Mode of action of spinosad is that it:

Correct option is C

Spinosad is a naturally derived insecticide obtained from the actinomycete bacterium Saccharopolyspora spinosa. It is known for its unique dual mode of action, making it highly effective against a wide range of chewing and some sucking insect pests, especially in organic and IPM (Integrated Pest Management) systems.
⚙️ Mode of Action of Spinosad:
1. Nicotinic Acetylcholine Receptors (nAChRs):
· Spinosad acts as an agonist at nicotinic acetylcholine receptors, but with prolonged activation, it causes neuronal excitation.
· This leads to hyperexcitation, then paralysis and death of the insect.
2. GABA-Gated Chloride Channels:
· Spinosad also affects GABA receptors (gamma-aminobutyric acid), disrupting inhibitory neurotransmission.
· This compounds the neural disruption, leading to loss of muscle control, tremors, and eventual death.
➤ The combined action at two key neural targets makes spinosad both fast-acting and potent, especially against insects resistant to other insecticide classes.
Explanation for Each Option
(a) Blocks nicotinic acetylcholine receptor ❌
· Partially correct, but doesn’t account for its action on GABA receptors.
(b) Affects GABA receptor ❌
· Also partially correct but not complete; nAChR interaction is equally important.
(c) Causes both Blocks nicotinic acetylcholine receptor & Affects GABA receptor ✅
· Correct answer.
· Reflects the dual action of spinosad, which enhances its effectiveness and reduces resistance risk.
(d) Some other mode of action ❌
· Incorrect. The mode of action is well-characterized and fits option (c).