Take‐all in spring‐sown cereals under continuous cultivation: disease progress and decline in relation to crop succession and nitrogen

Abstract

SUMMARYIncidence and severity of the take‐all disease in spring wheat and spring barley caused by Gaeumannomyces graminis (syn. Ophiobolus graminis) were studied during seven years of monoculture.The fungus apparently survived for much longer periods in the soil under non‐susceptible break‐crops than previously recorded. The incidence and severity of infection increased progressively with each successive cereal crop from initially low levels to a maximum within 3–7 years, which was followed by a progressive but limited decline in the disease. Spring wheat was more susceptible to take‐all than spring barley and the development of take‐all decline (TAD) was recorded earlier in the sequences of wheat than of barley crops. Nitrogen did not influence the disease until the point of maximum incidence and severity, when it caused a reduction in disease levels in addition to that associated with TAD. Factors influencing the time of onset and the rate of development of take‐all and of TAD are discussed and possible explanations for TAD are suggested.

Conservation agriculture and ecosystem services: An overview

“…Abundance and diversity of populations of natural enemies of parasitic nematodes may be higher with NT . Studies have shown initial increases in pests and diseases with the implementation of NT and residue retention, followed by gradual decreases (Gerlagh, 1968;Shipton, 1972). It is assumed to be related to the re-establishment of more diverse communities with CA.…”

Influence des successions culturales sur les maladies du pied et des racines du blé d'hiver

“…Les 2 agents pathogènes infectent le même site sur la plante et il y a compétition pour les mêmes tissus (Steinbrenner et Höflich, 1980 ;Shipton, 1981 (Shipton, 1972) (Glynne, 1950 ;Pitt, 1964 ;Steinbrenner et al, 1990 (Ponchet, 1959 ;Wehner et al, 1988).…”

Biology of Gaeumannomyces graminis var. graminis isolates from rice and grasses and epidemiological aspects of crown sheath rot of rice

“…Gerlagh (1968) considered ascosporic infection of wheat as less important than in grasses. According to Shipton (1972) the substantial increase of take-all disease in mono culture of wheat and barley was probably due to Ggt ascospores. Gerlagh (1968) reported that the spontaneous infection of healthy wheat plants in the greenhouse and the spread of take-all disease in Netherlands to newly reclaimed polders were caused by wind-dissemination of ascospores of Ggt.…”

“…The ascospores of Ggg can be actively released from the ascus in the atmosphere (Gregory & Stedman, 1958), but its role in the epidemics remains controversial (Gerlagh, 1968;Shipton, 1972). There is little information on the epidemiology of crown sheath rot of rice (Webster & Gunell, 1992) and only preliminary data on pathogenicity of Ggg in Brazil (Prabhu & Filippi, 2002).…”