Factors affecting density of airborne Gibberella zeae inoculum

Ponte, Emerson M. Del; Fernandes, J. M. C.; Pierobom, Carlos R.

doi:10.1590/s0100-41582005000100009

Cited by 23 publications

(18 citation statements)

References 13 publications

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“…The effect of moisture coming from the soil on inoculum production was previously mentioned by Xu (27), who reported that ascospore production is prevented when the soil moisture is Ͻ30% and is at its maximum when soil moisture is Ͼ80%. The dynamics of ascospore discharge were similar in the two conditions (stalks on a moist substrate versus stalks on a grass lawn exposed to rain), suggesting that ascospore discharge is not affected by stalk moisture but is mainly driven by rain and atmospheric humidity (18,46,47,48).…”

Section: Discussionmentioning

confidence: 90%

Effects of Temperature and Moisture on Development of Fusarium graminearum Perithecia in Maize Stalk Residues

Manstretta

Rossi

2016

Appl Environ Microbiol

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Fusarium graminearum is the predominant component of the Fusarium head blight complex of wheat. F. graminearum ascospores, which initiate head infection, mature in perithecia on crop residues and become airborne. The effects of temperature (T) and moisture on perithecium production and maturation and on ascospore production on maize stalk residues were determined. In the laboratory, perithecia were produced at temperatures between 5 and 30°C (the optimum was 21.7°C) but matured only at 20 and 25°C. Perithecia were produced when relative humidity (RH) was >75% but matured only when RH was >85%; perithecium production and maturation increased with RH. Equations describing perithecium production and maturation over time as a function of T and RH (R 2 > 0.96) were developed. Maize stalks were also placed outdoors on three substrates: a grass lawn exposed to rain; a constantly wet, spongelike foam exposed to rain; and a grass lawn protected from rain. No perithecia were produced on stalks protected from rain. Perithecium production and maturation were significantly higher on the constantly wet foam than on the intermittently wet lawn (both exposed to rain). Ascospore numbers but not their dispersal patterns were also affected by the substrate. Fusarium head blight (FHB) is one of the most widespread and dangerous diseases of wheat and other small-grain cereals (1, 2). Up to 17 species belonging to the genera Fusarium and Microdochium have been recognized as responsible for FHB (3). Fusarium graminearum has been considered the predominant species in most cereal-growing areas of the world (4, 5, 6). Symptoms of the disease include premature bleaching of spikes or spikelets, sterile florets, poorly filled grains, and grains that are shriveled and discolored (white to pale pink) (7). The disease reduces yield, grain quality, including contamination by mycotoxins, and seed quality (3).Wheat spikes are receptive to infection from flowering to the soft-dough stage (8). Ascospores and macroconidia are the main inocula (3,7,9) and are typically produced on the residues of the previous crop (4, 7). The fungus can survive as a saprophyte on the previous crop's residue for 2 or more years (10,11,12). Although both ascospores and conidia can be detected in cereal crops, ascospores are more prevalent than conidia in many areas (3,4,7,13). Macroconidia are produced in sporodochia and are dispersed for short distances by splashing rain (14,15,16). Ascospores mature in perithecia and are forcibly discharged into the air; they are then airborne and can travel meters to kilometers (9,17,18,19).The main factors influencing production of perithecia and ascospores are light, temperature, and moisture. Light with wavelengths between 300 and 320 nm is essential for the induction of perithecium (20). Paulitz (21) observed more perithecia on the side of debris exposed to direct light; perithecia were also found on grains buried at 5 to 10 cm, but they did not produce ascospores (10).Perithecia and ascospores are formed under warm and moist co...

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Section: Discussionmentioning

confidence: 90%

Effects of Temperature and Moisture on Development of Fusarium graminearum Perithecia in Maize Stalk Residues

Manstretta

Rossi

2016

Appl Environ Microbiol

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“…The model assumes inoculum as a non-limiting factor. In southern Brazil, most wheat is cropped under a no-till system, and airborne inoculum seems to be always present when the environment is highly suitable for infections (rainfall and RH>80%), which corresponds well with peaks of spore detection (Reis, 1990;Panisson et al, 2002;Del Ponte et al, 2005). Other locations may be more dependent on exogenous inoculum sources, and infections may be absent or low if inoculum is not present or at very low levels.…”

Section: Discussionmentioning

confidence: 96%

“…Models for predicting the daily relative density of a GZ spore cloud were developed by the observation on the night-and day-time deposition of G. zeae airborne inoculum in Passo Fundo, Brazil (Del Ponte et al, 2005). A linear equation was adjusted to the relative density of colony forming units that was observed during the night-time to estimate the relative density of a spore cloud [3].…”

Section: Inoculum Factormentioning

confidence: 99%

A risk infection simulation model for fusarium head blight of wheat

Ponte¹,

Mauricio²,

Fernandes

et al. 2005

Fitopatol. bras.

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Fusarium Head Blight (FHB) is a disease of great concern in wheat (Triticum aestivum). Due to its relatively narrow susceptible phase and environmental dependence, the pathosystem is suitable for modeling. In the present work, a mechanistic model for estimating an infection index of FHB was developed. The model is process-based driven by rates, rules and coefficients for estimating the dynamics of flowering, airborne inoculum density and infection frequency. The latter is a function of temperature during an infection event (IE), which is defined based on a combination of daily records of precipitation and mean relative humidity. The daily infection index is the product of the daily proportion of susceptible tissue available, infection frequency and spore cloud density. The model was evaluated with an independent dataset of epidemics recorded in experimental plots (five years and three planting dates) at Passo Fundo, Brazil. Four models that use different factors were tested, and results showed all were able to explain variation for disease incidence and severity. A model that uses a correction factor for extending host susceptibility and daily spore cloud density to account for post-flowering infections was the most accurate explaining 93% of the variation in disease severity and 69% of disease incidence according to regression analysis.

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“…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). A grande disponibilidade de inóculo no ar (PANISSONN et al, 2002b;DEL PONTE et al, 2005), durante o período de floração (antese), associada a períodos de molhamento contínuo (REIS & BLUM, 2004), ocorrentes com freqüência na Região Sul do Brasil, tem levado a danos significativos na cultura no trigo (PANISSON et al, 2003;CASA et al, 2004 a,b).…”

Section: Introductionunclassified