Silver bullet or double edged sword?

The shot-hole borer has came to prominence in recent years.  This little known insect with its fungus  buddy  have been killing off thousands of trees in our country. Little is know  about the effective control and eradication of this pest.

A workshop has been organised in affected areas country wide to give guidance on how to deal with the problem.  Here in Knysna on the 23rd February a workshop will be held at the  Hotel Claude,  15 Hill Street, Upper Town at 10.00 am – 13.30.  Cost is R1800.00.  For further details see see posting under  promotional events.

Herbicides, pesticides and fungicides all have a detrimental effect on the environment.  My question is would it not be better to remove and burn effected trees rather than treating compromised ones? I also wonder about the recovery of treated trees, will the damage tissue recover or will the branches die off? That will leave you with a disfigured specimen – is it worth while? Furthermore, how will it affect  other insects, reptiles, rodents, monkeys and birds that visit and feed on these treated trees?

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Below an article on Emamectin benzoate, one of the insecticides mooted to be effective.

Emamectin benzoate – toxicity, side effects, diseases and environmental impacts

Emamectin is a compound produced by the bacterium Streptomyces avermitilis that exists in numerous forms: as the free base emamectin, as emamectin benzoate salt, and as emamectin hydrochloride. Emamectin benzoate is a cream-colored powder that is the most common form of emamectin.

This chemical belongs to the avermectin compound family, of which all types are toxic to various insect pests. The efficacy of emamectin benzoate against mites, nematodes, and moths has made it a relatively popular insecticide in the U.S. and Canada.

List of known side effects

Emamectin benzoate can be highly toxic if swallowed. Animal studies have shown that the ingestion of emamectin benzoate can result in acute oral toxicity or death. Abamectin, from which emamectin is derived, has been linked to at least one successful suicide attempt, and has been known to cause such health complications as:

  • Coma
  • Convulsions
  • Emesis (vomiting)
  • Mydriasis (pupil dilation)
  • Sedation
  • Tremors

This compound can be just as toxic if inhaled. The dust or fumes of emamectin benzoate can cause respiratory discomfort and distress, making this chemical particularly dangerous to persons with impaired respiratory function or pre-existing respiratory diseases such as emphysema or chronic bronchitis. Long-term exposure to emamectin benzoate can lead to changes in lung function, most notably pneumoconiosis, an occupational lung disease caused by breathing in dust.

Repeated dermal contact can result in abrasive skin damage. Open cuts and irritated skin are especially vulnerable to the detrimental effects of emamectin benzoate as it can enter the bloodstream through these openings and cause systemic injuries. Furthermore, testing on rats and rabbits has shown that dermal contact with large amounts of abamectin can produce tremors, weight loss, and result in death.

Emamectin, particularly emamectin benzoate, is toxic to non-target animals. In addition to intoxicating mollusks and zooplankton, emamectin benzoate can be highly toxic to fish and honeybees.

This chemical has the potential to become groundwater contaminant. While not mobile, emamectin benzoate breaks down gradually, depending on various environmental conditions. During the breakdown process, emamectin benzoate releases toxic byproducts that can impact the surrounding environment.

As a combustible solid, emamectin benzoate can emit poisonous fumes when exposed to a source of ignition. These fumes tend to contain carbon monoxide, carbon dioxide, and other pyrolysis products that result from the burning of organic materials.

Body systems affected by emamectin benzoate

Emamectin benzoate is a dermal, respiratory, gastrointestinal, and ocular irritant. Repeated or prolonged exposure to emamectin benzoate can damage these organs.

Items that can contain emamectin benzoate

This pesticide is typically used on ornamental trees, leafy and fruiting vegetables, cereal crops, nut trees, herbs and tea plants. As such, it’s highly likely that fruiting and leafy vegetables contain trace amounts of emamectin benzoate.

How to avoid emamectin benzoate

Emamectin benzoate exposure usually occurs through the ingestion of contaminated food or water, making it all the more important to check food and water sources to verify if emamectin benzoate was used.

When handling emamectin benzoate, wear the appropriate protective clothing: fully sealed chemical-protective goggles, chemical-resistant gloves, long-sleeved pants and shirts, and, if necessary, respirators. Avoid drinking, eating, or smoking while around this material, and thoroughly wash hands before handling and prior to drinking, eating, or smoking.

To store emamectin benzoate, keep it in its original container or one recommended by the manufacturer. Place emamectin benzoate in a cool, dry, and well-ventilated area away from foodstuffs and incompatible materials, such as pool chlorine, nitrates, and other oxidizing agents.

Where to learn more

Summary

Emamectin benzoate is a pesticide that can cause harm to the lungs, skin, eyes, and digestive system, depending on the route of exposure. However, ingesting emamectin benzoate is highly dangerous as doing so has been known to cause numerous health problems and has even lead to death.

Far from just harming target pests, emamectin benzoate can be dangerous to other organisms, namely bees, fish, mollusks, and zooplankton.

If left to degrade in water, emamectin benzoate can release toxic byproducts that make the surrounding environment toxic.

Sources include:

FAO.org
Sitem.Herts.AC.uk
PubChem.NCBI.NLM.NIH.gov
PesticideInfo.org
Datasheets.SCBT.com