The predominantly Afrotropical fruit fly genus Ceratitis contains many species of agricultural importance. Consequently, quarantine of Ceratitis species is a major concern for governmental regulatory agencies. Although diagnostic keys... more
The predominantly Afrotropical fruit fly genus Ceratitis contains many species of agricultural importance. Consequently, quarantine of Ceratitis species is a major concern for governmental regulatory agencies. Although diagnostic keys exist for identification of all described Ceratitis species, these tools are based on adult characters. Flies intercepted at ports of entry are usually immatures, and Ceratitis species cannot be diagnosed based on larval morphology. To facilitate identification of Ceratitis pests at ports of entry, this study explores the utility of DNA-based diagnostic tools for a select group of Ceratitis species and related tephritids, some of which infest agriculturally important crops in Africa. The application of the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to analyse three mitochondrial genes (12S ribosomal RNA, 16S ribosomal RNA, and NADH-dehydrogenase subunit 6) is sufficient to diagnose 25 species and two species cl...
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4 Abstract- True fruit flies are one of the world's worst pests of fruit and fruiting vegetables, causing millions of dollars worth of damage each year. While Africa has a number of native fruit flies of its own, some exotic species... more
4 Abstract- True fruit flies are one of the world's worst pests of fruit and fruiting vegetables, causing millions of dollars worth of damage each year. While Africa has a number of native fruit flies of its own, some exotic species present in some continents has in recent years raised some serious biosecurity concerns among local experts. Bactrocera invadens is one of the exotic fruit flies that recently invaded Africa. Evidence of competitive displacement of indigent fruit flies in some mango agro ecosystem by this species has been recently documented. Effective control of this fruit flies can best be achieved through an IPM based control programme which will involve the use of bait in traps or spot treatments. However, no fruit flies bait is currently registered and is available on Ghanaian market for use in the management of this species by the farmers. The use of some readily available insecticidal products namely Cydim Super, Pyrinex 50 EC, Diazol 50 EW and Deltapaz as kil...
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Objective: A trapping exercise to assess the range of fruit fly species from mango orchards in three agroecological zones in Ghana (Coastal Savanna (CS), the Transitional (TT) and Guinea Savanna (GS) zones) where mango is commercially... more
Objective: A trapping exercise to assess the range of fruit fly species from mango orchards in three agroecological zones in Ghana (Coastal Savanna (CS), the Transitional (TT) and Guinea Savanna (GS) zones) where mango is commercially grown was undertaken for two successive fruiting seasons in 2009 and 2010. Methodology and results: Using traps baited with three different attractants (Methyl eugenol (ME), Terpinyl acetate (TA) and Trimedlure (TML), a total of 39,011 fruit flies were collected, with 9,398 (24.1%) and 29,613 (75.9%) flies collected during the 2009 and 2010 seasons, respectively. Five fly species (in two genera), Bactrocera invadens, B. cucurbitae, Ceratitis cosyra, C. ditissima and C. capitata were identified. The highest relative fly densities (number of flies per trap per day, F/T/D) ranged from 1.86-31.40 and 16.25-121.39 in the 2009 and 2010 seasons, respectively. Conclusion and application: The most abundant flies in all six localities of the three zones were B. ...
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The high yield loss reported from the infestations of fruits by Bactrocera invadens Drew, Tsuruta and White in West Africa can impact negatively on the growth of horticulture in the region. Similarly, the shortage of insecticides... more
The high yield loss reported from the infestations of fruits by Bactrocera invadens Drew, Tsuruta and White in West Africa can impact negatively on the growth of horticulture in the region. Similarly, the shortage of insecticides specifically registered for the control of this pest in Ghana makes decision by farmers on which insecticide to use against this pest uncertain and risky. The result for the acute lethal toxicity shows that the lethal concentration (LC) values of the tested insecticides are 0.59 (diazinon (Diazol)), 0.81 (chlorpyrifos (Pyrinex)), 1.21 (cypermethrin+dimethoate (Cydim super)), and 3.12 (deltamethrin (Deltapaz)) ml L−1 of water. The result for the residual toxicities of three concentrations for each of the tested insecticides shows that the lethal times LT (LT50 and 90) for the adult B. invadens differed significantly for all the ages of the residues. Some insecticides exhibited low lethal time even on panels that are up to 6 days old after treatment. We concl...
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1 SUMMARY Three varieties of mango, Jaffna , Palmer and Kent were infested with different first instar larval densities (10, 20 and 30) of the invasive fruit fly species, Bactrocera invadens Drew, Tsuruta & White. This was to determine... more
1 SUMMARY Three varieties of mango, Jaffna , Palmer and Kent were infested with different first instar larval densities (10, 20 and 30) of the invasive fruit fly species, Bactrocera invadens Drew, Tsuruta & White. This was to determine the effect of each of the densities on three fruit quality parameters. The parameters included Total Soluble Solids (TSS), Percentage Titratable Acidity (% T.A.) and pH, of which TSS and pH showed decreasing trends while % T.A. showed an increasing trend with time. In the controlled treatments where fruits were either held intact or punctured but with no introduction of larvae, there was an increase in pH and TSS and a decrease in %T.A.. The shelf-life, which was taken as the period from the first day of treatment till signs of damage were observed, saw the three varieties infested with 10 larvae lasting up to 6 days, while fruits infested with 20 and 30 larvae lasted for 3 days. The shelf life of the controlled treatments for all the varieties lasted...
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The Sweet potato weevil, Cylas species, is a key pest of sweet potato, and widely distributed on the Africancontinent. The management of the pest is limited because its taxonomic status is not clear. Populations of thesame species... more
The Sweet potato weevil, Cylas species, is a key pest of sweet potato, and widely distributed on the Africancontinent. The management of the pest is limited because its taxonomic status is not clear. Populations of thesame species occupying distinct localities experience different ecological and climatic pressures that mightresult in differentiation in traits. This study sought to identify and compare body sizes of Cylas species fromfour regions in southern Ghana – Central, Eastern, Greater Accra and Volta. Of the 6,686 samples collected fromthe four regions, two species were identified: Cylas brunneus Fabricius, and Cylas puncticollis Boheman. Twelvemorphometric characters were examined and measured, of which four traits - elytra and rostrum lengths,pronotum and head widths contributed most to the variations observed. In C. puncticollis, individuals with thelongest body were recorded in Greater Accra Region (7.084 ± 0.089 mm), while those in the Central Region hadthe smallest body ...
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The African invader fly Bactrocera invadens Drew, Tsuruta and White, generally considered as the most devastating pest of mango was detected in Africa (in Kenya, East Africa) in 2003. It was first detected in Ghana, West Africa in 2005.... more
The African invader fly Bactrocera invadens Drew, Tsuruta and White, generally considered as the most devastating pest of mango was detected in Africa (in Kenya, East Africa) in 2003. It was first detected in Ghana, West Africa in 2005. The perception of mango farmers from Dangbe West and Yilo Krobo districts in Ghana on the pest status and the current management options adopted for the control of this pest was sought by use of a Questionnaire. The survey results indicated that Ghanaian farmers rank B. invadens among the major pests of mango in Ghana. Farmers generally, believed that it is more damaging than other arthropod pest of mango. Possible losses such as loss of market value, rejection of produce at the international markets and quarantine restriction due to the presence of the pest were also reported by the farmers Several strategies are being adopted by farmers for the control of fruit flies (including B.invadens) in Ghana. These strategies include the use of insecticides,...
The Ghana vegetable exports experienced several interceptions from 2012 to 2015, largely due to the presence of harmful organisms, specifically quarantine pests (thrips, whiteflies, fruit flies and false codling moth) in the consignments... more
The Ghana vegetable exports experienced several interceptions from 2012 to 2015, largely due to the presence of harmful organisms, specifically quarantine pests (thrips, whiteflies, fruit flies and false codling moth) in the consignments destined for export to the European Union. Therefore, Ghana was placed under a ban for some vegetables, such as chili pepper, eggplant, aubergine, and gourds. This situation lasted from 2015 until December 2016, and was further extended to December 2017. Consequently, the Ministry of Food and Agriculture (MoFA) set up an Exports Taskforce to help reverse the ban. In spite of the progress made, well-coordinated scientific research was weak in these efforts. Here we discuss the outcome of the scientific interventions undertaken between 2016 and 2017, to ensure that these pests of quarantine importance were effectively managed at the farm level. These interventions also endeavoured us to equip the Plant Quarantine Inspectors (PQI) of the National Plant...
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An important aspect of fruit fly management is accurate information on the species and their host spectrum. Studies were conducted between October 2011 and September 2013 to determine the host range and species diversity of pest fruit... more
An important aspect of fruit fly management is accurate information on the species and their host spectrum. Studies were conducted between October 2011 and September 2013 to determine the host range and species diversity of pest fruit flies in the northern savannah ecology of Ghana. Fruit samples from 80 potential host plants (wild and cultivated) were collected and incubated for fly emergence; 65 (81.5%) of the plant species were positive to fruit flies. From records in Africa, 11 plant species were reported to be new hosts to the African invader fly,Bactrocera invadens(Drew, Tsuruta and White, 2005). This study documented the first records ofDacus ciliatus(Loew) andTrirhithrum nigerrimum(Bezzi) in northern Ghana although both species have been previously reported in other parts of the country. Infestation byB. invadenswas higher in the cultivated fruits;Ceratitis cosyradominated in most wild fruits. Cucurbitaceae were mainly infested by three species ofDacusandBactroceracucurbitae...
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This chapter discusses the biological control of fruit flies infesting Mango in Africa. The use of entomopathogens, parasitoids and chemical signals that modify pest behaviour is discussed.
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The false codling moth (FCM), Thaumatotibia leucotreta (Lepidoptera: Tortricidae) is an insect pest which represents an important threat to the production and marketing of a wide range of agricultural crops in the... more
The false codling moth (FCM), Thaumatotibia leucotreta (Lepidoptera: Tortricidae) is an insect pest which represents an important threat to the production and marketing of a wide range of agricultural crops in the African-Caribbean-Pacific (ACP) countries. The FCM reduces not only the yield and quality of the crop but also as a quarantine insect pest, restricts the trade of susceptible agricultural produce on the international market. In addition, little research has been conducted in the ACP countries on the bio-ecology and sustainable management of this pest, especially on vegetables for export. Thus, action-oriented research aimed at understanding the bio-ecology of this important pest is essential to achieve effective management. Various management interventions against this pest have been used in some parts of the world, especially in South Africa on citrus. Currently, farm sanitation is regarded as the key management strategy. Exploring and improving on other interventions suc...
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A species in the Bactrocera dorsalis (Hendel) complex was detected in Kenya during 2003 and classified as Bactrocera invadens Drew, Tsuruta & White. Having spread rapidly throughout Africa, it threatens agriculture due to crop damage and... more
A species in the Bactrocera dorsalis (Hendel) complex was detected in Kenya during 2003 and classified as Bactrocera invadens Drew, Tsuruta & White. Having spread rapidly throughout Africa, it threatens agriculture due to crop damage and loss of market access. In a recent revision of the B. dorsalis complex, B. invadens was incorporated into the species B. dorsalis. The potential distribution of B. dorsalis has been previously modelled. However, previous models were based on presence data and did not incorporate information on the seasonal phenology of B. dorsalis, nor on the possible influence that irrigation may have on its distribution. Methyl eugenol-baited traps were used to collect B. dorsalis in Africa. Seasonal phenology data, measured as fly abundance throughout the year, was related to each location's climate to infer climatic growth response parameters. These functions were used along with African distribution records and development studies to fit the niche model for...
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ABSTRACT Objective: The susceptibility of four economically important mango varieties (Kent, Keith, Palmer and Haden) in Ghana to the attack by Bactrocera invadens was assessed through a series of laboratory-based choice and no-choice... more
ABSTRACT Objective: The susceptibility of four economically important mango varieties (Kent, Keith, Palmer and Haden) in Ghana to the attack by Bactrocera invadens was assessed through a series of laboratory-based choice and no-choice experiments, as well as some fruit quality parameters. The developmental periods of immature stages of flies in the varieties were also determined. Methodology and results: Susceptibility was determined by counting and comparing the number of puparia recovered from the different varieties after exposure to the flies in cages. Kent was found to be the most susceptible, followed by Palmer, Haden and Keith. Flies took significantly longer periods to complete development on the least susceptible variety (Keith) (25.53 ± 2.3 days), than on the most susceptible variety (Kent) (19 ± 2.3 days). Significant differences (P ˂ 0.05) were also observed in the peel thickness, firmness, Percent Titratable Acidity (% T.A.) and Total Soluble Solids (TSS) of the four va...
The African invader fly Bactrocera invadens Drew, Tsuruta and White, generally considered as the most devastating pest of mango was detected in Africa (in Kenya, East Africa) in 2003. It was first detected in Ghana, West Africa in 2005.... more
The African invader fly Bactrocera invadens Drew, Tsuruta and White, generally considered as the most devastating pest of mango was detected in Africa (in Kenya, East Africa) in 2003. It was first detected in Ghana, West Africa in 2005. The perception of mango farmers from Dangbe West and Yilo Krobo districts in Ghana on the pest status and the current management options adopted for the control of this pest was sought by use of a Questionnaire. The survey results indicated that Ghanaian farmers rank B. invadens among the major pests of mango in Ghana. Farmers generally, believed that it is more damaging than other arthropod pest of mango. Possible losses such as loss of market value, rejection of produce at the international markets and quarantine restriction due to the presence of the pest were also reported by the farmers Several strategies are being adopted by farmers for the control of fruit flies (including B.invadens) in Ghana. These strategies include the use of insecticides,...
Research Interests: Landscape Ecology, Biomass, DISTRIBUTION, Waterbirds, Insecta, and 3 moreForage, Forages, and Distribution
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ABSTRACT Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) invaded Kenya in 2003. Before the arrival of B. invadens, the indigenous fruit fly species Ceratitis cosyra (Walker) was the predominant fruit fly pest of... more
ABSTRACT Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) invaded Kenya in 2003. Before the arrival of B. invadens, the indigenous fruit fly species Ceratitis cosyra (Walker) was the predominant fruit fly pest of mango (Mangifera indica L.). Within 4 yr of invasion, B. invadens has displaced C. cosyra and has become the predominant fruit fly pest of mango, constituting 98 and 88% of the total population in traps and mango fruit at Nguruman, respectively. We tested two possible mechanisms responsible for the displacement namely; resource competition by larvae within mango fruit and aggression between adult flies. Under interspecific competition, larval duration in B. invadens was significantly shorter (6.2 +/- 0.6-7.3 +/- 0.3 d) compared with C. cosyra (8.0 +/- 1.2-9.4 +/- 0.4 d). Pupal mass in C. cosyra was affected by competition and was significantly reduced (7.4 +/- 0.3-9.6 +/- 0.6 mg) under competitive interaction compared with the controls (12.1 +/- 1.5-12.8 +/- 1.1 mg). Interspecific competition also had a significant adverse effect on C. cosyra eclosion, with fewer adults emerging under co-infestation compared with the controls. Interference competition through aggressive behavior showed that fewer C. cosyra (3.1 +/- 0.8) landed on mango dome compared with the controls (14.2 +/- 1.5) when adults were mixed with B. invadens adults in Plexiglas cages. Similarly the number of times C. cosyra was observed ovipositing was significantly lower (0.2 +/- 0.2) under competitive interaction compared with the controls (6.1 +/- 1.8). Aggressive encounters in the form of lunging/ head-butting and chasing off other species from the mango dome was higher for B. invadens compared with C. cosyra. Our results suggest that exploitative competition through larval scrambling for resources and interference competition through aggressive behaviors of the invader are important mechanisms contributing to the displacement of C. cosyra by B. invadens in mango agroecosystems.
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... The GPS position of each trap in each site and altitude was recorded using a Magellan 315 device. ... within Kenya and lack of any records from Nairobi, all the collected fruits were secured in containers closed with fine cloth, and... more
... The GPS position of each trap in each site and altitude was recorded using a Magellan 315 device. ... within Kenya and lack of any records from Nairobi, all the collected fruits were secured in containers closed with fine cloth, and transferred into a closed ICIPE Quarantine facility. ...
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Morphometric studies of five allopatric parasitoid populations (genus Psyttalia Walker) from coffee plantations in Cameroon (Nkolbisson), Ghana (Tafo) and Kenya (Rurima, Ruiru and Shimba Hills) and one non-coffee population (from Muhaka,... more
Morphometric studies of five allopatric parasitoid populations (genus Psyttalia Walker) from coffee plantations in Cameroon (Nkolbisson), Ghana (Tafo) and Kenya (Rurima, Ruiru and Shimba Hills) and one non-coffee population (from Muhaka, Kenya) were compared with individuals of Psyttalia concolor (Szépligeti), a species released in several biological control programmes in the Mediterranean Region since the 20th Century. Analyses of wing vein measurements showed the second submarginal cell of the fore wing and its adjoining veins had the heaviest principal component weights and served as the main contributing variables in the diagnostic differentiation of the populations. Two populations (Rurima and Ruiru) were found to be the closest to each other and with the strongest phenetic affinity toward P. concolor (and forming one cluster). Populations from Shimba Hills (of unknown identity), Nkolbisson (P. perproximus (Silvestri)) and Tafo formed a second cluster and were separated from P....
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... Pph, Pru and Prm, respectively. Ceratitis (C. capitata and C. cosyra) and Dacus ciliatus Loew larvae were obtained from fruit fly colonies maintained at ICIPE by the African fruit Fly Initiative (AFFI). Third instar larvae of these ...
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A species in the Bactrocera dorsalis (Hendel) complex was detected in Kenya during 2003 and classified as Bactrocera invadens Drew, Tsuruta & White. Having spread rapidly throughout Africa, it threatens agriculture due to crop damage and... more
A species in the Bactrocera dorsalis (Hendel) complex was detected in Kenya during 2003 and classified as Bactrocera invadens Drew, Tsuruta & White. Having spread rapidly throughout Africa, it threatens agriculture due to crop damage and loss of market access. In a recent revision of the B. dorsalis complex, B. invadens was incorporated into the species B. dorsalis. The potential distribution of B. dorsalis has been previously modelled. However, previous models were based on presence data and did not incorporate information on the seasonal phenology of B. dorsalis, nor on the possible influence that irrigation may have on its distribution. Methyl eugenol-baited traps were used to collect B. dorsalis in Africa. Seasonal phenology data, measured as fly abundance throughout the year, was related to each location's climate to infer climatic growth response parameters. These functions were used along with African distribution records and development studies to fit the niche model for...
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Research Interests: Landscape Ecology, Biomass, DISTRIBUTION, Waterbirds, Insecta, and 3 moreForage, Forages, and Distribution
... The GPS position of each trap in each site and altitude was recorded using a Magellan 315 device. ... within Kenya and lack of any records from Nairobi, all the collected fruits were secured in containers closed with fine cloth, and... more
... The GPS position of each trap in each site and altitude was recorded using a Magellan 315 device. ... within Kenya and lack of any records from Nairobi, all the collected fruits were secured in containers closed with fine cloth, and transferred into a closed ICIPE Quarantine facility. ...