RESIDUAL EFFICACY OF LAMBDA-CYHALOTHRIN FORMULATIONS IN SURFACE TREATMENT, FOR THE CONTROL OF BLATTELLA GERMANICA (DICTYOPTERA: BLATTELLIDAE)

ABSTRACT

The great variability of surfaces used in civil construction according to structure porosity or density can interfere in the action and in the residual effect of insecticides for the control of Blattella germanica. An evaluated was made of three types of lambda-cyhalothrin formulations: emulsifiable concentrate - CE (ICON 5CE^®), microencapsulated - CS (DEMAND 2,5CS^®) and wettable powders - PM (ICON 10PM^®) on the surfaces: green slate polished, ceramic tile and walls with paint latex. The application (40 mL/m²) was made with previous spray-set compression under pressure of 50 pounds, apray tip TT11003VP (Spraying System Co^®). The formulations CS and PM showed immediate efficiency of over 93.0% on green slate polished, ceramic tile and walls with paint latex showed efficiency less than 35.0%; the formulation CE showed efficiency less than 27.0%. With 30 days the formulations PM and CS presented 88.0 and 86.0% on ceramic tile and on polished green slate displayed efficiency of 78.0 and 44.0% respectively. With 60 days the formulations PM and CS displayed 78.0 and 88.0% efficiency in treatment on ceramic tile; on polished green slate presented 26.0 and 30.0% efficiency, respectively. In 90 days the formulation CS on polished green slate showed 62.0% efficiency and the other treatments lower than 27.0%. Scanning electron microscopy showed that porosity on walls with paint latex was very pronounced, where the biggest pores measure 0.032mm and the smallest 0.005mm. The polished green slate shows irregular surface with superimposed layers sediment plates, within porosity. The ceramic tile, at 1000 x magnification did not show porosity. The different surface types interfered with the efficiency of different formulations of lambda-cyhalothrin.

KEY WORDS:
Blattella germanica ; residual effect; insecticide formulation; building material.