**Author details**

priority now as farmers are currently relying on pesticides to control the aphids. The high cost of chemical control and concern for extensive and frequent use of insecticides has led to search for Russian wheat aphid resistance. Using host plant resistance instead could be economical, effective throughout the growing season, environmentally safe and it will require no elabo‐ rate technology transfer to farmers. Natural enemies and host plant resistance are considered as more desirable alternatives to insecticides because of their low cost and environmentally friendly mitigation strategy [12, 51] for effective management of cereal aphids in wheat.

Research has focused on screening wheat genotypes for possible source or sources of resistance against Russian wheat aphid for use in our national wheat breeding program as an alternative to chemical control. A search for sources of resistance from among introductions collected from other countries (CIMMYT, Mexico, South Africa and Turkey) identified four sources of resis‐ tance, viz., RWA 9, RWA 8, RWA 16 and RWA 230 [34]. These sources have been incorporated into the breeding program using back‐crossing technique. In addition, doubled haploid tech‐ nique is being used to shorten the breeding cycle by about 5 years. Host plant resistance should be used as on more control strategy with IPM, as the strategy is nonpollutant to the environ‐ ment and does not demand specific knowledge by the wheat farmers. The use of host plant resistance that rarely requires treatment by application of aphicides has also been reported elsewhere as one of the most important methods for control of cereal aphids [10, 11, 19, 38, 61].

Action thresholds are lacking and there is urgent need to develop economic action levels (economic injury levels and economic threshold levels) for cereal aphid species infestation in wheat growing areas of Kenya during different seasons. They will be used as basis for making recommendation for cereal aphids control programs in wheat crops which will improve the

Breeding for resistance to cereal aphids is the most effective means of reducing yield losses associated with cereal aphids' infestation. Recently acquired wheat germplasm with resis‐ tance to cereal aphids especially Russian wheat aphid are now being screened and will be utilized in the breeding program. Resistance information of wheat genotypes to cereal aphids is important to be known by wheat breeders as a guide in selecting source of resistance genes to be used in the improvement of wheat varieties resistant to cereal aphids. However, since breeding is a slow procedure, it is necessary to consider other strategies to minimize yield losses. The use of one or more applications of aphicides, together with cultural practices such as early planting, application of right amounts of fertilizers and good seed rates could be very

Cereal aphids are major insect pests of wheat in Kenya. Their outbreaks have significant eco‐ nomic impact through increased production costs due to the need to control barley yellow dwarf virus and aphid infestations with insecticides. In order to reduce the crop losses and minimize

**8. Future research needs**

220 Wheat Improvement, Management and Utilization

**9. Conclusion**

development of integrated pest management strategies.

effective in providing considerable control of cereal aphids.

Munene Macharia\*, Zilpher A. Nyakwara, Michael N. Njuguna and Immaculate N. Maina

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

Kenya Agricultural and Livestock Research Organization, Food Crops Research Institute – Njoro, Njoro, Kenya
