Insecticide
Some insecticides (including common bug sprays) are effective against other non-insect arthropods as well, such as scorpions, spiders, etc.
[2] Worldwide sales of insecticides in 2018 were estimated as $ 18.4 billion, of which 25% were neonicotinoids, 17% were pyrethroids, 13% were diamides, and the rest were many other classes which sold for less than 10% each of the market.
Insecticides with systemic activity against sucking pests, which are safe to pollinators, are sought after,[4][5][6] particularly in view of the partial bans on neonicotinoids.
Revised 2023 guidance by registration authorities describes the bee testing that is required for new insecticides to be approved for commercial use.
[15] The contemporaneous rise of the chemical industry facilitated large-scale production of chlorinated hydrocarbons including various cyclodiene and hexachlorocyclohexane compounds.
Although commonly used in the past, many older chemicals have been removed from the market due to their health and environmental effects (e.g. DDT, chlordane, and toxaphene).
Organophosphates interfere with the enzymes acetylcholinesterase and other cholinesterases, causing an increase in synaptic acetylcholine and overstimulation of the parasympathetic nervous system,[18] killing or disabling the insect.
Organophosphate insecticides and chemical warfare nerve agents (such as sarin, tabun, soman, and VX) have the same mechanism of action.
Treated insects exhibit leg tremors, rapid wing motion, stylet withdrawal (aphids), disoriented movement, paralysis and death.
[25] In the late 1990s neonicotinoids came under increasing scrutiny over their environmental impact and were linked in a range of studies to adverse ecological effects, including honey-bee colony collapse disorder (CCD) and loss of birds due to a reduction in insect populations.
[35] Butenolide pesticides are a novel group of chemicals, similar to neonicotinoids in their mode of action, that have so far only one representative: flupyradifurone.
Although the classic risk assessment considered this insecticide group (and flupyradifurone specifically) safe for bees, novel research[37] has raised concern on their lethal and sublethal effects, alone or in combination with other chemicals or environmental factors.
It has no observable acute toxicity in rats and is approved by World Health Organization (WHO) for use in drinking water cisterns to combat malaria.
Most of its uses are to combat insects where the adult is the pest, including mosquitoes, several fly species, and fleas.
Two very similar products, hydroprene and kinoprene, are used for controlling species such as cockroaches and white flies.
A more recent type of IGR is the ecdysone agonist tebufenozide (MIMIC), which is used in forestry and other applications for control of caterpillars, which are far more sensitive to its hormonal effects than other insect orders.
[43] The US EPA defines biopesticides as “certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals”.
[44] Biochemical pesticides (meaning bio-derived chemicals), which are naturally occurring substances that control pests by non-toxic mechanisms.
[49] Many botanical insecticides used in past decades (e.g. rotenone, nicotine, ryanodine) have been banned because of their toxicity.
[49] The first transgenic crop, which incorporated an insecticidal PIP, contained a gene for the CRY toxin from Bacillus thuringiensis (B.t.)
[50] For the next ca 25 years the only insecticidal agents used in GMOs were the CRY and VIP toxins from various strains of B.t, which control a wide number of insect types.
[52] Monsanto introduced the trait DvSnf7 which expresses a double-stranded RNA transcript containing a 240 bp fragment of the WCR Snf7 gene of the Western Corn Rootworm.
[51] GreenLight Biosciences introduced Ledprona, a formulation of double stranded RNA as a spray for potato fields.
[54] Vestaron introduced for agricultural use a spray formulation of GS-omega/kappa-Hxtx-Hv1a (HXTX), derived from the venom of the Australian blue mountain funnel web spider (Hadronyche versuta).
[54] HXTX acts by allosterically (site II) modifying the nicotinic acetylcholine receptor (IRAC group 32).
[63] Solid bait and liquid insecticides, especially if improperly applied in a location, get moved by water flow.
[65][66][67] Many causes are proposed to contribute to this decline, the most agreed upon are loss of habitat, intensification of farming practices, and insecticide usage.
Domestic bees were declining some years ago[68] but population and number of colonies have now risen both in the USA[69] and worldwide.
Spraying of especially wheat and corn in Europe is believed to have caused an 80 per cent decline in flying insects, which in turn has reduced local bird populations by one to two thirds.
[71] Instead of using chemical insecticides to avoid crop damage caused by insects, there are many alternative options available now that can protect farmers from major economic losses.
