Despite Ugandan coffee farmers’ preference for Maesopsis eminii as a shade tree, the species is an alternate host for the black coffee twig borer, Xylosandrus compactus (Eichhoff)—a major insect pest of coffee in the country. Wilting and drying of leaves and branches of young M. eminii trees (<5 m tall) observed in Kiboga District, Uganda. The branches were trimmed off the trees, separated into primary and secondary branches and then the percentage of those possessing characteristic X. compactus entry holes determined separately. Additionally, the number of entry holes on both primary and secondly branches was established to determine the extent of damage of X. compactus. X. compactus characteristic holes were observed on both primary and secondary branches of M. eminii - percentage of branches having entry holes and the number of entry holes higher on primary than secondary branches. Dissecting the branches at the entry holes revealed various life stages of X.compactus in the gallery, proving that the damage was due to the pest. Presence of this pest on trees that are inter-planted in the coffee agroforestry systems presents a dilemma in managing it. Therefore, research should be geared towards designing management strategies for the pest in the coffee agroforestry systems. In the meantime, farmers should always trim-off and burn all infested parts from coffee and other plants inter-planted in it.

Low yields of coffee in Uganda are due to a number of factors with insects, diseases and weeds being paramount. In response, farmers respond by applying all kinds of pesticides to control these stresses. A questionnaire to elucidate farmers' knowledge and perceptions of pesticide use was therefore administered to 325 randomly selected respondents in the Arabica coffee growing regions of Uganda. Our results showed that only 23% of the respondents had ever used or were using pesticides, although, >50% of these respondents had knowledge on pesticides use. However, the methods of pesticide disposal were poor with >40% of these respondents disposing the wash water and unused/waste pesticide on their farms whereas, used containers were being burned. Also, >60% of these respondents were re-entering their coffee fields in less than one week after spraying. These practices expose the farmers, their animals and the environment to pesticide poisoning. Nevertheless, >50% of these respondents were aware of the negative effects pesticides are likely to cause to humans, animals and environment. Therefore, in order to minimize pesticide exposure and toxicity, training and awareness campaigns on pesticides use, particularly pesticide disposal should be rolled out to all the coffee growing agro-ecologies of Uganda.

Coffee is generally stressed by several biotic constraints including insect pests, diseases, weeds, nematodes among others, due to its nature. In response, farmers use all sorts of pesticides so as to manage these problems. However, detailed studies to determine the types of pesticides used in the diverse Arabica coffee agro-ecologies of Uganda are yet to be conducted. This information is vital for guiding research, policy and other agendas on pesticide issues, since their misuse can cause serious negative effects on humans, livestock and environment. A questionnaire was therefore, administered to 325 households in the 3 major Arabica coffee growing regions of Uganda (Mt. Elgon, West Nile and southern), with the aim of determining which pesticides are commonly being used by farmers. The study specifically aimed at investigating which pesticides have been banned in Uganda but still being used by farmers in these Arabica coffee agro-ecologies. Results showed that pesticides use in the Arabica coffee growing regions of Uganda was limited, with only 23% of the farmers using them. The highest percentage of farmers (39%) using pesticides was recorded in the southern region, while the lowest percentage of farmers (11%) was observed in West Nile region. A total of 22 of pesticides namely, 13 insecticides (59%), 5 fungicides (23%) and 4 herbicides (18%) were being used by farmers. Most of the pesticides recorded (64%) belonged to class II chemicals which are defined as moderately hazardous. Farmers should, therefore, be encouraged to use these pesticides instead of the class I chemicals which are defined as highly hazardous. The commonest insecticide was cypermethrin, being used by 15.4% of the farmers, while mancozeb was the most common fungicide, used by 7.7%. On the other hand, glyphosate was the most commonly used herbicide, by 15.4% of the farmers. The study further revealed that three insecticides-carbofuran (Furadan 5), dichlorvos 100% (Lava 100% EC) and fenitrothion (Sumithion/Fenitrothion) and one herbicide, gramoxone (Paraquat), which were being used by farmers, have been banned from use in Uganda. However, none of the fungicides observed has been banned from use in Uganda. Thus, farmers in all coffee growing agro-ecologies should be educated on pesticide use particularly those that have been banned from use. This will reduce pesticide misuse, toxicity and exposure.

Coffea canephora has non-limiting but unexploited yield and quality potential when compared with C. arabica. Coffee tree density optimization can improve fortunes of smallholder farmers. An attractive example is that high productive countries where high plant densities do increase area yield but across boardrecommendations are illogical especially with variety and agroecological variations. We aimed to compare two spacing regimes for growth response and pest incidence using Kituza Robusta clone. Randomized complete block designs with three replications and eight plants per plot were established at four agroecologically diverseon-farm locations. Eleven plant growth variables were measured. In addition incidences of five key pests were assessed. Data was collected on a 3-month interval starting from 12 up to 21 months after planting. Highly significant differences between spacing regimes (p<0.01) were obtained for majority of variables. Mean growth response was generally higher under 3 m x 1 m (high density) than 3 m x 3 m (low density) particularly with stem girth, plant height, length of longest primary branch, and leaf blade length. Conversely, pest incidence of black coffee twig borer, leaf eating beetles, leaf miners, and tailed caterpillars, except skeletonizers was higher under high than low plant densities. The findings provide aguide on implications of high plant densities on growth robustness which is translatable into yield potential; amidst a pest prevalence dilemma in studied type of C. canephora.

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.