Fungicides and biotechnical agents in the protection of heathers against Pestalotiopsis sydowiana and their influence on plant growth

Abstract

In the protection of heathers against shoot dieback caused by Pestalotiopsis sydowiana, the highest percentage effectiveness of 92.6% to 100% was found on plants sprayed 12 times every 7 days with the active substances: iprodione, pyraclostrobin + boscalid and trifloxystrobin and with the biotechnical agents containing: microcrystalline chitosan and extract from grapefruit seed and pulp, with an efficacy of 76.9% to 100%. The active substances like chlorothalonil, fluopyram + trifloxystrobin, iprodione, pyraclostrobin + boscalid, as well as microcrystalline chitosan and extract from grapefruit seed and pulp also stimulated plant growth. Heather plants sprayed with these agents and also those sprayed with cyprodinil + fludioxonil, trifloxystrobin and potassium carbonate + monopotassium phosphate were found to produce the highest number of new shoots. An increase in the fresh weight of the aboveground parts of the heather plants of more than 55.7% compared with the control plants was found after spraying the plants with the active substances such as: fluopyram + trifloxystrobin, iprodione, pyraclostrobin + boscalid, cyprodinil + fludioxonil, trifloxystrobin and with the biotechnological agents containing microcrystalline chitosan extract from grapefruit seed and pulp, and potassium carbonate + monopotassium phosphate. Similarly, the highest average dry weight of the aboveground parts was found after the application of these agents.