Ever wondered exactly what pesticide residues might be lingering on your delicious durians? Food safety and health safety is on everyone’s mind today, but the agricultural chemical world is still mysterious and confusing to most of us.
Rather than nihilistically throwing up our hands and assuming we’re all being poisoned with every bite — let’s learn about durian pesticides!
*Please note that this is not ALL the chemicals used on durian in Thailand. This is not a comprehensive list, just an explainer of what we saw in one Agro-chem shop on one day in Thailand.
***I am also not an agricultural scientist. If you are one, please give your comments below!!
From a Tree Doctor
We were lucky enough to meet Santos Ruenrom, a local “Tree Doctor” who owns an agricultural chemical shop in Rayong, Thailand.
While we visited, a woman stopped on her motorbike to describe a problem she was having with one of her trees. Ruenrom knew what to do, and promptly sold her a natural anti-fungal to take care of her fungal issues.
We want to thank him for taking the time to walk us through each product on the shelf. Later I researched the toxicity, environmental affects, and whether or not it’s approved for use in the USA.
This is a long read — definitely for you health and agricultural nerds ONLY! Try as I might, there is just no jazzing up photos of bottles covered in Thai script into a titillating visual experience.
But if you want to understand what chemicals you might be exposed to while eating durian in Thailand, read on.
The Rising Concern over Pesticide Use in Thailand
Pesticides have been a huge topic of national debate in Thailand.
In 2019, the government moved to ban 3 toxic chemicals after Japan rejected a shipment of fruit due to excess residues. Every year, Thailand’s fruits get rejected from places like Hong Kong, Taiwan, European countries, and the USA.
A non-profit agency, the Thailand Pesticide Alert Network, has reported that nearly 64% of Thai produce exceeds its MRL (maximum residue limits), and should be deemed unsafe.
According to World Atlas, Thailand is #4 in the World’s Top Pesticide Consuming Countries (but still behind the USA, #2).
But pesticide use becomes ugliest for Thai farmers, of whom 90% report adverse affects of using pesticides on their own health.
The issue is so dire that farmers in Thailand are becoming a lot more careful and conscientious about which pesticides they use, and how they use them. There’s a huge movement in Thailand and within the Durian Farming community toward less toxic agro-chemicals.
So with that in mind, I was curious to see what kind of chemicals Ruenrom was selling in his shop.
Fertilizers & Growth Stimulators
The first group of bottles we picked up had pretty pictures of fruits all over the labels. These are often multi-vitamins for trees, containing Boron, Calcium, Sulfur, Magnesium, or other micro-nutrients a tree needs to produce yummy fruit. Some are also plant hormones used to convince trees to grow extra roots, focus on making a strong trunk, or trick them into flowering off-season.
Approved For Use on Food Crops?
Most of what we saw on the shelf are organic fertilizers that are approved for organic farming. There were 3 or 4 different brands, and each have enough miraculous benefits that I wonder if the CEO is Donald Trump.
For example, Plantonics Fruit Special Blend from an Indian company, Gujarat Bio Organics, claims to help trees deal with the stresses of global warming and atmospheric pollution, as well as improving fruit taste, size, weight, color and overall attractiveness and creating an unforgettable taste.
All with just fabulous nutrition.
I couldn’t find a Nutrition Label for exactly which nutrients are being targeted, but I’m assuming it’s like a compost tea. Most contain seaweed, which is known to contain many trace minerals. The liquid is meant to be diluted in water, either added to irrigation or sprayed on the leaves for increased absorption.
Approved for Food Crops?
✅United States – Bonzi®, Clipper®, Coltar®, Trimmit®, Profile®
History and Use
Paclobutrazol appears to have been first marketed around 1985 as a growth retardant for turf — like golf courses and sports arenas.
The chemical inhibits the production of the plant hormone Gibberellin, forcing the plant to grow a sturdier base/trunk, a stronger root system, and in general just grow really slow.
Paclobutrazol was inspired by electricity companies trying to keep power lines cleared and golf courses trying to spend less money on mowing the lawn.
But using Paclobutrazol has a lot of other perks too.
It turns out that not only does Paclobutrazol keep trees shorter and sturdier, it also works as a fungicide, gives a darker green color to leaves and lawns (so prettier golf courses), and even changes the way plants absorb water, making them more drought resistant!
In Thailand it was introduced around 1987 for artificially inducing flowering in mangoes — and now it’s widely used for inducing flowering in durians too.
It’s well known that Paclobutrazol does not break down quickly in the soil – a perk if you don’t want to keep reapplying but a downer if you want to plant anything else around your trees and have the new crop actually grow.
Because paclobutrazol is so widely used, there’s a ton of it in our environment. It’s estimated by some sources that California alone uses 11,000 pounds per year.
But the consequences of paclobutrazol in ground water or run-off are pretty unclear. It seems to be non-toxic to mammals and birds, but is stated “paclobutrazol is very toxic to aquatic organisms.”
- 1985. Cornell Herbicide Profile of Clipper 50.
- Purdue. Growth Retardants: A Promising Tool for Managing Urban Trees
- 2019. Molecules. Residue of Paclobutrazol and Its Regulatory Effects on the Secondary Metabolites of Ophiopogon japonicas
- Official Gazette of the United States Patent and Trademark Office: Trademarks: TRIMMIT
- Trimmit 2SC: A New Trade Name for Paclobutrazol
IBA and Cytokinin
The brand is Plant Science Co. LTD
Approved for Food Crops?
History & Use
Root stimulation is used in all agricultural crops to make plants hardier and less likely to fall over. It’s all used a lot for root crops, like carrots, beets, potatoes, etc.
There are two chemicals at work here:
- Indole-3-butyric acid (IBA): This hormone is in the auxin family of plant growth hormones. It’s believed to be extracted from plants in the Saalix (willow) family. It basically induces the plant to create a lot of stem cells.
- Cytokinin: This hormone was first extracted from coconut milk in the 1950’s, after researchers realized that fertilizing your plants with coconut milk and meat made the plants grow more roots. It basically communicates to the stem cells created by that they should probably become roots.
The US EPA says: “Because it is similar in structure to naturally occurring substances and is used in tiny amounts, this plant growth regulator poses no known risks to humans or the environment.”
IBA and Cytokinin break down quickly in soil and water sources. The small amount used in agricultural is not considered harmful to animals or people.
The biggest struggle for durian farmers everywhere is protecting their trees from the various fungi that can infect and kill durian trees.
Treatments for funguses range from trying to boost the tree’s immune system with nutrients and fertilizers to some pretty intense chemicals. Here’s what we saw in Ruenrom’s Agro-chem shop.
Approved on Food Crops?
History and Use
This is an antiobiotic for plants.
Validamycin is a natural toxin produced by Streptomyces hygroscopicus var. limoneus bacteria. This bacteria was first discovered around 1944, when it was used in humans to fight tuberculosis.
In 1966, the Japanese pharmaceutical company Takeda Chemical Industries discovered that fermenting the bacteria produced toxins that work against a very terrible fungus family called Rhizoctonia, whose name literally means “root killer.” Rhizoctonia is a problem for potato, beet, rice, and vegetable farmers around the world, as well as being deadly for our beloved DURIAN.
Validamycin works by preventing the Rhizoctonia from producing the enzyme that converts its food to sugar, trehalase. So the Rhizoctonia starves to death (and the crowd goes wild 🙌🙌)
In the USA, the EPA classifies Validamcyin as Class IV or “Practically Non-toxic.” It breaks down very quickly (with a half-life of less than 5 hours) and doesn’t leave residue in the soil or water supplies. It doesn’t seem to hurt bees, and is non-irritating when rubbed on the skin of rabbits.
However, it is an antibiotic. Like other antibiotics, there are fears that widespread use of Validamycin might create resistant strains of Rhizoctonia, the MRSA of the fungal world.
Studies also show that Validamycin affects the soil biome and other “healthy” bacterias that live there, the same way antibiotics affect the gut biome in humans. It might be good to the feed the soil with the equivalent of agricultural yogurt after spraying with Validamycin.
- EU Pesticides Database
- History in Japan
- Not Approved by European Union
- More History & Background
- Cornell Info Sheet
CARBENDAZIM (MBC) and THIOPHENATE-METHYL (TM)
A 2015 study found that Carbendazim and its Auntie TM are the second most common fungicides in Thailand, which is a little scary. Shipments of fresh durian to the USA, Europe, Japan, Hong Kong and Australia have been rejected due to excess residue of Carbendazim.
Approved on Food Crops?
✅❌Australia — TM is approved, but pure Carbendazim is banned on all food crops except restricted use on Macadamia Nut farms.
✅❌European Union — TM is still also allowed, but Carbendazim and Benomyl are banned.
✅❌United States, TM is still widely sprayed on strawberries, and other food-crops, but both Carbendazim and Benomyl are banned from all food.
History and Use
Thailand’s Bureau of Agricultural Commodity and Food Standards lumps the benzimidazole triad — Benomyl, Thiophenate-methyl, and Carbendazim — together when discussing pesticide residue — which the EPA DOES NOT.
Of the 3, Auntie Benomyl is the oldest, developed in 1968 by DuPont in the scramble to replace DDT. Carbendazim and Thiophenate-methyl (TM) followed in 1970 and 1973.
All three are fungicides used on mildews, molds, blights, rusts, and fruit rot both pre-harvest and post-harvest.
Since they are highly toxic for soil organisms, Carbendazim has also been used on golf courses and sports arenas to kill earth worms that would otherwise leave their little muddy poos all over the top of the lawn.
Of the three, only TM is still permitted in the United States, although who really knows why that one’s allowed. Concerns about carbendazim’s toxicity were raised as early as 1996, when a Miami mother won a court case for her baby born without eyes.
The EPA Fact Sheet describes all three as “non-toxic” to humans, other mammals and birds, yet also notes that Carbendazim causes birth defect and infertility.
The Australian Pesticides Authority says that exposure to Carbendazim can result in “irreversible male infertility.”
In 2008, two court cases in New Zealand were settled after more babies were born without eyes.
Carbendazim binds tightly with soil and doesn’t appear to run off into water supplies — which is a relief — but it also doesn’t break down quickly. Since Auntie TM breaks down into carbendazim in 3-4 days, and Benomyl in 2-19 hours, the IPCS says:
Benomyl and thiophanate-methyl that enter the environment are converted to carbendazim, which can be regarded as the environmentally relevant compound.
Earthworms and farmers regularly exposed to carbendazim are the most at-risk.
- Fungicide Carbendazim to be Banned
- Two-headed Fish & Carbendazim
- DuPont brought to Trial Over Carbendazim
- FAO Benomyl Info
- EU Pesticides Database
This brand is Erawan
Approved for Use on Food Crops?
Bayer Company sells Fosetyl-Al under the name “Aliette.” You can buy it at gardening shops or even on Amazon.
History and Use
You’ve already eaten fruit sprayed with Fosetyl-Al.
Nicknamed “Fosetyl-Al,” this one is common in conventional agriculture pretty much everywhere. It’s a fungicide and protects the tree against all kinds of root rots and stem rots and mildews, including the ever-pernicious and evil Phytophtora.
It’s used on everything that could possibly get root rots or stem rots and mildews, including avocados, pineapples, blueberries, cranberries, citrus, leafy greens, onions, peas, macadamia nuts, turnips…. and so on.
Fosetyl-Al is most dangerous for the workers spraying it. It’s a corrosive and can be really damaging for the eyes, so the EPA suggests wearing goggles when applying it to trees.
By the time most of us come in contact with fruits n veg sprayed with Fosetyl-Al, it’s long gone. It breaks down quickly into other chemicals, primarily Phosphonic Acids, which are a huge class of chemicals that coincidentally include glyphosate and etephon. So I really don’t feel I can say whether or not eating Phosphonic acid residue is safe or not.
- EPA’s Write Up From 1991
- FAO Evaluation of Fosetyl-Al
- Pubchem Fosetyl-Al
- EU Report on Fosetyl-Al use in Europe
- Another Report on Fosetyl-Al and Phosphonates
Approved for Food Crops?
✅ Canada placed heavier restrictions on Thiram usage and residue in 2019
❌European Union withdrew it’s approval in 2019
✅ United States
History & Use
Thiram was patented in 1934 by William Tisdale, who was the Chief Pathologist for Bayer.
It was developed as a sulfur-based fungicide, but has had many uses over the years, including as a treatment for human scabies and in soap for various skin conditions. Oddly, it was also prescribed in pill form by alcohol addiction centers to help people get clean, since combining Disulfide pills with alcohol is asking for a major, major hangover.
Today, it’s primary use is in nurseries to prevent seed-rot. It also can deter rodents and small mammalian pests that don’t like the sulfurous aroma.
In the 1970’s, the US CDC (Center for Disease Control) began questioning the safety of Thiram after a study on nursery and forestry workers reported nausea, dizziness, headaches, stomach complaints, and, unsurprisingly, intolerance to alcohol.
Contemporary studies show that Thiram exposure may be damaging to the thyroid and liver.
Eco groups have also advised that birds and small mammals that eat seeds are more likely to be exposed to Thiram, and raised concerns about endangered species, like Attawar’s Prarie Chicken, coming into contact with Thiram.
- Cornell Fact Sheet: Thiram
- 2016, Canada Threatens to Ban Thiram
- EPA Fact Sheet: Thiram
- USDA Report: Thiram
- Thiram Fact Sheet
- Beyond Pesticides
- History of Thiram
INORGANIC MICRO-THIOL GOLD SULFUR
At first glance I thought this floppy bag was just a fertilizer.
Durians get their eggy, oniony, gassy smell from thiols — organic sulfur-containing compounds
But it turns out this souped up sulfur is more than a fertilizer.
Approved For Food Crops?
✅ United States
In the USA, this product marketed as Microthiol® Disperss®
History and Use
Sulfur doubles as a non-toxic pesticide and fungicide often used in organic farming for treating powdery mildews and mites, just like people use sulfur soaps for treating skin conditions like athlete’s foot, acne, and even the horror that is scabies.
But this bag is more than sulfur — it’s “Sulfur and Science” — and that’s hard for a layman like me to decipher if that’s a good thing.
Sulfur doesn’t mix well with water, making it clumpy and difficult to spray – easily clogging hoses and sprayers. So the scientists have basically mixed finely ground sulfur with gold nano-particles to make it easier.
Since the active ingredient in Microthiol Sulfur is just Sulfur, the EPA judges its safety as just Sulfur.
Which means that it’s pretty benign in the environment and to human bodies.
This brand is AAA Agritec & Aquaculture
✅ United States
You can buy it at Home Depot under the brand names Real Kill and Spectricide Bug Off, or Cyanara, available on Amazon.
History and Use
In the late 1800’s, John Zacherl made his fortune selling powdered Dalmation Daisies as an insecticide he branded Zacherlin. He made a killing 😆
The Dalmation Daisy (C. cinerariifolium) is deadly, if you’re an insect.
These pretty white-petaled flowers come from the Balkan Mountains in present-day Bulgaria. For centuries, the flower heads were dried, pounded, and sprayed in gardens and on lice-infected heads as an effective insecticide.
They were also planted in garden as companion plants to ward off the creepy-crawlers.
In the 1920’s, German scientists isolated the 6 pyrethrin esters in the daisies and learned how they work to kill insects. The toxins paralyze the insect by disrupting sodium transport in the nervous system, effectively giving the insect a huge body-wide Charlie Horse muscle spasm.
By the late 1940’s, scientists already concerned about the health effects of widespread DDT use in agriculture began looking for alternatives. An American named Milton Schelton began synthesizing human-made versions isolated pyrethrins in the flowers (remember there are 6 separate pyrethrin chemicals). These synthesized, isolated pyrethrins were called Pyrethroids.
Issues he wanted to solve was that the flower powder was only effective for a few hours; and it didn’t necessarily kill the insects, just stun them. They wanted something more shelf-stable, longer-lasting in the field, and more effective. His final product, allethrin and bioallethrin, was 20x more effective than DDT without the obvious environmental problems.
Lambda-cyhalothrin was developed in 1977 and is now just one of over 1,000 pyrethroids used in agriculture around the world.
In 2007, pyrethroids comprised 17% of all insecticides sold around the world, worth $8 billion. Even the WHO has promoted using pyrethroid insecticides to reduce insect-borne disease like malaria.
Quick Vocab Summary
Pyrethrins: A family of the 6 toxic esters found in Chrysanthemum flowers
Pyrethrum: An essential oil made from Chrysanthemum flowers that is high in pyrethrins, usually containing a blend of all 6 esters.
Pyrethroids: Means “pyrethrum-like” and refers to any of the 6 Pyrethrin esters, but isolated and artificially synthesized.
All pyrethrins, synthetic or natural, are toxic to ALL invertebrates. That includes nice ones like bees and dragonflies and butterflies 🦋 If the pyrethroids get in the water supply, they can also kill lobsters, shrimps, mussels, and other water invertebrates.
And although natural flower-derived pyrethrins are basically non-toxic to mammals, the same can’t be said for the super-pumped pyrethroids.
There are disturbing cases of lamda-cyalothrin being used in hotels against bed-bugs and accidentally killing tourists.
But it’s unlikely that you’ll eat much lamda-cyalathrin as a residue, especially not on durian. It breaks down in sunlight in a matter of days and doesn’t dissolve easily in water.
However, if you’re a farmer reading this, maybe consider trying the natural-form of pyrethrins? The ones still derived from the flowers? Like GardenTech® from Worry Free® Brand?
- Pyrethroid Timeline
- Beyond Pesticides Fact Sheet
- Wikipedia on Pyrethrum Flowers
- Wikipedia on Cyhalthrin
- The EPA report on Lamda-cyhalthrin
- Pyrethroids vs Pyrethrins
- National Pesticide Information Center Fact Sheet
Approved For Food Crops?
✅ United States
History & Use
Propargite was first registered in the United States in 1969 by Uniroyal Chemical Co, which then was repeatedly sold and merged and sold and merged until I’m confused.
It’s used specifically for killing spider mites – teeny bitty arachnids that damage fruit.
It seems like Propargite has been getting some media attention, especially in California where it is widely used on citrus, grapes, walnuts, almonds, and corn. One of the concerns is “drift spray” where the pesticide drifts out of the field and into the neighborhood, where contact can cause skin rashes.
The last bottles we came to were complicated.
Surfactants are a huge family of chemicals that basically make the active ingredient stick to the leaves/roots and make whatever the fertilizer/pesticide/fungicide more effective.
The first recorded agricultural surfactant (literally soap) was mixed with *arsenic or sometimes lead* as the active ingredient and spread on food crops as an insecticide during the Medieval Ages.
Which was probably as bad for human health as a modern day pesticides. YAY.
Surfactants function using the chemistry of water molecules. Basically, they reduce the surface tension of water, making water more willing to bind to other things than just itself. This means that water can mix with and suspend a chemical inside it — whether that’s a pesticide or a just a nutrient.
If you missed high school chemistry 🙋, this Youtube video by Dow Agrosciences gives a pretty good explanation of how this works.
When water is sprayed on leaves or roots, surfactants alter the shape of the water from a perfect no-outsiders-allowed tear drop to a flat, fat dome with a larger surface area for doing things like transferring nutrients into the tree. Like this:
And little insects, who might generally use water’s surface tension to tiptoe over insectide-laced water ala water skippers, find the insecticide sticking to their wee legs and torsos like water on the inside of a glass.
But from what I can gather, the different names/types of surfactants depend on whether or not the part of molecule that wants to bond with water (the hydrophilic side) is carrying a positive or negative charge.
All of this makes me wish my high school chemistry teacher had been less interested in funny cat videos and more interested in chemical bonds and hydrophobic somethings.
- Anionic Surfactants: These have a negative charge on their water-loving side. These are soaps and are ubiquitous in laundry detergent, shampoo, and most other cleaning solutions.
- Nonionic Surfactants: These are better at suspending the pesticide/fertilizer evenly throughout the water and are more commonly used in agrochemical products. A perk is that they don’t bind with calcium and magnesium in the soil, like Anionic surfactants.
- Amphoteric Surfactants: These are too complicated, but they are very mild and used in cosmetics.
The Good Thing about Surfactants is that they reduce chemical-run off into water sources.
The Bad Thing is that the US EPA has been slow about assessing their impact on the environment or really regulating them, since they are basically considered non-active ingredients.
The EPA got slammed in 2017 when it turned out that a nonionic surfactant used in Monsanto’s Roundup Ready mixture was actually more toxic than the glyphosate itself (polyethoxylated tallow amine or POEA).
Another Sulfactant recently been criticized is nonylphenol ethoxylates, which has been found to mimic the female hormone estrogen.
So why not use just soap or detergent to make your active ingredient more sticky, like in Medieval Age?
You could, except if you choose an anionic kind, they might bind with the calcium and/or magnesium in your soil *instead* of the active chemical, giving your plant a nutrient deficiency.
BUT. If you need an organic surfactant, there’s always sugar.
- Natural non-toxic surfactants
- How Surfactants Work and Types of Surfactants
- An easy to read explanation from a carpet cleaner
- EPA’s List of “Safe” Surfactants
- European Union not happy with nonylphenol ethoxylates
- Monsanto in trouble for toxic sulfactants
All durian farmers take care of their durian trees like little babies. They feed them, water them, take care of their boo-boos, and try to make their trees the healthiest and most productive forms of themselves.
But sometimes farmers don’t take care of themselves.
After my own research, I would like to see farmers shift away from using these 3 chemicals specifically:
Not because of residue left in the durian flesh, but because of the possible health effects on orchard workers and the environment — rivers and streams seem to take an especially hard hit.
The best way to make a difference is to talk to your local Durian Dealer about what agro-chemicals they are using and support farmers who are making conscious choices for their own health and the world around their farms.
If you are a Durian Farmer, or an Agriculturalist, please leave your comments below!
A List of Organic Durian Farms in Thailand
- Kireebunchorn Organic Durian Farm
- Suan La Ong Fah
- Suan Pol Ampai (see map below⇩⇩)
Find more durian farms in Thailand on our new map or mobile app for iOs.
Mike Lewis says
Thank you for this knowledge.
Presently, there are approximately 400 active ingredients (AI), that include formulations with differing percentages or combinations of AIs, registered for importation. Over 20,000 pesticide formulations (accounting for 80% of all pesticides used in Thailand) are licensed for production ( Danutra, 2004 ; OAR, 2011 ). The certificate of pesticide registration lasts for six years and can be renewed upon expiration. The registration process of new pesticides includes efficacy testing and analysis of their chemical and toxicological properties. The responsibility for efficacy testing is put upon manufacturers and must be performed according to an experimental design approved by the Office of Plant Protection Research and Development (OPPRD) of the DOA. Recent regulations require that new pesticides must undergo evaluation of pre-harvest intervals (PHIs) and maximum residue limits (MRLs) under supervision of the Office of Agricultural Production Science Research and Development (OAPSRD) prior to registration being granted. Presently there are 1,504 pesticide products that have established PHIs ( OAR, 2011 ).
Paul Recher says
Natural pyrethrins ergo pyrethrum can not be widely adopted as substitutes because they are ALOT more expensive and, more important, break down in 24 hours whereas the synthetics e.g. permethrin lasts 7 or so days and the even more toxic biphenthrin > 10 years!!!!! Biphenthrin is GREAT for termite control but the reality is its used on a wide range of crops incl food. Though it binds tightly to soil so is unlikely to contaminate ground water, surface run-off into waterways is not good as this class of chemicals are highly toxic to fish and Crustacea. Aside I was shocked, disturbed, dismayed at the prevalent use of paraquat, a highly toxic organo-phosphate, in oil palm plantation as a knock down weedicide. They should be using the much much safer glyphosate. The problem tho is being sure the sprayers do not inadvertently spray the obvious above ground roots of the palm.
[email protected] says
Thank you for the feedback Paul! It’s always good to hear from a grower’s perspective. Have you looked into the sulfactant being used in combination with Glyphosate? As I understand it, it’s the so-called “inactive” chemicals that are the most dangerous element of Round Up — no the glyphosate. I am not sure which is more currently considered more toxic, Paraquat or Round Up.
Craig Hepworth says
Thanks for your thoroughness in compiling this amazing resource, Lindsay. So much useful information, organized in such an easily accessible format.
Peter Kring says
Thank You for researching this very complex subject.
Ideally all the durian farms would be organic and we know that, on a small scale at least, it can work well.
In Malaysia I saw a combination of many wise sustainable and organic practices mixed in with conventual agriculture. Farmers use lots of compost along with non-organic NPK fertilizers. This isn’t much of an issue. The application of amendments, even when not strictly within what is allowed organically would not be a problem for me.
For my own consumption the two systemic fungicides, aliete and benomil, worry me. These are products that are applied to the foliage and soil, then taken in by the trees vascular system all the way to the root tips, fruits, everything. Systemic is very different from contact toxins which may not be absorbed by the plants, depending.
Pyratroids are contact insecticides like what are used in households to get rid of ants, termites, etc. some are very strong and others fairly benign. Actually, some natural chemicals which are allowed in organic farming can cause more problems than a weak pyratroid in the case of killing soil microorganisms.
As an organic durian farmer in Costa Rica I have studied conventional durian farming with the concept of adapting what works conventionally to my organic practice. The durian farmers apply in cycles. Beginning with the post harvest, they prune the trees and apply compost and regular fertilizer to stimulate foliage growth during the rainy season. It’s easy for us to achieve this organically. If we need more nitrogen we apply aged chicken manure, etc. seaweed is good at this time too. As the weather gets drier they want to apply potassium to force/support flowering. Ash of durian skins, banana stems, cacao pods, are good for potassium. Healthy soil takes care of root fungus, this is long term care of the soil that is often overlooked with little appreciation of the importance of a living soil.
I think we need to strive for healthier agriculture, not just for the consumer but for the workers and especially, the soil.
[email protected] says
Thank you so much for taking the time to give insight from your daily experience working with trees and soil! It’s a very complicated subject since it involves adding an ingredient to an entire ecosystem — and there is so much fear about words like “pesticide” and “chemical” when as you mention isolated organic compounds can also be very harmful — like when they sprinkled arsenic or lead dust on plants in the middle ages to act as a pesticide!
I hope to keep learning about how farmers can use conventional agricultural science to find more benign alternatives.