Dear Majid,

The following study entitled "The Effect of Insecticide Synergists on the Response of Scabies Mites to Pyrethroid Acaricides " by Pasay et al. published in PLoS Negl Trop Dis. 2009 Jan; 3(1): e354 describes the use of PBO (piperonyl butoxide), DEF (S,S,S-tributyl phosphorotrithioate) and DEM (diethyl maleate)  for synergistic activity with permethrin in a bioassay of mite killing. The methods depicted in the publication (Test using plastic petri dishes)  may be helpful to set up your procedure.

For quick view I have copied a relevant part of the methods text:

Bioassays

In preliminary experiments, a small number of mites (30/synergist) were exposed to each synergist alone (serially diluted starting from 300 mM) to determine maximum concentration that the mites could tolerate and remain alive for 24 hours (data not shown). The result of this preliminary experiment led us to select a concentration (30 mM) of each synergist for use in subsequent bioassays.

Acaricide bioassays were performed on live scabies mites as previously described [12] with some modifications. Briefly, acaricide and synergists were spread thinly on plastic petri dishes and then groups of female scabies mites were placed in the dish. Mites were exposed to 5% Permethrin alone, 30 mM of each synergist alone (PBO, DEF and DEM), 30 mM of each synergist alone (PBO, DEF or DEM) plus 5% Permethrin, Benzyl Benzoate (positive control acaricide) and mineral oil (negative control) for 24 hours. Petri dishes containing the mites were held in a 28°C incubator at 100% relative humidity. The mites were held at 28°C because lower temperature and higher relative humidity have been found to favour survival of mites outside the host [14]. Individual mites were observed at hourly intervals for 24 hours under a microscope. The time of death, defined as complete absence of movement and a cessation of peristalsis of the gut was recorded. A total of 100 mites in each treatment group were assayed in each set of synergist bioassay. Survival times of mites in acaricide and controls were analysed using Survival Analysis in Graph Pad Prism 4. Kaplan-Meier survival curves of mites in each treatment group were generated and statistical significance of differences in survival curves determined by logrank test.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2603020/

Hoping this will be helpful,

Rafik

Thanks dear Rafik.

But I faced with a problem in preliminary experiments. I use the test tube method and synergist( especially PBO solution) did not solved very well and Aphides are drown in synergist solution.

Dear Majid,

I suggest to use  plastic petri dishes as that used in the indicated paper.

Rafik