Agro-ecological Zones Of Uganda Research Articles

Physicochemical composition of Tamarindus indica L. (Tamarind) in the agro-ecological zones of Uganda.

The relationships between the physicochemical composition of Tamarindus indica pulp and seeds, and agro‐ecological zones and land use types were assessed in Uganda. The objective was to determine the relationship between the physicochemical composition, agro‐ecological zones, and land use types. The samples were processed by manually depulping the T. indica pods, sun‐drying the pulp and seeds, and grinding into powder. The powdered samples were analyzed for β‐carotenoids, vitamin C (ascorbic acid), calorific value, crude oil, acid, and peroxide values. Data were analyzed using ANOVA in the general linear model (GLM). Principal component analysis (PCA) was used to relate the physicochemical properties to the agro‐ecological zones and land use types. There were significant differences (p ≤ .05) in the physicochemical composition variables between agro‐ecological zones and land use types. Land use types showed strong correlations with physicochemical properties while agro‐ecological zones did not show correlations. The results show that in terms of general properties, T. indica pods provide a valuable, rich, and exceptional source of vitamin C, compared to many widely consumed indigenous and conventional fruits and vegetables. The pods from land use types characterized by natural habitats had relatively more nutrient levels than the land use types influenced by anthropogenic activities.

Planting Time and Pesticide Application on the Agronomic Performance of Chickpea in Semi-arid Zone, South Western Uganda

Chickpea (Cicer arietinum L.) is an under-utilised food legume in Uganda with great potential to contribute to household food, nutrition and income security. The objective of this study was to investigate the effects of planting time on the agronomic performance of Desi and Kabuli chickpea genotypes. The study was conducted on-station in Mbarara district during the 2011A, B and 2012A seasons. In the 2011A season, the unusual shorter rainfall and high temperatures favoured high pod borer (Helicoverpa armigera) infestation that resulted in low grain yields (347-521 kg ha-1). In the excessively rainy and cool long 2011B season, chickpea planted before and at the onset of rainfall had high Ascochyta blight plant infection. The highly wet and dry conditions significantly (P ≤ 0.05) reduced the grain yields (400 t ha-1) of chickpea, to below its potential of 1000-3000 kg ha-1. Crops that coincided with well distributed rains alternating with sufficient sunshine (planted in late March 2012A) had higher yields (> 1200 kg ha-1). Yield losses associated with pests and diseases were managed when sowing was done after the peak of the rain season (end of March and October). Therefore, chickpea requires moderately low well distributed rains, with adequate sunny days during the vegetative and reproduction stages for higher grain yields. Integration proper planting time, variety and judicial pesticide application constituted the appropriate strategy for pod borer and Ascochyta blight management for the enhanced chickpea agronomic performance in the South Western Agro Ecological Zone of Uganda.

Assessment of Honeybee Colony Performance in the Agro-Ecological Zones of Uganda

Honeybees (Apis mellifera) live in colonies composed of worker groups of diverse genotypes and behaviours which are artificially altered when a beekeeper moves combs between colonies

Analysis of the molecular diversity of R. solani isolates from five Ugandan agro-ecological zones using inter - simple sequence repeat markers

This study used seven inter-simple sequence repeat (ISSR) markers to characterize 55 R. solani isolates in order to establish their genetic diversity. The isolates were from five common bean growing agro-ecological zones of Uganda; the Southwest highlands (SW), Lake Victoria crescent and Mbale farmlands (LVC), Teso farming system (TFS), the Northern mixed farmlands (N) and the Western highlands and Semliki flats (W). DNA was extracted from 7-day old R. solani isolates growing on potato dextrose agar and amplified using PCR. Molecular analysis based on the ISSR fingerprints established moderate genetic diversity (mean = 0.389 ± 0.022). In addition, a high degree of intraspecific variation was observed by cluster analysis which generated a dendrogram with 5 highly reliable clusters (p ≥ 0.95) whose composition was independent of agro-ecological zones. Further evidence of intraspecific variation was provided by analysis of molecular variance which ascribed all the observed variation to genetic differences within the isolates. Isolates from SW, W, TFS and N had significant standardized index of association values indicative of clonal reproduction while isolates from LVC did not have significant values whence were sexual. The genetic diversity revealed by our study means that screening common bean germplasm for sources of resistance to R. solani should be done using diverse pathotypes and secondly, the breeders should pyramid many disease resistance genes in elite cultivars to provide durable resistance against R. solani.

English

The incidence and severity of sweetpotato virus disease (SPVD) was reported to be highly variable under different agroecological zones in Uganda, a situation that could be partly attributable to differences in temperature. This raised a need for understanding the effect of temperature on the biology of SPVD causative agents which ultimately influences disease development and symptom expression that undermines productivity among sweet potato cultivars. This study was carried out at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK). Initially clean sweet potato cultivars were inoculated with two viruses namely Sweet potato chlorotic stunt virus (SPCSV) and Sweet potato feathery mottle virus (SPFMV) that cause SPVD when co-infecting sweet potato and established at two temperature environments; field and glasshouse, followed by a weekly interval monitoring of the plants for symptom expression and growth response. Temperature differences significantly (p<0.001) influenced SPVD severity and the growth response of different sweet potato cultivars. Overall, the plants under field conditions where temperature was lower produced higher SPVD severity than under glasshouse where higher temperatures were recorded. SPVD severity for most of the cultivars was higher in the field than under glasshouse. Cultivar (cv.) Ejumula displayed the highest severity levels followed by cvs. Tanzania and Beauregard. Conversely, New Kawogo, Dimbuka and Naspot 1 showed none to mild severities particularly under the glasshouse conditions. Therefore temperature influenced the development of SPVD; low temperatures of 20 to 29°C produced more disease severities than high temperatures of 30 to 39oC. It is suggested that reasonably high temperatures under a controlled environment should be incorporated in any sweet potato seed production system for possible elimination of SPVD. Key words: Temperature, disease symptom expression, viruses, Ipomea batatas, growth response.

English

Despite the global interest to increase the world&#39;s carbon stocks, most carbon sequestration strategies have largely depended on woody ecosystems whose production is threatened by the continuous shortage of land, hence the need to explore viable alternatives. The potential of bananas to sequester carbon has been reported but there is limited knowledge on the performance of various cultivars as specific carbon stocks are often lost in global assessments. Therefore, this study aimed at exploring the potential of and variability in carbon stocks of selected East African Highland Banana (EAHB) cultivars. Plant and soil data were collected using destructive and non-destructive techniques in 30&times;30m2 sampling plots for 4 cultivars Kibuzi, Nakitembe, Enyeru and Nakinyika growing in two agro-ecological zones of Uganda being the L.Victoria Crescent and the South-western region. Total carbon and Soil Organic Carbon (SOC) stocks did not differ considerably across cultivars (P&gt;0.05). However, there was significant variation (P&lt;0.05) in plant carbon stock being lowest in two cultivars: Nakinyika at 0.37&plusmn;0.19 Mgha-1 and Nakitembe at 0.40&plusmn;0.19Mgha-1; and highest in Enyeru at 1.64&plusmn;0.18 Mgha-1. The SOC stock variation difference across depth was 2.9-8.5 Mgha-1 being higher in top soil than sub-soil. Despite the small plant carbon stock amounts, the system enables much more carbon to be stored in the soil considering the proportion of what is contained in the plant to that in the soil across all cultivars (0.4-2%). The study therefore recommends revision of existing carbon frameworks to incorporate the contribution of non-woody perennials like bananas in the carbon cycle so that the poor small scale farmers who cannot afford large acreages to establish tree plantations can also benefit from such initiatives.&nbsp; Key words: Agro-ecological zone, growth stage, carbon stock, cultivars, SOC

Combined Application of Biofertilizers and Inorganic Nutrients Improves Sweet Potato Yields.

Sweet potato [Ipomoea batatas (L) Lam] yields currently stand at 4.5 t ha−1 on smallholder farms in Uganda, despite the attainable yield (45–48 t ha−1) of NASPOT 11 cultivar comparable to the potential yield (45 t ha−1) in sub-Saharan Africa (SSA). On-farm field experiments were conducted for two seasons in the Mt Elgon High Farmlands and Lake Victoria Crescent agro-ecological zones in Uganda to determine the potential of biofertilizers, specifically arbuscular mycorrhizal fungi (AMF), to increase sweet potato yields (NASPOT 11 cultivar). Two kinds of biofertilizers were compared to different rates of phosphorus (P) fertilizer when applied with or without nitrogen (N) and potassium (K). The sweet potato response to treatments was variable across sites (soil types) and seasons, and significant tuber yield increase (p < 0.05) was promoted by biofertilizer and NPK treatments during the short-rain season in the Ferralsol. Tuber yields ranged from 12.8 to 20.1 t ha−1 in the Rhodic Nitisol (sandy-clay) compared to 7.6 to 14.9 t ha−1 in the Ferralsol (sandy-loam) during the same season. Root colonization was greater in the short-rain season compared to the long-rain season. Biofertilizers combined with N and K realized higher biomass and tuber yield than biofertilizers alone during the short-rain season indicating the need for starter nutrients for hyphal growth and root colonization of AMF. In this study, N0.25PK (34.6 t ha−1) and N0.5PK (32.9 t ha−1) resulted in the highest yield during the long and the short-rain season, respectively, but there was still a yield gap of 11.9 and 13.6 t ha−1 for the cultivar. Therefore, a combination of 90 kg N ha−1 and 100 kg K ha−1 with either 15 or 30 kg P ha−1 can increase sweet potato yield from 4.5 to >30 t ha−1. The results also show that to realize significance of AMF in nutrient depleted soils, starter nutrients should be included.

The buzz about bees and poverty alleviation: Identifying drivers and barriers of beekeeping in sub-Saharan Africa.

The potential of beekeeping to mitigate the exposure of rural sub-Sahara African farmers to economic stochasticity has been widely promoted by an array of development agencies. Robust outcome indicators of the success of beekeeping to improve household well-being are unfortunately lacking. This study aimed to identify the key drivers and barriers of beekeeping adoption at the household level, and quantified the associated income contribution in three agro-ecological zones in Uganda. Beekeepers were generally the most economically disadvantaged people in the study areas and tended to adopt beekeeping following contact with non-government organisations and access to training. Whilst incomes were not statistically lower than their non-beekeeping counterparts; their mean household well-being scores were significantly lower than non-beekeeping households. The inability of beekeeping to significantly improve well-being status can in part be attributed to a lack of both training in bee husbandry and protective equipment provision such as suits, gloves and smokers. These are critical tools for beekeepers as they provide the necessary confidence to manage honey bees. Rather than focussing solely on the socio-economic conditions of farmers to effectively adopt beekeeping, future research should also attempt to evaluate the effectiveness of development agencies’ provision to the beekeeping sector.

Morphological Characterization of Ugandan Isolates of Sphaceloma sp. Causing Cowpea Scab Disease

&lt;p&gt;Scab is an important fungal disease of cowpea, affecting both young and old tissues including stems, leaves and pods of susceptible cowpea genotypes, leading to significant yield losses of up to 100% under severe infections. Colony characteristics on agar media, symptomatology, phylogenetic affinity of hosts and host range have been used to justify taxonomic distinctions. The correct identification and description of a pathogen is paramount in understanding its control or developing genotypes resistant to it. This study involved the isolation and culture of the scab fungus (&lt;em&gt;Sphaceloma&lt;/em&gt; sp.) from infected plant parts (leaves and pods) collected from farmers’ fields across major cowpea growing districts and agro-ecological zones in Uganda. The fungus was characterized using growth habit on potato dextrose agar (PDA) media, conidia features, variability in radial growth rate (mm/day) among the isolates and pathogenicity and virulence of some isolates on 20 selected cowpea genotypes with different levels of resistance. A total of 495 &lt;em&gt;Sphaceloma&lt;/em&gt; sp. isolates comprising of 419 from infected leaves and 76 from infected pods were obtained following isolation and culture. There was a wide variation in the isolates based on the amount, nature, colour, depth and rate of mycelia growth, features of conidia and number of septations. Based on the mean incidence, severity, AUDPC and pathogenicity on the 20 genotypes, the isolates were put into three pathogenicity groups. Isolates were mostly slow growing (&amp;gt; 14 days to cover entire 90 mm petri dish). Genotypes NE 31 and NE 70 showed broad spectrum of resistance to the isolates and could therefore be recommended as parental lines in the cowpea breeding programme to develop cultivars with wide horizontal resistance to the scab disease.&lt;/p&gt;

The presence of varroa in Uganda and knowledge about it by the beekeeping industry

Varroa mites are important honey bee ecto-parasites that have caused disaster to the beekeeping industry in Europe and America. The extent of spread of these mites in Africa is not clearly known, but several sub-Saharan African countries including Uganda have been on the varroa-suspect list. We surveyed 16 districts falling in eight agroecological zones in Uganda with the aim of establishing the presence of varroa mites. Within each district, at least two subcounties were visited for honey bee sample collection and varroa detection between September 2011 and April 2013. Honey bee samples collected were screened for varroa mites by dusting with thymol. Farmers and beekeeping extension workers were interviewed on their knowledge of varroa. The results indicate that varroa mites were present in all the districts and agroecological regions sampled. Bee farmers and beekeeping extension workers were completely unaware of the presence of the varroa mites. The farmers reported no changes in honey production and honey bee foraging. We recommend empirical studies to establish the effects of varroa on local honey bee productivity and the validity of the purported resistance of the African honey bees to varroa.

Integrating cassava varieties and &lt;i&gt;Typhlodramulus aripo&lt;/i&gt; to sustain biological control of cassava green mite

The cassava green mite (CGM), Mononychellus tanajoa, is a pest that reduces root yield of cassava (Manihot esculenta Crantz) by 30-80% in the cassava belts of Africa. The objective of this study was to identify cassava varieties that enhance abundance and persistence of Typhlodramulus aripo on cassava and increase its efficiency in controlling CGM. Nine cassava (Manihot esculenta Crantz) varieties were evaluated in Kenya based on CGM abundance and HCN of leaves for their ability to sustain low CGM populations to enhance biocontrol of T. aripo. Cassava fields were surveyed in five agro-ecological zones in Uganda and samples of cassava apices were analysed for cassava varieties to sustain high population of T. aripo. In the screening study of CGM abundance and HCN content of leaves and the lowest cumulative CGM population densities (&lt;1200 mites/leaf) were recorded on MM97/3567, Tajirika and MM96/9308, with the lowest cyanide content of leaves, 8.5 ± 4.9, 12.5 ± 3.2 and 12.3 ± 2.5 mg kg-1, respectively. Cassava varieties with hairy and non-hairy tips sustained T. aripo with highest densities (0.96 actives per tip) on hairy TME14. High T. aripo population densities corresponded to high densities of hairs on cassava tips. There were significant inverse linear relationships between CGM densities and T. aripo on TME14 at moderate CGM population densities (CGM damage level 2).Key Words: Cyanide, Manihot esculenta, Mononychellus tanajoa

English

Productivity of common bean (Phaseolus vulgaris L.) in Uganda is less than 30% of the yield of improved varieties grown on research stations. This yield gap has been attributed mainly to low soil fertility and susceptibility of local varieties saved by farmers to pest and disease infestations. This study evaluated the impact of four improved varieties and soil fertility improvement on bean yields on small-landholder farms in three agro-ecological zones in Uganda. Yields of common bean on-farm without fertilization were on average 523 kg/ha. Enhancing soil fertility on-farm with cattle manure (10 t/ha), P (60 kg/ha), or manure (5 t/ha) + P (30 kg/ha) led to average yields of 631, 615, and 659 kg/ha, respectively. On average, improved varieties produced more yield than the local farmer-saved variety, with or without soil fertility improvement. Improved variety K131 yielded 807 kg/ha, on average, in response to manure application, which was 54% greater than the yield of the local variety. P intensification up to 180 kg/ha per season, however, did not increase bean yields significantly at any of three research stations. These results confirm the yield advantage of growing improved varieties on small-landholder farms. The combination of improved genetics and fertility intensification alone, however, did not eliminate the yield gap between on-farm and potential bean yields.&nbsp; &nbsp; Key words: Food security, improved varieties, farmer-saved seed, soil fertility, seed quality.

English

Groundnut rosette virus disease is the most destructive disease of groundnut in Sub-Saharan Africa, Uganda inclusive. Over the past years, a wide range of management options for this disease have been developed and recommended for farmers in Uganda.&nbsp; Relevant efforts have also been made by researchers in disseminating improved technologies to farmers in several parts of the country. However, questions on the extent to which farmers are currently utilizing these technologies and their effectiveness in controlling the disease in their fields remain unanswered. This study aimed at assessing the effect of farmers&rsquo; practices on the severity patterns of groundnut rosette virus disease in Uganda. A survey was conducted within five agro-ecological zones in Uganda to obtain information on the various practices farmers employ in the management of the crop and disease in their fields using a structured questionnaire. Disease severity was scored in each farmer&rsquo;s field.&nbsp; Farmers were found to be employing a range of practices in groundnut production, including: early sowing, intercropping, use of improved groundnut genotypes, crop rotation; and uprooting and burning diseased plants among others. However, only two management practices: early sowing and use of improved varieties were found to significantly (P&lt;0.05) reduce rosette severity in groundnut fields. Special consideration should therefore be given to these two GRVD management strategies while developing and promoting management packages for this disease. &nbsp; Key words: Groundnut, rosette, incidence, severity, farmers, management.

Evaluation of Cowpea Genotypes for Virus Resistance Under Natural Conditions in Uganda

Cowpea (Vigna unguiculata L. Walp) is an important grain legume in most parts of Sub Saharan Africa. However, viral diseases are a major limiting production factor causing significant yield losses. An experiment was conducted to evaluate the reaction of 105 different cowpea genotypes to viral infection in different agro-ecological zones of Uganda. The aim was to identify genotypes that could serve as sources of resistance to virus infection. Virus infection in these experiments occurred naturally through insect vectors. Results showed that there were significant differences in disease reaction among genotypes within and among agro-ecological zones in terms of Area Under Disease Progress Curve (AUDPC) and incidence. Interactions of genotype by season (GXS), genotype by location (GXL) and genotype by location by season (GXLXS) also significantly affected reaction to viral infection among genotypes. Introduced cowpea genotypes exhibited a more susceptible viral disease reaction compared to the landraces over the two seasons in the three locations. A number of landraces such as WC32, WC18, NE43, NE15, WC35B consistently showed resistance to virus infection in the three locations and therefore could be good sources of resistance. Low disease pressure (AUDPC) was also recorded on SECOW2W (released variety) as reported by previous studies. The landraces also gave consistently higher grain yield values compared to the introduced genotypes. Overall, data from this study showed that locally adapted cowpea genotypes offer resistance to virus infection and may be desirable germplasm for Ugandan cowpea breeding programs.

Cassava Pests and Diseases’ Prevalence and Performance as Revealed by Adaptive Trial Sites in North Western Agro-Ecological Zone of Uganda

Cassava adaptive trial was planted in ten sub counties across West Nile Agro-ecological Zone (WNAEZ) with six cassava varieties to test their performance and reactions to major pests and diseases present in the Zone. Th six cassava varieties comprised of improved (TME 14 and 204, NASE 13 and 14 and Akena – TMS I92/00067) and a local (Abiria) were selected based on their availability and preference in the region. The experiment was planted in RCBD design with three replicates. The experiment was planted in ten locations with the plot size was 6x6 metres. Results showed Cassava green mite (CGM), Cassava mosaic disease (CMD) and cassava bacterial blight (CBB) as major pest and diseases across all sites. Cassava Anthracnose (CA) and Cassava mealy bug (CM) were not present in the study sites. Cassava brown streak disease (CBSD) foliar symptoms was observed in three locations of Dranya s/c, Gimara s/c and Nyaravuru s/c on the three varieties of TME 204, TMS-I92/00067 and TME 14, whereas CBSD root necrosis was seen across all sites on TME 204, TMS-I92/00067, NASE 13, TME 14 and the Local except on NASE 14. In terms of yields, results showed that it was highest in TMS-I92/00067 (53.0 t/ha), TME 204 (46.0 t/ha), NASE 14 (39.4 t/ha), TME 14 (34.6 t/ha), NASE 13 (33.4 t/ha) and the local (22.7 t/ha) in that order. Farmers’ ranking of the studied cassava varieties in order of preference was in the order of NASE 14, TME 204, TMS-I92/00067, TME 14, NASE 13 and the Local. In conclusion, absence of both foliar and root symptoms on NASE 14 across all sites indicated that this variety is still tolerant to CBSD and can still be multiplied for production in West Nile Agro-ecological Zone.

Farmers’ Perception of and Coping Strategies to Climate Change: Evidence From Six Agro-Ecological Zones of Uganda

In Uganda, weather-related events such as prolonged dry seasons, floods, storms, mudslides, extreme rainfall, and delayed/early rains have become more frequent and/or intense. This has left most of the rural poor farmers’ food insecure and their livelihoods threatened. A total of 192 sweetpotato farmer households distributed in six agro-ecological zones were interviewed to assess how farmers perceive the effects of changes in climatic variables, and how they have adjusted their farming practices to cope with the changes in climate. Gender of the household head and size of land owned significantly affected adaptation. Ninety nine percent of all households interviewed had observed a change in the climate in the last 10 years. Drought and floods had the highest impact on crop production across agro-ecological zones. Coping strategies towards extreme events included storing food, income diversification and digging drainage channels. Other strategies were planting trees; high-yielding, early-maturing, drought-tolerant, disease and/or pest-resistant varieties; planting at onset of rains; increased pesticide/fungicide application among others. The smallholder farmer households studied have a high awareness of changes in rainfall and temperature and have taken measures to cope with effects of a changing climate.

Total Economic Value of Wetlands Products and Services in Uganda

Wetlands provide food and non-food products that contribute to income and food security in Uganda. This study determined the economic value of wetland resources and their contribution to food security in the three agroecological zones of Uganda. The values of wetland resources were estimated using primary and secondary data. Market price, Productivity, and Contingent valuation methods were used to estimate the value of wetland resources. The per capita value of fish was approximately US$ 0.49 person−1. Fish spawning was valued at approximately US$ 363,815 year−1, livestock pastures at US$ 4.24 million, domestic water use at US$ 34 million year−1, and the gross annual value added by wetlands to milk production at US$ 1.22 million. Flood control was valued at approximately US$ 1,702,934,880 hectare−1 year−1 and water regulation and recharge at US$ 7,056,360 hectare−1 year−1. Through provision of grass for mulching, wetlands were estimated to contribute to US$ 8.65 million annually. The annual contribution of non-use values was estimated in the range of US$ 7.1 million for water recharge and regulation and to US$ 1.7 billion for flood control. Thus, resource investment for wetlands conservation is economically justified to create incentives for continued benefits.

Recombination and selection pressure in the ipomovirus sweet potato mild mottle virus (Potyviridae) in wild species and cultivated sweetpotato in the centre of evolution in East Africa

Sweet potato mild mottle virus (SPMMV) is the type member of the genus Ipomovirus (family Potyviridae). SPMMV occurs in cultivated sweetpotatoes (Ipomoea batatas Lam.; Convolvulaceae) in East Africa, but its natural wild hosts are unknown. In this study, SPMMV was detected in 283 (9.8 %) of the 2864 wild plants (family Convolvulaceae) sampled from different agro-ecological zones of Uganda. The infected plants belonged to 21 species that were previously not known to be natural hosts of SPMMV. The size of the SPMMV coat protein (CP) was determined by Western blot analysis, N-terminal protein sequencing and peptide mass fingerprinting. Data implicated a proteolytic cleavage site, VYVEPH/A, at the NIb/CP junction, resulting in a CP of approximately 35 kDa. Nearly complete sequences of 13 SPMMV isolates were characterized. Phylogenetic analysis of non-recombinant CP-encoding sequences placed five isolates from wild species sampled in the central zone of Uganda into a separate cluster. Recombination events were detected in the 5'- and 3'-proximal parts of the genome, providing novel evidence of recombination in the genus Ipomovirus. Thirteen amino acids in the N terminus of the P1 protein were under positive selection, whereas purifying selection was implicated for the HC-Pro-, P3-, 6K1- and CP-encoding regions. These data, supported by previous studies on ipomoviruses, provide indications of an evolutionary process in which the P1 proteinase responds to the needs of adaptation.

Eucalyptus infestation by Leptocybe invasa in Uganda

AbstractVery little is known about Leptocybe invasa Fisher &amp; LaSalle, a new fast‐spreading alien pest infesting Eucalyptus in several countries. This study examined L. invasa infestation on Eucalyptus germplasms in different agroecological zones of Uganda. The incidence and severity of the pest infestation were higher in hotter and drier agroecological zones than in cooler and wetter zones. There were direct negative relationships between altitude and L. invasa infestation on Eucalyptus species. No infestation was observed on any Eucalyptus species in stands at altitudes ranging from 1938 to 2452 (the maximum encountered) m above sea level. Leptocybe invasa infestation occurred on all Eucalyptus species encountered (Eucalyptus grandis, Eucalyptus camaldulensis, Eucalyptus saligna, Eucalyptus robusta), except Eucalyptus maidenii that escaped attack because it was located outside the ecological range of the insect. The incidence and severity of L. invasa infestation was generally higher on clonal hybrids E. grandis × E. camaldulensis than on E. grandis × Eucalyptus urophylla. Research on host germplasms, L. invasa biology and ecology, impact of the pest infestation and possible control strategies are suggested to facilitate the development of sustainable management strategies.

Abundance and diversity of lepidopteran stemborers and their parasitoids on selected wild grasses in Uganda

Surveys were conducted in four agroecological zones in Uganda to catalogue wild host plants of lepidopteran stemborers. Among those sampled, Panicum maximum, Pennisetum purpureum, Pennisetum polystachion and Sorghum arundinaceum were selected for further studies on stemborer diversity and density. Overall, stemborer incidence was low (<10.8%) with the highest infestations on S. arundinaceum. Among the 11 borer species identified, there were seven noctuids, two crambids, one pyralid and one unidentified cossid. The economically important crambid Chilo partellus and the noctuid Busseola fusca were mostly found on S. arundinaceum and were rare on the other three grass species. Braconid larval parasitoids were commonly obtained from C. partellus on S. arundinaceum and parasitoids of Sesamia spp. were most often found on P. purpureum. We concluded that in Uganda, with the exception of S. arundinaceum, wild grasses play a minor role in the seasonal persistence of C. partellus and B. fusca.