Influence of Some Compounds on Germination and Development of Puccinia Pelargonii- Zonalis and Pelargonium Growth

The effectiveness of 7 fungicides (Amistar 250 SC, Bayleton 5 WP, Bumper 250 EC, Discus 500 WG, Folicur BT 225 EC, Folicur Multi 50 WG, Score 250 EC) and 2 bioproducts (Biochikol 020 PC and Biosept 33 SL) in the control of Puccinia pelargonii-zonalis was tested on pelargonium cv. Pulsar F1 Salmon. Additionally, their influence on plant growth, size of pustules, percentage of germinated spores and phytotoxicity were assessed. Plants were sprayed 4 times at weekly intervals. Among tested compounds the most effective in suppressing new uredia formation were Amistar 250 SC, Bayleton 5 WP, Biosept 33 SL, Bumper 250 EC, Folicur BT 225 EC and Score 250 EC. Furthermore, some fungicides inhibited germination of urediospores on PDA medium. Fourteen days after the last spraying more than 76% of germinating urediospores were found on control leaves. At the same time spores collected from plants protected with Amistar 250 SC, Bayleton 5 WP, Folicur BT 225 EC and Folicur Multi 50 WG germinated sporadically in 1.5 to 4.0%. In the next part of experiment, plants with visible sporulation of P. pelargonii-zonalis were sprayed with tested compounds. After 1, 7 and 14 days of incubation, total number of spores and number of germinating spores were counted. After 1 or 7 days, urediospores collected from untreated plants germinated in more than 80% whereas from plants sprayed with tested fungicides except Amistar 250 SC in 20–66.6%. Amistar 250 SC was the most effective in suppressing urediospore germination. All fungicides used in protection of young pelargonium plants, except Amistar 250 SC and Biochikol 020 PC, decreased plant growth. None of tested compounds showed phytotoxicity toward tested pelargonium cultivar.