Możliwość bezpośredniego działania nawozu Actifos na niektóre patogeny roślin

An in vitro study was conducted on the direct action of the fertilizer Actifos (an ammonium form of phosphite that contains 10% nitrogen and many microelements: B, Cu, Fe, Mo, Zn) in doses of 0, 100, 500, 1000, 3000 and 6000 μg·ml-1 added to potato dextrose agar (PDA) medium against the growth of pathogen cultures. The study included the pathogens: Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. dianthi, Myrothecium roridum, Paraconiothyrium fuckelii, Phytophthora cinnamomi, P. cryptogea, Pythium ultimum, Rhizoctonia solani, Sclerotinia sclerotiorum. Actifos added to potato dextrose agar (PDA) at a dose of 6000 μg·ml-1 was shown to completely inhibit the growth of the mycelia of P. cinnamomi and S. sclerotiorum. For the mycelia of B. cinerea, P. fuckelii, P. cryptogea and P. ultimum, the inhibition of growth was more than 80%. However, it was observed that at a concentration of 100 μg·ml-1 the fertilizer stimulated the growth of B. cinerea and P. ultimum cultures, and in doses of 1000 and 3000 μg·ml-1 that of C. gloeosporioides. The study also showed that the fertilizer Actifos introduced into the medium at concentrations of 100 to 1000 μg·ml-1 inhibited the germination of Diplocarpon rosae spores by 27% to 79.7%. At concentrations of 3000 μg·ml-1and higher, spore germination was not observed. By comparison, the fertilizer Actifos used for spraying rose bushes at a concentration of 0.6% caused the germination of D. rosae spores to be inhibited by 82% after 1 day, 87.9% after 7 days, and by 37.5% after 14 days.