Abstract
A description is provided for Calonectria rigidiuscula[Nectria rigidiuscula]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Theobroma cacao and many other hosts represented by the following families: Anonaceae, Anacardiaceae, Apocynaceae, Bombacaceae, Euphorbiaceae, Gramineae, Leguminosae, Malvaceae, Meliaceae, Moraceae, Sterculiaceae, Tiliaceae. Also pathogenic on wound inoculation to hosts in the above and following additional families: Bignoniaceae and Ulmaceae (31: 232). DISEASES: Causing die-back and canker of branches associated with capsid injury, 'green-point' cushion gall of buds, and pod rot of cacao; panel decay of Hevea rubber associated with Pbytophthora spp. ; stem canker of robusta coffee associated with Xyleborus morstatta; stem rot of durian; and blight of rice plants including grain. GEOGRAPHICAL DISTRIBUTION: Africa (Cameroons, Central African Republic, Congo, Ghana, Ivory Coast, Madagascar, Nigeria, Sierra Leone); North America [United States (Okla.)]; Central America and West Indies (British Guiana, Costa Rica, Grenada, Guatemala, Honduras, Panama, Trinidad); South America (Argentina, Colombia, Surinam, Venezuela); Asia (Ceylon, India, Indo-China, Java, Malaya, Philippines); Australasia & Oceania (New Caledonia, North Borneo, Tahiti). TRANSMISSION: By air-borne spores, either microconidia produced on recently infected tissue of injured, living stems, or macroconidia from sporodochia on recently dead stems, or ascospores from perithecia produced on long dead stems or cracks in bark (25: 548). The pathogen has been transmitted to cacao cotyledons by means of mealybugs (Pseudococcus njalensis[Planococcoides njalensis] and Ferrisiana virgata[Ferrisia virgata]) in the laboratory, but not elsewhere. Also a soil invader commonly recovered from previous sites of cacao (13: 128, 594) or coffee plantations (34: 179), and in grassland areas (33: 687); seed-borne on rice (32: 449).