To evaluate the efficacy of multilines in rice blast control, panicle blast severity was evaluated for Sasanishiki near-isogenic lines after inoculation with a virulent isolate with or without pre-inoculation with an avirulent blast isolate. Disease severity generally differed among lines, high for Sasanishiki BL No.6, moderate for No.3 and low for No.4. The disease on Sasanishiki BL No.4 was suppressed when panicles were pre-inoculated with a high concentration of an avirulent spore suspension (2.5×106spores/ml). However, this suppression was not observed on Sasanishiki BL No.3 or No.6.
From lettuce (Lactuca sativa L.) with big vein symptoms, two bands were detected by Western blot analysis using antisera to Tobacco stunt virus and Tulip mild mottle mosaic virus (As-TMMMV), respectively. One band reacted to antiserum to Mirafiori lettuce virus (MiLV) stronger than As-TMMMV. Unstable filamentous Ophiovirus-like particles (LBV-O) decorated with As-TMMMV in immunogold labeling were observed along with Lettuce big-vein virus-like rod-shaped particles in diseased plants. Manual inoculation with lettuce sap caused chlorotic local lesions in Chenopodium quinoa and systemic infection in lettuce. Along with LBVV, LBV-O was transmitted by Olpidium brassicae. LBV-O was identified as MiLV for the first time in Japan.
Seedlings of garland chrysanthemum, Chrysanthemum coronarium L. var. spatiosum L.H. Bailey, developed damping off in hydroponics in the summer. The causal agent was identified as Pythium ‘group F’ and P. myriotylum, and the disease named damping off or tachigare-byo.