The control of the camel tick, Hyalomma dromedarii is very crucial. This study evaluated the novel toxicity of photosensitizers
and Phoxim insecticide against H. dromedarii males using the adult immersion tests. Ticks were subjected to sunlight
for 10 min post-treatment (PT). The optical characters of the applied materials were determined by UV–Vis spectroscopy
(250–900 nm wavelengths). The intensity of spectra decreased as dye concentration decreased. The optical bandgap energies
of the dyes at different concentrations were not changed as the concentration changed and decreased as the absorption peak
of individual dyes red-shifted. The mortalities 72 h PT reached 42.2%, 44.4%, 51.1%, 71.1%, 46.7%, 48.9%, 44.4%, and
55.6% for chlorophyllin, echinochrome, field stain, methylene blue, phthalocyanine, rhodamine 6G, riboflavin, and safranin,
respectively. Methylene blue recorded the highest median lethal concentration (
LC50 = 127 ppm) followed by safranin, field
stain, rhodamine 6G, phthalocyanine, echinochrome riboflavin, and chlorophyllin (
LC50 = 209, 251, 271, 303, 324, 332, and
362 ppm, respectively, 72 h PT). Their median lethal time, LT50,
values PT with 240 ppm were 45, 87, 96, 72, 129, 115,
131, and 137 h, respectively. The relative toxicities of the LC50
values 72 h PT showed that chlorophyllin, echinochrome,
field stain, methylene blue, phthalocyanine, rhodamine 6G, riboflavin, and safranin were 3.2, 3.6, 4.6, 9.1, 3.8, 4.3, 3.5, and
5.6 times, respectively, more effective than Phoxim. Methylene blue, safranin, and field stain showed a broad absorbance
area indicating a large photoactivity and better phototoxicity and could be used as alternative agents to synthetic acaricides. |
