The spore forms of the sooty moulds on sugar canes are extraordinarily diverse, not infrequently no less than six forms being found on the same leaf in Formosa. The fungi spread on the leaves infested with the aphid, Ceratovacuna lanigera ZEHNT., and appear to be closely related to those of India, Queensland and other countries. The results of the studies made on the cultures originated from a single spore of each form reveal that the moulds on the sugar cane can be separated into at least three different species, namely, olivaceous, black, and brownish sooty moulds. 1. The olivaceous sooty mould, Fumago vagans PERS., fine powdery; thin subiculum generally on the upper surface of the leaves. Conidiophores simple, erect, more or less geniculate at the upper part, yellowish brown to dark brown, 3-16-septate, 22-16 × 3.6-6μ. Conidia acropleurogenous, catenulate in short chains, ellipsoid, ovoid or oblong, continuous or 1-septate, rarely 2-septate, light fuscous to dark olive, 5-16 × 3-6.5μ, rarely up to 23 μ. Gemma-like chlamydospores irregularly ellipsoid, ovoid, oblong or subglobose, generally 2 to several muriform-septate, or sarcinaeform, olivaceous brown to dark brown, thick-walled, 7-23 × 5-19μ.
Specialization in Sphaerotheca fuliginea (SCHLECHT.) POLL. parasitic on various plants in Formosa was studied by inoculation experiments as well as by comparing the morphological characters of the conidia. So far as the present experiments are concerned, the following six biological species can be distinguished inter se. A. Conidia with an average length of 29μ 1. Parasitic on Balsam (Impatiens Balsamina) B. Conidia with an average length of 32μ a. Conidia with an average width of 18μ 2. Parasitic on Cucurbitaceae 3. Parasitic on Lactuca indica var. dracoglossa and related species b. Conidia with an average width of 20μ 4. Parasitic on egg plant (Solanum Melongena) 5. Parasitic on Hibiscus mutabilis C. Conidia with an average length of 36μ 6. Parasitic on Emilia sonchifolia
1. In the present work were studied the penetration phenomena in Pseudoperonospora cubensis BERK. et CURT. inoculated on its hosts and other plants. 2. A large number of zoospores are often observed to encyst on the surface of their suspension drop on a slide or cover glass and the cysts produce the germ tubes uprightly above the surface. 3. The zoospores in a suspension drop on the lower surface of a cucumber leaf often swim along the boundary line of the epidermal cells, dashing themselves repeatedly against the stomata or the boundary line. This mode of the swimming movement appears to show the response of the zoospores to a stimulating substance diffused from the epidermis. 4. On the leaf of the cucumber zoospores encyst on the stomata and along the boundary line of the epidermal cells, being more numerously in the former than in the latter. Usually only a single cyst is found on a stoma irrespective of its size. 5. The zoospore encysted on the stoma sends out a penetrating hypha into the stomatal aperture and forms the vesicle in the substomatal cavity. Then the infection hypha developed from the vesicle reaches the parenchymatous cell and inserts the haustorium into it. 6. The cyst lying on the boundary line produces a slender hypha which is in a rare case successful in penetration through the stomata. 7. Penetration through the stomata is observed on the cotyledon. but not on the petiole, stem, and hypocotyle. 8. Inoculations on 73 species of Phanerogams ranging over 32 families including the Cucurbitaceae and on a fern plant show that 49 dicotyledonous plants (22 families) are penetrated by this fungus, always through the stomata and as easily on several plants as on the host. 9. On the upper surface of the epidermis stripped from the cucumber leaf encystment of zoospore and penetration take place in the same manner as on the intact one. On the other hand, when inoculated on the under surface of the stripped epidermis encystment and penetration are usually found on the boundary line. 10. The zoospores are attracted by the mesophyll cells of the cucumber leaf and after encysting upon their surface are able to produce the hyphae and haustoria. 11. On the lower surface of the cucumber leaf killed with boiling water the occurrence of encystment and penetration are less frequent than on the living one. The penetrations are obtained through the boundary line as well as the stomata, but the hyphae soon degenerate.
1. This paper described the extent of the wastage, the classification of diseases of the banana in transport from Formosa and their etiological relations. Moreover, by studying the relations of temperature to the growth of several important fungi, the general control method was discussed. 2. The wastage of the banana in transport from Formosa is counted to be about 2% of the total number of the discharging cargos and ca. 300, 000 Yen per year. 87% of the wastage is regarded to be the loss due to diseases, among which 59% of the wastage is due to non-infectious diseases and 28% to infectious diseases. 3. The writer classified the diseases of the banana in transport as follows: (1) non-infectious diseases, so-called physiological diseases green-ripeness, “Kaze-hiki”. (2) infectious diseases a) main-stalk rot- “Ziku-kusare” disease b) finger-stalk rot-finger dropping c) finger rot-black-rot disease, sclerotium disease, graymould disease, anthracnose, black-spot disease. 4. The green-ripeness is a physiological disease due to excessive high temperatures, and on the contrary “Kaze-hiki” is caused by excessive low temperatures. The causal fungi of the infectious diseases were proved to be as follows: “Ziku-kusare” disease - Thiclaviopsis paradoxa (de SEYNES) von HÖHN., Botryodiplodia Theobromae PAT., Glocosporium musarum CKE. et MASSEE, Fusarium spp. etc. finger dropping - Glocosporium musarum CKE. et MASSEE etc. blcak-rot disease - Botryodiplodia Theobromae PAT. sclerotium disease - Corticium centrifugum (LÉV.) BRES. gray-mould disease - Rhizopus nigricans EHR. anthracnose - Gloeosporium musarum CKE. et MASSEE black-spot disease-Macrophoma Musae (CKE.) BERL. et VOGL. 5. Botryodiplodia Theobromac PAT. and Glocosporium musarum CKE. et MASSEE grow scarcely at ca. 11°C, While Thiclaviopsis paradoxa (de SEYNES) von HÖHN. is able to grow a little slowly at the same temperature. 6. Judging from the results of the writer's experiments, the refrigerated transport at about 11°C seems to be the most effective control method for the wastage.