Pymetrozine is a fast-acting, selective inhibitor of aphid feeding. field research using electronic feeding behavior monitoring. The novel insecticide pyromethazine, a pyridyl azomethine molecule, exhibits selective action against Homoptera insects. Aphids are not stricken upon touch, but instead seem to starve to death, which is how it operates. This indicates that feeding behavior is impacted by pymetrozine. The current study aimed to clarify the intricate process by which pymetrozine impedes phloem nutrition and the precise point at which this interference occurs. Using electropenetration mapping (EPG), the effects of varied applications of pymetrozine on the various stages of xstylet penetration and individual aphid feeding activity were investigated. Pymetrozine does not appear to have any deterring or antifeedant effects based on preliminary selection studies. Application topically (150 ng/mg fresh weight) prevents the plant from absorbing the probe. Less than 30 ng/mg of injection is needed to provide the same impact. Aphids start feeding properly once pymetrozine is given via a root absorption device or plant spray. Eventually, though, they remove their probes from the phloem and continue to travel normally. Aphids ultimately recovered and started eating again at low levels. Large doses, however, have the potential to permanently interfere with feeding and hinder xstylet reinsertion. Aphid motility is expected to remain unaffected until the hemolymph concentration reaches 1 mM pymetrozine. Aphids treated with pymetrozine that eventually quit feeding displayed a disrupted EPG salivary/uptake pattern [2].

Absorption, Distribution and Excretion
A metabolic study in rats…using radiolabeled pimecrozin, administered orally or intravenously to five male and female animals in each group, assessed absorption and excretion. Within 24 hours of administration, the radioactive material content in the urine of all oral-administered rats ranged from 52.0% to 73.5% of the administered dose. The 24-hour urinary radioactive material content in the intravenously administered rats was comparable, at 63.6% in males and 68.3% in females. At the end of the study (7 days post-administration), radioactive material recovered from urine (56.3–80.3%), exhaled air (0.2–1.4%), tissues (0.3–3.8%), feces (15.4–38.9%), and cage cleaning fluid (0.2–0.7%) represented 91–100.7% of the administered dose across all groups. A metabolic study in female rats… used… pimecrozine (labeled in either the triazine or pyridine fraction), and animals were orally administered a single low dose (0.5 mg/kg) or a high dose (100 mg/kg). Regardless of the labeling site, the time to peak plasma concentration (tmax) was 1 hour and 8 hours after oral administration of the low and high doses, respectively. … Peak plasma concentration was dose-dependent but not related to the labeling site. Tissue residual levels (ppm) were consistently highest in the kidneys and liver, regardless of dose or labeling site. Except for the gastrointestinal tract, skeletal muscle showed the highest percentage of administered dose in all tissues (both labelings), with 7–8% after 1 hour in the low-dose group and 19–21% after 8 hours in the high-dose group. The calculated residual half-lives (t_1/2) of triazine compounds in all tissues were 2.9–4.8 hours (low dose) and 1.9–3.5 hours (high dose); the residual half-lives of pyridine compounds were 31.7–110.3 hours (low dose) and 2.5–13.9 hours (high dose). The high-dose group showed lower uptake rates, with both radiolabeled compounds showing up to approximately 82% of the administered dose. Regardless of the labeling site, bile excretion was higher in the low-dose group than in the high-dose group. Including cage cleaning, the total excretion over 48 hours was higher in the triazine-labeled group (low/high dose: 103%/95%) than in the pyridine-labeled group (low/high dose: 85%/81%). …Therefore, the metabolites of pyridine residues are more persistent than those of the triazine moiety. A study on skin absorption in male rats… Twenty-four male animals were exposed to 98.1-99.5% radiolabeled pimecrozine at dose levels of 0.084, 0.503, or 4.69 mg/rat (0.0067, 0.0402, or 0.375 mg/cm²). After blood collection, four rats from each dose group were sacrificed, and skin absorption was assessed at 0.5, 1, 2, 4, 10, and 24 hours after exposure. Urine and feces were collected at sacrifice. At 24 hours after exposure, skin absorption was extremely low (0.05% in the low-dose group, 0.01% in the medium-dose group, and <0.005% in the high-dose group). In all dose groups, the majority of the dose (81.4-100.0%) was not absorbed but excreted through skin washes. In all dose groups, the dose adsorbed to the skin from the test site (0.18–8.84%) accounted for the second largest proportion of the dose, with only trace amounts (≤0.05%) of radioactive material excreted in urine and feces. Within each dose group, the amount of radioactive material remaining on the skin after washing did not appear to increase with prolonged exposure time. Similarly, absorption (measured by excretion plus retention) did not appear to increase over time. Metabolism/Metabolites A rat metabolism study… used radiolabeled pimecrozin, administered orally or intravenously to five male and female animals in each group, to assess absorption and excretion. …Relatively high levels of unmetabolized test substance in urine indicated that metabolic saturation was reached at the high dose of 100 mg/kg. Biological Half-Life Calculated half-life (rat): 1–2 hours at 0.5 mg/kg dose (both labels), 2–11 hours at 100 mg/kg dose. (Data from tables)

[1]. I D BEDFORD, et al. The effect of Pymetrozine, a feeding inhibitor of Homoptera, in preventing transmission of cauliflower mosaic caulimovirus by the aphid species Myzus persicae (Sulzer). Annals of Applied Biology. 1998 Jun; 132(3): 453-462
[2]. Paul Harrewijn, et al. Pymetrozine, a Fast-Acting and Selective Inhibitor of Aphid Feeding. In-situ Studies with Electronic Monitoring of Feeding Behaviour. Pest Management Science. 1997 Feb;49(2):130-140.

According to the U.S. Environmental Protection Agency (EPA), imidacloprid may be carcinogenic. Imidacloprid belongs to the 1,2,4-triazine class of compounds, with the chemical formula 4,5-dihydro-1,2,4-triazine-3(2H)-one, substituted with a methyl group at position 6 and a (pyridin-3-ylmethylene)amino group at position 4. It is a feeding deterrent, environmental pollutant, exogenous substance, and TRPV channel modulator. It belongs to both the 1,2,4-triazine and pyridine classes of compounds. Imidacloprid is a neuroactive insecticide that selectively affects string-mechanoreceptors. Physiologically, its mechanism of action appears to be to prevent these insects from inserting their antennae into plant tissue. It can control various aphids on potatoes and many cruciferous vegetable crops. Imidacloprid has been shown to have low acute toxicity to humans, birds, aquatic organisms, mammals, and bees.

C10H11N5O

217.22724

217.096

123312-89-0

9576037

Colorless crystals

1.3±0.1 g/cm3

401.1±37.0 °C at 760 mmHg

217ºC

196.4±26.5 °C

0.0±1.0 mmHg at 25°C

1.665

-0.5

1

4

2

16

325

0

O=C1NN=C(C)CN1/N=C/C2=CC=CN=C2

QHMTXANCGGJZRX-WUXMJOGZSA-N

InChI=1S/C10H11N5O/c1-8-7-15(10(16)14-13-8)12-6-9-3-2-4-11-5-9/h2-6H,7H2,1H3,(H,14,16)/b12-6+

6-methyl-4-[(E)-pyridin-3-ylmethylideneamino]-2,5-dihydro-1,2,4-triazin-3-one

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~33.33 mg/mL (~153.43 mM)
H2O : < 0.1 mg/mL

Solubility in Formulation 1: ≥ 2.5 mg/mL (11.51 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (11.51 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)