Contribution No. 55.

The sensitivity of Lagenidium spp. isolated from Penaeus monodon and Scylla serrata to 34 antimycotic compounds was determined. Mycostatic effects were evaluated from observations of chemicals on the development of vesicles, zoospores and mycelial growth and on these bases three classes of mycostatic effect were recognized. Zoospores were inhibited by < 1 mg/1 of clotrimazole, crystal violet, econazole nitrate, malachite green, treflan and trifluralin; 1-5 mg/1 of benzalkonium chloride, daconil, domestic detergent, basic fuchsin and furanace; and 10-50 mg/1 benlate, formalin, griseofulvin, phenol and potassium permanganate. Variable mycostatic levels, however, were exhibited with copper sulphate, 2,4-D, hydrogen peroxide, methylene blue, pimaricin, resiguard and tolnaftate while amphotericin, iodine, nystatin, triacetin, boric acid, fungitox and PVP-iodine proved to be poor antifungal agents.