Sadly, its value as an insecticide is directly related to sufficient enough toxicity to have effect on insects. However, nicotine breaks down more quickly in the environment than some chemically manufactured pesticides, potentially making it a good biodegradable option. Many pesticides/insecticides do not degrade as quickly or to the same extent, easily accumulate more persistent concentrations within higher organisms, pollute water supplies, and damage entire ecosystems.
It may be worth mentioning that because anyone can add or edit information disseminated by Wikipedia it should not be referenced as a definitive source of information. You never know if the person providing the information can be considered a trusted source. False information has been proliferated through Wikipedia since its launch. Wikipedia has been widely scrutinized for this fact by bona fide authoritative sources, the media, and even suspicious members of the general public. Wikipedia is widely regarded as being rife with spurious information (aka, Internet Fudge), therefore citing it is generally a risky proposition at best. Many
students consulting Wikipedia for research have learned this lesson the hard way.
See
Snared in the Web of a Wikipedia Liar,
Wikipedia Editor Out After False Credentials Revealed,
Teen's warning on the gospel of Wikipedia and
Internet fudge, Wikipedia and Misinformation
Mike McG wrote:“The LD50 of nicotine is 50 mg/kg for rats and 3 mg/kg for mice. 40–60 mg (0.5-1.0 mg/kg) can be a lethal dosage for adult humans.”
Taking into consideration that this statement was sourced from Wikipedia, lets put this into proper perspective. LD50 (or median lethal dose) is the dose required to kill half the members of a tested population. Created by J.W. Trevan in 1927, it is being phased out in many jurisdictions in favor of other tests. As a measure of toxicity, LD50 is
unreliable and results often vary widely between testing facilities, due to factors such as testing population genetics, environmental factors and
mode of administration.
Anyway, if you still want to take LD50's as gospel, then it is worth noting that while the LD50 provided by Wikipedia (i.e., The Internet Fudge Factory) for Rats is listed as 50 mg, it fails to mention that this was orally administered, NOT absorbed through casual contact with nicotine. (*
UNSW Embryology)
Additionally, a home brewed tobacco tea (further diluted through use of a hose-end sprayer) can not be considered as a pure source of concentrated nicotine through any stretch of the imagination. Don't get me wrong, I am fairly certain drinking enough of it would make people ill, BUT in order to ingest 60 mg of nicotine from a weak "Tobacco Tea" brewed through the recipe provided above, you would need to drink an awful lot of it. My guess is that you would most likely get ill long before a terminal concentration of nicotine was reached. Anyone foolish enough to try this is probably more likely to die from the same electrolyte dilution affect observed in cases of liquid intoxification (aka, hyperhydration or water poisoning). Some may be familiar with the case of Jennifer Strange, age 28, who died as a result of drinking to much water while participating in a radio contest sponsored by KDND 107.9 back in January, 2007.
See
Police Probe Water Intoxication Death and
Remember Jennifer Strange, Beware the danger of water intoxication for further information.
Turns out even water is toxic...
Mike McG wrote:Fortunately, in most cases people are only using dilute solutions, but you should still be careful.
Absolutely, one should always exercise caution when working with
any pesticide, whether chemically manufactured or from naturally occurring botanical origins. People should take all recommended safety precautions and any additional precautions that make them feel more comfortable.
See Precautions at
PERMITTED SUBSTANCES FOR THE PRODUCTION OF ORGANIC FOODS
Mike McG wrote:Also as Brad mentioned using tobacco can also spread tobacco mosaic virus to other plants you may have that are in the Solanaceae family.
This is the most compelling argument against the use of unsterilized tobacco that I have seen. According to one report attributed to a former Director of Plant Pathology at NCSU, TMV was found in concentrations of 0.237% in cigarette tobacco, and 0% was found in pipe, cigar, or chewing tobacco. However, I was unable to cross-verify these findings.
Personally, I have experienced no problems since I first began using tobacco tea on the landscape (including a few Datura). However, it may be prudent to pasteurize or at least boil the concoction for at least five minutes if uncertain regarding the tobacco used in its preparation. Alternatively, growing a small quantity of TMV free
tobacco for organic pesticide use might be worth consideration, as it would eliminate viral contamination concerns over purchased tobacco products.
Mike McG wrote:Just because it is “natural” does not mean it is harmless. Radon, as an extreme example, comes to mind having lived for at least forty years in houses that had higher than acceptable levels.
I could not agree more and I have often made the same argument myself.
Caffeine, another natural insecticide, is brought to my own mind. Millions of people around the world consume caffeine or products containing caffeine, despite related health issues, including cardiovascular problems, emotional disturbances, blood sugar swings, gastrointestinal problems, nutritional deficiencies, male health issues, female health problems, adrenal exhaustion and more.
See
How Caffeine Can Affect Your Health,
Combining Acetaminophen With Caffeine Might Cause Liver Damage, and
Links to Learning Disabilities, ADD and Behavior Disorders
I wont even get into damage caused by alcohol. And lets not forget all "natural" water.
Anything can be abused or misused through intent or ignorance. Fire is the heat and light energy released from the natural chemical reaction known as combustion. If you are not careful around it you can get burned, yet mankind has managed to greatly benefit from it for thousands of years.
As with most things, it is all about safe responsible use.
Mike McG wrote:Part of the chemical structure of Imidacloprid is similar to nicotine and it has a similar effect on insects but it is not as toxic to animals as nicotine.
The above statement is potentially misleading, as it depends entirely on data which has not been provided, such as units of measurement used for comparison, purity, persistence, cummulative effect, etc.
Imidacloprid is a nicotine analogue. Since companies can not obtain exclusive marketing rights to naturally occurring substances through legal monopoly they often resort to creating derivatives of a parent compound that
can be patented. Its all about increased profit potential, since naturally occurring substances generally do not pay as well due to wide spread availability and competition (Think Aspirin). Analogues may differ from a parent compound by as little as a single element. The goal is generally to find one that exhibits the characteristics desired, while affording opportunity for legal protection of its unique properties, thus enabling the company to extort whatever fees their perceived corner on the market will bare. Safety is often not the primary motivator. Even if it was, sometimes modification of a compound produces unpredictable results that are not immediately evident.
Increasingly alarms are being raised that the neonicotinoid Imidacloprid is systemic, persistent and more damaging in subtle ways to bees at lower exposure levels than previously imagined. (*
Imidacloprid and Honey Bees). In honey bees, imidacloprid at very low doses has been shown to cause mortality and adverse effects on laboratory-conditioned behavioral responses associated with feeding. (*
Imidacloprid - Human Health and Ecological Risk Assessment). Since honey bees have been disappearing at an alarming rate worldwide AND they are indispensable to food production, this should be of concern to everyone that does not fancy the prospect of famine. The most recent projections that I am aware of state that if the disappearance of honey bees continues at its present rate they could be extinct within the USA by 2035. PBS covered the phenomenon of CCD (Colony Collapse Disorder) in a documentary that premiered October 28, 2007, titled "
Silence of the Bees."
On the basis of both acute and chronic toxicity, the order of sensitivity to imidacloprid among terrestrial organisms is honey bees (most sensitive), followed by birds, and then mammals. (*
Imidacloprid - Human Health and Ecological Risk Assessment)
The U.S. Forest Service typically restricts applications of imidacloprid to either tree injection or soil injection in clay or loam soils. Soil injection of imidacloprid is a relatively specific application method and exposures to most nontarget species will be far below a level of concern. An obvious exception, however, involves soil dwelling organisms such as earthworms, soil arthropods, and soil microorganisms. After soil injection, concentrations of imidacloprid will be in the range of soil concentrations that have been shown to cause sperm deformity in earthworms. In addition, field studies have demonstrated decreases in earthworm populations after applications of imidacloprid. (*
Imidacloprid - Human Health and Ecological Risk Assessment)
Liquid formulations will result in much greater exposures to a wider variety of nontarget species than will selective applications tree injection or soil injection. Liquid formulations are likely to result in substantially greater residues than granular formulations. The broadcast application of liquid formulations lead to acute hazard quotients that exceed a level of concern for a large mammal consuming vegetation (HQ=1.4), a small mammal consuming insects (acute HQ=2), and large birds consuming grass (HQ=10). For sensitive bird species, the broadcast application of liquid formulations of imidacloprid could be associated signs of frank toxicity and possibly with substantial mortality after acute exposures. (*
Imidacloprid - Human Health and Ecological Risk Assessment)
Imidacloprid and its nitrosoimine metabolite (WAK 3839) have been well studied in rats, mice and dogs. In mammals, the primary effects following acute high-dose oral exposure to imidacloprid are mortality, transient cholinergic effects (dizziness, apathy, locomotor effects, labored breathing) and transient growth retardation. Exposure to high doses may be associated with degenerative changes in the testes, thymus, bone marrow and pancreas. Cardiovascular and hematological effects have also been observed at higher doses. The primary effects of longer term, lower-dose exposure to imidacloprid are on the liver, thyroid, and body weight (reduction). Low- to mid-dose oral exposures have been associated with reproductive toxicity, developmental retardation and neurobehavioral deficits in rats and rabbits. (*
Imidacloprid - Human Health and Ecological Risk Assessment)
Imidacloprid acts by interfering with the transmission of impulses in the nervous system. Like acetylcholine, the common nerve transmitter, imidacloprid stimulates certain cells by binding to the nicotinic receptor (Bayer, 2000 and NRA, 1994). Signs of neurotoxicity include reduced muscle tone, tremors, and in extreme cases muscle cramps and difficulty in breathing due to effects on the muscles associated with respiration.
In short, no pesticide that I am aware of is perfect, or perfectly harmless - nicotine not excepted. Whether chemically manufactured or botanical in origin, I encourage anyone considering the use of any pesticide to research it for themselves and come to their own conclusion as to whether it suitable for use in their particular situation.
Visit the FAO (Food and Agriculture Organization) for more information regarding precautions and acceptable use of nicotine at
PERMITTED SUBSTANCES FOR THE PRODUCTION OF ORGANIC FOODS, TABLE 2: SUBSTANCES FOR PLANT PEST AND DISEASE CONTROL, Section I. Plant and Animal, Tobacco tea (except pure nicotine).