Fusarium ear blight (scab) in small grain cereals—a review

Abstract

This review of Fusarium ear blight (scab) of small grain cereals has shown that up to 17 causal organisms have been associated with the disease, which occurs in most cereal‐growing areas of the world. The most common species were Fusarium graminearum (Gibberella zeae), F. culmorum, F, avenaceum (G, avenacea), F, poae and Microdochium nivale (Monographella nivalis). The disease was recorded most frequently under hot, wet climatic conditions where significant yield losses and mycotoxin accumulation in grain were reported. Possible sources of inoculum were reported as crop debris, alternative hosts and Fusarium seedling blight and foot rot of cereals. The mode of dispiersal of inoculum to ears remains unclear, but contaminated arthropod vectors, systemic fungal growth through plants, and wind and rain‐splash dispersal of spores have been proposed. Infection of wheat ears was shown to occur mainly during anthesis, and it has been demonstrated that fungal growth stimulants may be present in anthers. Despite the importance of the disease, particularly during epidemic years, control methods are limited. Much effort has gone into breeding resistant wheat varieties and into improving our understanding of the possible mechanisms and genetic basis of resistance, with only moderate success. There are also surprisingly few reports of successful fungicidal or biological control of the disease in the field.

Época de aplicação e desempenho de fungicidas no controle da giberela em trigo

“…(anamorfo Fusarium graminearum Schwabe) é o agente causal predominante na giberela do trigo (REIS & CASA, 2005). A doença é de ocorrência generalizada no mundo, causando danos significativos na produção de trigo em regiões onde coincidem clima úmido e quente durante a fase de floração (SUTTON, 1982;PARRY et al, 1995;REIS et al, 1996b;McMULLEN et al, 1997 Hoje a giberela é considerada a doença do plantio direto. A sobrevivência saprofítica do patógeno em diversos hospedeiros, como espécies de plantas cultivadas, nativas e invasoras (REIS & CASA, 2004), assim como a facilidade de dispersão dos ascosporos, transportados a longa distância pelo vento, faz com que a giberela não seja controlada eficientemente pela rotação de culturas (ZAMBOLIM et al, 2000;REIS & CASA, 2005).…”

Occurrence of the orange wheat blossom midge [Diptera :Cecidomyiidae] in Quebec and its incidence on wheat grain microflora

“…However, for infection of wheat heads, the principal réservoir of inoculum of F. graminearum is host débris (Sutton 1982). Since the émergence of wheat midge adultfemales from soil and the period of egg laying (heading and flowering) can overlap at a time when wheat is susceptible to infection by thefungus (anthesis) (Parry et al 1995), it is likely that thèse insects may serve as efficient vectors for F.…”

Weather requirements and rain forecast to time fungicide application for Fusarium head blight control in wheat

“…FHB more frequently occurs in the wheat regions of hot and humid weather, especially where rainfall is high and spike wetness duration is > 48 hours (1,11,12). Such a wetting duration is the result of rain instead of dew.…”

“…For wheat, initial FHB was long reported to occur via the anthers (2,11,12). In the 1970s, the relationship between FHB and anthesis was associated with the presence of high concentrations of the molecule stimulants betaine and choline (16).…”