*5.3.1 Insecticides*

Chemical control for insect pest management contributes as the major part of insect pest management strategies used all over the world [37]. Insecticides have been used since early 1940s for the effective pest management and have been a successful tool for the pest management as saving serious crop losses through insect pest infestations [38]. But, at the same time, the negative effects of these synthetic chemicals have created havoc throughout the world by suppressing the overwhelming populations of several non-target insect species, mainly including the biological control agents and the pollinators. Honey bees are susceptible to many insecticides and different harmful effects of these insecticides are believed to be the prime most reason for the decline in global honey bee populations [9, 39, 40]. The different insecticides have been highly criticized for their possible role in widely discussed and seriously concerning worldwide losses of honey bee colonies [41, 42]. Since the first detailed report and description of the term 'colony collapse disorder' (CCD) in 2006 [43] in America and followed by Europe, had again initiated the long term agitation of banning the use of insecticides, posing a serious threat to the billion dollar industry. Since the CCD, possible role of insecticidal residues in weakening the honey bee colonies for an increased susceptibility towards different environmental and pathogenic pressure on different colony levels has widely been discussed in scientific community [7, 44–50].

Lethality of any pesticide to honey bee is measured during toxicological tests of lethality by observing the mortality of bees after the application of pesticides either by oral administration or by topical application. The bee is usually considered dead when it exhibits "no movements after prodding". Investigation on lethality of any insecticide includes the use of correlation metrics to link the lethality and dose of a toxic chemical or substance to the bees [51, 52]. List of lethality of different class of insecticides was compiled from supporting information from Hardstone and Scott [53], and for the same information regarding fungicides and herbicides was compiled through ECOTOX database [54].

The different class of chemical insecticides poses variable threat to the individual honey bee and a colony level health, thus, the toxic effects and toxicity symptoms of different insecticides can be discussed under one umbrella of major classes of insecticide causing toxicity to the honey bees which is described here.

**21**

**Table 3.**

**Table 2.**

*Detailed Review on Pesticidal Toxicity to Honey Bees and Its Management*

The two widely used groups of insecticides, organophosphates and carbamates acts on insects in a similar way as acetyl cholinesterase (AChE) inhibitors which in normal conditions, inhibits the activity of neurotransmitter acetylcholine in the insect nervous system [53]. These two groups of insecticides have deeply investigated for their toxic effects on honeybees and have been reported to have high larval as well as chronic toxicity to the adult bees causing toxicity symptoms like memory loss and behavioral agitations [55–60]. These two classes of insecticides have a variable amount of topical toxicity to the bees with LD50 ranging between 0.018 and 31.2 μg/bee [61, 62], with some of the widely used insecticides enlisted

**Insecticide (organophosphate) LD50 (μg/bee) Risk ranking**

**Insecticide (carbamates) LD50 (μg/bee) Risk ranking**

Oxamyl 0.094 — High Methomyl 0.16 — High Carbaryl 1.1 — High Carbofuran 1.55 1.49–1.60 High Aldicarb 2.36 1.52–2.85 High Bendiocarb 2.64 1.00–4.28 High Aminocarb 4.40 0.85–11.2 High

**Mean Range**

Chlorpyrifos 0.01 — High Coumaphos 31.2 — Low Diazinon 0.2 — High Dicrotophos 1.62 0.410–3.05 High Dicholorvos 2.73 0.290–5.01 High Fenitrothion 1.66 0.180–3.83 High Malathion 0.2 — High Methidathion 0.236 — High Methyl parathion 1.66 0.610–3.24 High Paraoxon 0.600 — High Parathion 1.36 0.100–3.50 High Phorate 2.45 0.910–3.20 High Phosmet 1.06 — High Phosphamidon 4.89 0.020–14.5 High TEPP 0.410 0.010–1.20 High

**Mean Range**

*DOI: http://dx.doi.org/10.5772/intechopen.91196*

*5.3.1.1 Acetyl cholinesterase Inhibitors*

*Source: Data compiled in Hardstone and Scott [53].*

*Source: Data compiled in Hardstone and Scott [53].*

*List of carbamates insecticides with respective toxicity to the bees.*

*List of organophosphate insecticides with respective toxicity to the bees.*

in **Tables 2** and **3**.

*Detailed Review on Pesticidal Toxicity to Honey Bees and Its Management DOI: http://dx.doi.org/10.5772/intechopen.91196*
