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This survey aimed at generating information to guide improvement of oil palm fruit-set in Uganda by testing the hypothesis that diversity and abundance of oil palm insect flower-visitors were influenced by sampling site, distance from natural vegetation and flower sex. Sampling was done on male and female oil palm flowers from (i) five oil palm experimental fields in different districts and (ii) oil palm plantations on Bugala Island on Lake Victoria. The plantations on Bugala Island were subdivided into near (0–15 m) and far (100–200 m) from natural vegetation. We recorded 162,677 insects in 23 morpho-species, dominated by weevils in the genera Elaeidobius and Metamasius (Family: Curculionidae); beetles (Families: Nitidulidae, Staphylinidae and Scarabidae); Diptera (Families: Muscidae, Drosophilidae and Platystomatidae); and honeybees (Apis mellifera), respectively. All morpho-species occurred on both flower sexes, except four Elaeidobius spp which occurred on only male flowers. All morpho-species recorded on both flower sexes were more abundant on male than female flowers, except Apis mellifera and one Elaeidobius sp whose mean counts were comparable between flower sexes. The insects were more abundant and divers on oil palm trees near a natural vegetation than on those positioned farther away; and on the Island than the mainland sites. This suggests a need for location specific interventions and manipulation of natural vegetation in designing strategies for boosting oil palm pollination in Uganda. Further research is necessary to understand ecology and biology of the identified oil palm flower visitors to boost oil palm pollination in Uganda. [ABSTRACT FROM AUTHOR]

Recent evidence has shown that improved light traps comprising modified drums and light emitting diode bulbs are more efficient and safer in mass trapping of wild swarms of Ruspolia differens compared to mercury light traps with open-ended drums commonly used in Uganda. However, financial analysis of the improved traps had not yet been conducted prior to this study. Here, we carried out a cost–benefit analysis of the improved trap compared to the existing trapping technique. A pre-tested questionnaire was used to collect data on the demographic characteristics, revenue, capital expenditures and operating costs of the current trapping method from 30 commercial R. differens trappers in Masaka Uganda. The costs and revenue from the improved trap were collected basing on the market price and estimates for the 30 trappers. Net present value (NPV), benefit–cost ratio (BCR) and payback period were computed for the improved and current method and compared using an independent sample t-test. The results revealed that the improved trapping technique was more profitable than the current technique. Moreover, high costs of electricity and harmful non-target insects, especially the Nairobi fly (Paederus sp) which causes dermatitis were other difficulties associated with the current trapping technique. We, therefore, recommend adoption of the improved R. differens trapping technique as a more profitable alternative to the current technique. [ABSTRACT FROM AUTHOR]

Euwallacea spp. (Coleoptera: Scolytidae) are polyphagous globally distributed invasive ambrosia beetles. One of the species was recently detected attacking Ricinus communis growing in Coffea canephora gardens in Uganda. This study was undertaken to: (a) determine the distribution, incidence, and relative abundance of Euwallacea sp. on R. communis in Uganda; (b) determine the influence of the presence of C. canephora on the incidence and abundance of Euwallacea sp. on R. communis; and (c) identify ambrosia fungus of Euwallacea sp. on R. communis. Five C. canephora farms with R. communis and five others with R. communis but without C. canephora were sampled in each of the six districts surveyed. Incidence of Euwallacea sp. on R. communis was measured, by inspecting the host trees in each farm for the presence or absence of the pest. Abundance of Euwallacea sp. on R. communis was estimated, by counting holes of Euwallacea sp. at the lower 1.7 m of R. communis stems. A fungus was isolated from galleries of Euwallacea sp. on R. communis and identified. Results show that Euwallacea sp. was present on R. communis in all districts surveyed, with 30–70% of the farms infested in each district and 5–28 holes of Euwallacea sp. found on each sampled stem of R. communis. Coffea canephora appeared to facilitate the infestation of R. communis by Euwallacea sp., although it did not seem to influence the multiplication of the insect inside the host. Cunninghamella echinulata appeared to be the ambrosia fungus associated with Euwallacea sp. Therefore, Euwallacea sp. is a threat to many economically important plants in Uganda that are known to be hosts of this pest. [ABSTRACT FROM AUTHOR]