Nedělník J., Lindušková H., Kmoch M. (2012): Influence of growing Bt maize on Fusarium infection and mycotoxins content -a review. Plant Protect. Sci., 48 (Special Issue): S18-S24.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.

The differences of air temperature and relative air humidity in wheat, rape and maize canopies at three heights (ground level, effective canopy height and 2 meters above the soil surface), and their comparison with the temperature values of the nearest standard climatological station at the height of 2 meters were studied. The microclimatic data were obtained at the field trial station of the Mendel University in Brno in the Žabčice municipality (South Moravia) in the canopies of winter wheat, winter rape and maize and from the standard climatological station located immediately next to the canopies. It was found, that wheat, rape and maize canopies microclimate differed significantly from those of their surrounding environments. The temperature was usually lower in the ground level and effective height in the wheat and rape stands, air humidity was usually higher in these crops. On the other hand, maize canopies had diverse air temperature values during the studied period.

The pectinolytic Dickeya solani bacterium is an important pathogen found in potatoes. We conducted laboratory and field experiments mimicking severe and mild Dickeya spp. infection and investigated the application of a mixture of two lytic bacteriophages before and after bacterial infection to protect the plants. Application of the phage solution to tuber disks and wounded tubers did not completely eliminate the infection but reduced the development of soft rot symptoms by 59.5–91.4%, depending on the phage concentration. In the field trial, plants treated with bacteriophages after severe Dickeya infection had 5–33% greater leaf cover and 4–16% greater tuber yield compared to untreated plants. When simulating a mild infection, leaf cover was 11–42% greater, and tuber yield was 25–31% greater compared to untreated plants. We conclude that the phage mixture has the potential to protect potatoes ecologically from D. solani.

Figure 1Figure 2 (Henricot & Culham, 2002;Brand, 2005;Cech et al., 2010)

The protective effect of bacteriophage suspensions (Ds3CZ + Ds20CZ and PcCB7V + PcCB251) on phytopathogenic bacteria causing soft rot of potato tubers, namely Dickeya dianthicola (D50, D200) and Pectobacterium carotovorum (P87, P224), was observed in ex vivo and in vitro experiments. Ex vivo tests were performed (with air access) on potato slices, on cylindrical cuts from the center of the tubers, and directly in whole potato tubers. In vitro experiments were carried out in a liquid medium using RTS-8 bioreactors, where bacterial growth was monitored as optical density. In particular, the inhibitory effects of phages were confirmed in experiments on potato slices, where suppression of rot development was evident at first glance. Phage treatment against selected bacteria positively affected potato hardness. Hardness of samples treated with bacteria only was statistically significantly reduced (p < 0.05 for D50 and p < 0.001 for D200 and P87). Ex vivo experiments confirmed significant inhibition of P87 symptom development, partial inhibition of D200 and D50 in phage-treated tubers, and no effect was observed for P224. The inhibitory effect of phages against bacteria was not observed in the in vitro experiment.