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Applying pesticides to control various organisms and diseases that affect human interests in agricultural and urban environments, has effects on honeybees and other pollinators in general. From reading this article, you will understand why pesticide use is bad for bees and other pollinators. The article also looks into the various factors that impact the degree of effects of pesticides on bees.
In addition to understanding the problem, read on to know the various methods you can use to alleviate the harmful effects of pesticides on bees. You also learn about many available alternatives to pesticides. Using the information in this article, you can thus easily change your practices to provide better environments for honeybees and be able to control pests, diseases and weeds.
Which Pesticides are bad for Bees and Other Pollinators?
The word ‘pesticide’ is a collective name for a range of toxic substances that kill many different organisms and plants. It is used to collectively refer to insecticides, acaricides, bactericides, fungicides, miticides, and herbicides. Highly toxic compounds in pesticides which are bad for bees and other pollinators include organophosphates, chlorinated cyclodienes, carbamates, neonicotinoids and synthetic pyrethroids.
Why do Pesticides Affect Honeybees and Other Pollinators?
Pests are often insects in their larval or adult stages. Honeybees and other pollinators are also insects. Pesticides that target insect pests end up affecting all insects, even the insects that are not pests. Additionally, these fungicides, herbicides, acaricides, bactericides and miticides have compounds in them that are toxic to honeybees and other insects. They cause many different effects in ecosystems once they are present in the environment. All species in an ecosystem suffers from these pesticides.
Can Pesticides Affect Entire Honeybee Colonies?
Effects of pesticide exposure in bees and other pollinators range from individuals to entire populations, such as a honeybee colony. Usually, the individual that is exposed to the pesticide suffers the most severe effects.
Other members of a population that get secondary or indirect exposure may not die, but suffer other effects of the pesticide on their bodies. Some of the effects cause gradual death of the exposed individual. The colony may also undergo gradual degradation of their capabilities due to the exposure to the pesticide and die out gradually.
Honeybee and pollinator colonies that have had contact with a harmful pesticide must implement drastic measures and adjustments to increase the chances of the colony surviving exposure to the pesticide. Such measures include using up stored food resources instead of foraging, and producing many new members of the colony because the exposed members will die prematurely.
Why Are Bees Highly Affected By Pesticides?
Specific to honeybees, the colony is an organism by itself. Members of the colony play different roles in the colony as their contribution in keeping the colony alive. Different members in the colony have the work that they do and are present in enough numbers to effectively do that work. Any change in the population or work capabilities of one type of colony members affects the entire colony. In honeybees, this can cause rapid decline in the number of colony members and eventual death of the colony.
Forager bees are often the first to be exposed to pesticides. They may die before they can make it back to their beehives or come back to the beehive and expose other members of the colony to the pesticide. Unfortunately, the foraging habits of honeybees make them unable to avoid contact with pesticides when it they are applied in foraging areas that the bees visit. Plants benefit a lot from the pollination activities that honeybees and other pollinators carry out. It is sad that the pollinators die in the process of performing their ecological duties.
Beehive resources that contain pesticides as contaminants from contaminated foraging fields, may enter the beehive when forager bees return from foraging trips. The contaminant pesticides in the beehive resources affect the other members of the colony in various ways and thus affect the entire colony too.
Negative Effects of Pesticides
Most pesticides harm honeybees and other pollinators. These include insecticides, fungicides, and herbicides. One of the most harmful groups of pesticides is neonicotinoids. Despite the best adaptations and adjustments of honeybees, contact with pesticides usually means death of the bee, or suffering from one or more of many other adverse effects.
The following are the main negative effects of pesticides on bees and other pollinators:
1. Individual and Colony Death
Exposing honeybees to pesticides often results in the death of the bee that had direct contact with the pesticide. When this exposure is colony-wide, the entire honeybee colony is likely to die. Pesticides hinder some functions of the colony and affect the ability of individual bees to thrive. When a significant number of colony members die, or important colony members die, the colony is not able to recover from the losses and also dies soon after. Some important colony members whose loss is not easy for the colony to recover from, are the queen bees and forager worker bees.
2. Reducing Availability of Plants to Forage on
Here, herbicides are the major culprit. They cause death of some plants that may be useful to honeybees and other pollinators. People that apply these pesticides to plants may not intend to harm honeybees and other pollinators, but do so inadvertently.
This is often the case when wind speeds increase or changes occur in the forecast wind direction causes herbicides to drift and land on unintended areas. They kill some or all plants in the unintended area or affect the ability of the plants to provide resources that honeybees need. Mostly, broad-leafed plants and weeds are affected by herbicides, yet they are an important group of forage plants for bees.
3. Sub-lethal Effects
Pesticides at low concentration may not kill the bees and other pollinators that they come into contact with. They, instead, cause harmful effects on the performance of various tasks and bodily functions. Such functions include foraging, olfactory learning, navigation, immune system response, and reproduction. Interfering with these functions affects the ability of the honeybee colony to survive. It shortens the lifespans of different types of bees depending on exposure levels.
4. Undisclosed Toxicities and Toxicity in Combination
Manufacturers of pesticides use many different chemicals and raw materials to make the product. There are also other additives in pesticides that add to the effectiveness of the pesticide. Such additives may help a pesticide adhere onto surfaces, or penetrate barriers to enter organisms more easily.
The individual additives may be toxic to honeybees or can form toxic compounds when they come into contact with another additive. Protective laws that require manufacturers to study and disclose the toxicity status of their products to bees do not extend to additives in the pesticides. This leaves honeybees and other pollinators open to exposure and injury by the pesticide additives.
5. Compounding Effects of Other Stressors
Pesticides compound the negative effects of other stress factors that may be impacting the bees and other pollinators that the pesticide comes into contact with. Honeybees and other pollinators face many challenges in their rapidly evolving environments and ecosystems due to human activities and natural changes over time. At any time, honeybees are dealing with many different stressors such as exposure to pathogens, parasite infestations, unusual weather and loss of habitat.
6. Losses in Beekeeping
Beekeeping is highly affected by pesticides when the chemicals come into contact with various aspects of beekeeping operations. Famously, the death of all honeybees in a colony is the most visible loss in beekeeping. It is often called colony collapse disorder and is under a lot of investigation, research and discussion.
Other losses stem from reduced production, the costs of buying replacement colonies and equipment, implementation of additional preventive measures to prevent honeybee contact with pesticides, and relocation of affected beehives and apiaries. In extreme cases of losses in beekeeping, pesticides force beekeepers to go out of business when they cannot recover from the losses that they suffer.
7. High Food Prices
When pesticides kill off bees and other pollinators, there is a drop in the yields of food crops that require pollination. The reduced amount of these foods cannot satisfy the demand in the market. Prices of the foods rise as a result of this supply and demand dynamic. In the interconnected modern world, the rise in food prices is felt across the globe due to the interconnectedness of markets and commodities.
Alternatives to Pesticides
Synthetic pesticides were not available or in wide use before the 1940s. Since their invention, production in bulk and widespread use, pesticides have enjoyed a period of success and adoration. Unfortunately, pesticides have also shown that they can be hazardous to many organisms including plants and humans. They have a long list of both short-term and long-term effects on the environment and the living things that they come into contact with. Humans have come to the realization that synthetic pesticides are ecologically unacceptable, despite their effectiveness and reliability among other advantages.
There is, therefore, social pressure among other pressures, to stop the use of pesticides. Any person or organization that wishes to avoid using pesticides has many alternatives available to them. The alternatives may not be perfect, but even their worst disadvantages are not as bad as the effects of pesticides on the health of humans, ecosystems and their members.
Below are the best alternatives to pesticides that you should consider using:
1. Cultural Methods for Pest Control
Use agricultural techniques that discourage pests while encouraging vigorous plant growth.
Choose garden plants that are pest-resistant and which provide habitat for wildlife and insects of interest. Stinging nettle and Rhubarbs provide natural ‘soft’ chemicals that are excellent alternatives to pesticides.
Plant a wide variety of plant species and practice crop rotation.
Use companion-planting. This is natural pest deterrence. Marigold is a desirable plant because it keeps away many species of insects. Companion plants deter insects, are sustainable and can improve soils by nitrogen fixation. Allium species such as onions, leeks, garlic, chives and shallots are great companion plants. They repel aphids, carrot flies, cabbage worms, slugs and Japanese beetles among others from vegetables such as potatoes, tomatoes, broccoli, carrots, cabbages and roses. Petunias are repellent to aphids, leafhoppers, tomato hornworms and squash bugs. Lavender repels fleas, mosquitoes, moths and their caterpillars and is great for garden paths and entryways.
Provide optimal conditions for plant growth by managing soil fertility, watering and the drainage of the soil. Plants that are healthy have high natural resistance to pests. You should water your plants using drip irrigation methods or avoid the use of overhead sprinklers in the evenings to prevent mildew on your plants.
2. Biological Control of Pests
Beneficial insects such as Ladybugs, Syrphid Flies, Green Lacewings, Praying Mantises and Trichogramma Wasps are not toxic to mammals and other animals, and establish control for a long time once you introduce them into an area.
Encourage the presence of these insects, birds, frogs, chameleons and animals that eat or parasitize on pests in your farmland or garden. Frogs and toads eat snails, slugs and some other insects. Lacewings eat blackflies, aphids and whiteflies.
Ladybugs, especially their larvae, control aphids very well. Nematodes are great for controlling many unwanted pests including lawn grubs and Japanese beetles among others. Nosema Locustae fungal spores on wheat seeds is a reliable control for grasshoppers. Wasps are effective against pests not limited to aphids, whiteflies, scale and caterpillars of many insects.
Planting native plants in your garden or farmland provides habitation for native pest controllers such as birds and beneficial insects.
3. Microbial Pesticides, Botanical Pesticides and Biopesticides
Botanical insecticides e.g. Rotenone, Sabadilla, Pyrethrum, Chrysanthemum, Neem, and Ryania, are rapidly broken down and have rapid action. Additionally, they have low toxicity to plants and mammals. They, unfortunately, require precise timing and frequent application. Natural homemade fungicides are great for control of black spots on roses, mildew, rusts, and blight on tomatoes.
Microbial insecticides such as bacillus thuringensis and M-One that are selective with limited toxicity to only the targeted pests. They are non-toxic to humans and wildlife. These microbial insecticides can establish control of pests and keep working for long when you use them. They are also called biopesticides. Corn gluten, black pepper, and garlic compounds are great for use as biopesticides. Genetically modified plants are also considered biopesticides if they have had genes for the production of pest control compounds incorporated in their genetic material (DNA).
Use these natural pest control substances in rotation, at low dosages or concentrations, applying them at night, and only when necessary. This limits the exposure of beneficial insects such as bees and other pollinators to the substances, and also limits the effects that the beneficial organisms suffer in case they are exposed to the substances.
4. Mechanical Pest Control Methods
Traps such as Tanglefoot and sticky white or yellow boards. They leave no residues in the environment and are not toxic to wildlife, mammals or humans. Traps can, however, trap both beneficial insects and the pests. They also have widely varying effectiveness depending on maintenance, cleanliness and location.
Physical barriers such as fence meshes, copper tape for snails, slugs and other gastropods, netting and row covers. These are used to control insect pests and weeds, instead of spraying herbicides in your land. Row covers and nets allow water, sunlight and air through them. They are non-toxic and leave no residues in the soil. Nets also prevent birds from damaging your crops and fruits. Row covers may prevent pollination by insects and their durability varies. Additionally, row covers may provide cover for pests that will damage your crops.
Reduce pest habitats in your area such as pots, boards, papers and debris of other objects. Pests such as snails and slugs use these objects as hiding places from which they emerge at night. You can also create barriers for snails and slugs using grit, crushed eggshells and oyster shells or any other prickly materials.
Reduce the growth of weeds using a combination of methods such as mulching between plants, spreading cardboard or newspapers between garden rows, and using cloth crop covers. You may also hand-pull weeds to uproot them or cut them at the base before they produce seeds. Stalks of cut weeds may sprout again but can be killed by pouring hot water on them.
Cultivation and Handpicking
This is the least expensive of all alternatives to pesticides. It needs to be used long before pest damage is apparent and should be timed to target the proper stage of development of insects of interest. Cultivation and handpicking contributes to reducing pest habitats in your area.
Plant Ventilation and Aeration
Ensure adequate plant ventilation and aeration by carrying out pruning and preventing waterlogging of soil. This keeps many diseases and fungal infections of plants that are caused by humid conditions and poor air circulation. Also remove and destroy the damaged, dead or diseased branches of plants and trees.
5. Natural Pest Control Products
Attractants and lures in traps are largely made up of pheromones that are very specific to the adults of an insect species. They are non-hazardous to humans and animals. Attractants and lures have no residues and leave beneficial insects unharmed. The effectiveness of these traps laced with attractants and lures is highly affected by the weather, locations and can be expensive. It is best used for monitoring the presence of insect species of interest.
Diatomaceous earth such as Perma-guard is a non-poisonous application for the control of pests. The diatomaceous earth dehydrates the pests, instead of poisoning them. This is not toxic to birds and animals. It is however likely to harm beneficial insects and also has less effectiveness in humid weather. Diatomaceous earth is listed as an allowed organic pesticide alongside hydrogen peroxide, iron sulfate, sodium hypochlorite (chlorine bleach) and pyrethrins in the USDA’s National List of Allowed and Prohibited Substances.
Natural Fungicide Recipe
- In a 5 liter container, add one tablespoonful of baking soda and one tablespoonful of horticultural oil.
- Add 4 liters of water and mix well.
- Spray the fungicide on the leaves of plants.
Using Milk to control mildew
- Mix a 50/50 solution of milk and water.
- Spray the solution onto plants and leaves when you see mildew.
- Repeat application of this solution every 3-4 days.
- You can use this method on a weekly basis as a measure for preventing the growth of mildew on your plants.
Dormant oils and horticultural superior oils can be applied pre-bloom to plants. Volck is also oil for this type of use. These oils are effective controls for overwintering pests. They leave no residues on fruits and do not affect humans and other animals.
Food-grade oils of castor, clove, cinnamon, corn, garlic, peppermint, thyme, cottonseed, linseed, soybean, rosemary, and spearmint are effective when used to control pests. Other oils are eucalyptus, geranium, and lemongrass.
7. Spice Plants for Pest Control
You can also use food-grade spices such as cinnamon, cornmint, cloves, rosemary, white pepper, peppermint, thyme and spearmint.
8. Minimum Risk Chemicals and By-Products
Use minimum-risk by-products and food-grade chemicals such as citric acid, potassium sorbate, sesame, lauryl sulfate, sodium lauryl sulfate, corn gluten meal, ground sesame plant, putrescent whole egg solids, and sodium chloride deter or kill various pests. Despite being natural, consider these products to be toxic and use them with care because some of them can cause irritations, harm the skin, eyes or mucous membranes, and can cause severe reactions when used in excessive concentrations.
9. Insecticidal Soaps
Insecticidal soaps that have rapid action and rapidly broken down. They are selective so they do not harm most beneficial insects when you use them. These insecticidal soaps have low toxicity to mammals, plants and animals. They only affect the insects that have direct contact with the soaps before the soap dries. One disadvantage of the soaps is that they are toxic to some plants, especially houseplants and ornamental plants.
BioSolarization uses microbial activity and solar heating to persistently kill pests in the soil while being safe for humans. It utilizes fermentation to create organic acids in the soil. The acids kill pests and are far less toxic to humans and animals than pesticides. Organic matter used in the process also improves soil fertility and soil structure. Use it in the following manner;
- Spread biodegradable organic matter over the soil in your target area, e.g. mustard meal, rice bran, almond hulls and shells, tomato skins or wheat bran. Approximately 9 tons per acre are enough.
- Incorporate the organic matter into the soil, down to 6-12 inches.
- Smoothen the soil surface and lay drip lines or tapes.
- Cover the soil and drip irrigation equipment with clear plastic tarp that has no holes in it.
- Bury the edges of the plastic tarp to trap the sun’s heat in the soil.
- Irrigate the soil.
- Keep the tarps on for 1-2 weeks during the warm months of summer.
- Remove the tarps to allow the soil to stabilize, at least 2 weeks before you plant crops in the soil.
Concepts of Pesticide Replacement
There are several concepts of pest control that reduce or eliminate the need to use pesticides. You should consider adopting these concepts in your gardening and agricultural practices. They include Integrated Pest Management (IPM), Conservation Agriculture, Organic agriculture, Agroecology, PEAT and Plantix.
Investigations into the effects of pesticides on bees and other pollinators have produced conclusive evidence that they have negative, harmful effects. Humans should reduce their use of pesticides with an aim to eventually stop using pesticides. The many negative effects on ecologies outweigh the benefits we get from the use of pesticides. Availability of a variety of alternatives to pesticides makes it possible to stop using pesticides without losing the ability to control pests, diseases and weeds. These alternatives are effective and their use costs just about the same as pesticide use.
Most pesticides can pose a risk to humans and animals. Bees are very susceptible to chemicals used especially in the garden. Follow this link for organic, homemade, and agricultural alternatives to round-up and other garden chemicals.
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Very informative article. Thank you very much for posting.