scholarly journals Fungal biodiversity on maize kernels in an insecticide evaluation trial

2019 ◽  
Vol 34 (1) ◽  
pp. 31-37
Author(s):  
Sonja Tancic-Zivanov ◽  
Mirjana Lalosevic ◽  
Radivoje Jevtic ◽  
Filip Franeta ◽  
Zeljko Milovac ◽  
...  

The European corn borer (ECB) Ostrinia nubilalis and Fusarium ear rot Fusarium spp. pose a continuous threat to maize production worldwide. There are several reports indicating that ECB damage to maize ears promotes Fusarium ear rot infection. The aim of this study was to monitor the influence of different insecticide treatments (a.i. chlorantraniliprole, indoxacarb, and chlorantraniliprole+lambda-cyhalothrin) on the ECB and fungal diversity on maize kernels in the field in a four-year trial (2013-2016). A total of 16 different fungal genera were isolated from maize kernels, and Fusarium species were confirmed to be the dominant pathogens, present in all treatments, throughout the four years of experiments. The incidence of Aspergillus spp. and Penicillium spp. was established to be low. Apart from Fusarium species, the most frequent genera were: Aspergillus spp., Mortierella spp., Mucor spp., Penicillium spp., Acremonium spp. and Rhizopus spp. Treatments with chlorantraniliprole and chlorantraniliprole+lambda-cyhalothrin showed higher efficacy, though not statistically significant, compared to indoxacarb, in reducing the number of ECB larvae and damage they cause. However, no direct effect on the number of isolated fungal genera has been observed in any of the three insecticide treatments.

2009 ◽  
Vol 2 (4) ◽  
pp. 409-418 ◽  
Author(s):  
M. Blandino ◽  
A. Reyneri ◽  
F. Vanara ◽  
G. Tamietti ◽  
A. Pietri

Mycotoxins in cereals are an economic and health problem. They are mainly produced in the field and are influenced by environmental conditions during ripening and by agricultural practices. The aim of this research was to evaluate the effect of combined agronomic techniques on fumonisins and deoxynivalenol contamination in maize kernels. Six experimental fields were prepared in North Italy from 2005 to 2007. Two hybrids with different maturity times and 6 different combinations of agricultural practices (sowing time, plant density, N fertilisation and European corn borer (ECB) control with insecticide) were compared for ECB incidence and severity, Fusarium ear rot incidence and severity, F. verticillioides and F. graminearum kernel infection and fumonisin and deoxynivalenol contamination. In temperate climates, where ECB attack is consistent, the production of maize kernels with a low fumonisin content can be enhanced by a correct insecticide application against second-generation ECB larvae and by an early sowing date. In this study the application of the most careful practice led to a reduction in the Fusarium ear rot severity and fumonisin by 62% and 91%, respectively, compared to the worst practice. The fumonisin levels were less affected by N fertility, plant density and hybrid maturity. The presence of deoxynivalenol is related to late sowing and harvesting times, late maturity hybrids, high plant density and N fertilisation. The insecticide treatments did not significantly reduce deoxynivalenol contamination. The data in this study clearly show that the application of good agricultural practices in crop management strategies can effectively lead to good control of fumonisins and deoxynivalenol.


1997 ◽  
Vol 87 (10) ◽  
pp. 1071-1077 ◽  
Author(s):  
G. P. Munkvold ◽  
R. L. Hellmich ◽  
W. B. Showers

Field experiments were conducted in 1994, 1995, and 1996 to evaluate the incidence and severity of Fusarium ear rot and the incidence of symp-tomless Fusarium infection in kernels of maize hybrids genetically engineered with Bacillus thuringiensis genes encoding for the δ-endotoxin CryIA(b). Treatments included manual infestation with European corn borer (ECB) larvae and insecticide applications to limit ECB activity to specific maize growth stages or mimic standard ECB control practices. Fusarium symptoms and infection were affected by the specific cryIA(b) transformation used in each hybrid that determines tissue-specific expression of CryIA(b). In hybrids expressing CryIA(b) in kernels, incidence and severity of Fusarium ear rot and incidence of symptomless kernel infection were reduced compared with near-isogenic hybrids lacking cryIA(b) genes. In plants that were manually infested with ECB, ear rot incidence was reduced by 87, 58, and 68%; severity was reduced by 96, 54, and 64%; and incidence of kernel infection by Fusarium species was reduced by 17, 38, and 38% in 1994, 1995, and 1996, respectively. Results were similar in treatments that were not manually infested, but differences between transgenic and nontransgenic hybrids were smaller. Most kernel infection was due to F. moniliforme, F. proliferatum, and F. subglutinans (section Liseola) collectively, and it was within this group that transgenic hybrids exhibited reduced infection. Expression of CryIA(b) in plant tissues other than kernels did not consistently affect Fusarium symptoms or infection. Disease incidence was positively correlated with ECB damage to kernels. Insecticide applications also reduced Fusarium symptoms and infection when applied to nontransgenic plants.


2016 ◽  
Vol 62 (No. 8) ◽  
pp. 348-354 ◽  
Author(s):  
K. Gromadzka ◽  
K. Górna ◽  
J. Chełkowski ◽  
A. Waśkiewicz

This work presents a survey on mycotoxins (seasons 2013 and 2014) and Fusarium species (seasons from 1985 to 2014) in maize ear rot in Poland. Twelve mycotoxins were identified in maize kernel samples exhibiting symptoms of Fusarium ear rot or rotten kernels at the harvest in two locations in Poland during the seasons 2013 and 2014. This is the first complex survey on the co-occurrence of four Fusarium mycotoxin groups in maize kernels: the group of the mycohormone zearalenone; the group of trichothecenes – deoxynivalenol and nivalenol; the group of fumonisins; and the group of cyclic hexadepsipeptides – beauvericin and enniatins; and in addition, moniliformin. Four Fusarium species were identified in preharvest maize ear rot in the 2013 and 2014 harvests namely:<br /> F. graminearum, F. poae, F. subglutinans and F. verticillioides. Since 1985, eleven Fusarium species have been identified in 13 investigation seasons. Apart from those mentioned above, F. avenaceum, F. cerealis, F. culmorum and<br /> F. sporotrichioides were observed with irregular frequencies, and three species, i.e. F. proliferatum, F. tricinctum and F. equiseti, were identified sporadically. A significant increase of F. verticillioides frequency and a decrease of F. subglutinans frequency and changes of mycotoxin profile have been observed in the two decades since 1995.  


2013 ◽  
Vol 6 (2) ◽  
pp. 127-135 ◽  
Author(s):  
E. Bowers ◽  
R. Hellmich ◽  
G. Munkvold

Field trials were conducted in 2008, 2009 and 2011 to assess fumonisin contamination in transgenic (Bt) and non- Bt maize hybrids infested with European corn borer, corn earworm, and Western bean cutworm. Comparisons were made among maize hybrids expressing two transgenic insect resistance proteins (Cry1Ab × Vip3Aa), a single resistance protein (Cry1Ab), or no insect resistance. The field design was a randomised complete block design with four replicates of each hybrid × insect combination. Kernel injury, Fusarium ear rot, and fumonisins (FB1+FB2+FB3) in maize grain were measured. These measurements differed significantly among years of the study. In all years, significant positive correlations were present between insect injury and Fusarium ear rot, insect injury and grain fumonisin levels, and Fusarium ear rot and grain fumonisin levels. Under all insect infestation treatments, Cry1Ab × Vip3Aa hybrids were the most resistant of the hybrids with regard to any of the grain quality measurements. Averaged over all insect infestations and years, insect injury, Fusarium ear rot, and grain fumonisin levels were all low in Cry1Ab × Vip3Aa (0.1% and 2.2% of total kernels, and 0.56 mg/kg, respectively). The highest average levels of insect injury, Fusarium ear rot, and grain fumonisin contamination (3.3% and 7.2% of total kernels, and 5.47 mg/kg, respectively) were found in the non-Bt hybrids. The presence of transgenic insect protection (Cry1Ab × Vip3Aa or Cry1Ab) resulted in significant reductions in all grain quality measurements as compared with the non- Bt hybrids. Only grain obtained from Cry1Ab × Vip3Aa hybrids consistently had acceptable fumonisin content according to both US guidance levels and EU regulatory limits. These results indicate that Cry1Ab × Vip3Aa maize hybrids are more likely to yield high quality, low-fumonisin grain compared to hybrids expressing only Cry1Ab or lacking insect resistance.


2020 ◽  
Vol 13 (2) ◽  
pp. 213-224 ◽  
Author(s):  
P.W. Qin ◽  
J. Xu ◽  
Y. Jiang ◽  
L. Hu ◽  
T. van der Lee ◽  
...  

Maize is currently the most important crop in China. A major concern in maize production is maize ear rot caused by Fusarium spp., which results in yield losses, reduction of seed quality and the accumulation of mycotoxins in the harvested grains. To identify the importance of the different Fusarium species in maize infection, we performed a comprehensive survey on 9,000 asymptomatic and randomly collected maize kernels. Seeds were collected from 12 different provinces covering all major maize growing areas in China and included five maize varieties. In total 1,022 Fusarium isolates were retrieved that were identified based on morphological characteristics, by species specific diagnostic PCRs and by EF1-α gene sequencing. Eight different species were identified: Fusarium verticillioides (75.34%), Fusarium graminearum (8.32%), Fusarium proliferatum (7.14%), Fusarium subglutinans (4.11%), Fusarium meridionale (1.57%), Fusarium oxysporum (1.37%), Fusarium semitectum (1.17%), and Fusarium asiaticum (0.98%). The distribution of Fusarium species was found to be different in different regions with the largest diversity observed in Hubei province, where all eight Fusarium species were isolated. Genetic chemotyping within the F. graminearum species complex indicated that all of the 85 F. graminearum isolates showed the 15-acetyldeoxynivalenol chemotype, whereas all F. asiaticum (n=10) and F. meridionale (n=16) isolates had the nivalenol chemotype even when isolated from the same maize field. To our knowledge this is the largest collection of Fusarium isolates from maize and further exploitations of this collection are discussed.


Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1428-1428 ◽  
Author(s):  
H. Zhang ◽  
W. Luo ◽  
Y. Pan ◽  
J. Xu ◽  
J. S. Xu ◽  
...  

Maize (Zea mays L.) is an important food crop worldwide. Some Fusarium species cause maize ear rot leading to significant yield losses and, for some Fusarium species, potential risk of mycotoxin contamination. In 2013, a survey was conducted to determine the population composition of Fusarium species on maize in Dongyang, Zhejiang Province, China, where about 5% of maize ears in each field were found with reddish-white mold. Symptomatic maize ears were collected from several cultivars including forage corn Zhedan724 and Zhengdan958, sweet corn Chaotian4 and Chaotian135, and waxy corn Heinuo181 and Zhenuoyu6; no association between the disease and maize cultivars was observed. Maize kernels showing a pink or white mold were surface-disinfested with 70% ethanol and 10% sodium hypochlorite, followed by three rinses with sterile distilled water and placed onto potato dextrose agar (PDA). After 3 days of incubation at 25°C in the dark, mycelia were transferred to fresh PDA and purified by the single-spore isolation method (4). Species were identified based on morphological characteristics (2), and sequence analysis of the translation elongation factor-1α (TEF) gene. The results indicated that Fusarium verticillioides Sacc. (84.6%) is the main causal agent of maize ear rot in this region. However, morphological characteristics of two strains (7.7%) from the same field were found to be identical to F. andiyazi Marasas, Rheeder, Lampr., K.A. Zeller & J.F. Leslie. Colonies on PDA showed floccose to powdery mycelium and pale-purple pigmentation. Hyaline and straight or slightly curved macroconidia were observed with 3- to 6-septate and a slightly curved apical cell. Chlamydospores were absent. In order to validate this result, partial translation elongation factor (TEF-1α, 646 bp) gene sequences of isolates were generated (GenBank Accession No. KJ137019) (1). BLASTn analysis of TEF-1α with the GenBank database revealed 99.7% sequence identity to F. andiyazi (JN408195 and JN408196), and much lower (94 to 98%) identity with other Fusarium spp. Thus, both morphological and molecular criteria supported identification of the strains as F. andiyazi. A pathogenicity test was performed on maize cv. Zhengdan958 in a greenhouse. Four days post-silk emergence, a 2-ml conidial suspension (105 macroconidia/ml) of each isolate was injected into each of 10 maize ears through the silk channel. An equal amount of sterile distilled water was injected into 10 ears as a control. Typical Fusarium ear rot symptoms (reddish-white mold), which were observed in the ears inoculated with these strains 20 days after inoculation, were similar to the original symptoms in the sampling sites, and no symptoms were observed on the water control ears. The same fungus was re-isolated from the infected kernels using the method described above. F. andiyazi are the major pathogens of sorghum (2) and also proved to attack maize kernels recently (3). To our knowledge, this is the first report of F. andiyazi causing Fusarium ear rot on maize in China. Further investigation is needed to gain a better understanding of the spatial and temporal dynamics of this new pathogen. Also, the new species must be considered in the development of maize cultivars with broad-based resistance to the pathogens. References: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (3) A. Madania et al. J. Phytopathol. 161:452, 2013. (4) H. Zhang et al. PLoS ONE 7:e31722, 2012.


Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 130-138 ◽  
Author(s):  
Gary P. Munkvold ◽  
Richard L. Hellmich ◽  
Larry G. Rice

Maize hybrids genetically engineered with genes from the bacterium Bacillus thuringiensis (Bt maize) express CryIA(b) and other Cry proteins that are toxic to certain insects, particularly the European corn borer (Ostrinia nubilalis). Maize kernel feeding by O. nubilalis often leads to infection by fungi in the genus Fusarium, including the fumonisin-producing species F. verticillioides and F. proliferatum. In field experiments in 1995, 1996, and 1997, transgenic maize hybrids and near-isogenic, nontransgenic hybrids were manually infested with neonatal European corn borer larvae. Manual infestation increased Fusarium ear rot severity and fumonisin concentrations in kernels of nontransgenic hybrids. Transgenic hybrids with kernel expression of CryIA(b) consistently experienced less insect feeding on kernels and less Fusarium ear rot than their nontransgenic counterparts. In manually infested treatments, these hybrids also exhibited lower concentrations of fumonisins in kernels compared with their nontransgenic counterparts. In manually infested treatments in 1995, mean fumonisin B1 concentrations were 8.8 μg/g in the nontransgenic hybrid and 6.7 or 3.0 μg/g in transgenic hybrids. In 1996, mean fumonisin B1 concentrations in manually infested treatments were 4.9 μg/g (range 2.3 to 8.8) for nontransgenic and 1.2 μg/g (range 1.0 to 1.3) for transgenic hybrids with kernel expression. Mean total fumonisin concentrations (fumonisin B1 + B2 + B3) were 7.0 μg/g (range 3.0 to 12.2) for nontransgenic and 1.7 μg/g (range 1.5 to 1.9) for transgenic hybrids with kernel expression. In 1997, mean fumonisin B1 concentrations in manually infested treatments were 11.8 μg/g (range 7.6 to 17.3) for nontransgenic and 1.3 μg/g (range 0.8 to 2.2) for transgenic hybrids with kernel expression of CryIA(b) or Cry9C. Mean total fumonisin concentrations were 16.5 μg/g (range 10.7 to 24.0) for nontransgenic and 2.1 μg/g (range 1.5 to 3.1) for transgenic hybrids with kernel expression. Transgenic hybrids that do not express CryIA(b) or Cry9C in kernels did not consistently have fumonisin concentrations different from the nontransgenic hybrids. Higher fumonisin concentrations in nontransgenic hybrids were associated with high European corn borer populations during the early reproductive stages of the maize plants. These results indicate that under some conditions, genetic engineering of maize for insect resistance may enhance its safety for animal and human consumption.


2012 ◽  
Vol 48 (Special Issue) ◽  
pp. S18-S24 ◽  
Author(s):  
J. Nedělník ◽  
H. Lindušková ◽  
M. Kmoch

The literature linking Bt maize versus non-Bt maize and the changes in the fungal microflora spectrum and in the mycotoxins content have been summarised. The European corn borer reportedly promotes the infection of maize by Fusarium spp. Stalk and ear rots caused by Fusarium spp. are often related to mycotoxin accumulation in maize kernels. As a result, food and animal feed from maize are more severely contaminated with Fusarium mycotoxins: e.g. fumonisins (FUM), deoxynivalenol (DON), and zearalenone (ZEA). Mycotoxins in field maize lead annually economic losses of hundreds of millions of dollars in all regions of the world. The insecticidal proteins in genetically modified hybrid Bt maize reduce insect damage caused by certain Lepidopteran larvae, which in turn can reduce the infection of the grain by the mycotoxigenic fungi. Where such insect damage is a major factor in mycotoxin contamination, Bt maize can lower mycotoxin levels in many cases. The protection of maize plants against insect damage (European corn borer) through the use of Bt technology seems to be one of the ways to reduce the contamination of maize by Fusarium species and mycotoxins.


Toxins ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 297 ◽  
Author(s):  
Maryam Fallahi ◽  
Hossein Saremi ◽  
Mohammad Javan-Nikkhah ◽  
Stefania Somma ◽  
Miriam Haidukowski ◽  
...  

Fusarium species are among the most important fungal pathogens of maize, where they cause severe reduction of yield and accumulation of a wide range of harmful mycotoxins in the kernels. In order to identify the Fusarium species and their mycotoxin profiles associated to maize ear rot and kernel contamination in Iran, a wide sampling was carried out from field in ten major maize-producing provinces in Iran, during 2015 and 2016. From 182 samples of maize kernels, 551 strains were isolated and identified as belonging to Fusarium genus. Among the 234 representative strains identified at species level by translation elongation factor (EF-1α) sequences, the main Fusarium species were F. verticillioides and F. proliferatum, together representing 90% of the Iranian Fusarium population, and, to a lesser extent, F. incarnatum equiseti species complex (FIESC), F. thapsinum and F. redolens. Fumonisin (FBs) production by F. verticillioides and F. proliferatum representative strains was analysed, showing that all strains produced FB1. None of F. verticillioides strains produced FB2 nor FB3, while both FB2 and FB3 were produced only by F. proliferatum. Total mean of FBs production by F. verticillioides was higher than F. proliferatum. The occurrence of different Fusarium species on Iranian maize is reason of great concern because of the toxigenic risk associated to these species. Moreover, the diversity of the species identified increases the toxigenic risk associated to Fusarium contaminated maize kernels, because of the high possibility that a multi-toxin contamination can occur with harmful consequences on human and animal health.


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