Abstract
A mosaic disease of squash (Cucurbita maxima) and pumpkin (C. moschata and C. Pepo) occurs extensively in the Kanto District in Japan. Its initial spmptoms consist of faint veinclearing and green leaf mottling, developing into a mosaic. The typical veinbanding with dark green raised areas is infrequently observed. The most conspicuous and spectacular symptom is the presence of filiform leaves, infected leaves are reduced to only the veinous system with patches of green mesophyll, followed by a severe distortion of leaves, especially when the plants have been infected in their early stage of growth.
The virus isolated from squash was readily transmissible by mechanical inoculation with carborundum, or by aphids, viz. Aphis gossypii and Myzus persicae, but not by cucumber beetle, Aulacophora femoralis. It was found to be seed-borne in a certain variety of squash, although the percentage of infection was low (0.6%).
The virus was capable of infecting plants of 10 species in 2 families among 73 species in 25 families tested. Systemic infection was obtained on squash, pumpkin, cucumber, melon, oriental pickling melon (Cucumis Melo var. Conomon), white gourd (Benincasa hispida), white flowered gourd (Lagenaria leucantha) etc. Local necrotic spots was developed on Chenopodium album. From these results, the virus seems to be practically confined to the Cucurbitaceae. Accounts of the physical properties and identification of the virus will be given in the next paper.
