Evaluation of Insecticide Activity of Two Agricultural Detergents against the Long-Tailed Mealybug, Pseudococcus longispinus (Hemiptera: Pseudococcidae), in the Laboratory

Tomislav Curkovic1*, Gary Burett1, Jaime E. Araya1

The insecticide effect of agricultural detergents SU 120 and Tecsa Fruta was evaluated on females and nymphs II of Pseudococcus longispinus (Targioni & Tozzetti) in the laboratory. Mortality at 24 h was subjected to Probit analysis to obtain the LC50. For Tecsa Fruta, a volume of 9.5 mL solution was sprayed, while for SU 120, volumes of 2, 4, and 8 mL 100 mL-1 solution were evaluated. Mortality was directly related to the concentration used. Nymphs II were more susceptible than females to both detergents. LC50 for Tecsa Fruta were 17.9 mL 100 mL-1 for females, and 5.4 mL 100 mL-1 for nymphs II, whereas for SU 120 they were 3.1, 1.6, and 1.9 mL 100 mL-1 on females, and 0.8, 0.5, and 0.5 mL 100 mL-1 (with 2, 4, and 8 mL, respectively) on nymphs II. For the latter, there were no significant differences among volumes, and for females, the LC50 with 4 and 8 mL solution were not statistically different, although these two volumes were statistically smaller than in the treatment with 2 mL. For the same SU 120 concentration, mortality of females increased with greater volumes sprayed. SU 120 had a significantly greater insecticide effect than Tecsa Fruta on P. longispinus nymphs II and females. Nymphs II were the most susceptible stage. Results suggest that it would be possible to reduce detergent concentration using greater spray volumen to achieve similar mortality.

Keywords: agricultural detergents, bioassays, LC50, Pseudococcus longispinus, SU 120, Tecsa Fruta.
1 Universidad de Chile, Facultad de Ciencias Agronómicas, Casilla 1004, Santiago, Chile. E-mail: tcurkovi@uchile.cl *Corresponding autor.