We present the first report of Amblycerus dispar (Sharp) attacking stored almonds [Prunus dulcis (Mill.) D. A. Webb] in Argentina. A summarized diagnosis, illustrations, and photographs of the adult and mature larva are provided to facilitate identification. We performed species distribution models for A. dispar and its main host plant Geoffroea decorticans (Gillies ex Hook. & Arn.) Burkart. We include A. dispar into a previous morphological character matrix and conduct a phylogenetic analysis to infer its phylogenetic position. The evolution of host plant associations of the genus Amblycerus is herein re-analyzed. A. dispar and its main host shows high suitability areas especially in central-west Argentina and Chile, whereas for the USA, high suitability areas were found for the south-western which include the area of almond production in this country. Although the presence of A. dispar in the USA region is very unlikely, we recommend some awareness as other bruchines are present in the area. Although A. dispar is unlikely to become an economically important risk, monitoring for early detection is recommended to avoid productivity loss, especially when the native host is nearby cultivated areas. A. dispar is hypothesized to be the sister species of A. schwarzi Kingsolver. The colonization of a Rosaceae species is a novelty for this genus, being host shifts known as an important factor affecting both natural and agricultural systems.

In Western Burkina Faso, the host range of fruit flies was evaluated in three plant formations between May 2017 and April 2019. Samples of 61 potential hosts were collected and incubated for fruit fly emergence. Twenty-seven hosts including cultivated and wild fruit were identified. Among cultivated fruit species, mango, and guava were the most infested while high infestation incidences were observed in the fruit of the indigenous plants Vitellaria paradoxa, Annona senegalensis, Sarcocephalus latifolius, and Saba senegalensis. Low infestation rates were observed in Anacardium occidentale, Citrus species, Opilia celtidifolia, and Cissus populnea. The highest infestation index (1648.57 flies kg−1) was observed from V. paradoxa. Eleven new host fruit infested with many fruit fly species are reported in Burkina Faso. A total of 18 fruit fly species were reared; Bactrocera dorsalis (42.94%), Ceratitis cosyra (29.93%), and Ceratitis silvestrii (22.33%) dominated those that emerged. Four fruit fly species have been detected for the first time in Burkina Faso. The main suitable fruit hosts are abundant and available from May through August during the rainy season and become rare and have low infestation from November to April during the dry season. This is the first study of its kind in the region. This study shows that the three plant formations had an impact on population dynamics of the three tephritid species of economic importance in Western Burkina Faso. This information should be integrated into the development of a fruit fly pests management strategy.

Tibraca limbativentris (Hemiptera: Pentatomidae) is a major pest in Neotropical rice agroecosystems. In autumn–winter, this pest takes refuge in rice stubble and in native vegetation, which allows it to re-colonize the crop during the rice growing season. However, it is still unknown whether this vegetation is a pest sink or is actually a natural trap that contributes to pest population biocontrol. Here we present information on the insect's alternative host plants, a preliminary outline of the relationship between plant phylogeny and insect abundance, and the impact that winter natural enemies have in pest population. Also, we include a proposed methodology for pest density analysis in winter hosts. Our results show significant differences in the abundance/density that T. limbativentris reaches in the 12 host plant species present in our study areas, with a plant-use pattern significantly related to the phylogenetic clade of Poales. Stink bug winter populations mainly comprised diapause adults, and 40% of insect digestive tracts had content. Survival of T. limbativentris was 56.92% in winter hosts. About mortality, 10% was due to undetermined causes and 33.08% due to entomopathogenic fungi, showing a natural regulation of the pest population. Our results suggest that native vegetation impacts winter survival of T. limbativentris. Although these plants offer shelter, they offer a greater contribution to Integrated Pest Management: the natural regulation of winter pest populations through entomopathogenic attack. Further studies on T. limbativentris population dynamics and the preservation of native areas near rice fields will be required for the development of best control practices.

Cotton mealybug, Phenacoccus solenopsis Tinsley is an important polyphagous insect pest and causes severe losses to different crops worldwide. In the current study, we investigated the effect of different host plants, such as Caesalpinia pulcherrima, Plumeria rubra, Anthurium andraeanum, Jasminum sambac, and Hibiscus rosasinensis, on the biological parameters of P. solenopsis. The survival rate from crawler to adult, female nymphal duration, development time from crawler to female adult, and female adult weight were significantly different on the different hosts. Male nymphal duration, development time from crawler to male adult, pupal weight, emergence rate of male adults, and mean relative growth rate for male were similar on all the tested host plants. Pupal duration and generation time of male and female on H. rosasinensis were significantly shorter than on the other hosts. Adult male and female P. solenopsis longevity was significantly shorter on H. rosasinensis compared to other hosts. The fecundity was lower on C. pulcherrima and A. andraeanum and hatchability was lower on C. pulcherrima than on the other hosts. The net reproductive rate, the intrinsic rate of natural increase, and biotic potential and mean relative growth rate for female of P. solenopsis were significantly different on the tested hosts. Our results point to the role of host plants in increasing the populations of P. solenopsis and could help to design cultural management strategies.

Dicyphus errans (Wolff) has been shown to be a suitable biocontrol agent for Tuta absoluta (Meyrick). This generalist predator shares various host plants with the exotic pest, and these interactions could be exploited to enhance pest control. Therefore, host preference, survival rate and development times of the predator and prey were investigated on crop and non-crop plant species. Among the tested plants, the favourite hosts were Solanum species for T. absoluta, and herb Robert, European black nightshade, courgette and tomato for D. errans. Tuta absoluta accepted the same plant species as hosts for oviposition, but it never developed on herb Robert and courgette in all the experiments. Based on our results, we would suggest the use of courgette and herb Robert in consociation with tomato and as a companion plant, respectively, which may keep pest densities below the economic threshold. Moreover, the omnivorous and widespread D. errans could be a key predator of this exotic pest, allowing a high encounter probability on several cultivated and non-cultivated plant species.

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 of Dacus ciliatus (Loew) and Trirhithrum nigerrimum (Bezzi) in northern Ghana although both species have been previously reported in other parts of the country. Infestation by B. invadens was higher in the cultivated fruits; Ceratitis cosyra dominated in most wild fruits. Cucurbitaceae were mainly infested by three species of Dacus and Bactroceracucurbitae, a specialized cucurbit feeder. Among the commercial fruit species, the highest infestations were observed in mango, tomato, sweet pepper and watermelon, whereas marula plum, soursop, tropical almond, sycamore fig, African peach, shea nut, persimmon, icacina and albarillo dominated the wild host flora. The widespread availability of host plants and the incidence of diverse fly species in the ecology call for particular attention to their impact on commercial fruits and the development of sustainable management strategies against these economically important pests in Ghana.

Introduction. This study was carried out in French Guiana, over ten years (1994–2003) by three institutions (SPV, FDGPC and CIRAD); it updates the current state of knowledge of Tephritidae (both Dacini and Toxotrypanini tribes) species present in this country. Materials and methods. The work was mainly conducted in inhabited areas (from the Brazilian border to the Surinamese border) where cultivated fruit crops are located. Specimens were obtained by adult trapping and fruit sampling in nearby orchards and at the edge of the rainforest. Trapping was done consistently for 10 years, while fruit sampling was a discontinuous activity. We present only the results for fruit sampling from three consecutive years (2001–2003) in which a total of 880 kg from 45 fruit species in 22 plant families were collected. Results. Twenty-nine plant species from fourteen plant families were found to be hosts of twenty-one Anastrepha species and one Bactrocera species, Bactrocera carambolae Drew and Hancock. During this period, no specimen of Ceratitis capitata (Wiedemann) was collected in traps or fruit samples. We registered the main fruit trees which were hosts for B. carambolae and Anastrepha spp. Five hymenopterous parasitoid species were identified. Among them, Diachasmimorpha longicaudata (Ashmead) (Hymenoptera, Braconidae) is an exotic species and was introduced into French Guiana in collaboration with Brazilian authorities (EMBRAPA) in 2000 and 2001 within the framework of a classical biological control program. Conclusion. Our data provide baseline information about the tephritid species of economic importance present in French Guiana and assist in developing potential future control programs of both the B. carambolae and Anastrepha species in the Amazon Basin. These preliminary results are discussed in the light of their implication for rainforest conservation efforts and also evolutionary relationships between fruit flies and their hosts.

The interplay between the host plant of an insect herbivore and an insect predator (here two-spot ladybird beetles; Adalia bipunctata (L).; Coleoptera: Coccinellidae), feeding upon such a herbivore was examined in the laboratory as factors possibly determining the differential abundance and success of green and red host races of pea aphid, Acyrthosiphon pisum Harris. The experiment comprised three treatments: two host plants (bean and clover), two treatment levels (control and predation) and three colour morph levels (green alone, red alone and green and red in mixture). Green morphs had higher fitness on the general host plant, bean Vicia faba, than on the derived host, clover (Trifolium pratense), in the absence of predation. Although green morph fitness was reduced by predation when infesting bean together with reds, there was no observable net fitness loss due to predation on clover in mixed colonies with red morphs. Red morphs exhibited fitness loss alone on both bean and clover, while clover plants seemingly prevented fitness loss in the presence of predation when red morphs were mixed with green ones. According to this scenario, when colour morphs existed as a mixed colony, the net fitness of either pea aphid morph was not influenced by predation on clover. Predators had significant effects only on red morphs on broad bean either when alone or were mixed together with green morphs. Thus, only red morphs experienced the benefits of switching from the general to the derived host red clover in the presence of predation. For green morphs, there was no apparent cost of switching host plants when they faced predation. Hence, the co-existence of green-red colour polymorphism of pea aphids on single host plants appears to be maintained by the morph gaining fitness on the derived host due to a host plant– and predation–reduction effect. These findings have important implications for understanding the ecology and evolution of host switching by different colour-plant host adapted races of pea aphids.

Tea is prepared from the tender leaves and buds of Camellia sinensis (L.). In sub-Himalayan tea plantations of North-East India, different management practices are followed to protect the tea crop against different sucking insect pests such as Helopeltis theivora (Hemiptera: Miridae), Empoasca flavescens (Homoptera: Cicadellidae) and Scirtothrips dorsalis (Thysanoptera: Thripidae). Most plantations are managed conventionally through the use of different organo-synthetic insecticides, whereas some are managed organically by using herbal and microbial insecticides. In conventional tea plantations, organo-synthetic insecticides of different functional groups (organochlorines, organophosphates, synthetic pyrethroids and neonicotinoids) are routinely applied round the year to keep the sucking insect pest populations under control. A variety of defence mechanisms, including enzymatic detoxification systems (carboxylesterases, glutathione S-transferases and cytochrome P450 monooxygenases), physiological tolerance and behavioural avoidance, protect insect herbivores from these hazardous compounds. Insect pests have evolved mechanisms to degrade metabolically (enzymatically) or otherwise circumvent the toxic effect of many types of chemicals synthesized as modern insecticides. The extent to which insects can metabolize and thereby degrade these toxic or otherwise detrimental chemicals is of considerable importance for their survival in an unfriendly chemical environment. These mechanisms continue to evolve as insects attempt to colonize new plant species or encounter newer molecules of synthetic insecticides. The level and type of detoxifying mechanisms differs greatly, which, therefore, results in varying toxicity among different stages, species and populations. Variation in detoxifying enzyme activity is responsible, in part, at least for the selective toxicity of different insecticides, the development of resistance to insecticides and the selection of host plants. Overexpression of these detoxifying enzymes, capable of metabolizing insecticides, can result in higher levels of metabolic tolerance/resistance to synthetic insecticides.

Diverse agroecosystems offer phytophagous insects a wide choice of host plants. Myzus persicae is a polyphagous aphid common in moderate climates. During its life cycle it alternates between primary and secondary hosts. A spatial genetic population structure may arise due to environmental factors and reproduction modes. The aim of this work was to determine the spatial and temporal genetic population structure of M. persicae in relation to host plants and climatic conditions. For this, 923 individuals of M. persicae collected from six plant families between 2005 and 2008 in south-eastern Spain were genotyped for eight microsatellite loci. The population structure was inferred by neighbour-joining, analysis of molecular variance (AMOVA) and Bayesian analyses. Moderate polymorphism was observed for the eight loci in almost all the samples. No differences in the number of alleles were observed between primary and secondary hosts or between geographical areas. The proportion of unique genotypes found in the primary host was similar in the north (0.961 ± 0.036) and the south (0.987 ± 0.013), while in the secondary host it was higher in the north (0.801 ± 0.159) than in the south (0.318 ± 0.063). Heterozygosity excess and linkage disequilibrium suggest a high representation of obligate parthenogens in areas with warmer climate and in the secondary hosts. The FST-values pointed to no genetic differentiation of M. persicae on the different plant families. FST-values, AMOVA and Bayesian model-based cluster analyses pointed to a significant population structure that was related to primary and secondary hosts. Differences between primary and secondary hosts could be due to the overrepresentation of parthenogens on herbaceous plants.

Introduction. Senegal producesup to 150,000 t of fruit, of which 60,000 t are mangoes. Fruit productionis important for the Niayes region, where 60% of total productionis of mangoes, with citrus production coming next at 24%. Mango losseshave become more substantial since the arrival of Bactrocerainvadens in Senegal. The pest population increases in the mangoripening period, but little is known about its secondary hosts. Materialsand methods. Fruits of cultivated and wild plants were collectedregularly from April to December 2008 inside and around 19 orchards ineleven localities in the Niayes and Thiès areas in Senegal. Thesamples were monitored to identify any fruit flies present so thata list of host plants could be compiled. For mango, the study focusedon establishing the influence of certain parameters such as thevariety, the fruit size, the color, the flowering pattern and thephysiological levels of infestation due to B. invadens andCeratitis cosyra. Orchards were classified either as traditional (manymango varieties and many fruit species grown together in a stand) orintensive (fields of monovarietal mango trees), according to theircomposition and how they were managed. Results and discussion.A total of 663.2 kg of fruit, including those of 24 mango varieties,13 citrus species with five lime varieties, two orange varietiesand four pomelo varieties along with other cultivated and wild plants,were sampled both as fallen fruit and from the trees. Traditional orchardswere more infested than the modern ones. B. invadens was significantlydominant over the other flies emerging such as C. cosyra, C. capitata, C. punctata, C. bremii,Bactrocera cucurbitae, Capparimyia bipustulata, Carpomyia sp. and Dacus sp.B. invadens wasfound on the 24 varieties of Mangifera indica,the 13 citrus species, and the other cultivatedplants and wild plants sampled. Some host plants supported a relativelyhigh level of fruit flies before the mango ripening period. Mangifera indica wasinfested principally by B. invadens and C. cosyra. C. cosyra was significantly present on the firstfruit trees to flower, mostly in early varieties, while B.invadens infested all the varieties whatever the fruitdevelopment stage, the color, or the flowering pattern. Conclusion.Because of the host plants' diversity and varieties the traditionalorchards were more infested than the modern ones. The managementof this pest needs an Integrated Pest Management system based ona back-to-basics study of the infesting fruit flies, existing parasitoidsand their hosts.

Pieris brassicae (Linn.) is a destructive cosmopolitan pest of cruciferous crops. It is present wherever its host plants occur, and it is considered to be one of the most widely distributed of all the Lepidoptera. We investigated the affect of various host plants on the food consumption and utilization by P. brassicae. We quantified consumption of food, larval duration, pupal duration and weight on cabbage (Brassica oleracea var. capitata), cauliflower (Brassica oleracea var. botrytis), radish (Raphanus sativus), broccoli (Brassica oleracea var. italica) and mustard (Brassica campestris) under laboratory conditions. Insect-host relationships can be better understood by knowing the rate of food consumption, its digestibility and conversion of food eaten to body tissue. The consumption of food generally increased with the advancement of larval age. In our study we found that consumption of food was highest on radish and lowest on broccoli. The highest consumption of a particular host does not always indicate greater suitability of that host, until and unless other factors like consumption index (CI), relative growth rate (RGR), efficiency of conversion of ingested food (ECI), approximate digestibility (AD) and efficiency of conversion of digested food (ECD) are also considered. In the current investigation, factors like CI, RGR, ECI and ECD were highest on cabbage. Low body weight of pupa is associated with rapid development. On cabbage, the weight of pupa of both sexes was found lowest. Thus, from the present study, it can be concluded that cabbage is a more suitable host for P. brassicae than other host plants evaluated. Hence, on cabbage, the values of Waldbauer indices were highest and P. brassicae developed with a faster rate.

Ile Amsterdam (37°50′S, 77°30′E, 55 km2) and Ile Saint-Paul (38°43′S, 77°31′E, 7 km2) are very isolated volcanic islands which were originally colonized by a few invertebrate fauna and flora. Invasive species richness has then increased along with human activity. A three-year monitoring programme (1997, 2000, 2001) and a summer campaign (2007) allowed species diversity, host plants, abundance and phenology of introduced aphids and natural enemies to be described. Seven cosmopolitan aphid species have been found on Ile Amsterdam (Aulacorthum solani, A. circumflexum, Macrosiphum euphorbiae, Myzus ascalonicus, M. cymbalariae, M. ornatus and Rhopalosiphum padi) and three on Ile Saint-Paul (A. solani, M. cymbalariae and R. padi). On Ile Amsterdam, these aphids were found on 28 host plants (out of 57 sampled plants), mainly introduced species. Phylica arborea was the only native plant much colonized by one aphid species, A. circumflexum. Aphids were mainly present on the base or in this vicinity. One Hymenopteran parasitoid, Aphidius matricariae, and two hyperparasites (Dendrocerus aphidum and Phaenoglyphis villosa), probably introduced along with their host, were collected. Aphid activity is very low during the autumn (March–May) and at a maximum in spring and summer. Their density and diversity decrease with distance from the research station. From these results, the possible impact of aphids on native plants is discussed.

Adults of the leaf weevil Phyllobius pyri (L.) (Coleoptera: Curculionidae) feed on a wide variety of broadleaved trees and occasionally cause severe defoliation in newly established farm woodlands. There is little information, however, on the relative susceptibility of different tree species to damage or on the habitat associations of adults and larvae of P. pyri, which might indicate the conditions that predispose trees to attack. Captures of adult P. pyri in emergence and flight traps in the current study indicated population densities in grassland of 0.5–6.4 adults per m2 at emergence but higher densities up to 13.5 per m2 in young pine plantations, where there was a mixture of grassy patches and young, naturally regenerating birch trees. The close proximity of larval food resources (grass roots) and a favoured adult host-plant, which also occurs in young farm woodlands, provided ideal conditions for P. pyri and allowed high population densities to develop. Feeding and performance experiments indicated that cherry, birch, oak and hornbeam were most susceptible to P. pyri, whereas field maple, hawthorn, rowan, lime and especially ash were resistant. Adult female P. pyri emerged in May reproductively immature and fed on tree foliage for 15.9±0.9 days before laying their first batch of eggs. Adults lived for 33.3±1.5 days, on average, and females laid a mean of 191.9±34.5 eggs (maximum=589) during their lifetime. Eggs hatched after 16–20 days. During 2003 and 2004, 11–16% of adult P. pyri were parasitised by Pygostylus falcatus (Hymenoptera: Braconidae) and 19–29% were parasitised by Rondania fasciata (Diptera: Tachinidae).

The extent of genetic differentiation between native and groundnut-feeding forms of the groundnut seed beetle Caryedon serratus Olivier was studied. Sixteen samples (560 individuals of both sexes collected in four localities in Senegal) of C. serratus were reared from pods of four distinct host plants (Arachis hypogaea L., Bauhinia rufescens Lam., Piliostigma reticulatum (DC) Hochst and Tamarindus indica L.), and five microsatellite loci were analysed. Phylogenetic and statistical analyses indicated that host plants strongly influence the degree of genetic differentiation between sampled individuals. Within host plants, genetic differentiation was low. Genetic differentiation between hosts was highly significant (average θ = 0.374) and geographical distances between localities did not influence the genetic structuration of C. serratus populations from a given host plant. The results of this study show that C. serratus could be under a host race formation process.

The results presented in this paper refer to a host survey, lasting approximately three and a half years (February 2003–July 2006), undertaken in the Vale do Rio Doce Natural Reserve, a remnant area of the highly endangered Atlantic Rain Forest located in Linhares County, State of Espírito Santo, Brazil. A total of 330 fruit samples were collected from native plants, representing 248 species and 51 plant families. Myrtaceae was the most diverse family with 54 sampled species. Twenty-eight plant species, from ten families, are hosts of ten Anastrepha species and of Ceratitis capitata (Wiedemann). Among 33 associations between host plants and fruit flies, 20 constitute new records, including the records of host plants for A. fumipennis Lima and A. nascimentoi Zucchi. The findings were discussed in the light of their implications for rain forest conservation efforts and the study of evolutionary relationships between fruit flies and their hosts.

Recent unusual high damage of finger millet Eleusine coracana (L.) Gaertn. and wheat Triticum spp. by Busseola fusca (Fuller) in Ethiopia prompted the initiation of this study that has involved comparing the host status of these crops with the main host, maize Zea mays. One improved variety and one local land race each of wheat, finger millet and maize were grown with and without fertilizer in a randomized complete block design to evaluate the effect of nitrogen and phosphorous fertilizers and varietal differences on the suitability of these host plants for the development of borer larvae. The results indicated that B. fusca larvae managed to survive up to the adult stage in the stems of finger millet and maize, while wheat failed to support larval development to pupation. The stems of fertilizer-treated crops hosted more larvae than those of untreated ones and these were significantly longer and heavier. Improved varieties tended to be more suitable for B. fusca development. Furthermore, irrespective of the crop species, improved varieties grown with fertilizer were more suitable for the development of B. fusca. An improved finger millet variety, KNE No. 1098, grown with fertilizer was as suitable as the improved maize variety A-511, grown without fertilizer. For wheat, however, immature mortality was 100% irrespective of variety and fertilizer level.

Introduction. The data on Bactrocera cucurbitae collected over a large area of West Africa for around the past ten years enables us to make a synthesis, since this economically significant species is now widespread. Fruit samples were collected in the course of various trips to Africa; we focused on looking for the melon fly, B. cucurbitae (Coquillett). Equipment and methods. The Tephritidae were captured by means of trapping the adults and collecting holed fruit containing larvae. The fruit samples were taken from Cucurbitaceae found in the sub-region, and from other plant families hosting melon fly larvae. Fruit holed by flies were collected from untreated orchards and taken to the laboratory to be weighed, counted and classified by species, variety, date and location. The larvae collected metamorphosed into pupae. After hatching from the pupae, the adults were recovered. Results and discussion. The samples taken enabled us to determine the distribution of B. cucurbitae in West Africa; this species was found in Benin, Burkina Faso, Cameroon, Côte d’Ivoire, Guinea, Mali, Niger and Senegal. The fruit collected in these countries enabled us to draw up a list of B. cucurbitae host plants in these regions; besides Cucurbitaceae, there were two Anacardiaceae species, two Rutaceae species, one Annonaceae species, one Solanaceae species and one Oxalidaceae species. There were four economically important fruit species among them. Unlike Reunion, where the dietary pattern of the melon fly is oligophagous, in West Africa it appears to be polyphagous instead. Conclusion. The data collected from B. cucurbitae host plants is subsequently to be validated, and then refined by quantitative analyses for the different West African countries.

The developmental, survivorship and reproductive biology of Eretmocerus sp. nr furuhashii Rose & Zolnerowich parasitizing Bemisia tabaci (Gennadius) biotype B on tomato, cucumber, eggplant and collard at 26±0.5°C was studied. The mean longevity ranged from 6.5 days on tomato to 8.1 days on collard. The mean lifetime fecundities on tomato, cucumber, eggplant and collard were 35.4, 37.3, 41.4 and 46.4 eggs, whereas the mean lifetime fertility was 20.2, 22.7, 28.3 and 33.6 offspring, respectively. Developmental time was longest on cucumber (17.1 days) and shortest on collard (15.9 days). Survival rates varied significantly across host plants. Sex ratio (♀:♂) varied from 1.71 to 1.93 across the four hosts. The intrinsic rate of increase (rm) was highest (0.157) on collard and lowest on tomato (0.133). Mean generation time (R0) ranged from 14.7 to 20.9 days. All the data demonstrated that the reproductive success and overall performance of E. sp. nr furuhashii increased as the density of leaf hairs declined. As leaf hairs play a key role in determining efficacy, it is unlikely that effective biological control of B. tabaci using E. sp. nr furuhashii will be achieved on non-glabrous crop varieties.

Introduction. Citrus canker, caused by the bacterium Xanthomonas axonopodis pv. citri, is a serious disease of most commercial citrus cultivars and some citrus relatives. Surveys were conducted in small-scale farms, commercial plantations, backyard orchards and nurseries in order to quantitatively study the occurrence and distribution of the disease and determine the intensity and field host range. Materials and methods. Seventeen locations in four regional states of Ethiopia were surveyed. Incidence on leaves was determined by counting total number of leaves and expressed as a proportion of leaves with at least one lesion. Incidence on fruits was determined on attached fruits, recorded as presence or absence of the symptoms. Severity was also measured on leaves and fruits. The identity of the pathogen was confirmed by morphological, biochemical and physiological characterization and detached leaf tests of representative isolates. Results. The surveys indicated the occurrence of citrus canker in Ethiopia. Overall incidence on leaves was 71.4% of leaves with at least one lesion and severity was 26.8% of leaf area infected. Incidence on fruits was 30% of fruits infected and severity was 21.25% fruit area infected. Morphological, biochemical and physiological characterization and detached leaf tests of isolates indicated characteristics similar to X. axonopodis pv. citri. The host range for citrus canker in Ethiopia was limited to Mexican lime (C. aurantifolia) and sour orange (C. aurantium). Based on the field host range and detached leaf tests, it appears that the X. axonopodis pv. citri variant that occurs in Ethiopia has similar host ranges to that of atypical Asiatic (Xac-A*) form. Canker severity significantly correlated with temperature but not with rainfall, elevation or tree age. Conclusion. This is the first confirmed report of the disease in Ethiopia.