Browsing by Author "Michael H. Otim"

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Bean Leaf Beetle (Ootheca spp.) (Coleoptera: Chrysomelidae) Management via Planting Timing and Insecticides
(Insects, 2022-08-07) Charles Halerimana; Samuel Kyamanywa; Samuel Olaboro; Pamela Paparu; Stanley T. Nkalubo; John Colvin; Robert A. Cheke; Darren J. Kriticos; Michael H. Otim
Bean leaf beetles (Ootheca spp.) (Coleoptera: Chrysomelidae) are one of Africa’s most important pests of the common bean (Phaseolus vulgaris L.). Roots, leaves, floral parts, and young pods are all attacked, leading to a considerable loss in grain yield. In Uganda, there are no comprehensive prescribed management strategies for bean leaf beetles, but farmers typically try to control the pest by delaying bean crop sowing, and to a lesser extent, using insecticides. Although farmers have consistently implemented the two approaches, there is no information on the effects of the approaches in Uganda. To assess the impact of planting timing and insecticide spray regimes on bean leaf beetle populations, concomitant foliar damage, and grain yield, we set up trials in three agro-ecological zones with known presence of the beetles during the second rainy season of 2016 (2016) and the first rainy season of 2017 (2017). The first planting, coinciding with early planting, was conducted within one week after the onset of rains. The second planting, coinciding with mid planting, followed two weeks later, while the third planting, considered late planting in this study, was conducted one month after the second planting. A foliar application of cypermethrin commencing at 7 days after emergence (DAE), 14 DAE, 21 DAE, 28 DAE, and 35 DAE; a soil drench of imidacloprid at planting combined with a foliar spray starting at 7 DAE; and an untreated control were among the insecticide spray regimes evaluated. Higher bean leaf beetle abundance was recorded from mid-planting, while higher foliar damage was recorded from late planting in two of the three agro-ecological zones. However, higher marketable grain yield was recorded from early planting in all agro-ecological zones, suggesting that delayed planting may not be beneficial. Insecticide application reduced foliar damage and increased marketable grain yield, with a combination of soil drench and foliar spray resulting in much less foliar damage and, as a result, higher grain yield. However, this did not result in economic benefits. Furthermore, marketable grain yield was higher when insecticide spray regimes were combined with early planting in all agro-ecological zones during both seasons. Our findings suggest that the common bean should be planted early and that the control of the bean leaf beetle should target both the adults and the juvenile stages in the soil. Therefore, there is a need for farmers to be able to access less-expensive soil treatments.
Farmer perception of impacts of fall armyworm (Spodoptera frugiperda J.E. Smith) and transferability of its management practices in Uganda
(CABI Agriculture and Bioscience, 2023-04-18) Andrew Kalyebi; Michael H. Otim; Tom Walsh; Wee Tek Tay
Background The Fall armyworm (FAW) Spodoptera frugiperda (Lepidoptera: Noctuidae) is now established across the African continent and is a highly polyphagous and destructive pest of many crops. In Uganda, FAW has become the major maize pest, causing heavy damage especially on shoots and growing points. The objectives of this study were to: (i) document local farming practices that have been useful to manage FAW, (ii) establish farmers’ perspective on the time of FAW’s arrival to their localities, (iii) investigate the economic impact (yield) of FAW to maize farmers, (iv) establish the farmers’ perception on the current status of the FAW, and (v) document alternative practices used to manage the FAW and the perceived efficacies. Methods A questionnaire survey was undertaken in November 2020 in Kamuli and Namutumba districts of Uganda and 99 farmers were interviewed to understand their profiles and perceptions about the FAW. A descriptive analysis of this data was undertaken to establish the socio-economic profiles and perceptions of the farmers. Results Farmers’ education levels in the two districts ranged from basic (completed primary education) to advanced (completed University degree), with most farmers having 10–30 years experience in growing maize (F = 20.8; df = 3,7; P = 0.0067), and with mainly small- and mid-sized production scales (F = 436.2; df = 2,5; P = 0.0002). Famers in Kamuli (98%) and Namutumba (96%) reported 25–50% yield losses due to FAW infestation that negatively impacted their income. We found a significantly higher percentage of farmers (84% and 92% in Kamuli and Namutumba districts, respectively), could correctly identify the FAW by its appearance (P < 0.0001). While FAW was officially reported in Uganda in 2016, farmers confirmed noticing damage symptoms similar to those caused by FAW as early as 2013 and 2014 in Namutumba and Kamuli districts, respectively. 98% of the farmers in Kamuli and 96% of those in Namutumba strongly agreed that FAW infestation reduced their income, while 74% in Kamuli and 86% in Namutumba also strongly considered the FAW as a threat to maize production (P < 0.0001). The majority of farmers (64% in Kamuli, 82% in Namutumba) still considered the FAW to be a very serious challenge to maize production in their localities, six years since officially being reported in Uganda. To manage the FAW, 84% and 90% of Kamuli and Namutumba respondents respectively, predominantly use chemical control methods. Other methods used also included cultural control practices (i.e., by regular weeding and handpicking), while the use of biological extracts (pepper, tobacco, Aloe-vera, Lantana, sisal) was evident though not common. Pheromones and biological control methods to manage FAW were not reported, although a farmer in Kamuli district reportedly observed weaver birds (Ploceus spp.) predating on the FAW in maize. A small number of farmers (ca. 4%) in both districts reportedly took no intentional action against FAW. Conclusions The farmers believe they can manage FAW if they have the appropriate and efficacious chemical insecticides as they are able to correctly apply them and follow recommended procedures. The farmers advocated for an area-wide approach as one of the best alternatives to manage this invasive pest.
Farmers’ Knowledge, Control Methods, and Challenges of Managing Bean Leaf Beetles (Ootheca spp.) in Uganda
(Sustainability, 2023-03-15) Julius Mugonza; James P. Egonyu; Michael H. Otim
Bean leaf beetles (BLBs) (Ootheca spp.) are important field insect pests of the common bean (Phaseolus vulgaris L.) in agricultural communities in Sub-Saharan Africa. A survey of 128 farmers was conducted in Arua, Hoima, Lira, and Lwengo districts in Uganda, where the common bean is a major food and income crop. This paper evaluated farmers’ knowledge, control strategies, and challenges in managing BLBs. Over 87% of the farmers in Arua and Lira could identify BLBs by local names, compared to less than 45% in Hoima and Lwengo. Less than 8% of the farmers in all districts were aware that BLBs oviposit, diapause, and then emerge from the soil. Many farmers (75%) in Lwengo perceived BLBs infestation as mild, 65.6% in Hoima thought it was moderate, and 78% and 56% in Arua and Lira respectively thought it was severe. The use of chemicals was popular in all districts and also perceived to be the most effective method for controlling BLBs. The reported obstacles to controlling BLBs were a lack of understanding of proper control methods, and the existence of fake insecticides on the market. We recommend that the Ministry of Agriculture, Animal Industry and Fisheries customizes the agricultural extension information packages to include BLBs and cost-effective control strategies for them.
Performance of Bt maize event MON810 in controlling maize stem borers Chilo partellus and Busseola fusca in Uganda
(Crop Protection, 2022-06-05) Michael H. Otim; Simon Alibu; Godfrey Asea; Grace Abalo; Julius Pyton Sserumaga; Stella Adumo; Jane Alupo; Stephen Ochen; Tadele Tefera; Anani Y. Bruce; Yoseph Beyene; Barbara Meisel; Regina Tende; Francis Nang’ayo; Yona Baguma; Stephen Mugo; Sylvester O. Oikeh
Stem borers are major insect pests of maize in Uganda. A study was conducted in 2014–2016 to assess the performance of Bt hybrids expressing Cry1Ab (event MON810) against the two major stem borer species in Uganda – the African stem borer (Busseola fusca) and the spotted stem borer (Chilo partellus) – under artificial infestation. The study comprised 14 non-commercialized hybrids, including seven pairs of Bt and non-Bt hybrids (isolines), three non-Bt commercial hybrids and a conventional stem borer resistant check. All stem borer damage parameters (leaf damage, number of internodes tunneled and tunnel length) were generally significantly lower in Bt hybrids than in their isolines, the conventionally resistant hybrid, and local commercial hybrids. Mean yields were significantly higher by 29.4–80.5% in the Bt hybrids than in the other three categories of non-Bt hybrids. This study demonstrated that Bt maize expressing Cry1Ab protects against leaf damage and can limit entry of stem borers into the stems of maize plants, resulting in higher yield than in the non-transgenic hybrids. Thus, Bt maize has potential to contribute to the overall management package of stem borers in Uganda.