Effect of Mycostop on Fusarium root-rot agents of raspberry

Transcription

1 SCIENTIFIC WORKS OF THE LITHUANIAN INSTITUTE OF HORTICULTURE AND LITHUANIAN UNIVERSITY OF AGRICULTURE. SODININKYSTĖ IR DARŽININKYSTĖ (1). Effect of Mycostop on Fusarium root-rot agents of raspberry Alma Valiuškaitė, Elena Survilienė, Laimutis Raudonis Lithuanian Institute of Horticulture, Babtai, Kaunas distr., LT-54333, Lithuania The studies were carried out in at the Plant Protection Laboratory of Lithuanian Institute of Horticulture. Fungi of species Fusarium avenaceum, F. culmorum, F. oxysporum, F. sambucinum, F. semitectum, F. sporotrichioides, F. tricinctum, F. solani, F. solani var. argillaceum and Fusarium sp. were isolated and identified in raspberry seedlings rhizosphere and peat mulch substrate as potential root-rot agents. Mycostop containing Streptomyces griseoviridis inhibited in vitro growth of Fusarium avenaceum, F. culmorum, F. sporotrichioides and F. tricinctum colonies about % and was aggressive against F. oxysporum, F. solani, F. solani var. argillaceum and Fusarium sp. in peat mulch substrate. Key words: Fusarium spp., Streptomyces griseoviridis, inhibition, raspberry. Introduction. Sustainable farming systems strive to minimize the use of synthetic pesticides and to optimize the use of alternative management strategies to control soilborne pathogens. Of particular importance are bioprotection conferred to plants against genera of Aphanomyces, Cylindrocladium, Fusarium, Macrophomina, Phytophthora, Pythium, Rhizoctonia, Sclerotinium, Verticillium and Thielaviopsis (Whipps, 2001). Mulch is a useful means for growing raspberries. The data on the impact of different mulches on raspberry cane and root infections are almost absent in literature. The combination of suitable mulches with resistant varieties provides a possibility for environmentally friendly production of raspberry (Hanni, Libek, 2003). Various species and strains of Streptomyces produce one or more antibiotics active against bacteria, fungi, algae and viruses. Streptomycete density is higher near the root surface in comparison to non-rhizosphere soil (Dormanns-Simon, 1996). The antagonistic microorganism colonizes the rhizosphere of host plants and competes for space and nutrition with other soil microbes (Dormanns-Simon, 1996). The strain K61 of Streptomyces griseoviridis is a wild type and originally isolated from Sphagnum peat. It has not been genetically modified (Dietz, 1986). Both in Europe and United States this strain is known under commercial name Mycostop. The aim of experiment was to investigate the influence of Mycostop on Fusarium species isolated from raspberry rhizosphere and peat mulch substrate. Object, methods and conditions. The studies were carried out in at the Plant Protection Laboratory of Lithuanian Institute of Horticulture. The strains 47

2 of Fusarium spp. were isolated earlier from raspberry roots with symptoms of rot necrosis. To isolate micromycetes, pieces of raspberry roots of 1 cm -2 were plated onto Malt and Potatoes Dextrose agars. Plates were incubated at 26 ± 2 C temperature for 7 days in dark. Antagonistic effect of S. griseoviridis against Fusarium spp. was studied in vegetative boxes and in vitro. Peat substrate was sprayed with Mycostop (min CFU/g S. griseoviridis), at a rate of 5 g m -3 and it was used as mulch for growing raspberry plants in vegetative boxes (0.024 m -3 ). Mycological analysis was carried out of samples taken from raspberry rhizosphere and peat substrates were analyzed before and after treatment with Mycostop. Inhibition of Fusarium spp. growth by Mycostop (0.01 %) on Malt extract medium was tested in vitro and was detected after 4 days by Abbott formula (Waller et al., 1998). Isolation of the target fungus was performed according to the methods described by Bilai (1977). Results. For investigations there were separated out raspberry seedling cv. Kostinbrodskaja with visible symptoms of Fusarium root rot. They were chosen for mycological analyses of their rhizosphere. Target fungi species Fusarium avenaceum, Fusarium culmorum, Fusarium oxysporum, Fusarium sambucinum, Fusarium semitectum, Fusarium sporotrichioides and Fusarium tricinctum were isolated and identified as potential root-rot agents (Table). Fungi Fusarium oxysporum, F. solani, F. solani var. argillaceum and Fusarium sp. were isolated and identified in non-treated by Mycostop peat mulch substrate. After treatment peat mulch substrate with Mycostop at dose of 5 g m -3 only Fusarium sp. were isolated (Table). Table. Fusarium species isolated of from peat and rhizosphere of raspberry Lentelė. Fusarium rūšys, izoliuotos iš durpių ir aviečių rizosferos 48

3 Mycostop at dose of 100 µg/ml inhibited the growth of Fusarium avenaceum, F. culmorum, F. sporotrichioides and F. tricinctum colonies on malt extract medium in vitro. The detected fungicide activity was from ± 2.10 to ± 2.60 % (Fig.). Fig. The effect of Mycostop on Fusarium spp. in vitro growth after 4-day incubation Pav. Mykostopo poveikis Fusarium sp. augimui in vitro po keturių dienų inkubacijos Discussion. The most harmful diseases of raspberry are root-rot caused by Cylindrocarpon destructans and pathogenic micromycetes from Pythium, Rhizoctonia and Fusarium genera. Fusarium is a large genus of filamentous fungi widely distributed in soil and in association with plants. Most species are harmless saprobes and are relatively abundant members of the soil microbial community (Noble, Coventry, 2005). Fusarium wilt and root rot affects many different horticultural plants and is the most important pathological problem of plants grown in artificial growing media (Ellis et al., 1991). In our investigations there were isolated and identified seven Fusarium species from raspberry seedlings rizosphere and three from peat mulch substrate. Fusarium oxysporum was detected both in rizosphere and peat mulch substrate. It is one of the most aggressive pathogens of agricultural plants (Bilai, 1977; Ellis et al., 1991). Soil mulching can not only save soil moisture but also positively influence soil and plant in other ways (Hanni, Libek, 2003). However, microorganisms (primarily fungi) in mulches and composts can harm and even cause certain diseases of plants (Survilienė, 2002). The activity of some organisms is depressed partly or completely, others can adapt and grow (Morgan, Whipps, 2001). Mycostop s primary targets are Fusarium fungi, which cause wilt, root and basal rot 49

4 diseases in ornamentals, vegetables, fruits and herbs. It also controls some other agents of diseases occurring in soil and seeds such as Alternaria spp. and Phomopsis spp. Mycostop has also shown suppression of damping-off (Rhizoctonia solani Kьhn), gray mould (Botrytis cinerea Pers. ex Fr.) and root rots (Pythium spp. and Phytophthora spp.) (Tapio, Pohto-Lahdenperд, 1991). According to our investigations, there is evidence for similar the antagonistic effect of biofungicide Mycostop (S. griseoviridis) to target Fusarium species isolated from raspberry seedlings rhizosphere and peat mulch substrate. Conclusions. 1. Fusarium avenaceum, F. culmorum, F. oxysporum, F. sambucinum, F. semitectum, F. sporotrichioides, F. tricinctum, F. solani, F. solani var. argillaceum and Fusarium sp. were isolated and identified in raspberry seedlings rhizosphere and peat mulch substrate as potential root-rot agents. 2. Mycostop inhibited the growth of Fusarium avenaceum, F. culmorum, F. sporotrichioides and F. tricinctum colonies about % in vitro. 3. Streptomyces griseoviridis was aggressive against F. oxysporum, F. solani, F. solani var. argillaceum and Fusarium sp. in peat mulch substrate. References Gauta Parengta spausdinti Bilai V. I Fuzarii. Naukova Dumka, Kiyev. 2. Dietz A Structure and taxonomy of Streptomyces. The Bacteria, 9: Dormanns-Simon E Effect of some preparates on soil microflora on the basis of soil bioassay. Journal of Environmental Science and Health, Part B, 31(3): Ellis M. A., Converse R. H., Williams R. N., Williamson B Compendium of raspberry and blackberry diseases and insects. APS Press. 5. Hanni L., Libek A Occurrence of some raspberry cane diseases depending on different mulching and varieties. Sodininkystė ir daržininkystė, 22(3): Morgan J. A. W., Whipps J. M Methodological approaches to the study of rhizosphere carbon flow and microbial population dynamics. In: R. Pinton, Z. Varanini, P. Nannipieri (eds.), The rhizosphere: biochemistry and organic substances at the soil plant interface. Marcel Dekker, New York, Noble R., Coventry E Suppression of soil-borne plant diseases with composts. Biocontrol Science and Technology, 15(1): Survilienė E Reaction of micromycetes to antagonistic organisms and fungicides in substrate. Biologija, 1: Tapio E., Pohto-Lahdenperä A Scanning electron microscopy of hyphal interaction between Streptomyces griseoviridis and some plant pathogenic fungi. Journal of Agricultural Science in Finland, 63: Waller J. M., Ritchie B. J., Holderness M Plant clinic handbook. Wallingford, New York. 50

5 11. Whipps J. M Microbial interactions and biocontrol in the rhizosphere. Journal of Experimental Botany, 52: SODININKYSTĖ IR DARŽININKYSTĖ. MOKSLO DARBAI (1). Mykostopo įtaka aviečių pašaknio ligų (Fusarium spp.) plitimui A. Valiuškaitė, E. Survilienė, L. Raudonis Santrauka m. atlikus mikologinę aviečių rizosferos ir durpinio mulčio analizę, nustatyta, kad grybai Fusarium avenaceum, F. culmorum, F. oxysporum, F. sambucinum, F. semitectum, F. sporotrichioides, F. tricinctum, F. solani, F. solani var. argillaceum ir Fusarium sp. yra potencialūs pašaknio ligų sukėlėjai. Mykostopas, kurio sudėtyje yra Streptomyces griseoviridi, % stabdė Fusarium avenaceum, F. culmorum, F. sporotrichioides ir F. tricinctum kolonijų augimа in vitro. Mykostopas buvo efektyvesnis nuo F. oxysporum, F. solani, F. solani var. argillaceum ir Fusarium sp., išskirtų iš mulčio. Reikšminiai žodžiai: Fusarium spp., Streptomyces griseoviridis, slopinimas, avietės. 51