In past laboratory and glasshouse experiments we developed an innovative plantlet inoculation biological control strategy to protect cauliflower plants against cabbage root fly (CRF). Within this paper we tested this one time, pre-transplantation prophylaxis with beneficial fungi in a field scenario, in commercial cauliflower production. The fungal-inoculation strategy was compared to low risk methods such as nitrogen lime, the insecticide spinosad, the Beauveria bassiana based biopesticide Naturalis, and commercial insecticides ?-cyhalothrin and thiamethoxam. The lowest number of cabbage root fly pupae recovered from cauliflower roots in the field experiments was recorded in plants treated with spinosad (significant reduction), followed by Naturalis and one of our unformulated Metarhizium brunneum strains (non-significant reduction). Significantly more pupae were counted in the nitrogen lime treatment. The field experiments showed that a single drench of cauliflower plantlets with spinosad offered consistent and enduring cabbage root fly control. Naturalis and non-formulated fungal isolates did not decrease cabbage root fly pressure significantly, apparently due to lack of statistical power. The benefits of using single plant treatments are discussed, and recommendations for improvement of rhizosphere-competence utilizing biological control strategies provided.
COBISS.SI-ID: 5330792
The cabbage root fly (CRF; Delia radicum) is difficult to control as insufficient plant protection products are available, especially in organic farming. In this study the influence of two strains of the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana (Hypocreales), straw mulch, spinosad and nitrogen lime were investigated in regard to CRF and root damage reduction in field trials. Furthermore, rhizosphere competence and endophytism, mineral uptake, chlorophyll a fluorescence, and growth parameters of M. brunneum treated plants were examined under field and/or greenhouse conditions. Neither fungi nor straw mulch or nitrogen lime decreased CRF pressure significantly, but spinosad did. M. brunneum colonized the rhizosphere of broccoli plants but did not show endophytic characteristics. A significant increase of Mg and N concentrations was detected in Metarhizium-treated plants, higher maximum quantum efficiency of photosystem 2 photochemistry and electron transport rate as well as enhanced growth. We conclude that for brassicas where the CRF damaged parts are not consumed (e.g. cauliflower) the tested low risk CRF management tools might be adequate. But for brassicas, where CRF directly damages the produce (e.g. turnips), treatments having greater impact on CRF (e.g. spinosad) should be considered.
COBISS.SI-ID: 5231976
We developed a method using hyperspectral imaging for distinguishing between plants in drought stress and those infested by the nematode Meloidogyne incognita. We were also able to determine infestation severity, even before any visible signs of infestation or drought stress developed.
COBISS.SI-ID: 5547880
The vascular plant pathogen Verticillium nonalfalfae causes Verticillium wilt in several important crops. In this study, we aimed to determine V. nonalfalfae candidate effectors, by analysing the available genomic and proteomic data, and the results of RNA-Seq experiments, and to confirm them with mutational analysis. From the annotated genetic models of V. nonalfafae, we initially identified in silico secretome enriched with enzymes involved in the degradation of cell walls, with proteases, lipases, cutinases and oxidoreductases, which corresponds to the hemibiotrophic life style of V. nonalfalfae. We further identified gene models expressed in planta, predicted candidate secretory effector proteins, and selected the best candidates based on the properties of already confirmed fungal effectors. We determined the expression of the most promising candidates by RT-qPCR in resistant and susceptible varieties of hop after infection with V. nonalfalfae. Using the ATMT method, we prepared five deletion mutants of candidates with the highest expression, and artificially inoculated susceptible varieties to determine their virulence.
COBISS.SI-ID: 8940665
The number of active substances registered for wireworm control is decreasing. Consequently, inventorization programs were launched to find and identify potential wireworm biological control agents. Metarhizium brunneum Petch was isolated from an adult Agriotes sp. (Coleoptera: Elateridae) in Slovenia. The strain belongs to a phylogenetic lineage of M. brunneum accommodating isolates from Asia and North America while it was reported from Europe (Denmark and Switzerland) only recently, and for the first time in Slovenia. Its pathogenicity to field-collected Agriotes spp. was tested in feeding and soil experiments. The latter lasted either 15 or 90 days and adopted different concentrations of fungal conidia. Coating potato slices with conidia had no effect on mortality. However, M. brunneum in soil significantly increased wireworm mortality in short- and long-term bioassays. The average LT50 based on Probit analysis was 44.6 days for the M. brunneum treated wireworms and 741 days for the negative controls.
COBISS.SI-ID: 5427560