Acaricidal efficacy of Myrrh [commiphora molmol] on the fowl tick argas persicus [acari: argasidae]

Five concentrations of purified extract of Myrrh from Commiphora molmol tree were prepared to study its effects on the fowl tick Argas persicus under laboratory conditions. The results revealed that Myrrh had dependant dose toxic effect on the adult female of A. persicus. Toxicity increased gradually daily post treatment. The LC 50 was 1.28%, 0.88%, 0.84%, 0.50% and 0.42% at 1st 2nd 3rd 6th and 12th days respectively. At 12th day, the recorded mortality rates were 63, 67, 76, 87 and 94% for concentrations. 0.625, 1.25, 2.5, 5 and 10%, respectively against 5% in control. Histopathological and Transmission election microscope [TEM] examinations showed the lysing of epithelial gut cells in treated groups. The lysed epithelial gut cells showed irregularly distributed nucleus, commonly at low concentrations and rarely in high concentrations of Myrrh. The lysed epithelial gut cells, without nucleus or with aggregated one beside the basal lamina. were common at high concentrations and rare in low concentrations of Myrrh. Consequently, Myrrh can rapidly penetrate the cuticle to body cavity, destroy the epithelial gut cells and finally cause the death of ticks

Labortary evaluation of Bacillus sphaericus recycling in mosquito larvae

After ingestion by Culex pipiens and Anopheles pharoensis 4th instar larvae, the spores of Bacillus sphaericus strain faiyoum rapidly germinated inside live mosquito midgut. Bacterial counts and electron microscopic observations on intoxicated larvae revealed that the number of viable spores rapidly decreased during the first 12 hours with a maximum between 12 and 24 hours. In cadavers, the number of heat-resistant spores quickly increased between the first and second day post-feeding. After one week, the number of spores inside the dead larvae reached approximately 20 times the number of ingested spores for both mosquito species [4 x 165 spores/larva]. Ultrathin sections of recycled spores showed the presence of a crystalline inclusion identical to that initially present in spores before ingestion. Bioassay on Cx. pipiens 4th instar larvae showed a similar toxicity between the in vivo recycled spores [LC50 = 1.1 +/- 0.3 x 105 spores/ml after 24 hours exposure] and culture-medium-grown spores of B. Sphaericus strain faiyoum [LC50 = 1.7 +/- 105 spores/ml]

Cytoplathological action in mosquito larvae fed with Bacillus sphaericus [Strain Faiyorum] spore crystal complex

The ingestion of Bacillus sphaericus [strain Faiyoum] spore/crystal complex by larvae of Anopheles pharoensis, Culex pipiens and Aedes caspius was rapidly followed by a dissolution of the protein crystalline inclusions inside the anterior stomach of the three species. During the first day, B. sphaericus spores were germinated within the mid-gut lumen and were in a vegetative stage between 36-48 hours after ingestion when larvae began to die. The ultrastructural observations focused on the larval mid-gut showed alterations, which differ according to the mosquito species, being localized mainly in the gastric caecae and posterior stomach. With the bacterial concentration used, neither general cell swelling nor complete breakdown of the mid gut epithelium was recorded before the larval death. In An. Pharoensis larval mid- gut epithelium large low- electron-density areas appeared, rough endoplasmic reticula formed numerous concentric structures and mitochondria swelled. Large vacuoles [of unknown origin] appeared early in the Cx. pipiens mid gut cells and rough endoplasmic reticula broke into small vesicles. Mid gut epithelial cells of Ae. Caspius showed mitochondria swelling, except in the anterior stomach and a vacuolization of smooth reticula; these aspects remained unchanged until the larvae died

Biochemical changes of culex pipiens larvae treated with oil and oleo-resin extracts of myrrh commiphora molmol

The mosquitocidal plant extracts of the myrrh Commiphora molmol; namely, oil and oleoresin demonstrated larvicidal activity against Culex pipiens larvae. Oleoresin induced a significant higher toxic action than oil. Solvent did not perform any toxic activity. The impact of both oleoresin and oil extracts on the protein profile of the treated larvae was evaluated in order to explain their mode of action. Electrophoretic analysis of total proteins, lipoproteins and glycoproteins revealed an inhibitory action of the used plant extracts on the protein contents. Larvicidal activity of the oleoresin and oil was related to the loss of certain enzymes inhibited by these extracts which affected the metabolic processes