RESUMEN
Aflatoxins (AFs) are a family of mycotoxins produced by molds in agricultural products. To deal with this problem, one of the control methods is the biological solution using a non-pathogenic strain Aspergillus flavus NRRL 21882 (Afla-Guard). This study was conducted to evaluate the potential of A. flavus NRRL 21882 to control the AF contamination of corn in the field and during storage in 2018 and 2019. The experimental design consists of treatment at different vegetative stages of infested corn in the field trial. After the field has been harvested, half the corn kernels from both treated and control plots were treated with biopesticide; the other half of the kernels from each group were not treated and used as the control of the storage. Consequently, storage applications consisted of kernels: (1) not treated at all; (2) treated prior to storage; (3) field-treated; and (4) treated both in the field and prior to storage. After field trials, the AF content was very low in the treated plots, ranging from 0.50 to 1.04 µg/kg and from 0.50 to 0.73 µg/kg in 2018 and 2019, respectively, while the AF content in the control was 98.3 and 73.9 µg/kg in 2018 and 2019, respectively. After storage, corn kernels from field plots that were treated with the biopesticide (treated/control) showed low levels of AFs, even after they have been stored under conditions conducive to AF contamination. The biopesticide effect ranged from 98 to 99% and from 69 to 99% in the field and during storage, respectively. This paper has provided the first indications on AF biocontrol based on a competitive exclusion in the corn-growing region of Turkey. The data showed that spraying during the storage period did not provide any further prevention of AF contamination, and only treatment in the field had a significant effect on AFs that occurred in storage.
RESUMEN
Perennial ryegrass (Lolium perenne L.) is a valuable forage and soil stabilisation crop. Perennial crops have long been associated with good environmental performance and ecosystem stability. Vascular wilt diseases caused by Fusarium species are the most damaging plant diseases affecting both woody perennials and annual crops. Therefore, the aim of the present study was the assessment of the preventive and growth-promoting effects of carvacrol against Fusarium oxysporum, F. solani, and F. nivale (phylogenetically analyzed on the basis of internal transcribed spacer (ITS) regions) causing vascular wilt of ryegrass in vitro and under greenhouse conditions. To accomplish this aim, various parameters were monitored including coleoptile development, rhizogenesis, the incidence of coleoptile lesions, disease index, the visual appearance of ryegrass health, ryegrass organic matter and soil fungal load. The results obtained showed that F. nivale was highly harmful to ryegrass seedlings compared to other Fusarium species. Furthermore, carvacrol with 0.1 and 0.2 mg/mL protected significantly the seedlings against Fusarium wilt diseases both in vitro and in the greenhouse. Simultaneously, carvacrol also functioned as a seedling growth promoter, as is reflected in all monitored parameters, such as the recovery of seedling height and root length, and the development of new leaf buds and secondary roots. Carvacrol proved to be effective plant growth promoter and a bio-fungicide against Fusarium vascular diseases.