There are many reports of inefficiency by pesticides in the pest control when they are prepared in solutions with water hardness and high pH. Therefore, the research aimed to evaluate the effects of water hardness, pH and time after preparation (0 and 24h) of acaricides spray solutions on control of the citrus leprosis mite, Brevipalpus phoenicis (Geijskes). The bioassay was carried out on fruit of Citrus sinensis (L.) Osbeck cv. Valência. A completely randomized design with fourteen treatments and four repetitions was used. The sample unit was composed by one fruit with ten mite females. The following acaricides were tested: propargite, hexythiazox and spirodiclofen. The spray on fruit was done by modified Potter tower adjusted to an equivalent volume of 1616 L ha-1. The evaluations were done until 49 days after the acaricide application by counting the number of adults, nymphs and the number of eggs in the last evaluation. Water hardness, hydrogenionic potential and time after preparation of spray solution did not interfere on leprosis mite control. After the mixture with different water types, the acaricides did not modify the pH of the spray solutions, which showed low variations in pH values over 24 h. All acaricides showed an efficient control of leprosis mite, regardless of the variations in water hardness and pH.
Chemical control; spray water quality; leprosis mite; citrus
