Dosage Table for Cotton Pests
The recommended dosage of Profenofos 40% + Cypermethrin 4% EC for cotton varies by target pest, all applied in 200 litres of water per acre. For bollworm (American bollworm Helicoverpa armigera, pink bollworm Pectinophora gossypiella, spotted bollworm Earias spp.), apply 400 ml per acre — approximately 12 ml per 15-litre knapsack tank. For aphids and thrips (sucking pest outbreaks on young plants or during flowering), apply 300 ml per acre — approximately 9 ml per 15-litre knapsack. For spider mites (red spider mite Tetranychus urticae, two-spotted mite), apply 500 ml per acre — approximately 15 ml per 15-litre knapsack. The higher rate for mites exploits Profenofos's acaricidal property, which is an advantage not found in pyrethroid-only or neonicotinoid formulations. All sprays should achieve full canopy coverage at 200 litres per acre spray volume for optimal contact and systemic action.
Why the Combination Works: Organophosphate + Pyrethroid Synergy
The Profenofos + Cypermethrin combination is effective because the two active ingredients attack the insect nervous system at different points simultaneously. Profenofos, an organophosphate, irreversibly inhibits acetylcholinesterase — the enzyme that clears the nerve signal. Without this enzyme, nerve impulses keep firing, causing uncontrolled muscle activity, paralysis, and death. Cypermethrin, a Type II pyrethroid, acts on voltage-gated sodium channels, keeping them open and preventing the nerve from resetting after each signal — producing a different type of continuous nerve firing. When both mechanisms are active simultaneously, the insect cannot recover from either mode of attack. This dual neurological disruption also explains the combination's effectiveness against pyrethroid-resistant or organophosphate-tolerant bollworm populations: a population that has developed resistance to one mode of action is still vulnerable to the other. The combination also provides broad-spectrum coverage across chewing pests (via Profenofos stomach action), contact-killed flying adults (via Cypermethrin knockdown), and mites (via Profenofos's acaricidal activity).
Application Timing and Season Restrictions
For cotton bollworm management, apply Profenofos + Cypermethrin at first economic threshold breach — when 5% of bolls or squares show fresh bollworm damage, or when larval counts exceed 2 per plant. The optimal application window is from square formation through early boll fill (typically 45–90 days after sowing for most medium-duration Bt cotton hybrids). Spray in the evening (after 4:00 PM) or early morning (before 8:00 AM) for two reasons: Cypermethrin degrades faster under direct UV radiation, so evening application maximises residual activity; and cotton flowers open in the morning, making mid-day spraying during flowering both less effective and hazardous to pollinators. Do not spray on open cotton flowers — Cypermethrin is highly toxic to bees, and open-flower spraying reduces fruit set. Limit to a maximum of 2 sprays per season with this combination to prevent organophosphate and pyrethroid resistance accumulation. Rotate to Emamectin Benzoate or a diamide after the second application.
Safety: PHI, Aquatic Toxicity, and PPE
The pre-harvest interval (PHI) for Profenofos + Cypermethrin 40+4 EC on cotton is 14 days. Do not harvest cotton within 14 days of the last application. Profenofos is moderately toxic to fish and aquatic invertebrates — do not spray near irrigation channels, fish ponds, or open water bodies. Avoid runoff from treated fields into drainage systems after rain. Wear full personal protective equipment during mixing and application: chemical-resistant gloves, full-face respirator or mask, goggles, a long-sleeved shirt, full trousers, and closed footwear. Organophosphate compounds are absorbed through skin — change out of spray clothing immediately after application and shower thoroughly. In case of accidental exposure with symptoms of dizziness, nausea, excessive sweating, or blurred vision (signs of cholinergic poisoning), seek medical attention immediately. The antidote for organophosphate poisoning is atropine, administered under medical supervision.