Effect of eradicative activity of strobilurin fungicides and difenconazole on mycelium and sporulation of Venturia inaequalis
The eradicative effect of two strobilurin fungicides (kresoxim-methyl and trifloxystrobin) and difenoconazole on activity of apple scab spots was studied in greenhouse and field conditions. The reaction of mycelium and sporulation of <i>Venturia inaequalis</i> after fungicides applications were observed in light and scanning electron microscope. Mixture of strobilurin fungicide and difenoconazole applied twice, in 5 days interval, gave the best eradicative effect. The inhibition of sporulation was long lasting and it was observed even 3 and 5 weeks after treatments. The conidiophores, conidia and mycelium were damaged. Also difenoconazole showed good eradicative activity, in field condition up to 5 weeks after application. Trifloxystrobin significantly reduced the number of active scab lesions and the effect was visible even 3 weeks after treatment. Kresoxim-methyl in both tested doses (0,2 and 0,3 kg/ha) was slightly less effective.