Photography credit: Vinícius Mendonça

Harmful Effects of Common Orchid Pesticides

Ailments Culture

by Anu Dharmani

Originally published in BellaOnline

Posted by Sys Admin about 2 years ago.

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We have been using pesticides and various other chemicals frequently to get rid of pests and diseases in plants, without realising the harmful effects of these chemicals. Now, studies and reports are coming out pointing to the dangers of using these. Sometimes accidents happen and direct exposure to pesticides produce dangerous consequences. 

Listed below are some of the commonly used pesticides and symptoms of the toxic effects. Please read these carefully. 

1. Malathion (an organophosphorus pesticide) has an indefinite shelf life but can decompose under high temperatures. It is relatively safe, toxic effects are seen only at very high doses in mammals (humans). However, impurities in the pesticide increase its toxicity. Malathion attacks the nervous system, symptoms of malathion poisoning include nausea, headache, breathlessness, slowed heart-beat rate, weakness, muscle cramps/tremors, upset stomach. 

2. Sevin (also called Carbaryl) is another pesticide that is recommended for use in orchids. A lot of health problems have been linked to it, as it inhibits enzyme action in the exposed individuals. Though it has an adverse effect on health even at low exposures taking over a long period of time, however, it is a neuro-toxic insecticide, so exposure to high amounts needs be avoided at all costs. First aid: Move to fresh air. Start artificial respiration if the patient is not breathing. 

3. Diazinon is also a neuro-toxic insecticide, with a shelf life of 5 -7 years. Exposure to it can be through inhalation, ingestion or by skin contact. Though it is not highly toxic and decomposes fairly quickly, however, when exposed symptoms can appear within minutes to 24 hours. Symptoms are similar to those listed under malathion. Seek immediate medical attention in case of severe symptoms. Other names of Diazinon are Alfatox, Gardentox, Basudin, AG 500 etc. 

4. Orthene is used to kill a broad range of insects. It is also known by the name Acephate. As it has a strong smell, it is advised to use outside the living area. Emergency Treatment for external exposure is washing repeatedly with running water. For inhalation: move to fresh air. If ingested do not induce vomiting or force feed an unconscious person. Call the emergency services. 

5. Isopropyl alcohol, also known as rubbing alcohol. Toxic effects of exposure have been reported in both adults and children. It has been reported that as small amount as 240 ml can be fatal. However, supportive care has helped recovery even after ingestion of 1 litre. 

6. Captan is a white amorphous fungicidal powder that is odourless in pure form. It has a shelf life of 3 years. Overexposure can have toxic effects in humans, however, sheep and cattle are especially susceptible. Human exposure can be through the skin or oral ingestion/inhalation. It can cause allergic dermatitis, eye irritation as well as gastrointestinal problems. First aid: Move the exposed individual to fresh air. In case of dermal exposure wash the area with soap and water. If the eye has come into contact with it and the individual is using contact lens then remove those first. After that wash the eyes freely with water for at least 15 minutes. 

7. Thiram, also known as Aatiram, Accelerator T and has a shelf life of about 4 years. Though exposure to this pesticide/fungicide has been reported as are, still it can happen by inhalation or skin contact. First aid: The contaminated clothing should be removed and the exposed area should be washed freely with water. 

8. Pyrethrum is a natural insecticide that is sourced from plants. It caused tumour formation in the laboratory animals. So, it is possible carcinogenic though there is no direct report. Exposure to it induces allergic reactions, dermatitis that becomes worse when exposed to the sun. Asthmatic people or those sensitive to ragweed are more susceptible to it. 

General Emergency Treatment: Keep the patient calm and maintain normal body temperature. Do not induce vomiting, but if voluntarily vomiting then you can assist by holding the head and if the patient is lying down then turn him/her on the side, so avoid choking/aspiration. Do not give any antidote or medicine if you are not qualified to do so. Always seek proper medical attention for qualified practitioners. 


Children are more susceptible to the toxic effects than adults, please keep them away from all pesticides/fungicides etc. 

Aerial spraying should be avoided especially during pregnancy. Pulmonary stress in agricultural workers. Potential to alter the immune system in mice. May increase incidences of allergic reactions. 


1. For more information checked out this Oregon University site at National Pesticide Information Center and 

2. Toxicology Data Network 

You Should Also Read:
Pest Control in Orchids
Scale Insects-Infestation and Control
Control Orchid Pests and Diseases Naturally

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