**5. Acaricidal effect of bee propolis extracts**

sects. Synergists are chemicals which directly increase the toxicity of insecticides. Usual‐ ly, the synergist, piperonyl butoxide, is added and a lower concentration of pyrethrins is

required to achieve insect control.

302 Insecticides - Development of Safer and More Effective Technologies

**Figure 7.** Pesticides synthesized from nitrophenols (Ju et al, 2010)

**Figure 8.** Lead Compounds from *Stellera chamaejasme* L

O O

1,5-diphenyl-1-pentanone 1,5-diphenyl-2-penten-1-one

Mostly pyrethrins may be used as a contact insecticide for household insects such as flies, mosquitoes or applied as aerosols or space sprays. Some formulations can be applied to ag‐ ricultural crops and due to their safety, pyrethrum extracts are used extensively in areas Propolis (bee glue) is a strongly adhesive resinous bee-hive product collected by honeybees *(Apis mellifera* Linnaeus) from leaf buds and cracks in the bark of various plants and is used in the hives to exclude draughts, to protect against external invaders and to mummify their carcasses. It typically consists of waxes, resins, water, inorganics, phenolics and essential oils. Chemical analysis of bee propolis from Europe is reported to contain various phyto‐ chemicals: phenolic acids and esters, flavanones, flavones and flavonols, cinnamic acids, phenylated p-coumaic acids and furofuran lignans, among others (Bankova V, 2005; Banko‐ va et al, 2002).

A number of researchers have reported insecticidal effect of bee propolis. Solvent extracts of propolis samples from Brazil and Bulgaria exhibited leishmanicidal activity against different species of *Leishmania* (Gerzia et al, 2007). In Nigeria, Osipitan et al (2010) tested propolis ethanolic extracts against the larger grain borer, *Prostephanus truncates* (Horn) in maize grains. A reduction of the borer population in maize was observed. Interestingly, pesticides commonly used in agriculture were detected in honey and propolis samples (Lucia et al, 2011) in Uruguay.

of 75 and 100 mg/ml was not significantly different with that of the positive control used. Ethanolic and ethyl acetate extracts acted on tomato red spider mites in a concentration and

Use of Botanicals and Safer Insecticides Designed in Controlling Insects: The African Case

http://dx.doi.org/10.5772/53924

305

Bee propolis extracts could thus be used as a safe insecticide in the control of red spider mites. However, further research need to be done on its potential on other life stages of red spider mites and other common tomato pests. The insecticidal activity was thought to be due to bioactive phytochemicals of plant origin ingested by the bees during pollination.

While development of safer insecticides is a noble idea in Africa, safety concerns are par‐ amount. Widespread misuse of pesticides, some of which are banned, affects farmers' health with fatal consequences. Due to ignorance on their part, farmers may keep pesti‐ cides near food stores where seepage of food is inevitable; over-spray food crops, inhala‐ tion and skin contact while in use, have adverse effects to their health. And although an alternative to pesticides use could be achieved through organic farming and integrated pest management practices, the future lies in investing in technology which will afford

and Esther Wamaitha Maina1

time dependent manner, and had no significant differences in activity.

**6. Conclusion**

**Author details**

**References**

safe application of insecticides.

Patrick Kareru1\*, Zacchaeus Kipkorir Rotich2

\*Address all correspondence to: pgkareru@yahoo.com

J. of Chem. Technology, 16:388-395

1 Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya

[1] Abatania L N, KO Gyasi, AB Salifu, ON Coulibaly, A Razak (2012). Factors affecting the adoption of botanical extracts as pesticides in cowpea production in northern

[2] Anamika R, J Bajpai and A K Bajpai, (2008). Development of calcium alignate-gelatin based microspheres for controlled release of endosulfan as a model pesticide, Indian

2 Presbyterian Church of East Africa University, Kikuyu, Kenya

Ghana, Ghana journal of agricultural Science, 43(1): 9-15

Recently bee propolis extracts have been reported to have acaricidal effect on red spider mites (*Tetranychus spp*.), which attack tomatoes, (Kareru and Wamaitha, 2012, unpublish‐ ed work).

**Figure 9.** The four stages of a red spider mite life cycle (egg, larva, nymph and adult). Source: http://www.biobee.com

Tomato is a vegetable crop grown worldwide and its selection and preference as a crop is due to its nutritional value and economic importance. Crop production losses to pests are estimated to exceed 35% annually. Red spider mites (*Tetranychus* species) are polyphagous, parenchyma cell feeding pests and have a serious economic impact on many crops, especial‐ ly tomatoes. Synthetic pesticides used for control of red spider mites end up in the environ‐ ment where they may affect non-target species, have adverse effects on wildlife, pollute soil and water and in addition are usually very expensive and beyond the reach of resource of poor African farmers.

Compounds present in propolis can provide potential alternative in the place of currently used insect pest control agents because they constitute a rich source of bioactive chemicals and may act in many way on various types of pest complex. They also have no or little harmful effects on non target organisms such as pollinators, natural enemies and are biode‐ gradable.

Both ethanolic and ethyl acetate extracts of bee propolis acted on red spider mites in a con‐ centration and time dependent manner. The activity of ethanolic extracts at concentrations of 75 and 100 mg/ml was not significantly different with that of the positive control used. Ethanolic and ethyl acetate extracts acted on tomato red spider mites in a concentration and time dependent manner, and had no significant differences in activity.

Bee propolis extracts could thus be used as a safe insecticide in the control of red spider mites. However, further research need to be done on its potential on other life stages of red spider mites and other common tomato pests. The insecticidal activity was thought to be due to bioactive phytochemicals of plant origin ingested by the bees during pollination.
