Spreading of drops solutions with biological insecticide in different concentrations of adjuvants in cassava leaves

Abstract

It was aimed to evaluate the efficiency of spreading drops in cassava leaves of Solutions with Biological insecticides and adjuvants in different concentrations. The experimental design was completely randomized in a factorial 2 x 3 x 5, with four replications. The treatments consisted in the preparation of solutions of two biological insecticide Bacillus thuringiensis (500 g ha^{- 1}, Dipel WP® - 32,0 g kg^-1) and baculovirus (0,41 g ha^{- 1}) , with addition of three adjuvants (Mineral oil-Nimbus®, vegetable oil- Aureo® and glycerine- Hygrogem® , soybean biodiesel byproduct ) in five concentrations (0,0; 0,2; 0,4; 0,6 and 0,8 % v v^{- 1}), cassava leaves comes the variety 'IAC 90'. The spreading of the drops (13μL) of the solutions were evaluated in adaxial and abaxial faces. There was triple interaction among factors insecticides, adjuvants and concentration of adjuvants. It was found that the B. thuringiensis + mineral oil (0,5% v v^-1)  and B. thuringiensis+ vegetable oil (0,3% v v^-1) provided the largest areas of spreading of droplets on the face adaxial and abaxial respectively. The Baculorívus+vegetable oil (0,6 e 0,8% v v^-1) provided higher spreading of drops on the face adaxial and abaxial respectivelyl. Glycerin in concentrations evaluated, not shown to be effective both in reducing the surface tension of the solutions, as in spreading drops. The efficiency of spreading drops on cassava leaves was dependent on the biological insecticide used and the adjuvant type and concentration used in the preparation of the spray solution.