The effect of a mixture of seed-borne Microdochium nivale var. majus and Microdochium nivale var. nivale infection on Fusarium seedling blight severity and subsequent stem colonisation and growth of winter wheat in pot experiments

Abstract

Greenhouse experiments were conducted in order to determine the impact of seed-borne Microdochium nivale var. nivale and var. majus inoculum, and seed treatment with a carboxin+thiram mixture, on the development of seedling blight, and on subsequent stem colonisation and growth of winter wheat (cv. Cadenza). Experiments were conducted at temperatures favourable (3°C) and unfavourable (22°C) to M. nivale. Seed-borne inoculum resulted in seedling blight symptom development when plants were grown at 3°C, but not when plants were grown at 22°C. For seedlings grown at 3°C, plants arising from heavily blighted seedlings developed more severe symptoms of stem colonisation, when compared with those arising from seedlings from carboxin+thiram treated seeds. In addition, the vigour of such plants (assessed by determining the number of tillers and ears per plant, stem length, green leaf area, dry weight and yield) was also significantly lower than for plants arising from carboxin+thiram treated seeds. Microdochium nivale var. majus and var. nivale appeared to have little effect on plant vigour from seedlings grown at 22°C. This is the first recorded incidence of seedling blight affecting subsequent plant growth. Microdochium nivale var. majus and var. nivale stem colonisation increased from growth stage (GS) 40-49 to harvest in plants raised from seedlings grown at both temperatures. Microdochium nivale var. majus and var. nivale were isolated from the second node at GS 40-49 and the third node at harvest of plants from seedlings grown at 3°C. For plants from seedlings raised at 22°C, M. nivale var. majus and var. nivale were isolated from the first node at GS 40-49 and the second node at harvest. Carboxin+thiram seed treatment decreased the extent and severity of stem colonisation on plants from seedlings grown at 22°C.

Evidence of Microdochium Fungi Associated with Cereal Grains in Russia

“…Information about the diseases, such as pink snow mold, grass decay, leaf spots, and head blight, caused by Microdochium fungi has been published previously [2][3][4][5][6][7][8]. Microdochium fungi were first identified in 1849 by Fries as Lanosa nivalis, which was later (1886) reclassified and placed in the genus Fusarium as F. nivale Ces.…”

Microdochium nivale and M. majus as causative agents of seedling blight in spring cereals

“…Cockerell et al (2009), based on the limited data sets in Scotland, suggested that spring wheat and oats are at risk from high levels of Microdochium infection, and spring barley is also at risk but at levels exceeding 30% seed infection. It is known that Microdochium affects seedlings at temperatures as low as 3°C (Haigh et al, 2009). In an inoculation experiment at 10°C, Simpson et al (2000) found that both Microdochium species were pathogenic to wheat and rye but only M. nivale caused significant disease in oats.…”

Evaluation of pathogenicity and aggressiveness of F. langsethiae on oat and wheat seedlings relative to known seedling blight pathogens

“…Symptoms on cereals range from preemergence death, post-emergence death and lesions on stems and leaves (Millar and Colhoun 1969;Wisnieska and Busko 2005). Infected seedlings surviving the disease have been reported to lack vigour, tiller poorly and frequently send up a single stem on which a small head develops (Parry et al 1995;Haigh et al 2009).…”