Quick Field Summary: Acephate 75 SP
Acephate 75% SP (Soluble Powder) is an organophosphate insecticide featuring dual systemic and contact activity. It translocates through xylem foliage to manage difficult sucking pests (aphids, jassids, thrips, whiteflies) and early-stage chewing larvae (bollworms, leaf folders). The standard application rate is 1.5 to 2.0 grams per liter of water (300–400 g/acre). Due to severe toxicity to pollinators, avoid application during active crop blossom.
1. Technical Specifications Profile
| Parameter | Technical Standard |
|---|---|
| Active Ingredient | Acephate (O,S-dimethyl acetylphosphoramidothioate) |
| Concentration & Form | 75% w/w Soluble Powder (SP) |
| Chemical Group & IRAC Code | Organophosphate | IRAC Group 1B (Acetylcholinesterase Inhibitor) |
| Action Mode | Acropetal systemic translocation, direct contact kill, and ingestion toxicity |
| Water Solubility | Completely soluble (~790 g/L at 20°C); forms a clear, non-abrasive solution |
| Residual Activity Window | 10 to 15 days under normal seasonal weather conditions |
2. Mode of Action & Biological Pathways
Acephate operates via a multi-tiered pathway that targets the invertebrate central nervous system:
- Acetylcholinesterase (AChE) Inhibition: Acetylcholine transmits impulses across neurological junctions. Acephate binds to and phosphorylates the AChE enzyme, preventing neurotransmitter breakdown. This causes uncontrollable motor nerve firing, physical tremors, paralysis, and death.
- Foliar Absorption & Acropetal Mobility: Once sprayed, plant leaf cuticles absorb the active molecule within 2 to 4 hours. It moves upward through the plant's xylem vessels, protecting newly emerging terminal shoots from cryptic pests like thrips and aphid colonies.
- Translaminar Movement: The active chemical penetrates through the leaf blade, effectively managing pests sheltered on the underside of foliage.
3. Comprehensive Crop-Wise Dosage & Application Matrix
| Crop | Target Insect Pests | Dose / Liter | Dose / Acre | Water Vol. | Waiting Period (PHI) |
|---|---|---|---|---|---|
| Cotton | Jassids, Aphids, Thrips, Bollworms | 1.5 - 2.0 g | 350 - 400 g | 200 L | 15 Days |
| Paddy (Rice) | Stem Borer, Leaf Folder, Plant Hoppers | 1.5 - 2.0 g | 300 - 350 g | 150 - 200 L | 15 Days |
| Chilli | Thrips (Scirtothrips dorsalis), Whiteflies | 1.5 g | 300 g | 200 L | 15 Days |
| Brinjal / Okra | Shoot & Fruit Borer, Jassids | 1.5 g | 300 g | 150 - 200 L | 15 - 20 Days |
| Pulses (Gram) | Pod Borer (Helicoverpa armigera) | 1.5 g | 300 g | 150 L | 20 Days |
4. Tank-Mix Compatibility Matrix
| Tank Mix Partner | Compatibility Status | Agronomic Observation / Precaution |
|---|---|---|
| Neutral Fungicides (Mancozeb, Carbendazim) | Compatible | Standard tank-mix for fungal leaf spot and sucking pest complexes. |
| Chelated Micronutrients (Zinc, Boron) | Compatible | Maintain spray solution pH between 5.5 and 6.8. |
| Alkaline Sprays (Bordeaux Mixture, Lime Sulfur) | Incompatible | High alkalinity (pH > 7.5) triggers rapid chemical hydrolysis, deactivating Acephate. |
| Non-Ionic Wetting Agents (Silicon Spreaders) | Highly Recommended | Improves droplet coverage across waxy leaf surfaces (0.5 ml / liter). |
Critical Agricultural Safety Protocols
- Pollinator Toxicity: Acephate is acutely toxic to honeybees. Never apply during open floral blooming or peak pollination foraging hours.
- Protective Gear (PPE): Always wear nitrile gloves, protective goggles, respiratory dust/vapor masks, and long-sleeved garments while measuring, mixing, and spraying.
- Medical Emergency & Antidote: In case of accidental ingestion or dermal overexposure showing cholinergic signs (pinpoint pupils, nausea, excessive salivation), seek emergency medical intervention immediately. Atropine sulfate is the specific clinical antidote.
5. Frequently Asked Questions (50 Technical Agronomy Q&As)
1. What is Acephate 75 SP?
It is an organophosphate insecticide formulated as a 75% water-soluble powder, providing broad-spectrum systemic and contact control against agricultural pests.
2. What does "SP" stand for in the product name?
"SP" stands for Soluble Powder. It completely dissolves in water without leaving suspended solid particles, preventing nozzle clogs.
3. What is the standard dilution rate per liter of water?
1.5 grams to 2.0 grams per liter of water for regular high-volume foliar spray rigs.
4. What is the standard application quantity per acre?
300 to 400 grams per acre, applied with 150 to 200 liters of water depending on crop canopy density.
5. How much chemical should be added to a standard 16-liter knapsack sprayer?
Mix 25 to 30 grams per 16-liter spray tank.
6. Does Acephate function as a systemic or contact chemical?
It exhibits both: systemic uptake through leaf tissue, as well as immediate contact and stomach poisoning upon insect exposure.
7. What physiological enzyme does Acephate disrupt?
It inhibits the acetylcholinesterase (AChE) enzyme, causing neurotoxic failure and lethal paralysis in insects.
8. Which major sucking insect species are controlled?
Green jassids, cotton aphids, thrips, mealybugs, and whitefly nymphs.
9. Is Acephate effective against chewing caterpillars?
Yes, it controls early instar larvae including rice leaf folders, spotted bollworms, and cutworms via stomach action.
10. How quickly does the plant absorb the spray solution?
Foliage absorbs the compound within 2 to 4 hours under warm, daylight conditions.
11. What is the rainfastness duration?
Once the spray dries for 3 to 4 hours, systemic absorption renders it resistant to rain wash-off.
12. Can Acephate be tank-mixed with neutral fungicides?
Yes, it is physically compatible with neutral fungicides such as Mancozeb, Carbendazim, and Azoxystrobin.
13. Can it be mixed with Bordeaux mixture or agricultural lime?
No. Alkaline conditions (pH > 7.5) cause rapid chemical hydrolysis, destroying its insecticidal properties.
14. What is the active residual window in open fields?
It provides continuous residual protection against pests for approximately 10 to 15 days.
15. What is the required Pre-Harvest Interval (PHI) for vegetables?
A mandatory minimum of 15 to 21 days must elapse between the last application and crop harvest.
16. Why does the formulation have a strong pungent odor?
Slow breakdown yields trace volatile organosulfur compounds and methamidophos, which create its characteristic odor.
17. Is Acephate hazardous to honeybees?
Yes, it is highly toxic to pollinators. Never spray blooming crops visited by bees.
18. What is the best time of day to apply?
Early morning before 9:00 AM or late afternoon after 4:30 PM to minimize photo-breakdown and protect beneficial insects.
19. Is Acephate used as a seed treatment?
While primarily a foliar spray, specific commercial dry seed dressing formulations are registered for cottonseed protection.
20. Does Acephate cause leaf scorch (phytotoxicity)?
No phytotoxicity occurs at standard rates (1.5–2.0 g/L). Exceeding recommended concentrations under intense heat can scorch young leaf tips.
21. How does it help manage chilli leaf curl virus?
Leaf curl is transmitted by vectors like thrips and whiteflies; suppressing these vectors prevents viral spread.
22. Does Acephate eradicate red spider mites?
No, it lacks acaricidal properties. Frequent use can worsen mite infestations by harming predatory insects.
23. Can Acephate be run through drip irrigation lines?
Foliar application is significantly more bio-available and cost-effective than soil injection for targeting foliar pests.
24. Can it be mixed with foliar micronutrients?
Yes, it can be combined with chelated Zinc, Boron, and balanced NPK foliar fertilizers in neutral spray water.
25. What is the IRAC resistance management classification?
It belongs to IRAC Group 1B (Organophosphates).
26. How can insect resistance to Acephate be prevented?
Rotate treatments with different chemical classes, such as Neonicotinoids (Group 4A) or Diamides (Group 28).
27. Does Acephate powder dissolve readily in cold water?
Yes, its high solubility ensures it dissolves quickly in ordinary ambient well water with brief agitation.
28. Is Acephate effective against papaya mealybugs?
Yes, particularly when paired with an agricultural silicon surfactant to penetrate their protective waxy layer.
29. What is its official toxicity classification label?
It is generally classified under the Blue Label (Moderately Toxic) warning symbol.
30. What is the emergency medical antidote for poisoning?
Atropine sulfate injection administered intravenously alongside Pralidoxime (2-PAM) under medical care.
31. How long can a mixed tank solution remain before spraying?
Spray within 4 to 6 hours of mixing. Do not store prepared spray liquid overnight.
32. What nozzle type delivers optimal results?
Hollow cone nozzles provide fine droplet dispersion across dense crop canopies.
33. Does it protect cotton against stem weevils?
It offers only marginal control over adults; targeted stem drenching treatments with specialized chemicals are needed for grubs.
34. Can Acephate be used on commercial tea plantations?
Only where permitted by regional tea authorities, adhering strictly to export maximum residue limits (MRL).
35. What is the standard commercial shelf life?
Two years from the production date when stored sealed in a cool, dry, dark storehouse.
36. Is it harmful to subterranean earthworms?
Standard foliar applications have minimal impact on soil earthworms; avoid direct ground saturation.
37. Is Acephate suitable for urban rooftop and kitchen gardens?
Bio-pesticides (Neem oil, Bacillus thuringiensis) are generally preferred in residential settings over organophosphates.
38. Does Acephate control rice Brown Planthopper (BPH)?
It provides fair suppression, though modern selective hopper chemicals (Pymetrozine, Triflumezopyrim) are more effective.
39. What safety precautions are required during slurry preparation?
Never agitate the liquid with bare hands; use clean measuring tools and a plastic or wooden paddle in an open area.
40. What is the premix combination of Acephate and Imidacloprid?
Acephate 50% + Imidacloprid 1.8% SP provides both immediate knockdown and long-lasting systemic protection.
41. Can Acephate protect sugarcane from shoot borers?
It controls early shoot borers during initial tillering stages before canopy closure.
42. What happens if water pH is alkaline during application?
High pH decomposes the molecule via alkaline hydrolysis; use a pH buffer if spray water exceeds 7.2.
43. What is the worker re-entry interval (REI) for sprayed fields?
Field workers should wait 24 to 48 hours before entering treated plots without personal protective gear.
44. Does Acephate control leafminers?
Yes, translaminar movement allows it to reach larvae feeding between the upper and lower leaf surfaces.
45. How should empty packaging be safely discarded?
Triple rinse, puncture or cut the empty sachets, and dispose of them through certified hazardous agricultural waste channels.
46. How does weather humidity affect spray efficiency?
Moderate to high humidity keeps the spray deposit moist longer, improving cuticular absorption.
47. Can Acephate protect mango panicles from hoppers?
Yes, it works well when applied early during panicle emergence, before flower buds open.
48. What are common commercial trade names?
Popular brands include Asataf (Rallis), Starthene, Tremor, and Acemain.
49. Does Acephate control subterranean soil termites?
No, it degrades too quickly in aerated soils. Dedicated termiticides like Fipronil or Chlorpyrifos are required.
50. What is the most critical agronomic guideline for Acephate use?
Calibrate water volume carefully, adhere to the 1.5–2.0 g/L rate, avoid spraying during bloom, and honor the pre-harvest interval.
