Philip Nyeko

Farmers’ knowledge and perceptions of pests in agroforestry with particular reference to Alnus species in Kabale district, Uganda

Abstract Ugandan farmers were interviewed in order to investigate their knowledge, perceptions and ability to manage pests in agroforestry generally and on Alnus species particularly. Farmers’ ability to recognise pest problems on Alnus species was significantly influenced by their length of experience in cultivating the species, but not their age, sex or formal education. Most farmers (77%) were aware of pest problems on Alnus species. However, identification of pest problems was based largely on damage type rather than causal agents. Whereas farmers had good knowledge of vertebrate pests of Alnus, insects and diseases that infest the tree species were unknown to most farmers. Apis mellifera damage on Alnus was the most frequently described damage, but its cause was either unknown or misdiagnosed. Most farmers did not control insect and disease infestations on Alnus because they did not know the causal agents and/or appropriate control measures. Farmers were generally more knowledgeable on insect and disease infestations on crops than on multipurpose tree species (MPTS) and most of them (98%) perceived that crops suffer more damage from such pests than do MPTS. However, farmers’ ability to manage insect pests and diseases seemed weak on both crops and MPTS. Most farmers suggested the use of pesticides to combat pests, but they mentioned only one insecticide, permethrin and one fungicide, mancozeb. More alarming were the suggestions by a few farmers on the use of mancozeb against aphids, and permethrin to combat crop wilt and dieback. Farmers need to be educated about diagnosis, basic ecology and management strategies for both crop and tree pests to ensure sustainable pest control in agroforestry.

Variations in Leptocybe invasa (Hymenoptera: Eulophidae) population intensity and infestation on eucalyptus germplasms in Uganda and Kenya

Leptocybe invasa, an invasive gall-inducing wasp of Australian origin, recently emerged as a serious eucalyptus pest of global importance. We examined the spatial and temporal variations in L. invasa adult populations and evaluated eucalyptus gemplasms for infestations by the wasp in Uganda and Kenya. There were significant differences in L. invasa abundance, gall incidence, severity and damage index between sites. Adults occurred throughout the year, indicating overlapping generations since the adults are known to live <7 d. There was no obvious peak in L. invasa population abundance although a general decline was observed in dry months. Out of 35 eucalyptus germplasms evaluated for L. invasa infestations, only Eucalyptus henryi and the clonal hybrids GC 578 and GC581 were resistant to the pest. Most germplasms were ranked as tolerant or moderately susceptible to wasp attack. Highly susceptible germplasms included Eucalyptus camaldulensis, GC540 and GC784 in Tororo, Uganda, and MAU1, GC14, GC15 and GC10 in Busia, Kenya. Implications of the year-round occurence of L. invasa adult populations and gall infestations, and the potential for host resistance in managing the pest, are discussed.

Does Farm Worker Health Vary Between Localised And Globalised Food Supply Systems

Significant environmental benefits are claimed for local food systems, but these biophysical indicators are increasingly recognised as inadequate descriptors of supply chain ethics. Social factors such as health are also important indicators of good practice, and are recognised by the organic and local food movements as important to the development of rounded sustainable agricultural practices. This study compared the self-reported health status of farm workers in the United Kingdom, Spain, Kenya and Uganda who were supplying distant markets with fresh vegetables. Workers on Kenyan export horticulture farms reported significantly higher levels of physical health than did Kenyan non-export farm workers and workers in the other study countries. Mean health levels for farm workers in the United Kingdom were significantly lower than relevant population norms, indicating widespread levels of poor health amongst these workers. These results suggest that globalised supply chains can provide social benefits to workers, while local food systems do not always provide desirable social outcomes. The causal mechanisms of these observations probably relate more to the social conditions of workers than directly to income.

Traditional management and conservation of shea trees (Vitellaria paradoxa subspecies nilotica) in Uganda

Traditional practices are universally recognised as a basis for conservation of biodiversity. However, such practices are often not included in natural resource conservation policies. This study assessed local conservation practices of shea trees (Vitellaria paradoxa) within different farming systems in Uganda and developed conservation guidelines for the species. The assessment involved 300 respondents, 15 focus groups and 41 key informants. Content analysis was used to identify the most important management and conservation practices. Local uses were categorised on the basis of shea tree products while differences in conservation practices were analysed using the Friedman test. The results show that eight shea tree products are used for 36 different purposes. Respondents’ age significantly influenced their knowledge about the shea tree. Traditional conservation practices include on-farm retention during cultivation and the use of folklore (mainly taboos), customs and rituals. Traditional management practices include weeding, bush burning, pollarding and pruning. Based on the current management and traditional conservation practices, a framework for the conservation of shea trees is proposed for integration into conservation policy decisions.

The potential impact on farmer health of enhanced export horticultural trade between the U.K. and Uganda.

The export of vegetables from African countries to European markets presents consumers with an ethical dilemma: should they support local, but relatively well-off farmers, or poorer farmers from distant countries? This paper considers the issue of farm worker health in the U.K. and Uganda, and considers the dilemma facing U.K. consumers if Uganda achieves their aim of exporting more vegetables to the U.K. Self-reported health scores of 1,200 farm workers in the U.K. and Uganda were measured with the internationally recognised SF-36 questionnaire and compared to an international population norm. The age-corrected health status of U.K. farm workers was significantly lower than the population norm, whereas Ugandans scored significantly higher (indicating good health) for physical health and lower for mental health. If Ugandan produce enters U.K. markets, then consumers may wish to consider both the potential benefits that enhanced trade could offer Ugandan farmers compared with its impacts on U.K. workers.

Mixed artificial diets enhance the developmental and reproductive performance of the edible grasshopper, Ruspolia differens (Orthoptera: Tettigoniidae)

Diet mixing is a common feeding habit among polyphagous insect herbivores and is believed to be advantageous for performance-related factors like growth, survival and oviposition. However, relatively little is known about the influence of artificial diet or their mixtures on the performance of edible insects. We examined the effects of artificial diet mixtures on the developmental and reproductive performance (survival, developmental time, fresh adult weight and female fecundity) of an edible grasshopper, Ruspolia differens (Orthoptera: Tettigoniidae). We raised individuals from eggs and reared newly hatched nymphs to adult stage on six different dietary treatments consisting of a single diet, and mixtures of two, three, five, six and eight artificial diets. More diversified diets resulted in shorter development time and greater adult fresh weight and female fecundity compared to the single diet or less diversified diets. Even with slight diet diversification, survival to adult stage was greatly improved. Overall, these results highlight the potential of diet mixtures in achieving maximum adult weights and female fecundity and shortening development time, information which could be used when designing mass-rearing programs for this edible grasshopper.

The fatty acid contents of the edible grasshopper Ruspolia differens can be manipulated using artificial diets

Edible insects have been suggested as an alternative and sustainable source of fats, proteins and vitamins for humans. However, their nutritional content may largely depend on the diets offered for insects. Diet-based manipulation of fatty acids in edible insects shows promise to possibly increase their essential and long-chained polyunsaturated fatty acid content and thus further enhance human diets. We reared the edible grasshopper, Ruspolia differens, under various diets with manipulated content of fatty acids, proteins and carbohydrates. The manipulated diets dramatically altered the insects’ content and composition of fatty acids, especially the content of polyunsaturated fatty acids. Dietary fatty acids were stored largely unaltered in insects. Artificial diets with high content of linoleic, α-linolenic, eicosapentaenoic or docosahexaenoic acids, increased the content of these fatty acids in the insect tenfold. The manipulated diets also affected the omega-6/omega-3 (n-6/n-3) fatty acid ratio and de...

Tree community composition and vegetation structure predict butterfly community recovery in a restored Afrotropical rain forest

Abstract Anthropogenic disturbances have led to a dramatic loss of biodiversity in the tropics. Habitat restoration can mitigate biodiversity loss but studies describing insect community recovery during tropical forest restoration are limited in Africa. Our aim was to compare the predictive power of tree community composition versus vegetation structure for butterfly community composition during tropical rain forest restoration. A fruit-feeding butterfly dataset from two primary and six restored forest areas of Kibale National Park (Uganda) was used. At the same sites, the tree community composition and six variables describing the vegetation structure, namely; (1) total stem density per hectare; (2) tree canopy cover; (3) elephant grass cover; (4) “other grass” cover; (5) shrub cover; and (6) herb cover, were sampled. Co-correspondence analysis and canonical correspondence analysis were used to predict butterfly community composition from tree community composition or vegetation structure, respectively. Both tree community composition and vegetation structure predicted butterfly community equally well. We also found a corresponding successional gradient of butterfly and tree communities, associated with the age of the forest since restoration started. Most butterfly species had their peak abundance (optima) in the late successional or primary forests, while most tree species had their optima in primary forests. Elephant grass cover and tree canopy cover were the most important predictors of the butterfly community composition. Our results demonstrate how tropical forest restoration can ignite successional changes in tree communities and vegetation structure, which in turn restructure the animal communities, according to resource availability and species-specific habitat requirements.

Bottom‐up manipulations alter the community structures of galling insects and gall morphs on Neoboutonia macrocalyx trees in a moist tropical rainforest

The effects of bottom‐up forces on the community structure of tropical insect gallers and within species variation in gall morphotype assemblages are not well understood. We tested the roles of increased nutritional quality and density of host plants with respect to structuring the galling insect communities and gall morphotype assemblages on Neoboutonia macrocalyx trees in Uganda. Plant nutritional quality and resource concentration were manipulated with four levels of fertilization and the group size of trees, respectively. After applying these treatments in May 2011, gallers established naturally on experimental replicates. Five months later, we sampled gallers and recorded their numbers and the different morphotypes. We analyzed the effects of treatments on the structures of galler communities and gall morphotype assemblages. We recorded 5237 individuals, representing four galler species. One species, Cecidomyiid leaf galler, was represented by three morphologically distinct galls. Fertilization, host tree density and their interactions significantly changed the structures of galler species communities and gall morphotype assemblages. The results of the present study demonstrate the important role of bottom‐up factors in structuring galler communities and the gall morphotype assemblages. These changes are likely caused by differential responses of different galler species and gall morphs to plant quality or quantity changes.

Population dynamics of herbivorous insects and potential arthropod natural enemies on Alnus species in Kabale district, Uganda

Monitoring populations of pests and their natural enemies under different management situations and seasonal weather parameters provides extremely useful information for taking preventive measures against pest outbreaks. The abundance, spatial and temporal distributions of herbivorous insects and arthropod natural enemies on Alnus species were monitored at four sites in Kabale district, Uganda between June 1999 and August 2000. Chewing insects, dominated by Coleoptera (75%), constituted the majority of insect herbivores sampled. Dominant and potentially serious pests of Alnus included Apion globulipenne, an unidentified Chrysomelidae (Coleopt. 27), Phymateus viridipes, Coloborrtics corticina and a Cacopsylla species (Homoptera: Psyllidae). Spiders were the predominant natural enemies accounting for 64% of the total natural enemies encountered, followed by parasitic Hymenoptera (30%). There were marked spatial and temporal variations in arthropod abundance. Among sites, mean abundance of total insect herbivores and total natural enemies on A. acuminata over 15 months ranged from 3.8–8.5 and 3.3–4.7 individuals per 1-m branch length respectively. Over the same period, mean number of total insect herbivores and total natural enemies on A. nepalensis that was studied at only one site were 11.9 herbivores and 4.2 natural enemies per 1-m branch length. Populations of most insect orders increased in the wet season although the greatest herbivore abundance was evident in the dry season. Further studies are necessary on the impact and management strategies of the potentially important insect pests and natural enemies on Alnus.