The addition of adjuvant oils to spray is frequently used without any adequate knowledge about the product adsorption by the target, spray retention and the crop-pest interactions. This work aimed to evaluate the effect of adjuvant oils addition in the cyhexatin acaricide solution to Brevipalpus phoenicis control and the spray retention by citrus leaves. The mites mortality was evaluated in a certain area surrounded by entomological glue over orange fruits. It was performed a totally randomized design, in a factorial scheme. It was used two cyhexatin formulations: WG and CS; two adjuvant oils: vegetal and mineral over two concentrations (0.5 and 1.0%) plus two additional check treatments (acaricide without oil) and control (without spraying). Application was performed in orange fruits over the point of runoff. After application, ten B. phoenicis were transferred to each fruit. The count of alive, dead and glue barrier stucked mites was made one day after. In order to estimate the spray retention, a spray application over orange leaves was performed, sprayed up to the runoff point, using the same treatments and statistical design analysis that had been previously mentioned, except for control plot. The liquid mass over the leaves after spraying was weighed. It was verified, for all treatments, that the mite mortality reaches above 90%, right away the day after application. Thus, both mineral and vegetal oil addition to cyhexatin acaricide spray did not affect its biological efficacy under CS and WG formulations. It was observed a larger number of mites stucked to the glue barrier in the treatments with oil addition compared to the treatments without it. The vegetal or mineral oil addiction to cyhexatin spray have reduced the maximum amount of liquid retention by the citrus leaves, which can contribute to reduce the essential spray amount in a great plant cover.
Citrus leprosis; citrus leprosis mite; spray technology and adjuvant
