Are vegetable adjuvants increasing the efficiency of the aqueous extract of Sarcomphalus joazeiro on Tetranychus ludeni?

This study aimed to evaluate the effects of using coconut, soy, canola, and sunflower vegetable oils as adjuvants on the efficiency of the aqueous extract of Sarcomphalus joazeiro (Mart.) Hauenshild in the management of the mite, Tetranychus ludeni Zacher. The lethal concentrations (LC50 and LC90) of the extract with the adjuvants (E + A) were tested for toxicity, residual effect, oviposition deterrence, and egg viability in T. ludeni females. The curative and preventive effects of E + A were evaluated. Soluble phenols in the extract were identified and quantified using UHPLC+. All tested adjuvants were observed to increase the efficiency of the S. joazeiro extracts against T. ludeni. LC50 was found to be more efficient in the curative test when sunflower and coconut oils were used, whereas LC90 caused 100% mortality of the mites in both tests. Adjuvants increased the residual effect of the extract and reduced the viability of T. ludeni eggs. The lowest number of hatched eggs was observed for the LC50 of extracts with either canola and sunflower oil and for the LC90 of the extract with soybean oil. In the curative test for LC50, the greatest reduction in oviposition was seen in treatments with sunflower, canola, and soybean oils; meanwhile, in the preventive test, deterrence was greater in treatments with sunflower oil compared to that seen with other oils. Gallic acid, a phenolic compound, was quantified to be 6.68 mg/mL at LC50 and 6.77 mg/mL at LC90, whereas the total amount of soluble phenols was 36.84 and 38.82 mg gallic acid equivalents 100 g−1 DW at LC50 and LC90, respectively. Adjuvant vegetable oils increase the efficiency of the aqueous extract of S. joazeiro; thus, their use is a viable alternative for the management of T. ludeni.