Phytotoxic effects of fungicides, insecticides and nonpesticidal components on pepper depending on water quality

Modern agriculture relies on simultaneous application of fungicides, insecticides, fertilizers\udand adjuvants. The selection of compounds for tank-mixes has been rarely studied and it\udpresents a risk in the application of pesticides but the quality of water should also be considered.\udThe aim of this study was to assess the phytotoxic effects of several fungicides, insecticides,\uda complex fertilizer, an adjuvant and their mixtures on pepper (Capsicum annuum L.) as a\udtest plant, depending on water quality. The effects of the pesticides: azoxystrobin (Quadris,\ud0.75 l/ha), mancozeb (Dithane M-70, 2.5 kg/ha), thiamethoxam (Actara 25-WG, 0.07 kg/ha)\udand cypermethrin (Cipkord EC-20, 0.3 l/ha), a complex fertilizer (Mortonijc plus /hereinafter:\udM+/ 3kg/ha), an adjuvant (Sillwet 77-L, 0.1 l/ha) and their mixtures, were assessed depending\udon the quality of water (well water – slightly alkaline, very hard and with high nitrite content;\udtap water – neutral and slightly hard; surface water – alkaline, slightly hard and with high\udcontent of nitrite and ammonia) using a puncture method. The effects were assessed after\udseven days by measuring the diameter of chlorosis and/or necrosis around puncture sites, and\udwere expressed in mm2. The significance of differences between treatments was analyzed\udusing a one-way ANOVA (LSD 0.05 %). In the slightly alkaline and very hard well water, all\udspray liquids containing Dithane M-70 caused a significant increase in leaf chlorosis area (from\ud6.0 to 25.2 mm2), compared to the control and other treatments. In the neutral and slightly\udhard tap water, all spray liquids containing Dithane M-70 caused a significant increase in leaf\udchlorosis (5.3 to 7.9 mm2) compared to the control and the other spray liquids, although its\udphytotoxicity in that water was at a lower level than it was in well water. However, in the\udweakly alkaline and slightly hard surface water from the river Sava, Dithane M–70, Dithane\udM-70 + Actara WG-25, Dithane M-70 + Sillwet L-77, and Dithane M-70 + Actara 25-WG + M+\udshowed a significant increase in phytotoxicity, compared to the control