Black coffee twig borer (BCTB), Xylosandrus compactus (Eichhoff) was recently reported as a pest ... more Black coffee twig borer (BCTB), Xylosandrus compactus (Eichhoff) was recently reported as a pest of cocoa in Uganda (Kagezi et al., 2014). Females bore into primary branches and introduce an ambrosia fungus, Fusarium solani (Mart.) for feeding their brood (Ngoan et al., 1976). Infested materials wilt and die, but the cause is not fully understood. It could be due to disruption of nutrient and water movement across BCTB-damaged galleries or disease effect by F. solani (Greco and Wright, 2015). We therefore tested the pathogenicity hypothesis by isolating the fungus from mycangia of the female beetles and scrapings from BCTB-infested galleries of coffee. Isolates were identified using spore description (microconidia) as Fusarium spp. and maintained separately on potato dextrose agar (PDA) at 25°C. Spores from 7-day-old cultures designated as isolates 36, 37 and 63 were diluted to a concentration of 1.36x106 spores per ml and injected into 10 healthy coffee and cocoa seedlings per isolate. Controls were injected with distilled water. Seedlings were grown in screenhouse and observed for wilting symptoms after 30 and 90 days. At 30 days, 20, 10 and 30% of cocoa seedlings inoculated with isolate 36, 37 and 63 respectively had wilted. No more wilting of other seedlings was observed. Re-isolated fungus from wilted seedlings confirmed that Fusarium spp. causes wilting of cocoa consequent to BCTB attack. To the best of our knowledge, this is the first report of BCTB-associated Fusariun spp. causing wilting in cocoa. However, confirmation of species involved needs to be done.
Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well e... more Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well exploited, can sustain coffee productivity amidst climate change effects. Drought and heat stress are major global threats to coffee productivity, quality, and tradable volumes. It is not well understood if there is a selectable variation for drought stress tolerance in Robusta coffee half-sibs as a result of watering deficit pre-exposure at the germination stage. Half-sib seeds from selected commercial clones (KR5, KR6, KR7) and a pipeline clone X1 were primed with deficit watering at two growth stages followed by recovery and later evaluated for tolerance to watering deficit stress in three different temperature environments by estimation of plant growth and wilt parameters. Overall, the KR7 family performed the best in terms of the number of individuals excelling for tolerance to deficit watering. In order of decreasing tolerance, the 10 most promising individuals for drought and heat ...
Outbreaks of cucumber mosaic virus (CMV) disease, caused by an aphid transmitted pathogen, great... more Outbreaks of cucumber mosaic virus (CMV) disease, caused by an aphid transmitted pathogen, greatly reduced yields of bell pepper in southern Illi n is in the mid-1990s. To provide the bas s for further studies of the roles of individual apbid species in virus transmission, we surveyed aphid flights in and around pepper fields in 1996 and 1997 by using suction traps, intercep tion nets, landing traps, sweep nets, and hand-picking. We collected 78 species of aphids, 15 of which have be n repor to transmit CMV to pep pers. The most abundant species taken from suction traps a d interception nets in combination were Lipaphis erysimi, Rhopalosiphum padi, Rhopalosi phum maidis, Schizaphis graminum, and Aphis craccivora. All of these species are known to transmit CMV to peppers, but tbe phenology of R. maidis in Illinois suggests it is not the vector that brings CMV to p pper fields to initiate disease outbreaks. Brachycaudus helichrysi was relatively abundant in 1996 in May and June w...
Coffee is the backbone of Uganda's economy, contributing about 18% of foreign exchange earnin... more Coffee is the backbone of Uganda's economy, contributing about 18% of foreign exchange earnings valued at US$ 446 annually. Additionally, nearly 15 million people, draw their livelihood from from coffee-related activities along the value chain. Currently, production of the crop is threatened by a relatively new pest, the black coffee twig borer, Xylosandrus compactus, (Eichhoff) (Coleoptera: Scolytidae). (Here-after referred to as BCTB). A country-wide survey conducted during 2012/13 showed that the pest is rapidly spreading from its secondary epicenter in Kayunga and Mukono districts (Central Uganda) to most of the Robusta coffee growing regions of the country. The survey results further revealed 8.6% death of primary branches that translates into 8.6% loss of coffee export volume and foreign exchange valued at US$40 million annually at the current market prices and production volumes. In related studies, higher BCTB incidences and damage was recorded on shaded than on un-shade...
INTRODUCTION Coffee and bananas constitute the food and income base for many smallholder farmers ... more INTRODUCTION Coffee and bananas constitute the food and income base for many smallholder farmers in Uganda. According to the Government of Uganda Vision 40, coffee is one of the major commodities to drive the 68% of the population to the middle class income by the year 2025. Coffee is the main cash crop harvested once or twice a year, while banana is a primary food and cash crop produced throughout the ABSTRACT Productivity of coffee and bananas in Uganda remains below attainable yields despite the importance of these crops to the smallholder farmers. This is due to agronomic and abiotic constraints among other factors. We therefore determined farmers’ knowledge of agronomic and abiotic factors limiting coffee and banana production in coffee-banana agro forestry systems of southwestern Uganda. Nine districts were randomly sampled and a questionnaire administered to 10 randomly selected households per district. Farmers had knowledge and mentioned five constraints with the majority (9...
Plant density in Robusta coffee is an unresolved issue in low volume producing countries especial... more Plant density in Robusta coffee is an unresolved issue in low volume producing countries especially when compared with leading producers. In this study, we aimed to compare the response of Robusta coffee to pest incidence, disease severity, growth and yield potential in two contrasting spacing regimes. Two spacing regimes of 3mx3m and 3mx1m were evaluated for selected parameters in a randomized complete block design with three replications. There was a highly significant difference in pest incidence between the spacing regimes (p<0.01) for all the pests except scales (p=0.126). The black coffee trig borer incidence was higher under close spacing of 3mx1m than for 3mx3m with a mean difference of 13.2%. There was no significant association between spacing regime and leaf rust disease incidence while the association was significant for red blister disease (χ2=33.56, df=1, p<0.001). Significant difference in growth response between spacing regimes (p<0.05) were also obtained fo...
Black coffee twig borer (BCTB), Xylosandrus compactus (Eichhoff) was recently reported as a pest ... more Black coffee twig borer (BCTB), Xylosandrus compactus (Eichhoff) was recently reported as a pest of cocoa in Uganda (Kagezi et al., 2014). Females bore into primary branches and introduce an ambrosia fungus, Fusarium solani (Mart.) for feeding their brood (Ngoan et al., 1976). Infested materials wilt and die, but the cause is not fully understood. It could be due to disruption of nutrient and water movement across BCTB-damaged galleries or disease effect by F. solani (Greco and Wright, 2015). We therefore tested the pathogenicity hypothesis by isolating the fungus from mycangia of the female beetles and scrapings from BCTB-infested galleries of coffee. Isolates were identified using spore description (microconidia) as Fusarium spp. and maintained separately on potato dextrose agar (PDA) at 25°C. Spores from 7-day-old cultures designated as isolates 36, 37 and 63 were diluted to a concentration of 1.36x106 spores per ml and injected into 10 healthy coffee and cocoa seedlings per isolate. Controls were injected with distilled water. Seedlings were grown in screenhouse and observed for wilting symptoms after 30 and 90 days. At 30 days, 20, 10 and 30% of cocoa seedlings inoculated with isolate 36, 37 and 63 respectively had wilted. No more wilting of other seedlings was observed. Re-isolated fungus from wilted seedlings confirmed that Fusarium spp. causes wilting of cocoa consequent to BCTB attack. To the best of our knowledge, this is the first report of BCTB-associated Fusariun spp. causing wilting in cocoa. However, confirmation of species involved needs to be done.
Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well e... more Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well exploited, can sustain coffee productivity amidst climate change effects. Drought and heat stress are major global threats to coffee productivity, quality, and tradable volumes. It is not well understood if there is a selectable variation for drought stress tolerance in Robusta coffee half-sibs as a result of watering deficit pre-exposure at the germination stage. Half-sib seeds from selected commercial clones (KR5, KR6, KR7) and a pipeline clone X1 were primed with deficit watering at two growth stages followed by recovery and later evaluated for tolerance to watering deficit stress in three different temperature environments by estimation of plant growth and wilt parameters. Overall, the KR7 family performed the best in terms of the number of individuals excelling for tolerance to deficit watering. In order of decreasing tolerance, the 10 most promising individuals for drought and heat ...
Outbreaks of cucumber mosaic virus (CMV) disease, caused by an aphid transmitted pathogen, great... more Outbreaks of cucumber mosaic virus (CMV) disease, caused by an aphid transmitted pathogen, greatly reduced yields of bell pepper in southern Illi n is in the mid-1990s. To provide the bas s for further studies of the roles of individual apbid species in virus transmission, we surveyed aphid flights in and around pepper fields in 1996 and 1997 by using suction traps, intercep tion nets, landing traps, sweep nets, and hand-picking. We collected 78 species of aphids, 15 of which have be n repor to transmit CMV to pep pers. The most abundant species taken from suction traps a d interception nets in combination were Lipaphis erysimi, Rhopalosiphum padi, Rhopalosi phum maidis, Schizaphis graminum, and Aphis craccivora. All of these species are known to transmit CMV to peppers, but tbe phenology of R. maidis in Illinois suggests it is not the vector that brings CMV to p pper fields to initiate disease outbreaks. Brachycaudus helichrysi was relatively abundant in 1996 in May and June w...
Coffee is the backbone of Uganda's economy, contributing about 18% of foreign exchange earnin... more Coffee is the backbone of Uganda's economy, contributing about 18% of foreign exchange earnings valued at US$ 446 annually. Additionally, nearly 15 million people, draw their livelihood from from coffee-related activities along the value chain. Currently, production of the crop is threatened by a relatively new pest, the black coffee twig borer, Xylosandrus compactus, (Eichhoff) (Coleoptera: Scolytidae). (Here-after referred to as BCTB). A country-wide survey conducted during 2012/13 showed that the pest is rapidly spreading from its secondary epicenter in Kayunga and Mukono districts (Central Uganda) to most of the Robusta coffee growing regions of the country. The survey results further revealed 8.6% death of primary branches that translates into 8.6% loss of coffee export volume and foreign exchange valued at US$40 million annually at the current market prices and production volumes. In related studies, higher BCTB incidences and damage was recorded on shaded than on un-shade...
INTRODUCTION Coffee and bananas constitute the food and income base for many smallholder farmers ... more INTRODUCTION Coffee and bananas constitute the food and income base for many smallholder farmers in Uganda. According to the Government of Uganda Vision 40, coffee is one of the major commodities to drive the 68% of the population to the middle class income by the year 2025. Coffee is the main cash crop harvested once or twice a year, while banana is a primary food and cash crop produced throughout the ABSTRACT Productivity of coffee and bananas in Uganda remains below attainable yields despite the importance of these crops to the smallholder farmers. This is due to agronomic and abiotic constraints among other factors. We therefore determined farmers’ knowledge of agronomic and abiotic factors limiting coffee and banana production in coffee-banana agro forestry systems of southwestern Uganda. Nine districts were randomly sampled and a questionnaire administered to 10 randomly selected households per district. Farmers had knowledge and mentioned five constraints with the majority (9...
Plant density in Robusta coffee is an unresolved issue in low volume producing countries especial... more Plant density in Robusta coffee is an unresolved issue in low volume producing countries especially when compared with leading producers. In this study, we aimed to compare the response of Robusta coffee to pest incidence, disease severity, growth and yield potential in two contrasting spacing regimes. Two spacing regimes of 3mx3m and 3mx1m were evaluated for selected parameters in a randomized complete block design with three replications. There was a highly significant difference in pest incidence between the spacing regimes (p<0.01) for all the pests except scales (p=0.126). The black coffee trig borer incidence was higher under close spacing of 3mx1m than for 3mx3m with a mean difference of 13.2%. There was no significant association between spacing regime and leaf rust disease incidence while the association was significant for red blister disease (χ2=33.56, df=1, p<0.001). Significant difference in growth response between spacing regimes (p<0.05) were also obtained fo...
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Papers by Godfrey Kagezi