SECONDARY EFFECTS OF FUNGICIDES IN TOMATO SEEDLINGS PRODUCTION

Several factors affect tomatoes production since their sowing until harvest. Seedlings production is considered one of the most important steps in the growing process. High quality seedling production requires use of high technology. Among it is worth to mention trays, substrates, automation controls, fertigation, and especially pest control established with the use of high efficiency pesticides and fungicides. Until recently, fungicides were mainly focused on pathogens control. Some, however, such as pyraclostrobin, a fungicide of strobilurine group, have shown advantages, because of its positive physiological benefits on plants. Several studies have shown that the main purposes of pyraclostrobin are related to the reduced production of ethylene, increased activity of the nitrate reductase enzyme, the greatest resistance of the water stress and the increased chlorophyll content. The objective of this study was to evaluate the effect of pyraclostrobin+metiram (50 g a.i. and 550 g a.i. kg^-1) and boscalid (500 g a.i. kg^-1) at different doses and times of application on substrate in the growth and development of tomato seedlings. Tomato seedlings answered positively to pyraclostrobin+metiram and boscalid, with maximal responses achieved in the dose range from 2.2 to 4.4 g L^-1 and 0.37 to 0.41 g L^-1 for pyraclostrobin+metiram and Boscalid, respectively. The application of pyraclostrobin+metiram and boscalid on substrate soon after the period in germination chambers is not recommended. The application after planting and before germination chamber is the most promising.