Activity and Residual Effect of Two Formulations of Lambdacyhalothrin Sprayed on Palm Leaves to Rhodnius prolixus

Abstract

The insecticidal activity and residual effect of two formulations of lambdacyhalothrin were evaluated withAmerican trypanosomiasis is a zoonosis of great importance in Latin American countries and is produced by the hemoflagellate parasite Trypanosoma cruzi. This protozoan lives and proliferates in the gut of blood-sucking Reduviidae insects and can be transmitted to humans, producing heart and intestinal lesions described as Chagas disease (Ferro et al. 1995). Transmission by insect vectors represents 80% of all the cases of this illness (Dias & Schofield 1999).The "domestic" species of triatomines, the most important vectors of Chagas disease, are very sensitive to control sprayings with modern insecticides and changes to hygienic house conditions. In this case the determination of the basic susceptibility of the target vector, as well as the residual effect of the product (OPS 1984) is of major importance.Considering the success of the Southern Cone initiative, and the Andean initiative in 1997 as a reference, the success of the Central American initiative for the control of Chagas disease vectors (Moncayo 1999, Ponce 1999) was promising.Our results from previous studies conducted during [1997][1998][1999][2000] Central America (Schofield & Dujardin 1997, Dujardin et al. 1998, Ponce 1999. On the other hand Triatoma dimidiata, distributed in the wild in the coastal areas of Chiapas could not be considered as a candidate for eradication (Dias & Schofield 1999, Acevedo et al. 2000.The purpose of this paper, was to carry out a biossay to determine mortality of laboratory grown R. prolixus fifth-instar nymphs when exposed to contact with three doses of two formulations (WP and SC) of lambdacyhalothrin under laboratory conditions and to determine the residual effect on R. prolixus applying the insecticide on palm leaves roofs in field conditions. R. prolixus is considered the most important triatomine species in the state of Chiapas, Mexico. MATERIALS AND METHODSTriatomines -The tests were performed on fifth-instar nymphs of R. prolixus bugs obtained from a colony maintained in our laboratory at 29 ± 1°C, 87 ± 3% RH, and fed on rabbits once per week (Ryckman 1951). These bugs come from insects captured inside houses in Palenque, northern Chiapas.Susceptibility to insecticide -Ten fifth-instar nymphs were placed on palm leaves previously sprayed with lambdacyhalothrin (Commodore® WP 10 and Demand® SC 2.5) by 60 min and observing the percent of mortality after 24 h (Mazariego-Arana 1997). Palm leaves were treated with two surfaces each time for different dose and each of these tests were repeated at least three times. In the control group were used palm leaves not treated previously. The percentage of mortality obtained with each dose were plotted in a log-probit scale with the help of a computer program (Raymond 1996). The LC 50 and LC 90 were then obtained, together with the 95% upper and lower confidence limits.Trial site -Field tests were conducted in the two neighboring communities (Arimatea and Nueva Galilea) ...

Biochemical effects of lambdacyhalothrin on activities of some detoxifying enzymes of Anopheles gambiae life cycle stages

“…Similarly, Okoh et al (2013) and (2014) achieved above 44.29% reduction in malaria infection and other morbidity indicators such as fever, hospital attendance, health seeking movement and school absenteeism in children of Oruku, Enugu state, Nigeria, with lambdacyhalothrin treated curtains, mats and blankets. Curtis and Mnzava (2000) achieved 60% reduction in malaria incidence with both spraying and impregnated netting intervention with lambdacyhalothrin in Kenya and United Republic of Tanzania; Miguel and Mazariego (2002) reported 100% effectiveness up to 12months after lambdacyhalothrin was sprayed on palm leaves against Rhodnius prolixus in the state of Chiapas Mexico.…”

“…Curtis and Mnzava (2000) reported that both spraying and impregnated netting intervention with lambdacyhalothrin reduced malaria vector and hence malaria incidence by about 60% in Kenya and United Republic of Tanzania. Miguel and Mazariego (2002) observed 100% effectiveness up to 12 months, after lambdacyhalothrin was sprayed on palm leaves against Rhodnius prolixus in the state of Chiapas, Mexico. Above 44.29% reduction in malaria infection and other morbidity indicators such as fever, hospital attendance, health seeking movement and school absenteeism was achieved in children of Oruku, Enugu State, Nigeria with lambdacyhalothrin-treated curtains, mats and blankets (Okoh et al 2013(Okoh et al , 2014.…”