Incidence and distribution of insect pests in rain-fed wheat in eastern Africa

Macharia, M.; Tebkew, D; Agum, W; Njuguna, Michael N.

doi:10.4314/acsj.v24i1.17s

Cited by 7 publications

(8 citation statements)

References 6 publications

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“…were the most dominant insect predators associated with wheat plants. Also, Macharia et al (2016) recorded the rose wheat aphid (Metopolophium dirhodum Walker), oat-bird-cherry aphid (R. padi Walker) and corn leaf aphid (S. graminum Rondani) as the major insect pests on wheat in East Africa.…”

Section: Insect Sweep Netmentioning

confidence: 99%

Population Fluctuations of the Dominant Pests and Their Associated Predators on Barley Plants

2017

Zagazig Journal of Agricultural Research

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The present work was conducted in order to study the population density of aphids, leafhoppers and mites infesting barley plants and their associated predators and its relation to the prevailing temperature and relative humidity at Salhia District, Sharkia Governorate, Egypt during the two successive seasons of 2013/2014 and 2014/2015. The obtained results showed that the main pests on barely plants were the aphid species, Rhopalosiphum padi (L.), Rhopalosiphum maidis (Fitch), Schizaphis graminum (Rondani) and Sitobion avenae (Fabr.). Leafhoppers included Empoasca decipiens (Paoli) and E. decedens (Paoli) in addition to the mite Petrobia tritici Kandeel, El-Naggar and Mohamed. The associated predators were Coccinella undecimpunctata (L.), Chrysoperla carnea (Stephens), Syrphus sp. and Orius sp. The aforementioned pests and predators were collected by two different methods from barley plants as follows: using plant sample and insect sweep net. The plant sample proved to be better to collect aphids, mite and associated predators of the present work, while sweep net proved to be better for the leafhoppers. The seasonal abundance of R. padi and R. maidis on barley plants showed one peak (354,178 and 210,189 insects/sample) occurred at the 2 nd week of February in 2013/ 2014 and 2014/2015 seasons, respectively. Also, S. graminum appeared one peak (134 and 114 insects/sample) at the 1 st week of February during the two seasons of study, respectively. On the other hand, one peak occurred at the 1 st week of March for both E. decipiens (38 and 27 insects/sample) and E. decedens (31 and 24 insects/sample) during the two seasons of study, respectively. The most abundant species of predators were C. undecimpunctata showing three peaks at the 4 th week of January, 1 st , 4 th weeks of February, the 2 nd week of March, the 1 st week of April and C. carnea appearing one peak in the 4 th week of February during the two seasons of study, respectively. Obvious relationships between the population density of pests, associated predators and prevailing weather factors including the effect of mean temperature and relative humidity as well as their total combined effect on the numbers of certain investigated pests was recorded.

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Section: Insect Sweep Netmentioning

confidence: 99%

Population Fluctuations of the Dominant Pests and Their Associated Predators on Barley Plants

2017

Zagazig Journal of Agricultural Research

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“…For example, high incidences of the Russian wheat aphid has been confirmed in Kenya, particularly in the Mt. Kenya region, compared to neighboring countries of Ethiopia and Uganda (Macharia et al, 2016). Diseases such as yellow rust and stem rust have remained problematic with minimal success in production of disease resistant varieties (Kamwaga et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Assessing Smallholder Farmer's Participation in the Wheat Value Chain in North-West Mt. Kenya

Mwangi¹,

Owuor²,

Kiteme³

et al. 2021

Front. Sustain. Food Syst.

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Wheat is the second most important carbohydrate staple in Kenya and is produced by both smallholder and large-scale farmers. Smallholders are the majority, but produce <20% of the total national production. Compared to large-scale farmers, they have been considered to be less efficient producers and thus fail to benefit fully from their participation in the wheat value chain. This study aims at establishing the value accruing to smallholder and large-scale farmers participating in wheat production in north-west Mt. Kenya. For comparative purposes and to explore the potential of smallholder farmers, a sample of 58 smallholder and seven large-scale farmers was selected for the study. We use budget analysis to determine the gross output, cost of production and gross margins attained by the smallholder and large-scale farmers. Further, an analysis of constraints to productivity is done to establish the factors hindering farmers from reaching high yield potential. Results of the study show that smallholder farmers obtain lower yields, have higher costs of production per bag of wheat and lower gross margins compared to large-scale farmers. High cost of inputs, low market prices, low bargaining power, high cost of machinery services, diseases and weeds were among factors excluding smallholder farmers from benefitting from their participation in the value chain. However, results also show that smallholder farmers can produce wheat profitably albeit with necessary support. Thus, interventions should consider these constraints and aim at improving smallholder farmers' horizontal and vertical integration in the value chain. We recommend continued investment in research and development on wheat, adoption of climate resilient agricultural practices, improvements in the fertilizer subsidy programme and creating or increasing participation in producer groups that will provide possibilities of increased bargaining power and reduction of costs through improved access to machinery services, markets and credit.

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“…The Russian wheat aphid was the most prevalent insect pest of rainfed wheat [31,32]. The maximum number of RWA per tiller was 58.0 while rose grain (M. dirhodum), oat-bird-cherry Wheat Improvement, Management and Utilizationaphid (R. padi) and corn leaf aphid (R. maidis) were prevalent at low density ranging from 0.1 to 9.0 per tiller.…”

Section: Survey Of Natural Enemies Of Cereal Aphidsmentioning

confidence: 99%

“…The six most important cereal aphid species reported as pests that atack wheat and barley include: Greenbug Schizaphis graminum R., English grain aphid Sitobion avenae F., Oat bird cherry aphid Rhopalosiphum padi L, Cereal leaf aphid R. maidis F., Rose grain aphid Metopolophium dirhodum W. and Russian wheat aphid D. noxia M. [31,32,42]. Of these species, the Russian wheat aphid which is a recent introduction in Kenya in 1995 is the most destructive followed by Greenbug S. graminum [25].…”

Section: Cereal Aphids Occurring On Rainfed Wheat In Kenyamentioning

confidence: 99%

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The Occurrence of Cereal Aphids in Rainfed Wheat in Kenya: The Problem and Possible Integrated Pest Management Strategies

Macharia¹,

Nyakwara²,

Njuguna³

et al. 2017

Wheat Improvement, Management and Utilization

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Cereal aphids cause direct damage to rainfed wheat through sucking of plants sap and cause losses of up to 90%, particularly in dry years in Kenya. The Russian wheat aphid (RWA) is the most destructive and may account for up to 50% yield loss or more depending on the severity and length of infestation. Current control strategies mainly rely on the use of insecticides to control cereal aphids' infestations. Chemicals improve yields in the short term, but adversely afect the environment, hence the need for development of efective IPM strategies. Early planted crops escape heavy aphid atacks and give good yields. A combination of seed rate of 100 kg and 100 kg N/ha provided the best cultural management of RWA. Ladybird beetles Adonia variegata, lacewings (Chrysoppa spp.) and parasitic wasp Aphidius sp. were the most important natural enemies. Control of cereal aphids can be achieved with systemic insecticides applied as seed dressings or foliar applied insecticides. Four lines of wheat were found to show RWA resistance and crosses with Kenyan wheat made and populations are being evaluated for resistance to cereal aphids.

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Incidence and distribution of insect pests in rain-fed wheat in eastern Africa

Cited by 7 publications

References 6 publications

Population Fluctuations of the Dominant Pests and Their Associated Predators on Barley Plants

Population Fluctuations of the Dominant Pests and Their Associated Predators on Barley Plants

Assessing Smallholder Farmer's Participation in the Wheat Value Chain in North-West Mt. Kenya

The Occurrence of Cereal Aphids in Rainfed Wheat in Kenya: The Problem and Possible Integrated Pest Management Strategies

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