Plant parasites and pathogens

Because of their economic importance, plant pathogenic fungi have been studied extensively (Tuite 1969), often with emphasis on factors affecting spore 

Many assays involving plant pathogenic fungi monitor tropic and tactic responses. Although presented anthropomorphically as mistakes made by these fungi during pre- and post-infection, a review by Wynn (1981) of common causes of failure to complete host plant infection is a useful compendium of variables that can confound design and interpretation of these kinds of experiments. 

Spore germination and host invasion by some plant pathogenic fungi, especially 

Light can profoundly affect in vivo and in vitro toxin bioassays, as has been documented by photosensitization experiments using livestock and poultry (Towers 1980 Ivie 1982). Photoactivation of quinones, certain alkaloids, and other compounds can be assessed by, for example, exposure of agar plates used in diffusion assays to UV-A light (320-400 nm, 5 W/m ) for 2 h while keeping control plates in the dark (Taylor et al. 1995). 

Epidemiological studies, as outlined previously, are difficult, and when bioassays are based on measuring spore survival, infection versus colonization rates, disease intensity, inoculum potential, or any other characteristic, careful experimental design is vital to generating meaningful results (Kranz Rotem 1988). 

---