A. Manrakhan

A New Invasive Fruit Fly Species from the Bactrocera dorsalis (Hendel) Group Detected in East Africa

Abstract—A new fruit fly species suspected to be from the Bactrocera dorsalis (Hendel) group (originating from Asia), was detected during routine field surveys in the Coast Province of Kenya. Since most species in this group are of tremendous quarantine concern when introduced, and considering the fact that it has never before been detected or reported in continental Africa, surveys were immediately initiated covering a distance of over 3000 km across major fruit-growing and trading localities within Kenya, to determine the extent of spread of the new invasive species. We report on the detection of the flies, preliminary results of the survey, and discuss the potential effects of these flies on the horticulture industry in East Africa.Résumé—Une nouvelle mouche des fruits appartenant vraisemblablement au groupe Bactrocera dorsalis (Hendel) (originaire dTnde), a été trouvée lors d’enquêtes de terrain de routine dans la province côtière du Kenya. Depuis que la plupart des espèces de ce groupe font l’objet de mesure de quarantaine très sévère lors de leur introduction et considérant qu’elle n’a jamais été trouvée ou signalée sur le continent Africain auparavant, une enquête couvrant près de 3000 km à travers les principales localités productrices de fruits du Kenya a immédiatement été lancée afin de déterminer l’aire d’extension de cette nouvelle espèce invasive. Nous présentons des résultats sur la découverte de la mouche ainsi que sur l’enquête, et discutons des effets potentiels de cette mouche sur l’industrie horticole de l’Afrique de l’Est.

Contribution of natural food sources to reproductive behaviour, fecundity and longevity of Ceratitis cosyra, C. fasciventris and C. capitata (Diptera: Tephritidae).

The influence of food sources comprising the natural diet on the reproductive behaviour, fecundity and longevity of three African fruit flies Ceratitis cosyra (Walker), C. fasciventris (Bezzi) and C. capitata (Wiedemann) was investigated. Three natural food sources, varying in protein and sugar content, were evaluated. These included bird droppings (farm chicken), aphid honeydew and guava (Psidium guajava L.) juice. For C. fasciventris and C. capitata, flies fed on a protein-rich diet displayed higher frequency of calling, mating and oviposition than flies fed on a protein-poor diet, whilst for C. cosyra, quality of diet significantly influenced the mating behaviour of the flies, but not the calling and oviposition behaviour. Net fecundity rates were lowest for C. fasciventris and C. capitata when fed only on guava juice (0.1, 2.6 eggs per female, respectively), and higher for those on a diet of honeydew only (9.5, 33.8 eggs per female, respectively) and a combined diet of guava, honeydew and chicken faeces (11.8, 25.8 eggs per female, respectively). For C. cosyra, due to low numbers of eggs collected, no significant differences in fecundity between diets could be detected. All species fed only on a diet of chicken faeces since emergence died within the first three days of adult life without laying eggs, but when carbohydrates were provided by addition of guava juice and honeydew, the longevity of the flies was sustained for more than four weeks after adult emergence. The practical implications of these findings for control purposes are discussed.

Susceptibility of the Mediterranean fruit fly (Ceratitis capitata) and the Natal fruit fly (Ceratitis rosa) to entomopathogenic nematodes.

The potential of entomopathogenic nematodes, Heterorhabditis bacteriophora, Heterorhabditis zealandica and Steinernema khoisanae, to infect pupariating larvae, pupae and adults of Ceratitis capitata and Ceratitis rosa was investigated in laboratory bioassays. Pupariating larvae and adult flies were susceptible to nematode infection, with no infection recorded for the pupae. Pupariating larvae of C. capitata were generally more susceptible to infection than those of C. rosa. Significantly more larvae of C. capitata were infected by H. bacteriophora. For C. rosa, highest infectivity of larvae was obtained with H. zealandica. In contrast, adults of both species were highly infected by S. khoisanae.

An integrative approach to unravel the Ceratitis FAR (Diptera, Tephritidae) cryptic species complex: a review

Abstract This paper reviews all information gathered from different disciplines and studies to resolve the species status within the Ceratitis FAR (Ceratitis fasciventris, Ceratitis anonae, Ceratitis rosa) complex, a group of polyphagous fruit fly pest species (Diptera, Tephritidae) from Africa. It includes information on larval and adult morphology, wing morphometrics, cuticular hydrocarbons, pheromones, microsatellites, developmental physiology and geographic distribution. The general consensus is that the FAR complex comprises Ceratitis anonae, two species within Ceratitis rosa (so-called R1 and R2) and two putatitve species under Ceratitis fasciventris. The information regarding the latter is, however, too limited to draw final conclusions on specific status. Evidence for this recognition is discussed with reference to publications providing further details.

Eradication of Bactrocera invadens (Diptera: Tephritidae) in Limpopo Province, South Africa

On 5 May 2010, Bactrocera invadens Drew, Tsuruta & White was detected in a methyl eugenol-baited surveillance trap in the northernmost part of the Limpopo Province in South Africa, an area adjacent to the Zimbabwe border. A delimiting survey was carried out to determine extent of spread in the area by trapping with both methyl eugenol and Biolure-3-component lures. A quarantine area of approximately 1100 km2 (surrounding the area of detection) was implemented to regulate movement of host fruits. Eradication of the pest was achieved in the quarantine area through male annihilation technique (MAT) using fibreboard blocks containing methyl eugenol and malathion in combination with protein bait sprays (application of GF-120 and LokLure mixed with malathion) and orchard sanitation. Eradication measures were carried out for a period of 12 weeks. Thereafter, MAT blocks were removed and trapping continued for a period of four weeks to confirm eradication. No B. invadens was caught in the area during the four weeks after control measures had stopped. No B. invadens was captured within a period of 12 weeks (approximately three generations) after the last fly find in the area. This constitutes the first successful eradication of B. invadens from an area of incursion.

Comparative analysis of development and survival of two Natal fruit fly Ceratitis rosa Karsch (Diptera, Tephritidae) populations from Kenya and South Africa

Abstract Comparative analysis of development and survivorship of two geographically divergent populations of the Natal fruit fly Ceratitis rosa Karsch designated as Ceratitis rosa R1 and Ceratitis rosa R2 from Kenya and South Africa were studied at seven constant temperatures (10, 15, 20, 25, 30, 33, 35 °C). Temperature range for development and survival of both populations was 15–35 °C. The developmental duration was found to significantly decrease with increasing temperature for Ceratitis rosa R1 and Ceratitis rosa R2 from both countries. Survivorship of all the immature stages of Ceratitis rosa R1 and Ceratitis rosa R2 from Kenya was highest over the range of 20–30 °C (87–95%) and lowest at 15 and 35 °C (61–76%). Survivorship of larvae of Ceratitis rosa R1 and Ceratitis rosa R2 from South Africa was lowest at 35 °C (22%) and 33 °C (0.33%), respectively. Results from temperature summation models showed that Ceratitis rosa R2 (egg, larva and pupa) from both countries were better adapted to low temperatures than R1, based on lower developmental threshold. Minimum larval temperature threshold for Kenyan populations were 11.27 °C and 6.34 °C (R1 and R2, respectively) compared to 8.99 °C and 7.74 °C (R1 and R2, respectively) for the South African populations. Total degree-day (DD) accumulation for the Kenyan populations were estimated at 302.75 (Ceratitis rosa R1) and 413.53 (Ceratitis rosa R2) compared to 287.35 (Ceratitis rosa R1) and 344.3 (Ceratitis rosa R2) for the South African populations. These results demonstrate that Ceratitis rosa R1 and Ceratitis rosa R2 from both countries were physiologically distinct in their response to different temperature regimes and support the existence of two genetically distinct populations of Ceratitis rosa. It also suggests the need for taxonomic revision of Ceratitis rosa, however, additional information on morphological characterization of Ceratitis rosa R1 and Ceratitis rosa R2 is needed.

The Distribution, Relative Abundance, and Seasonal Phenology of Ceratitis capitata, Ceratitis rosa, and Ceratitis cosyra (Diptera: Tephritidae) in South Africa

ABSTRACT Ceratitis capitata (Wiedemann), Ceratitis rosa Karsch, and Ceratitis cosyra (Walker) are fruit fly species (Diptera: Tephritidae) of economic importance in South Africa. These pests cause direct damage to a number of commercially produced fruit and are of phytosanitary concern. A study was conducted to determine the distribution, relative abundance, and seasonal occurrence of the three species in different climatic regions of South Africa. The relative abundance and seasonal phenology of C. capitata and C. rosa were also compared between production areas and home gardens in Stellenbosch, Western Cape. Yellow bucket traps baited with Biolure were used to trap the flies over a 2-yr period in the different sampling areas. Different fruit types were sampled in Stellenbosch to determine fruit fly infestation. C. capitata was found to have a widespread distribution in South Africa, whereas C. rosa were absent from or only present in low numbers in the drier regions. C. cosyra was restricted to the North East and East coast, following a similar pattern to the distribution of marula, Sclerocarrya hirrea, an important wild host. Fruit in home gardens provided a breeding ground for C. capitata and C. rosa and a source for infestation of orchards when fruit started to mature, highlighting the need for an area-wide strategy for the control of fruit flies.

Effect of food deprivation on attractiveness of food sources, containing natural and artificial sugar and protein, to three African fruit flies: Ceratitis cosyra, Ceratitis fasciventris, and Ceratitis capitata

The effects of food deprivation, age, and mating status on the responses of three fruit fly species, Ceratitis cosyra (Walker), Ceratitits fasciventris (Bezzi), and Ceratitits capitata (Wiedemann) (Diptera: Tephritidae) to natural and artificial sugar and protein food sources were investigated. Natural food sources included guava [Psidium guajava L. (Myrtaceae)] juice (a common host fruit for all three fruit fly species) and bird faeces (farm chicken). Artificial food sources included molasses (obtained from a local sugar factory) and a locally produced protein bait (the International Centre of Insect Physiology and Ecology yeast). In all species studied, sugar deprivation of immature (1–2‐day‐old) male and female flies increased their response to food odours, although it did not change their preference for the type of odour (protein or sugar). Protein deprivation of mature (14–17‐day‐old) male and female flies also increased their response to food odours compared to protein‐fed flies. Protein‐deprived females were highly attracted to odours from protein sources in particular. Odours from natural food sources, guava juice, and chicken faeces, were more attractive to food‐deprived flies than were odours from artificial sugar and protein sources. Attraction to food odours increased significantly with increasing age for protein‐deprived females of all species. For males and females of all species, nutritional state was a more important factor than mating status in influencing responses of flies to food odours. Practical implications of these findings are discussed in terms of strategies for fruit fly control using food baits.

Attraction of Ceratitis capitata, C. rosa and C. cosyra (Diptera: Tephritidae) to proteinaceous baits

Attractiveness of commercially available protein baits to three congeneric fruit fly species: Ceratitis capitata, Ceratitis rosa and Ceratitis cosyra was evaluated in field cage assays. Protein baits tested were HymLure, GF‐120 Naturalyte and M3 bait (also known as Questlure, used in M3 bait station registered for fruit fly control in South Africa). The influence of concentration on attractiveness of HymLure and GF‐120 was determined and the effect of ageing of M3 bait on response of the three fly species was evaluated. Responses to the three types of bait were species specific. C. cosyra had a low response to HymLure but responded well to the other two baits tested. C. capitata and C. rosa responded well to all baits tested. Ceratitis capitata was the most responsive of all species tested to protein baits. Female flies responded more to commercial baits than male flies, irrespective of fruit fly species. Concentration of HymLure and GF‐120 influenced attractiveness of flies but this was species and sex specific. Attractiveness of M3 bait did not change with ageing of the bait. A novel method of bait evaluation was used in this study and can be adopted for future screening of food attractants. The practical implications of this study were discussed with respect to control strategies adopted in areas of multiple fruit fly pest species, particularly on choice of baits to be used.

Assessment of fruit fly (Diptera: Tephritidae) management practices in deciduous fruit growing areas in South Africa.

BACKGROUND Ceratitis capitata (Wiedemann) and Ceratitis rosa Karsch are important fruit fly pests of deciduous fruit in the Western Cape Province, South Africa. The main techniques used for fruit fly control in the Western Cape are the sterile insect technique (SIT) targeting C. capitata and the bait application technique (BAT). We determined the relative success of SIT by comparing adult fly-trap catches and fruit infestation in commercial orchards between three regions under SIT and two regions under BAT in the Western Cape, from 2006 to 2008. RESULTS Ceratitis capitata was predominant in all regions. In commercial orchards, C. capitata catches peaked towards the end of the fruiting season (March to May) and were low between July and January. During the late season, C. capitata catches were significantly higher in two of the regions under SIT. The sterile to wild male ratio in those regions was found to be mostly <1. CONCLUSION SIT is not being properly applied in some regions. SIT should be implemented when the pest population is low. The sterile to wild fly ratios should be increased. Alternatively, BAT should be used to lower the pest population before SIT application. Control methods should be more integrated and applied area-wide.