By: Susan Albert, Freelance Garden Writer
While it might be tempting to go ahead and use up those oldcontainers of pesticides,experts say if garden products are more than two years old, they might do moreharm than good, or just be ineffective.
Proper storage plays a large part in pesticide (herbicide,fungicide,insecticide, disinfectant, and products used to control rodents) longevity.Garden products should be stored in a dry location free from cold or heatextremes. Even so, products can begin to degrade and it is worthwhile to label thesewith the date of purchase, using the oldest first. It is also prudent to buy insmall amounts that can be used in one season, even if that seems lesseconomical.
Pesticide and Herbicide Shelf Life
All pesticides have a shelf life, which is the amount oftime a product can be stored and still be viable. With proper storage in a drylocation free from cold or hot extremes or exposure to direct sunlight, theproducts should keep well.
Avoid storing liquids where temperatures drop below 40degrees F. (4 C.). The liquids may freeze, causing glass containers to break.Always store products in their original containers. You should always refer tothe product label for more storage recommendations.
Few garden products show an expiration date, but if it haspassed, it is probably wise to discard the product according to instructions onthe label. When no expiration date is listed, most pesticide manufacturersrecommend discarding unused product after two years.
Use the following guidelines to determine if the products’effectiveness has been compromised and should be safely discarded:
- Excessive clumping noticed in wettable powders, dusts, and granules. Powders will not mix with water.
- Solution separates or sludge forms in oil sprays.
- Nozzles clog in aerosols or propellant dissipates.
Can You Use Old Garden Products?
Expired gardening products most likely have degraded and mayhave changed form or no longer retain their pesticide attributes. At best, theyare ineffective, and at worst, they can leave toxins on your plants which cando damage.
Read the product label for safe disposal recommendations.
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Bacillus thuringiensis (Bt)
- What is Bacillus thuringiensis (Bt)?
- What are some products that contain Bacillus thuringiensis (Bt)?
- How does Bacillus thuringiensis (Bt) work?
- How might I be exposed to Bacillus thuringiensis (Bt)?
- What are some signs and symptoms from a brief exposure to Bacillus thuringiensis (Bt)?
- What happens to Bacillus thuringiensis (Bt) when it enters the body?
- Is Bacillus thuringiensis (Bt) likely to contribute to the development of cancer?
- Has anyone studied non-cancer effects from long-term exposure to Bacillus thuringiensis (Bt)?
- Are children more sensitive to Bacillus thuringiensis (Bt) than adults?
- What happens to Bacillus thuringiensis (Bt) in the environment?
- Can Bacillus thuringiensis (Bt) affect birds, fish, and other wildlife?
What is Bacillus thuringiensis (Bt)?
Bt is a microbe naturally found in soil. It makes proteins that are toxic to immature insects (larvae). There are many types of Bt. Each targets different insect groups. Target insects include beetles, mosquitoes, black flies, caterpillars, and moths.
With Bt pesticides, routine testing is required to ensure that unwanted toxins and microbes are not present. Bt has been registered for use in pesticides by the US Environmental Protection Agency (EPA) since 1961.
What are some products that contain Bacillus thuringiensis (Bt)?
Currently, Bt strains are found in over 180 registered pesticide products. Bt products are used on crops and ornamental plants. Others are used in and around buildings, in aquatic settings, and in aerial applications. These products are commonly sprays, dusts, granules, and pellets. Some of these products are approved for use in organic agriculture.
Some crops have been engineered to make the Bt toxin. These plant-incorporated protectants include corn, cotton, and soybeans.
Always follow label instructions and take steps to avoid exposure. If any exposures occur, be sure to follow the First Aid instructions on the product label carefully. For additional treatment advice, contact the Poison Control Center at 1-800-222-1222. If you wish to discuss a pesticide problem, please call 1-800-858-7378.
How does Bacillus thuringiensis (Bt) work?
Bt makes toxins that target insect larvae when eaten. In their gut, the toxins are activated. The activated toxin breaks down their gut, and the insects die of infection and starvation. Death can occur within a few hours or weeks.
The different types of Bt create toxins that can only be activated by the target insect larvae. In contrast, when people eat the same toxins, the toxins are not activated and no harm occurs.
Each type of Bt toxin is highly specific to the target insect. For example, the вЂkurstakiвЂ™ type targets caterpillars. The вЂisrealensisвЂ™ type targets immature flies and mosquitoes. Little to no direct toxicity to non-target insects has been observed.
How might I be exposed to Bacillus thuringiensis (Bt)?
People are most commonly exposed to Bt through their diet, at very low levels. Exposure can also occur if you breathe it in or get it on your skin or eyes. For example, this can occur while applying sprays or dusts during windy conditions. You may also be exposed after using a product if you donвЂ™t wash your hands before eating or smoking. Since Bt is commonly found in soils, exposures not related to pesticides are also possible.
Pets might be exposed to this product in treated birdbaths or water fountains. You can limit your exposure and reduce the risk by carefully following the label instructions.
What are some signs and symptoms from a brief exposure to Bacillus thuringiensis (Bt)?
Bt is low in toxicity to people and other mammals. Several studies have found no evidence of sickness or infection as a result of exposure. However, some products with Bt have caused eye and skin irritation. In one study, rats breathed in very high doses of concentrated Bt. Some had runny noses, crusty eyes, and goose bumps. Others were less active or lost weight.
In another study, people were surveyed before and after aerial applications of Bt. Most people were not affected. However, some people with hay fever reported certain symptoms. These included difficulty with sleep and concentration, stomach upset, and nose/throat irritation. Seasonal factors, such as pollen, may have contributed to some of the effects.
Scientists also evaluated whether Bt can cause allergic reactions. Researchers found that farmworkers exposed for one to four months did not experience any problems related to their airways, nose, or skin. However, further exposure showed evidence of an immune response and the potential for skin allergies to develop.
What happens to Bacillus thuringiensis (Bt) when it enters the body?
When eaten, Bt is confined to the gut. It does not reproduce, and the toxin is broken down like other proteins in the diet. Bt leaves the body within 2 to 3 days.
If breathed in, Bt can move to the lungs, blood, lymph, and kidneys. Bt is then attacked by the immune system. Levels of Bt decrease quickly one day after exposure.
Is Bacillus thuringiensis (Bt) likely to contribute to the development of cancer?
No data were found on the carcinogenic effects of Bt in humans. However, in one animal study, rats were fed very high doses of Bt for 2 years. No evidence of cancer was observed.
Has anyone studied non-cancer effects from long-term exposure to Bacillus thuringiensis (Bt)?
In a 2-year study, rats were fed high doses of Bt daily. Female rats had lower body weights. However, no evidence of an infection was found.
Bt is only activated in the alkaline environment of the insect gut, compared to the acidic environment of human stomachs. In human stomachs, it is easily digested. As such, no adverse effects are expected after long-term dietary exposure to Bt, whether its proteins are sprayed on plants or grown within plant tissues.
Are children more sensitive to Bacillus thuringiensis (Bt) than adults?
Children may be especially sensitive to pesticides compared to adults. However, there are currently no data showing that children have increased sensitivity specifically to Bt.
What happens to Bacillus thuringiensis (Bt) in the environment?
Toxins created by Bt are rapidly broken down by sunlight and in acidic soil. Other microbes in soil can also break it down. Bt does not readily leach in soil. It typically remains in the top several inches of soil. Bt remains dormant in most natural soil conditions. However, there has been some reproduction in nutrient rich soils. On the soil surface, dormant Bt cells last only a few days. However, below the soil surface, they can last for months or years. The half-life in unfavorable soil is about 4 months. Bt toxins break down much faster. In one study, 12% remained after 15 days.
In water, Bt does not readily reproduce. A study found Bt toxins in the air were broken down rapidly by sunlight. Forty-one percent (41%) of the toxin remained after 24 hours. On plant surfaces, sunlight breaks down Bt the half-life of Bt toxins is 1-4 days.
Can Bacillus thuringiensis (Bt) affect birds, fish, or other wildlife?
Bt is practically non-toxic and non-pathogenic to birds, fish, and shrimp. No adverse effect or infection was found in rats given large doses of two different Bt strains. There is no evidence that Bt can cause a disease outbreak among wild animals.
Little to no direct toxicity to non-target insects and other shelled invertebrates has been observed. Bt does not seem to hurt earthworms. However, the aizawai strain is highly toxic to honeybees. Other strains have minimal toxicity to honeybees.
Water fleas exposed to the kurstaki and israelensis strains showed moderate toxicity. The aizawai strains are highly toxic to water fleas. However, evidence suggests that toxicity to these non-targets may be related to impurities from the production of Bt.
Some herbicides require you to mix the weed killer with a solvent such as water. Before you mix your herbicide check the label to see what the ratios are. You must add the exact ratios stipulated on the label because herbicides have various additives that will only work if the product is mixed correctly. Mixing the weed killer in too much water will dilute the herbicide and it will lose its chemical effects.
Now it’s time to calculate the amount of herbicide needed. There will be mixing instructions on your label so follow these guides for safety precautions.
It’s important to use a container that’s convenient to use and that will help you apply the herbicide correctly to the weeds. There are five types of weed killer sprayers that you can use:
- Liquid Sprayers: This is the most common type of weed killer sprayer. They come in many varieties but the most prevalent design is a container with a long flexible hose and a wand. The flexible hose allows you to maneuver the piece so that you can apply the weed killer to the required areas where there are weeds. It will allow you to easily avoid the sensitive grass sections of your lawn. The wand will either deliver a fine spray or a coarse spray. You want to use a coarse spray in areas that need to be drenched in herbicide. A fine spray is ideal for areas that require controlled application in gardens with flowerbeds and vegetable patches you don’t want the herbicide to touch.
- Gas powered sprayer: A gas sprayer is a powerful device that is used for larger properties that need herbicides to be applied quickly and evenly. The herbicide is put into a large tank and gas is used to push the weed killer out through a nozzle in bursts when you pull a trigger. It’s used for severe weed problems in fields, commercial properties and residential lawns.
- Air Sprayer: Here is a device that doesn’t use chemical liquids. The air sprayer allows you to apply powdered herbicides to kill weeds and it’s used for delicate tasks. An air sprayer can apply weed killer to areas around flowerbeds and sensitive lawns.
- Compression Tank: The compression tank is similar to liquid sprayers. The only difference is this sprayer operates with a compression tank whereas a liquid sprayer may simply come in a bottle or container with a spray nozzle or hose. These sprayers have a hand operated trigger that builds compression in the tank to allow a continuous stream of weed killer to be dispersed through a wand. The wand has a design that allows you to twist it to switch the device on or off.
- Backpack weed sprayer: This weed killer sprayer can be carried on your back because it comes with straps. It’s easier to carry and offers more control when you’re applying herbicides to your garden.
Some mild herbicides that you mix can be placed in a recycled spray bottle. If you are using a recycled spray bottle ensure you wash the container out thoroughly before pouring the mixed weed killer liquid into the jug. The reason for this is because if there are chemicals left over from whatever was in the recycled sprayer before it might create a hazardous gas when combined with the herbicide. So always makes sure you wash containers before pouring the weed killer into the bottle.
Using a recycled spray bottle will allow you to apply weed killer to small sections of your garden where you see growth occurring. It will help you avoid spraying your entire lawn with chemicals when it’s not required. It will also allow you to save on product because applying small amounts at a time will make your herbicide last longer.
One important aspect to remember when applying herbicides to your garden is to follow the safety measures. The safety precautions you see on your label should never be taken lightly. These instructions are put in place to protect your health and to ensure the safety & wellbeing of the people and animals around you. Before applying your herbicide ensure you’re wearing the following safety gear:
- A mouth and nose mask: If you’re working with a mild weed killer make sure you’re wearing something to cover your nose and mouth. The mask prevents chemicals from entering your nasal cavities and mouth. These protectors are similar to dust masks and are ideal when working with powdered weed killers.
- Face mask: A facemask covers your entire face so that your eyes are protected as well as your mouth and nose. This protector is used as a safety precaution when dealing with liquid herbicides. The liquid chemicals can’t be absorbed into the mask because the protector is made from hard plastic.
- Goggles: It’s advised that you wear goggles with a mouth mask so that chemicals don’t reach your eyes. Herbicides can damage your eyesight so ensure you’re always wearing goggles to prevent liquids or powdered herbicides from flying into your eyes.
- Gloves: Some herbicides have acidic chemicals in them that can burn your skin. Always wear gloves when mixing the chemicals and applying it to your lawn to prevent injury from the weed killer you’re using. Don’t wear gloves made from fabric because liquid herbicides can be absorbed through them. Wear latex gloves when working with liquid or powdered weed killers.
- Overalls: The chemicals can damage clothes and liquid herbicides can be absorbed into certain fabrics if you’re out working in the garden for a while. If you have a big property and you’re using a large sprayer to apply weed killer onto a lawn ensure you’re wearing protective clothing.
Some weed killers have a strong odor and the effects can last for a few days. After you’ve sprayed an area you should block it off so that pets and children keep away from the zone until the chemicals wear off. Organic herbicides are safer to use so consider a product that has all-natural ingredients if you have kids or pets.
It’s crucial that you mix the correct ratios of weed killer with a solvent because the fumes can be too strong and kill other living organisms around your lawn. You don’t want to destroy the natural habitat in your garden because it’s responsible for creating vibrant lawns, flowerbeds and vegetable patches.
You should avoid spraying weed killers near vegetable patches because the chemicals can be absorbed into the edible plants and it will be unsafe to eat. Before spraying your garden with a weed killer cover your vegetable patch with mesh or plastic wrapping to avoid the chemicals from settling on the edible plants.
Another safety precaution to adhere to is the product shelf life. When a weed killer has expired it can either be ineffective because the chemicals in the product have degraded over time, or it can become extremely toxic. The toxins developed in the herbicide can destroy your lawn and it can be extremely hazardous to your health. If you see that your herbicide has expired it’s best to throw the product away and purchase a new one.