Whole-Body Acute Contact Toxicity of Formulated Insecticide Mixtures to Blue Orchard Bees (Osmia lignaria)

Blue orchard bees, [Osmia lignaria (Say) (Hymenoptera: Megachilidae)], have been developed as an important pollinator for orchard crops in North America over the last 40 years. The toxicity of several pesticides to O. lignaria and other Osmia species has been previously reported. However, the field-realistic toxicity of formulated premix insecticides comprised of multiple active ingredients (each with a different mode of action) to O. lignaria has not been assessed. Here, we use a customized spray tower in a laboratory setting to assess adult male and female whole-body direct contact exposure to four formulated pesticide mixtures: thiamethoxam + lambda-cyhalothrin (TLC), imidacloprid + beta-cyfluthrin (IBC), chlorantraniliprole + lambda-cyhalothrin (CLC) and methoxyfenozide + spinetoram (MS) by directly spraying anesthetized bees in Petri dishes. Separately, adult male and female whole-body direct contact exposure to formulated imidacloprid (I), beta-cyfluthrin (BC) and their 1:1 binary combination (IBC) was assessed using the same experimental method. Resulting mortality in each study was screened up to 96 h post-treatment to determine acute whole-body contact toxicity. In the first study, TLC and IBC resulted in statistically higher mortality at 24 and 48 h than the two other insecticide combinations tested. The CLC and MS combinations were slower acting and the highest mortality for O. lignaria exposed to these mixtures was recorded at 96 h. We did observe significant differences in toxicity between CLC and MS. In the second study, exposure to the 1:1 binary combination of IBC caused overall significantly higher mortality than exposure to I or BC alone. Both active ingredients alone, however, demonstrated equivalent levels of mortality to the 1:1 binary combination treatment at the 96 h observation reading, indicating increased speed of kill, but not necessarily increased toxicity. Significant differences in the onset of mortality following acute contact whole-body exposure to the formulated insecticide mixtures and individual active ingredients tested were consistently observed across all experiments in both studies.

Effect of Itraconazole-Ezetimibe-Miltefosine Ternary Therapy in Murine Visceral Leishmaniasis

ABSTRACT Drug combination therapy is an interesting approach to increase the success of drug repurposing for neglected diseases. Thus, the objective of this work was to evaluate binary and ternary therapies composed of itraconazole, ezetimibe, and miltefosine for the treatment of visceral leishmaniasis. Intracellular Leishmania infantum amastigotes were incubated with the drugs alone or in combination for 72 h. For in vivo experiments, we tested long-course (21 days, once per day) and short-course (5 days, twice per day) treatments for the binary combination of itraconazole and ezetimibe. For the ternary therapy including miltefosine, we adopted the short-course treatment and varied the vehicle. None of the combinations were toxic to macrophages. The binary combination of itraconazole plus ezetimibe and the ternary combination of itraconazole, ezetimibe, and miltefosine had synergistic effects in intracellular amastigotes, for some of the proportions evaluated. Although the in vivo long-course therapy had been more effective than the short-course protocol, it showed hepatic toxicity signs. Ezetimibe has been proven to be able to reduce the parasite burden alone or in combination. Both suspensions of the ternary combination were active, but when the drugs were suspended in the commercial Ora-Plus formulation instead of purified water, the parasite burden was reduced by 98% in the liver and spleen. Altogether, the results demonstrate for the first time the activity of ezetimibe in a viscerotropic species of Leishmania and indicate that ternary treatment composed of miltefosine, itraconazole, and ezetimibe at low doses is a promising therapeutic alternative for the treatment of visceral leishmaniasis.

EFFICACY OF BINARY COMBINATION OF DELTAMETHRIN+MGK-264 ON LEVELS OF BIOCHEMICAL CHANGES IN THE SNAIL LYMNAEA ACUMINATA

Objective: The objective of the present study is the evaluation of the effect of the sublethal (40% and 60% of 48h LC50) binary combination (1:5 ratios) of molluscicides deltamethrin+MGK-264 on the endogenous levels of protein, amino acid and nucleic acid in different tissues of snail Lymnaea acuminata. Methods: The snails were treated with 1:5 mixtures of sub-lethal concentration of (40% and 60% of 48h LC50) deltamethrin+MGK-264 on the protein, amino acid and nucleic acid levels in gonadal, nervous and foot tissue of L. acuminata. In order to study the effect of withdrawal from treatment, the snails were first exposed to the above concentrations for 96h, after which they were transferred to freshwater. Water was changed every 24h for the next seven days, after which different biochemical parameters were estimated. Results: There was a significant change in the levels of protein (sublethal concentration of 60% of 48h LC50 after 96h) gonadal, nervous and foot tissues are 48.1, 12.1 and 14.5%, respectively, amino acid are 273, 234 and 252%, respectively, DNA are 25.1, 38.9 and 42.1%, respectively and RNA are 12.2, 30.7 and 30.5%, respectively. These changes were time and concentration-dependent. In the withdrawal experiment, the snails were treated for 96h to transfer in freshwater for 7 d, which caused significant recovery in all the biochemical parameters. Conclusion: The present study concluded that the high molluscicidal activity of deltamethrin+MGK-264 simultaneous decrease in the levels of proteins, DNA, RNA and increase in the level of amino acids.

Biocontrol Potential of Some Entomopathogenic Fungal Strains Against Bean Aphid Megoura japonica (Matsumura)

This research reported the in vitro pathogenicity of Verticillium lecanii strains, L2 and L5, and Beauveria bassiana strains, B76 and B252, against Megoura japonica using leaf-dip method. The virulence potential of these four entomopathogenic fungal strains of V. lecanii and of B. bassiana were compared between fungi conidia (concentrations 1 × 106, 1 × 107, and 1 × 108 conidia mL−1) and culture filtrate. Moreover, binary combination of four different fungal strains (L2 + B76, B76 + L5, L2 + B252, and L2 + B76 + B252 + L5) were evaluated against M. japonica under control condition. Aphid mortality was recorded after two, four, six, and eight days of post-treatment. In the conidial concentration bioassay, strain B76 showed maximal mortality (85.3%) against bean aphid, and strain L5 showed the lowest effect (60.0%) at the highest concentration (1 × 108 conidia mL−1) at eight days post-treatment. Whereas, binary combinations of B76 and L2 strains showed the highest effect against M. japonica (90.5%) than other combinations. Moreover, in comparison with the effect of filtrate and conidia bioassay, 91.4% and 84.1% were achieved in strain B76, and the lowest effect (63.8% and 55.1%) was recorded in strain L5.

Synergistic Effect Between Gum Exudates of Eucalyptus Globles and 2,6-Diphenyl-3-Methylpiperidin-4-one on Corrosion Inhibition of MS in 1N HCl

Gum exudates of eucalyptus globles (GEG) was identified as green inhibitor for MS dissolution in 1N HCl using gravimetric method at 303-323K. Efficiency of GEG was synergistically increased with addition of 2,6-diphenyl-3methyl-piperidin-4-one (3MDPP). The binary combination of GEG and 3MDPP shows maximum inhibition potency and their Sθ value is >1 indicating that synergism exists between GEG and 3MDPP. Mechanism of inhibition of inhibitors on MS is physisorption and it obeys Langmuir’s isotherm. Polarization and impedance measurements confirm that inhibitors act as mixed type.