Treating of seed potato tubers with Prestige

Thanatephorus cucumeris (Frank) Donk is commonly found to persist in majority of soil types and cause the damage to many of economically important crops. In seed potato production infections cause the yields' losses of 20-50 %; affected tubers are smaller, cracked, with the small holes sourounded by dead tissue. When infected tubers are planted, the sprouts and young plants may partly or completely die. The fungus is spread by mycelium present in the form of black scurfs-sclerotia on the surface of infected tubers, or by mycelium present on the plant residues in the soil. The stuff of Mercator-KZK Kmetijstvo Kranj has been aware of the economical losses in the seed and ware potato production, due to Thanatephorus cucumeris infection, for many years. In 1998 nearly 80 % of potato tubers of cv. Jemseg, which was growing at the isolate field on the airport Brnik area, were found to be infected by sclerotia of Thanatephorus cucumeris. In 1999 the seed potato tubers were treated against Thanatephorus cucumeris by different fungicides (rizolex, maxim and prestige). In 2000, all seed potato tubers aimed at seed and ware potato production were treated by fungicide Prestige, using special equipment Mafex. Prestige contains 150g/l of active ingredient pensycuran, which is effective against the fungus Thanatephorus cucumeris and 140g/l of imidaclorprid, an insecticide active ingredient against colorado beatle (Leptinotarsa decemlineata), aphids (Aphidae) and wireworms (Agriotes sp.). The experiment of the Prestige treatment showed very good results. Only 1-2 % of tubers of the seed and ware potato were found to be superficially infected by sclerotia of Thanatephorus cucumeris. The damage and deformations of tubers caused by this fungus were noticed only in few cases. The potato fields were protected against the Colorado beatle, aphids, wireworms and against fungus Thanatephorus cucumeris with only one treatment of seed tubers with Prestige (1,5 l/t tubers) before planting, what seems economically and ecologically favourable.