusively demonstrate...
Managers of forest and plantation ecosystems are encountering growing problems involving plant pathogens and the expanding geographic ranges of these pathogens. Historically unexposed stands are exceptionally vulnerable when a non-native pathogen is introduced because these pathogens can cause devastating disease in a host population that lacks co-evolved resistance mechanisms. One...
The scale of pest and disease dispersal is often larger than the scale of individual farms. Therefore, an individual grower’s response to pests and diseases can affect and is affected by their surrounding growing region. Individual growers are also not isolated, and engage in various forms of information gathering, sharing,...
The teliospore of Tilletia caries germinates to produce a promycelium
with a whorl of primary sporidia at its tip. The time between
emergence of the promycelium and the development of primary sporidia
averaged 2.3 h. Fusion between compatible sporidia occurred within
an additional 3.8 h. Primary sporidia appeared to be...
Host-parasite interactions between the pathogen, Sphaerulina musiva, and its host, Populus spp., were examined in a series of studies. In the first study, variation in resistance of Populus nigra from 7 locations in Europe was differentiated based on the parameters cankers per cm and disease severity score. The analysis evaluated...
Partial reactions of photosynthesis were examined in the wild
type strain and six photosynthetic mutants (8, 11, 26, 40, 50, a') of
Scenedesmus obliquus, strain D₃. A reproducible procedure for the
isolation of active chloroplast fragments from Scenedesmus was
developed. Several chloroplast reactions were examined, as well
as two in...
Mycorrhizal fungi in arid and semiarid rangelands have received little study in southwest Asia and north Africa, although they are important in food production and rangeland productivity. The desert truffles of the genera Terfezia and Tirmania form fruiting-bodies and mycorrhizae with rangeland plants. This thesis treats the taxonomy and the...
A hierarchical series of studies, based mainly on molecular data, was conducted to elucidate the life history of the Douglas-fir Swiss needle cast pathogen Phaeocryptopus gaeumannii at macro- and micro-evolutionary scales. This information was then utilized to design and evaluate molecular diagnostic tools for use in studies on the epidemiology...