EIACP Centre on Plants and Pollution

Neonicotinoids

In reality, Neonicotinoids are beginner in the field of pesticides. Their development began in the 1980s, but they only became widely used in the 1990s. The name ‘neonicotinoids’ stems from their similarity in terms of chemical structure to nicotine, the well-known stimulant used in cigarettes; they are a family of compounds, with the three most commonly used being Imidacloprid, Thiamethoxam, and Clothianidin. There are also another four of the compounds currently on the agrochemical market: Acetamiprid, Thiacloprid, Dinotefuran, and Nitenpyram. From their initial use in the 1990s, neonicotinoids have gone on to become the most used insecticides worldwide – their total share of the global market for insecticides in 2007 was 24%. Imidacloprid, first marketed in 1991, accounted for almost 42% of that market Share and is the largest selling insecticide in the world. Their popularity, as well as being down to their effectiveness, is a consequence of their versatility. Most of the seven approved neonicotinoids can be applied either as a spray, by seed treatment, or by direct application to soil. This leads us on to how neonicotinoids exert their effects on insects. They are effective against a wide range of different pests, and all act in a similar manner. Neonicotinoids are systemic insecticides – meaning they are water-soluble, and can be absorbed by plants and distributed through their tissues. When insects ingest them, they bind to and block nicotinic receptors for the neurotransmitter acetylcholine in the central nervous system of insects. Acetylcholine is a neurotransmitter in many organisms, including humans. The effect of blocking the receptors for this neurotransmitter is overstimulation, which leads to paralysis and eventual death for the insects.

Source: http://www.compoundchem.com

Neonicotinoids contaminated ecosystem

Source: ajmag.co/neonics

In research reports that the EU (European Union) has passed a two-year ban on neonics are misleading. A few have been suspended for purposes mainly affecting honeybees – but they continue to be used widely. In a research study, “Macro-Invertebrate Decline in Surface Water Polluted with Imidacloprid,” found that agricultural runoff was so concentrated with imidacloprid that it could be used itself as an effective pesticide. This toxic runoff is leading to 70-per-cent less aquatic invertebrate species richness and abundance, a factor with unknown consequences for the broader ecosystem.

Source: http://www.alternativesjournal.ca

Agricultural performance of Neonicotinamide

Efficacy

Source: www.bayercropscience.co.uk

Imidacloprid is effective against sucking insects, some chewing insects, soil insects and fleas on domestic animals. It is systemic with particular efficacy against sucking insects and has a long residual activity. Imidacloprid can be added to the water used to irrigate plants. Controlled release formulations of imidacloprid take 2–10 days to release 50% of imidacloprid in water. It is applied against soil pests, seed, timber and animal pests as well as foliar treatments. As of 2013 neonicotinoids have been used In the U.S. on about 95 percent of corn and canola crops, the majority of cotton, sorghum, and sugar beets and about half of all soybeans. They have been used on the vast majority of fruit and vegetables, including apples, cherries, peaches, oranges, berries, leafy greens, tomatoes, and potatoes, to cereal grains, rice, nuts, and wine grapes.

Seed Coating

Source: http://seminisus.s3.amazonaws.com/wp-content/uploads/2015/10/Seed-treatment-illustration.png

In agric.ulture, usefulness of Neonicotinoid seed treatments for pest prevention depends upon the timing of planting and pest arrival. Neonicotinoid seed treatments do not appear to produce any benefits for pest management. For soybeans, Neonicotinoid seed treatments typically are not effective against the soybean aphid, because the compounds break down 35–42 days after planting, and soybean aphids typically are not present or at damaging population levels before this time. Neonicotinoid seed treatments can protect yield in special cases such as late-planted fields or in areas with large infestations much earlier in the growing season. Overall yield gains are not expected from Neonicotinoid seed treatments for soybean insect pests in the United States, and foliar insecticides are recommended instead when insects do reach damaging levels.

Source: Neonicotinoid#Agricultural_usage

Importance of bee in agriculture

• Bees are pollinators vital to our food chain. One third of the food we eat would not be available but for bees.
• Forget about honey, pollen and royal jelly. Just think of a world without beans, tomatoes, onions and carrots, not to mention the hundreds of other vegetables, oilseeds and fruits that are dependent upon bees for pollination.
• Add to that, the livestock that are dependent upon bee-pollinated forage plants, such as clover.
• To United States agriculture alone, the annual value of honey bee pollination can counted in billions of dollars.
• Poorly pollinated plants produce fewer, often misshapen, fruits and lower yields of seed with inevitable consequences upon quality, availability and price of food.
• An insecticide may be harmless to the health of the bees but may nevertheless inhibit pollination of the crop by acting as a repellent.
• Careful choice of pesticides may do much to reduce harm but farmers, especially in developing countries, may have few options and, on the whole, the more targeted the pesticide to the pest, the more expensive the product.
• Different bee species behave differently and different crops have different pollination requirements.
• Anything that can be done to enhance the pollination effectiveness of bees will be good for bees, beekeepers - and farmers.

Source: http://www.thatsfarming.com/news

Neonicotinoid and Pollinators

Neonicotinoids are already known as a major cause of the decline of bees and other pollinators. These pesticides can be applied to the seeds of crops, and they remain in the plant as it grows, killing the insects which eat it. The quantities required to destroy insect life are astonishingly small: by volume these poisons are 10,000 times as powerful as DDT. When honeybees are exposed to just 5 nanogrammes of Neonicotinoids, half of them will die. As bees, hoverflies, butterflies, moths, beetles and other pollinators feed from the flowers of treated crops, they are, it seems, able to absorb enough of the pesticide to compromise their survival.

Source: http://www.theguardian.com

Evidence for impacts on non-target organisms

The systemic nature of the chemicals and their persistence provide a variety of means through which toxicologically active compounds can be taken up by non-target organisms, including the following:

• Contaminated pollen and nectar (crop and non-crop plants)
• Direct spray
• Residue contact (e.g. with contaminated leaves or stems)
• Ingestion of treated seeds (insects, birds and mammals)
• Airborne particles released in seed planting
• Contaminated nesting areas or nesting materials.
• Guttation fluid and nectar producing glands outside flowers, root exudates.
• Contaminated soils and water.
• Consumption of contaminated prey by higher trophic consumers.

Environmental concerns

Source: www.farmnutrients.com

Initially Neonicotinoids were praised for their low-toxicity to many beneficial insects, including bees; however recently this claim has come into question. New research points to potential toxicity to bees and other beneficial insects through low level contamination of nectar and pollen with Neonicotinoid insecticides used in agriculture. Although these low level exposures do not normally kill bees directly, they may impact some bees’ ability to foraging for nectar, learn and remember where flowers are located, and possibly impair their ability to find their way home to the nest or hive. Despite the controlled studies completed to date, the actual impact of Neonicotinoid insecticides on honey bees in the field are difficult to measure. It is still not known whether these effects explain bee colony collapse disorder, or have had any effect in agriculture or, especially, in urban areas.

• Follow the label directions carefully
• Restrict Neonicotine applications to the soil or during times when bees are not foraging(e.g, in the evening).
• Treat only those individual plants which need treatment for a known pest infestation.

Source: http://citybugs.tamu.edu/factsheets/ipm/what-is-a-neonicotinoid/