| Summary |
In an effort to control diseases of cultured marine Crustacea caused by the fungi Lagenidium callinectes, Haliphthoros milfordensls and Fusarlum solani, isolates of each species were subjected to toxicity testing with a number of experimental fungicides and ozone. Three fungicides, R-41-782 (Tavolek), IL-780 (ICI Americas), and EL-131 (Eli Lilly and Co.), were shown to be most effective, with LC₁₀₀'s of less than 2 ppm. for both L. callinectes and H. milfordensis. For F. solani the LC₁₀₀ for all fungicides exceeded 50 ppm. Ozone was highly effective also and caused zoospore death within 8 minutes after ozonation. Another aspect of this study involved the fact that differences among various isolates of Lagenidium callinectes Couch have caused some investigators to question the validity of callinectes as a single species. Therefore, morphological and physiological characters for eight isolates were evaluated in an attempt to quantify differences, if any, among the isolates that might facilitate their recognition as one or more species. Although results of the morphological evaluation were inconclusive, clustering analysis of physiological characters grouped the isolates in distinct subgroups, with the isolates in each subgroup noted to occur in similar geographic regions. Although the physiological differences were consistent among the subgroups, such differences were not deemed sufficient for recognition of separate species within the callinectes "complex" because of the overall morphological similarity of the isolates. |
