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Soil moisture conservation practices (SMCPs) have been adopted in Uganda to adapt to the effects of climate variability. However, limited information exists on how conservation measures influence the physico-chemical properties of soil and coffee leaf nutrient concentrations. Thus, we determined the effects of selected SMCPs on the soil physio-chemical properties and leaf nutrient concentrations in Robusta coffee in a randomized incomplete block design, replicated three times, in Kituza, Uganda. Soil samples were collected from 0 to 20 cm and 20 to 40 cm depths, and analyzed in the laboratory following standard procedures for selected physio-chemical properties. Coffee leaf samples were picked from each treatment (open sun coffee (COSS), coffee cover crop, Desmodium intortum (CCS), coffee mulch, Miscanthidium violoceum (CMS), and coffee A. coriaria (ACS)). Bulk density was significantly (p < 0.001) the highest under ACS (1.61 gcm−3) and lowest under CCS (1.29 gcm−3), and it significantly (p < 0.001) increased with depth. The soil organic matter was higher than the optimum range of 1–3% at the 0–20 cm depth across different SMCPs, but within the optimum range at the 20–40 cm depth. Leaf nitrogen was significantly the highest under ACS (3.19%) and lowest under COSS (2.30%). Overall, the findings suggest that SMCPs improve the soil physio-chemical attributes and leaf nutrients for sustainable coffee productivity. However, ACS improved the leaf plant nutrition better compared to other SMCPs. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the relationship between characteristics of coffee shade systems and coffee pest infestation by the black coffee twig borer Xylosandrus compactus Eichhoff. The pest deprives Uganda of $40 millions annually, yet its control remains inadequate. The present study considered three rainfall zones in Central Uganda and 50 coffee plots that were randomly selected from each rainfall zone. Data were collected on X. compactus infestation and key shade indicators: canopy cover, tree‐species densities, diameter at breast height (DBH) and ratio of coffee to banana. Cluster analysis revealed two coffee shade systems: a matured shade tree (MST) system and a young poly‐culture (YPC) system. Xylosandrus compactus infestations were significantly less in the MST system than in the YPC system and significantly less in the low rainfall zone than in the high rainfall zone. An increase in the density of Carica papaya and Albizia chinensis significantly reduced and increased X. compactus infestation, respectively. A higher average DBH of individual trees and a higher density of trees that exude sap significantly lowered X. compactus infestation. Suppressing X. compactus infestation requires bigger trees, a high density of sap‐exuding trees and no Albizia chinensis. Further research should aim to investigate X. compactus flight activity and microclimate influencing X. compactus population dynamics. [ABSTRACT FROM AUTHOR]

Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animalmediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animalmediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the functionality of tropical forests can be maintained in moderately disturbed forest fragments. Conservation concepts for tropical forests should thus include not only remaining pristine forests but also functionally viable forest remnants. [ABSTRACT FROM AUTHOR]

Termites are important decomposers and 'ecosystem engineers' in tropical ecosystems. Furthermore, termite assemblages are sensitive to human land-use intensification and often termite density and the importance of soil-feeding termites decrease with land-use intensification. These changes in termite assemblages may also lead to a decrease in termite-mediated ecosystem processes (e.g. soil formation, cellulose decomposition). We compared density and functional composition of termites with cellulose removal from undisturbed primary forests to farmlands (Kakamega Forest, Western Kenya). In contrast to the expectation, we found no response of termite abundance along the gradient of land-use intensification. However, as expected, the relative abundance of soil-feeders decreased from primary forests to farmlands. In contrast, frequency of attack on tissue paper baits and removal of tissue showed a clear hump-shaped relationship to land-use intensification with high values in secondary forests. These nonconcordant patterns of density and functional composition of termite assemblages with cellulose removal by termites suggest that it may be misleading to infer changes in a process by the characteristics of the assemblage of organisms that mediate that process. [ABSTRACT FROM AUTHOR]

Candidate strains of Beauveria bassiana were identified for use in integrated pest management of the banana weevil Cosmopolites sordidus. Horizontal field transmission of B. bassiana between banana weevils using different delivery systems, including aggregation pheromones, was investigated. We observed that infected weevils could transmit the fungal pathogen to healthy individuals. Most dead weevils (52%) due to B. bassiana infection were found at the base of banana plants in the leaf sheath or in the soil near banana plants. Significantly more weevils died from the pathogen in plots where B. bassiana was applied in combination with the pheromone than where it was applied alone. Our data demonstrate that C. sordidus aggregation pheromone can be a valuable tool to enhance the dissemination of B. bassiana for the control of C. sordidus. [ABSTRACT FROM AUTHOR]

The coffee twig borer ( Xylosandrus compactus Eichhoff) is an economically important pest of Robusta coffee in Uganda. In this study, a formicid ant, Plagiolepis sp., found in X. compactus galleries at the National Coffee Research Institute in 2014, was evaluated for potential to provide biological control of the twig borer . In a Petri dish feeding bioassay, Plagiolepis sp. preyed on all stages of X. compactus except adults within 24 h. In field bioassays where Plagiolepis sp. was caged over X. compactus- infested twigs for one month in muslin sleeves, the predator colonized pest galleries and eliminated all life stages of X. compactus as opposed to the untreated control. In a survey of Plagiolepis sp. in 11 districts of eastern, central and western Uganda, the ant was present in nine of the districts with highest levels of colonization (over 18%) of X. compactus galleries in Luwero district in the central Lake Victoria crescent agroecological zone. These results appear to confirm that Plagiolepis sp. is an indigenous predator of X. compactus which invades pest galleries and feeds on the pest in the field. For prospective utilization of Plagiolepis sp. as a biological control agent of X. compactus , s tudies on the biology of Plagiolepis sp., its mass rearing protocols and factors favoring its proliferation in the field are highly recommended . [ABSTRACT FROM AUTHOR]