Can soil bacteria break down monocrotophos? What a 2023 study found
Monocrotophos is a highly hazardous insecticide that India has ordered phased out, but its residues can stay in farm soil. A study co-authored by Dr. Abhishek Mathur looked for soil bacteria that can break it down. Here is what it found, and what it did not show.
Key points
- From fields in Uttarakhand with heavy monocrotophos use, researchers found 24 soil bacteria (actinobacteria). Most also showed plant-friendly traits, such as freeing phosphate and making a root-growth hormone.
- In lab tests, some of these bacteria broke down monocrotophos on plates, and a pesticide-degrading gene from them worked in lab bacteria.
- Made into dry flour–clay granules, the bacteria gave the best field result: the paper reports 62% less soil toxicity, against 30% for a liquid version. The figures come from the five best plots, and key details are missing.
- This is early research, not a product or a way to make banned pesticides safe.
- What to do today: stop using monocrotophos, choose safer registered options with your KVK, and keep soil living so it can break residues down.
Why monocrotophos residues matter
Monocrotophos is an organophosphate insecticide that was widely used in Indian farming. It is highly toxic to people, and the World Health Organization lists it among the most hazardous pesticides. India had already barred it from vegetables, and in October 2023 the government ordered it phased out (Insecticides (Prohibition) Order, 2023).
Years of spraying can leave residues in soil, where they can harm soil life. Soil microbes are the main way such residues are broken down. That is why researchers look for bacteria that do this job well, the natural clean-up process we explain in The soil's clean-up crew.
What the researchers tested
The study was published in 2023 in the International Journal of Pharmaceutical Sciences and Research. Its authors are Ankita Rani and Sanjay Gupta of Swami Rama Himalayan University, Dehradun, and Dr. Abhishek Mathur, then at the R&D department of Prathista Industries. Dr. Mathur was the second author.
- Collected soil: 120 samples from fields in Uttarakhand where monocrotophos was used heavily. From 280 microbes, they picked out 24 actinobacteria.
- Checked plant-friendly traits: making the root-growth hormone IAA, freeing locked phosphate, making iron-catching siderophores, and others.
- Tested pesticide breakdown in the lab, by growing the bacteria on plates and in liquid containing monocrotophos.
- Copied a pesticide-breaking gene (called opd) into laboratory E. coli bacteria to see whether it worked there.
- Made three dry formulations of the actinobacteria (alginate–clay beads, flour–clay granules and a chalk-based powder) and compared them in field plots with a liquid version.
What they found
- Plant-friendly traits were common. Almost all 24 isolates freed phosphate strongly, and most made IAA and siderophores.
- Some bacteria broke down monocrotophos on lab plates. The paper reports this as 55% of Micromonospora strains, 45% of other actinomycetes and 42% of Streptomyces strains. These are shares of strains that cleared the pesticide, not the amount of pesticide removed.
- The gene worked in lab bacteria. E. coli carrying the opd gene reduced monocrotophos in broth; the paper's HPLC readings show a fall of about 10% after 48 hours (our calculation).
| Form of bacteria | Plant height | Leaves | Root length | Less soil toxicity |
|---|---|---|---|---|
| Liquid | 30 cm | 10 | 15 cm | 30% |
| Alginate–clay beads | 35 cm | 15 | 22 cm | 54% |
| Chalk-based powder | 37 cm | 18 | 22 cm | 58% |
| Flour–clay granules | 42 cm | 25 | 25 cm | 62% |
Each plot had 25 plants. The paper does not name the crop.
In simple words: the same bacteria did better in the field as dry granules than as a liquid, and the granule plots also had taller plants with longer roots. How the bacteria are packaged seems to matter.
What this study does not tell us
- The lab "degradation" figures are the share of strains that cleared the pesticide, not how much monocrotophos was removed.
- The gene test used genetically modified lab bacteria in broth. Such bacteria are not for use in fields.
- The field figures are averages of the five best plots. The paper does not say which crop, where or when, what dose was used, or how "soil toxicity" was measured.
- There were no untreated plots: every plot got the bacteria in some form, so we cannot tell how much better any of them was than doing nothing.
- No statistics, no yield, and the bacterial strains are not named to species level. No product was made.
The authors present this as screening work. Its most useful message for farmers is that soil already contains bacteria able to break this pesticide down, and that formulation matters.
What you can do today
- Stop using monocrotophos. Ask your KVK or agriculture officer for safer, registered alternatives for your crop, and use them only when pest monitoring shows a need.
- Handle old stock safely. Do not store it near food or water, never reuse its containers, and ask your agriculture office how to dispose of it.
- Keep the soil living. Farmyard manure, compost and crop residues feed the microbes that break residues down. Avoid burning stubble.
- Protect water. Don't wash sprayers or containers near wells, ponds or streams.
- Test land you are worried about. Ask a soil-testing lab or your KVK whether a pesticide-residue test is available.
What comes next
The next steps are clear: name the best strains, measure how much pesticide they remove in real soil, and test the granules against untreated plots on named crops. Dr. Mathur's wider work on microbial formulations is part of that path.
NanoKheti does not sell a pesticide-degrading product.
