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The story of butachlor traces back to the post-war era when food security pushed chemists and farmers to find new ways to control weeds and secure better yields. In the mid-1960s, with herbicide innovation picking up steam, butachlor entered the scene as part of a group of selective herbicides designed to target unwanted plants without harming key crops like rice. Since then, its role has expanded from small farm plots in Asia to wider fields in Africa. In the thick of the Green Revolution, farmers saw weed control transform from hand-pulling and flooding to chemical intervention, and butachlor became a trusted option because it could handle the rough edges of crowded, waterlogged rice paddies. Scientists who first developed it focused on its ability to stay effective under both wet conditions and high weed pressure, filling a gap left by earlier herbicides that simply didn’t hold up.
Today, butachlor stands as one of the core chloroacetanilide herbicides. Farmers lean on it for rice, maize, and even some vegetable cultivations where grass and broadleaf weeds threaten early plant development. Because of its selectivity, butachlor has become a staple in pre-emergence weed control. Most often, it comes as an emulsifiable concentrate so it can blend smoothly with water for application. After all these years in global markets, butachlor’s place as a go-to rice herbicide hasn’t faded, showing how much growers depend on reliable, targeted weed control.
Butachlor usually presents itself as a pale amber liquid or a colorless crystalline solid, depending on purity and the formulation method. It packs a distinct, almost sharp odor that you remember from time spent near a spray tank. At room temperature, butachlor remains stable, showing only mild volatility. It dissolves effectively in most organic solvents, but its solubility in water stays low. For storage and transport, these characteristics mean it doesn’t evaporate easily and won’t break down under normal farm conditions. In my own farm visits, I have noticed that most operators keep stocks of butachlor in shaded, cool spaces — not so much out of caution, but because the product asks for that sort of practical stewardship to maintain potency.
Regulators across various countries have set minimum technical requirements for butachlor formulations, often holding purity above 95 percent for technical-grade material. Popular formulations include emulsifiable concentrates of 50, 55, or 60 percent active ingredient. As a recurring user of agricultural chemicals, I can see why labels focus on clear guidance about mixing, pre-emergence timing, re-entry periods, and health precautions. Even with straightforward handling, labels bear a laundry list of warnings — aimed at keeping the chemical out of waterways and far away from unintended crops. Most labeling reflects lessons learned: mishandling once contributed to residue issues in groundwater, pushing regulators and manufacturers to revisit use directions and better communicate limitations. Product names differ worldwide, but common synonyms pop up, like Machete, Lambast, and Butanex, reflecting both local branding and regulatory registration needs.
The primary route to synthesizing butachlor begins with the acylation of 2,6-diethylaciline with chloroacetyl chloride. This chemical marriage happens in the presence of strong bases that help drive the reaction to completion. The process throws off by-products in the form of hydrogen chloride, which gets scrubbed or neutralized so that the final product doesn’t carry contaminants. Teams overseeing the synthesis must walk a fine line: keep reaction times low and heat just right, otherwise the process ends up producing low yields or break-down products that could affect herbicide performance. Scaling this up from laboratory glassware to factory vessels is where most companies have invested in process control — not only to ensure cost efficiency but to keep impurities from sneaking into commercial product.
Butachlor undergoes hydrolysis in moist environments, but its breakdown isn’t rapid — one reason it performs so well as a pre-emergence agent. Under alkaline soil conditions, its degradation ramps up, affecting both residual effect and environmental footprint. Modifications over the years have aimed to tweak solubility and selectivity, though butachlor’s main chemical skeleton remains largely unchanged. Some research groups have experimented with analogs by swapping out chlorine or ethyl groups, chasing after softer environmental profiles or altered weed control angles. Most attempts haven’t overtaken the mother compound in field trials, but the search keeps going given growing pressure for next-generation herbicides.
Butachlor’s identity in the market comes wrapped in a range of synonyms and commercial names, a result of both regional branding trends and regulatory quirks. Besides the scientific mouthful of N-(butoxymethyl)-2-chloro-2′,6′-diethylacetanilide, the product shows up as Machete, Butanex, and Lambast, among others. Across borders, each name brings its own history — some linked to the companies that first introduced it, others a nod to local language. Despite the name changes, any experienced agronomist can point to a jug and say, “That’s butachlor, for my rice.” This familiarity keeps conversation clear, even as chemical registration forms pile up higher each year.
Ever since organochlorines and older herbicides raised environmental flags, regulators and health agencies have kept a close watch on how farmers use butachlor. Today’s best practices call for gloves, masks, long sleeves, and washing stations near application sites. In the field, even the best labeling cannot replace training and muscle memory. Some agencies have rolled out QR code systems so farmers can check up-to-date safety tips right from their phones. Butachlor’s main risk arises from exposure to concentrated forms before mixing. In my experience, most accidental exposures on farms trace back not to the spraying itself, but to careless handling at storage sites where concentrates get splashed. The shift toward mechanized, closed-tank sprayers has cut the risk somewhat, yet ongoing education and infrastructure upgrades remain key in bringing down accident rates.
Rice production forms the backbone of butachlor use, especially in parts of Asia like India, China, Vietnam, and the Philippines, where dependable weed management can spell the difference between a full larder and lean months. Butachlor’s formulation as a pre-emergence herbicide fits the high-water, thick-weed conditions of flooded paddy fields. It works best applied to moist earth just after transplanting, before weeds get a foothold. Unlike some broad-spectrum agents, butachlor targets grassy weeds and certain broadleaf invaders that laugh off other cheap herbicides. This targeted control means lower overspray and less collateral damage to crops, wildlife, and soil diversity — a fact rice farmers raise to justify butachlor’s continued place in modern agriculture. It’s also gained traction as a rotational tool for maize and some vegetables. Each new crop group introduces its own best-practice wrinkles, keeping extension officers and product reps busy with field-day demos and troubleshooting sessions.
Butachlor research spans a dizzying range: new formulations for water savings, studies on environmental movement, genetics-based experimentation for crop resistance, and molecular modeling for next-gen analogs. Public and private research teams scan for ways to wring out higher productivity without pushing up resistance or contaminating groundwater. Some recent university trials have explored using encapsulated forms of butachlor that cut leaching, especially in sandy soils. Others mix in adjuvants designed to hold spray droplets longer on the target plant and keep drift under control. Butachlor’s chemistry has challenged researchers to design additives and mixtures that enhance its shelf life but won’t cause phytotoxicity for rice or maize. Gene-editing researchers are also looking at how crops metabolize butachlor, with the aim of either breeding extra tolerance or monitoring how residue levels build up. Extension agents translate these findings into field protocols so that the next generation of farmers keeps up with curveballs thrown by climate change or market pressures.
Long-term use and ongoing studies have brought butachlor’s toxicological profile into sharper focus. Animal studies show that, when handled properly, butachlor sits at a moderate level on the toxicity charts — acute poisoning remains rare outside of misuse scenarios. Chronic exposure over long periods has drawn more questions: current findings point to liver and kidney impacts from repeated high-level ingestion, while links to reproductive issues remain unresolved. The chemical doesn’t stack up as a persistent organic pollutant, thanks to its moderate half-life in field settings. Residue testing in harvested rice often shows levels well below international maximum residue limits, provided growers stick to pre-planting withdrawal timings. On-site, open mixing or careless disposal still creates risk of ecosystem disruption — especially affecting amphibians and fish in paddy ditches. Researchers continue to push for more comprehensive, real-world field studies, since controlled lab work occasionally underestimates risk seen on poorly managed farms.
Looking ahead, the future of butachlor hinges on two fronts: regulatory tightening and innovation in both chemistry and application. Many countries face mounting calls to slash chemical use in agriculture, especially on water-intensive crops like rice. Some of the new product development ties directly to environmental pressure: companies work overtime to create low-leaching, slow-release butachlor granules and microencapsulated sprays. These alternatives need real-world, on-farm proof — both for safety and for how they impact busy growing schedules. Others focus on integrating butachlor into digital farming systems, using drones and GPS-guided sprayers to shut down excessive overlap and minimize exposure. As weeds evolve and environmental scrutiny rises, butachlor’s claim to fame will rest on how adaptable the technology behind it stays in the face of both smallholder and industrial farm needs. The balance of food security, farmer economics, and environmental stewardship will shape where butachlor stands tomorrow, both on the shelf and in field rows bending under the world’s rice supply.
Butachlor lands in the category of pre-emergent herbicides with a reputation for controlling unwanted weeds long before they cause trouble. Across rice paddies in Asia and large grain fields in Africa, I’ve seen bags of this herbicide stacked next to sacks of seeds. Farmers look for ways to tame grassy weeds that soak up more water and nutrients than the crops themselves. Weeds aren’t just a nuisance—they compete for everything. Yields take a hit if nobody keeps the weeds in check.
Rice cultivation often deals with persistent intruders like barnyard grass, wild oats, and other fast-growing weeds. Butachlor comes out as a reliable solution. As a pre-emergent, it gets applied before the weeds even appear. Once mixed into the topsoil or standing water, it blocks cell division in young weed shoots. Roots never get established, and shoots rarely break ground. The rice, planted at the right time, stays unaffected.
For families depending on rice harvests to feed their communities, missing out on weed control often means missing out on enough food or income during the year. I remember speaking with a group of farmers in parts of Bangladesh who watched their harvest jump by as much as 40% after switching to pre-emergent weed control. Butachlor didn’t turn them into millionaires, but it made the hard months less painful and left more grain in storage.
Alongside its benefits, butachlor carries some serious baggage. Exposure links to symptoms like skin irritation, eye discomfort, and, in rare cases, nervous system issues. Field workers without gloves or boots face higher risks. In some countries, protective gear costs more than the herbicide itself, making safety difficult for smaller farms.
Residue in groundwater also sparks concern, especially where irrigation drains back into rivers or wells. Studies in southern India have shown trace amounts in water after intensive rice seasons. Regulatory checks help, but full-scale monitoring doesn’t always reach rural areas. Families pulling water for washing and cooking want to trust that their fields aren’t turning their wells into health hazards.
Better training and stricter labeling offer one route. Labels with local languages and clear images beat dense chemical jargon. Outreach by extension workers—many of whom grew up in the same communities they now serve—proves more effective than pamphlets or radio ads.
Switching to integrated weed management helps, as it combines early planting, hand weeding, and rotating herbicides to slow down weed resistance. Smarter policies can help, too. Governments rewarding farmers who use less risky weed control methods or who rotate crops more often often see healthier water, healthier people, and land that produces season after season.
Butachlor delivers heavy lifting for rice growers struggling to outpace weeds, especially in regions with stubborn weather and tight budgets. Still, its use means a tightrope walk between practicality and risk. Ensuring safe handling and pushing for cleaner alternatives could turn the story from simple weed control to real progress in healthier farms and food.
Weeds rob crops of a fighting chance. In many paddies across Asia, rice struggles not just against weather but against unwanted green invaders. Butachlor offers a tool for farmers who face this headache. With prices soaring and margins thinning, skipping herbicide often leaves little harvest to take home. More farmers reach for Butachlor not out of preference, but out of real necessity. But common sense says pouring a chemical into nature should come with care and wisdom.
Preparation makes all the difference. Loose soil opens paths for the chemical to do its work. Just after transplanting, or once there’s standing water to cover the field, becomes the sweet spot for application. The label might suggest a certain volume per hectare, but the story in the field differs. Sun, rain, and soil type can all change the rules, so it pays to talk with local extension officers or experienced neighbors—those who have seen mistakes and paid for them.
Like paint on a wall, Butachlor covers best on a still day. If wind picks up, the spray carries off target, risking neighboring crops or village water sources. Some mix Butachlor with water and spray with a knapsack machine, keeping a rhythm and pace that avoids gaps. Granular forms can be tossed by hand on small plots. Shoes and gloves aren’t just for show—exposure, even once, can mean rashes or worse for careless workers. Leaving equipment rinsed in canals poisons more than weeds.
Too late or too early, and it just becomes money wasted. Spraying right after transplanting rice lets Butachlor meet weeds before their real growth surges. In fields left too dry or flooded too deep, the chemical floats away or sinks beyond roots, doing little good. Butachlor prefers a shallow pool where it clings to surface weeds and newer shoots. I’ve seen results swing from mass weed death to full regrowth, all based on a farmer missing rain or letting the field dry after spraying.
A chemical never stays put. Runoff into streams can hit fish and frogs, and careless overdosing leads to stunted rice. My neighbors found lessons the hard way—more is not always better. Following directions on the package isn’t about bureaucracy; it’s about health and the life of the soil. Wearing worn-out shoes while spraying once put me on crutches for a week. I learned that safety gear isn’t more hassle than hospital bills.
Rotating Butachlor with other weed control methods can hold off resistance, something we’re now seeing in stubborn weedy rice strains. Burning stubble, hand-pulling tough patches, and using water levels wisely all work with Butachlor, not against it.
Making training widely available can change results. Many spray because “that’s how it’s done.” Demonstrations in villages, led by trusted farmers, can show what actually works instead of repeating past mistakes. Allowing smallholder access to protective equipment, even if through government subsidy, keeps more families healthy. Sharing warnings about unsafe practices through community groups spreads understanding faster than pamphlets from city offices.
Butachlor does a job many need, but it rewards respect and careful thought. The right dose, the right time, and common-sense precautions help everyone win—farmers, their crops, and the lands that feed us all.
Farmers don’t spend their mornings wishing for weeds to choke out their fields. They look for something that deals with these pests without hurting their crops. Butachlor steps in here. Used mostly as a pre-emergence herbicide, Butachlor fights grassy weeds before they cause trouble.
In the world of rice farming, Butachlor has built a strong reputation. Rice paddies get hit hard by grassy weed species like Echinochloa spp. and Leptochloa. Using Butachlor after transplanting but before weeds start sprouting keeps these problems under control. I’ve seen entire rice paddies stay clean with just one application—less effort, a better yield, and more money in the pocket. Research backs this up too. For example, the International Rice Research Institute lists Butachlor as a highly effective option against annual barnyard grass and many other usual suspects in rice fields.
Butachlor gets talked about for use in maize and wheat, but it doesn’t fit as nicely here as it does in rice. Corn and wheat tend to grow in drier soils or non-flooded fields, and Butachlor simply loses its punch under these conditions. I’ve watched some growers try to stretch the use of Butachlor into wheat or maize fields, and the weed suppression just isn’t consistent. Some maize fields show patchy results, with weeds creeping through the gaps. For these crops, other herbicides with better fit for their specific weeds and cultivation styles help more.
Soybeans, groundnuts, and mustard crops don’t usually see Butachlor in their chemical arsenal. Most oilseeds and pulses face weed threats that don’t bow to Butachlor’s particular chemistry. These crops may also risk stunted growth or yellowing if exposed. I’ve heard soil scientists warn against using Butachlor outside of its comfort zone, noting crop sensitivity and risk of yield loss. Farmers who grow these crops look toward other options, like pendimethalin or imazethapyr, which deal with a wider range of weed species and fit better with legume or oilseed biology.
Butachlor sometimes shows up in vegetable farming, especially in places pushing for intensive monocropping. But this isn’t common. Vegetable plants—cucumbers, tomatoes, beans—don’t handle Butachlor’s chemical residues well. The herbicide stays in soils longer under certain conditions and tends to affect sensitive roots or seedlings. Experience teaches most gardeners and commercial vegetable growers to steer clear.
Dumping chemicals on a field never works out well for long. Diagnostic services, government guides, and field trials help decide whether Butachlor fits the land, crop, and target weeds. Wearing gloves and a mask matters—long-term exposure hurts more than just weeds, and farmworkers face higher risks of skin irritation or headaches if they ignore safety steps.
Rotating with other herbicides helps keep resistance at bay. Sticking to recommended doses and respecting withdrawal intervals before harvest protects both consumers and the farm’s reputation. Farmers who talk to local agronomists, stay updated on label changes, and keep detailed records get ahead of the game. Their fields look cleaner, their yields rise, and they manage to balance productivity with responsibility.
Walking into a rice field in the early morning, you can see just how fast weeds take over when left unchecked. Farmers know the struggle of getting a good crop without losing yield to stubborn grasses. Butachlor offers a solution for many, helping rice seedlings outpace those swiftly growing weeds. Still, using the right amount makes all the difference between healthy fields and stunted crops. The soil, water conditions, and rice variety all play a role in how effective Butachlor turns out. Too much can harm young plants and put unnecessary chemicals into the ground; too little invites weeds back into the fight.
Research backed by agricultural universities points to a dosage of 1.0 to 1.5 kilograms of active ingredient per hectare for pre-emergence weed control in rice fields. This can mean 2.5 to 3 liters of a 50% emulsifiable concentrate formulation in a single hectare, mixed in about 500 to 1000 liters of water. This number is not pulled out of thin air. Years of field trials, including those run by extension workers and independent researchers, support this range as effective in keeping weeds suppressed while letting rice seedlings push ahead. Always read labels and lean on local extension service advice, since climate, soil type, and rice variety can shift the sweet spot.
Standing at the edge of the paddies, you watch different farmers approach spraying with their gear—some with knapsack sprayers, others using motorized options. A consistent and fine spray pattern changes outcomes. People who eyeball the mix or slack off on walking at a steady pace see patchy results. A calibrated sprayer gives better weed knockdown, less waste, and, importantly, less impact on nearby water bodies. I’ve seen how improper mixing or faulty nozzles let clumps of weeds survive, setting up a battle for the next season.
Butachlor, like other herbicides, comes with its baggage. Runoff following heavy rain can carry residues into ditches or streams. Farmers, extension workers, and rural communities face health risks if they handle Butachlor with bare hands or skip basic washing afterward. The World Health Organization classifies Butachlor as a moderate hazard. Wearing gloves, boots, and face protection makes a difference. I remember my uncle’s persistent skin rash, which finally cleared up after he switched to long sleeves and washed up after spraying. The extra five minutes of care cost nothing compared to a doctor visit.
Local farmer groups sharing real-world experiences set the stage for better outcomes. Village meetings show who mixed too strong and who tried to save money by diluting too much. Field demonstrations set up by ag officers teach smarter application, so reliable control gets paired with less chemical waste. Rotating herbicides and combining manual weeding with chemical options prevent resistant weed populations. Nothing replaces seeing the results up close—one patch thriving, another failing—because someone tuned the dosage right.
Trusted sources matter. Recommendations published by the Indian Institute of Rice Research or the International Rice Research Institute come from broad regional studies, not just corporate product sheets. Farmers using these guidelines find a better balance between input costs, yields, and the health of their soil for next year’s crop. Those numbers—1.0 to 1.5 kg per hectare—aren’t just a suggestion; they’re a ticket to healthier fields and fewer headaches down the line.
Butachlor has been a go-to weed killer in many of the world’s major rice-growing regions. It keeps fields clear and the harvests flowing. Plenty of farmers swear by it. The stuff works, and for food producers under pressure, that counts for a lot.
Research teams in Asia and beyond keep analyzing how Butachlor moves through soil and water and into living systems. People living near treated fields sometimes experience headaches, skin rash, or watery eyes—not a great sign. A few studies point to possible higher risks for long-term exposure. China suspended Butachlor sales in 2018, highlighting concerns over how much gets left behind in the environment.
Most big regulatory agencies, such as the EPA in the United States, have given Butachlor the green light for use—if it stays inside recommended limits. What scientists argue over is how reliably those rules get followed in places with little monitoring. Risk can sneak in quietly, especially where protective gear is rare and instructions get skipped. It’s that human element—people working in fields, their families living downstream—that raises tough questions.
Butachlor holds on in the top layers of soil, often for several months. Rains can send residue into rivers and lakes. Fish exposed to it can show changes in liver and gill tissue, which can ripple up the food chain. Earthworms, which help keep soil alive and kick-start decomposition, may end up with less energy to do their work. The pesticide has also shown up in drinking water samples near heavy-use rice paddies.
Rice paddies form the backbone of rural economies in several Asian countries. They’re not closed systems—anything that goes into the fields can move into local streams. Communities living near farms often get their water from these rivers. India has reported Butachlor traces in groundwater and surface water, sometimes above international safety limits.
No farmer wants to trade short-term weed control for long-term health scares. Basic rules like wearing gloves and boots help, but education plays a bigger part. Field schools and peer groups can offer practical tips, showing real-life examples of what safe handling looks like, especially where reading labels isn’t easy. Crop rotation and alternative weed-killing strategies, such as water management and hand weeding, take pressure off single-chemical solutions.
Some rice growers try integrated pest management, which limits chemical reliance and makes room for more natural weed control. That shift isn’t always quick or cheap, but the benefits—cleaner water, fewer doctor visits, and safer food—stick around. Policymakers have a role as well. More frequent field checks and honest outreach to farmers could catch unsafe practices before trouble spreads. Supporting scientists who keep tabs on long-term soil and water quality will help communities see whether their local environment is bouncing back.
Butachlor helped spark a farming revolution decades ago. As health and environmental evidence keeps mounting, it makes sense to ask tough questions and try new approaches. Farmers know their soil and water best, so listening to their stories will point the way to safer harvests.
| Names | |
| Preferred IUPAC name | N-(butoxymethyl)-2-chloro-N-(2,6-diethylphenyl)acetamide |
| Other names |
Machete Butanex Butacide Butanil |
| Pronunciation | /ˈbjuːtəˌklɔːr/ |
| Identifiers | |
| CAS Number | 23184-66-9 |
| Beilstein Reference | Beilstein Reference: 1912000 |
| ChEBI | CHEBI:31221 |
| ChEMBL | CHEMBL136483 |
| ChemSpider | 44519 |
| DrugBank | DB11449 |
| ECHA InfoCard | ECHA InfoCard for BUTACHLOR: **"03e99bcd-b848-4c58-99e9-413f9b07d592"** |
| EC Number | 602-876-4 |
| Gmelin Reference | 135383 |
| KEGG | C14268 |
| MeSH | D016507 |
| PubChem CID | 3034639 |
| RTECS number | CN7380000 |
| UNII | 09807A0X3S |
| UN number | UN3077 |
| CompTox Dashboard (EPA) | DTXSID3020219 |
| Properties | |
| Chemical formula | C17H26ClNO2 |
| Molar mass | 311.83 g/mol |
| Appearance | Light yellow to yellowish brown liquid |
| Odor | Aromatic odor |
| Density | 1.14 g/cm³ |
| Solubility in water | 20 mg/L (25 °C) |
| log P | 3.8 |
| Vapor pressure | 6.7 x 10^-4 mmHg (25°C) |
| Acidity (pKa) | 4.48 |
| Basicity (pKb) | pKb = 5.85 |
| Magnetic susceptibility (χ) | Diamagnetic |
| Refractive index (nD) | 1.517 |
| Viscosity | Low to medium |
| Dipole moment | 3.73 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 576.8 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -83.7 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -7230 kJ/mol |
| Pharmacology | |
| ATC code | QJ01CA13 |
| Hazards | |
| GHS labelling | GHS02, GHS07, GHS08 |
| Pictograms | GHS02,GHS07,GHS09 |
| Signal word | Caution |
| Hazard statements | H226, H315, H319, H335 |
| Precautionary statements | P202, P220, P273, P280, P333+P313, P337+P313, P391, P501 |
| NFPA 704 (fire diamond) | 2-1-1-ꓕ |
| Flash point | Above 110°C |
| Autoignition temperature | 410°C |
| Lethal dose or concentration | Oral rat LD50: 2600 mg/kg |
| LD50 (median dose) | LD50 (median dose): 2,600 mg/kg |
| NIOSH | NAK |
| PEL (Permissible) | 5 mg/kg |
| REL (Recommended) | 1.0-1.5 kg a.i./ha |
| IDLH (Immediate danger) | Unknown |
| Related compounds | |
| Related compounds |
Acetochlor Alachlor Metolachlor Propachlor Pretilachlor |
