Larvadex 1% Premix

Indications

• Control of dipteran insects in agricultural settings

Dosage

Children: Refer to the BNF for Children for paediatric dosing recommendations.

Adults: Refer to specific guidelines in the BNF for appropriate dosing information.

Mechanism of action

Cyromazine is an insect growth regulator with contact action, which interferes with moulting and pupation. Its exact mode of action is not fully understood; however, it is believed to interfere with the hormone system, sclerotization of the cuticle, or nucleic acid metabolism. Research has indicated that it may inhibit the function of a gene (CG32743) that is involved in phosphatidylinositol kinase-like kinase activity, which is important in cellular processes, including responses to DNA damage.

Pharmacodynamics

Cyromazine affects the growth and development of insects, leading to disruption in their life cycle. The insecticidal activity is primarily due to its interference with moulting and pupation. This results in the inability of insects to progress through their developmental stages, ultimately leading to their death.

Pharmacokinetics

Cyromazine demonstrates systemic action when applied to plants, suggesting it is absorbed and translocated within plant tissues. Specific pharmacokinetic data in mammals or detailed absorption, distribution, metabolism, and excretion profiles are not well-documented in the available literature.

Pregnancy

Cyromazine should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. Consult a healthcare professional for guidance.

Breast-feeding

It is not known whether cyromazine is excreted in human milk. Caution should be exercised when administering to nursing mothers.

Storage

Store in a cool, dry place away from direct sunlight and out of reach of children.

Formulations

• Insecticide formulations containing cyromazine for agricultural use

Mechanism of action

Insect growth regulator with contact action, which interferes with moulting and pupation. When used on plants, action is systemic. Cyromazine is an effective insecticide used to control dipteran insects. Its precise mode of action is yet to be determined, although it has been suggested that it interferes with the hormone system, sclerotization of the cuticle, or nucleic acid metabolism. To understand the way in which cyromazine acts, /the authors/ positionally cloned a cyromazine resistance gene from Drosophila melanogaster. Six cyromazine resistance alleles had previously been generated by ethyl methanasulfonate treatment. Two of these failed to complement each other and here /the authors/ identify them as having independent non-sense mutations in CG32743, which is an ortholog of Smg1 of worms and mammals and encodes a phosphatidylinositol kinase-like kinase (PIKK). RNAi experiments confirm that cyromazine resistance can be achieved by knocking down CG32743. These are the first cyromazine resistant mutations identified at the nucleotide level. In mammals Smg1 phosphorylates P53 in response to DNA damage. This finding supports the hypothesis that cyromazine interferes with nucleic acid metabolism.