Visual disease and PCR assessment of stem base diseases in winter wheat

Abstract

Stem base disease (eyespot, sharp eyespot and brown foot rot) was assessed visually and by the polymerase chain reaction (PCR) technique on single plants sampled at four-week intervals in two crops of winter wheat grown in the UK in 1992-3. PCR assays were conducted for Fusarium avenaceum, F. culmorum, both varieties of Microdochium nivale, both eyespot-causing species of Tapesia and Rhizoctonia cerealis. PCR diagnoses were compared with visual diagnoses at each time point. Eyespot was caused principally by T. acuformis (R-type) and developed rapidly late in the season. Visual diagnoses of eyespot were largely confirmed by PCR but T. acuformis was detected in many plants lacking eyespot symptoms. R. cerealis was detected at relatively low incidences on both sites, and sharp eyespot visual diagnoses did not correlate with the incidence of any of the pathogens assayed by PCR. Brown foot rot, caused principally by Microdochium nivale var. majus, accumulated earlier in the season than eyespot. Overall, visual diagnoses of stem base disease coincided poorly with PCR data until after growth stage (GS) 30.

Occurrence of Eyespot on Winter Wheat in the Central-Southern Region of Poland

“…The morphology of cultures was compared with literature data (Nicholson et al 1991;Nirenberg 1981;Dyer et al 1994). Fungi from these cultures were grown on water agar to obtain a sporulation (Bojarczuk 1970 (Smith 1990;Collet et al 1992;Turner 1999). In 2008 a study based on PCR technique was also done in the Department of Mycology Institute of Plant Protection -National Research Institute in Poznań to confirm laboratory results (Turner et al 1999).…”

Using Real‐time PCR to Discriminate and Quantify the Closely Related Wheat Pathogens Oculimacula yallundae and Oculimacula acuformis

“…herpotrichoides , W‐type) are the causal agents of eyespot, a disease affecting wheat, barley, oats, rye and many grass species in temperate climates. Eyespot, sharp eyespot (caused by Rhizoctonia cerealis ) and brown foot rot (caused by Microdochium nivale vars nivale and majus and often associated with Fusarium species; Turner et al., 1999) form a disease complex that causes stem base disease in cereals. Eyespot characteristically induces elliptical spots with diffuse margins on the leaf sheath at the base of the stem, which are white to light brown in immature plants, turning darker later.…”

Competitive interactions between Microdochium nivale var. majus, M. nivale var. nivale and Fusarium culmorum in planta and in vitro

“…Microdochium nivale is one of the predominant fungal pathogens causing brown foot rot and head blight of cereals in mainland Europe (Parry et al ., 1995; Schütze et al ., 1997) and the UK (Pettitt et al ., 1996; Turner et al ., 1999). As a seed‐borne pathogen, it has been reported to cause a reduction of up to 74% in seedling emergence and also significant yield losses when it infects the ears (Humphreys et al ., 1995).…”