Introduction. Kinnow is an important citrus crop grown in India, which suffers from several postharvest diseases during storage. Hence, an attempt was made to combat such diseases with the botanicals Aloe vera, Eucalyptus and Ocimum on Kinnow mandarin to prolong its availability for a longer time. Materials and methods. For this, in vitro and in vivo studies were conducted. The poisoned food technique was used for in vitro studies, and, for in vivo studies, Kinnow fruit were pre-inoculated with pathogens (Penicillium digitatum and P. italicum), treated with different botanicals, then stored at (5 ± 1) °C temperature and 85–90% RH. Results and discussion. Our results indicated that all botanicals inhibited the growth (colony diameter) of both pathogens over untreated PDA plates, but the inhibition was the strongest by Aloe vera extracts. Similarly, under in vivo conditions, all botanicals influenced the decay incidence, decay loss, lesion diameter, respiration rate, ethylene evolution and physiological loss in weight, but Aloe vera was the most effective. All the botanicals were able to retain postharvest quality of Kinnow fruits without any adverse effect on quality parameters such as TSS, TA and ascorbic acid. Under in vivo conditions, the incidence of Penicillium italicum was higher than P. digitatum; however, it was the reverse under in vitro conditions. Conclusion. Thus, it is evident from our studies that botanicals have the potential to control green and blue mold without causing any injury or harmful effects on Kinnow mandarin; botanicals can be recommended as a safe method for extending its storage life while maintaining fruit quality at the same time.

Introduction. México is one of the most important producers and exporters of blackberries in the world. During postharvest handling, blackberry fruits are exposed to the attack of phytopathogenic fungi. Materials and methods. To obtain Rhizopus stolonifer isolates, samples of leaves and rhizospheric soils were placed on Petri plates containing Potato Dextrose Agar (PDA). In addition, fruits were also placed in humidity chambers at 25 °C. To describe the infection process on blackberry fruits by Rhizopus stolonifer, samples were taken at different intervals for a period of 72 h. All fungal isolates obtained were maintained on PDA. The bacterial colonies were isolated and purified by streaking on PDA. The antagonistic activity of the bacteria was assessed against R. stolonifer by dual culture technique on PDA. To detect the production of siderophores, the chrome azurol S assay was carried out. Results. The infection process of R. stolonifer on blackberry fruits was described for the first time in this work. Eighty-six bacterial isolates from different parts of the plant and rhizospheric soil were obtained. Bacterial isolates with antagonistic activity were identified and the production of siderophores was measured. Four isolates showed antagonistic activity against R. stolonifer. Bacillus subtilis obtained from soil was the most effective isolate. Conclusion. In this study we isolated and identified antagonistic bacteria with potential for biocontrol on Rhizopus stolonifer obtained from blackberry fruits. To our knowledge this is the first report regarding this topic.

Introduction. Concerns about the potentially harmful effects of fungicides on human health and the environment encourage the search for alternative treatments for perishable fruit postharvest disease control. To this end, the potential use of oligochitosan as a natural antifungal compound to control postharvest anthracnose caused by Colletotrichum musae was investigated in banana fruits from the Cavendish group (genome AAA). Materials and methods. The influence of oligochitosan on the growth of C. musae was determined in vitro by micrographic analysis, while its in situ antifungal activity was monitored in banana fruits that were artificially injury-inoculated with C. musae; the activities of several defense-related enzymes were measured. Results and discussion. Oligochitosan at (4 and 8) g·L–1 markedly inhibited radial mycelial growth of C. musae in vitro. The scanning electron micrograph of C. musae treated with oligochitosan at inhibitory concentrations showed distortion and thinning of the hyphal wall and reduction in fungus colony diameter. Dipping banana fruits in oligochitosan solution at (5 to 20) g·L–1 significantly reduced the diameter of the anthracnose lesion, and 20 g oligochitosan·L–1 almost reached the same inhibitory effect as 0.5 g·L–1 of Sportak®, a synthetic fungicide. Activities of defense-related enzymes such as phenylalanine ammonia-lyase (PAL), β-1, 3-glucanase (GLU) and chitinase (CHT), but not polyphenol oxidase (PPO), increased in banana fruits treated with 0.5 g oligochitosan·L–1. Conclusion. The inhibitory effect of oligochitosan on anthracnose development is due to the combination of a direct antifungal effect on the pathogen and an indirect effect, whereby the activities of defense-related enzymes in the banana fruit were enhanced. To control anthracnose in harvested bananas, treatment with oligochitosan above 20 g·L–1 may substitute the use of synthetic fungicide.

Introduction. Traditionally the control of fruit flies is based on the use of pesticides, which increase production costs and have led to many environmental concerns. Our study aimed to evaluate the effect of neem cake on the larval and pupal stages of Ceratitis capitata. Materials and methods. Third instar larvae were transferred to plastic vials with neem cake in different proportions. The treatments consisted of vermiculite with neem cake in the concentrations: control (vermiculite only), then (10, 25, 50, 75 and 100)% of neem seed cake. The bioassay was completely randomized, with six treatments, ten replicates and ten third instar larvae per replicate. The results were statistically analyzed. Results. At concentrations of 75% or more of neem cake in vermiculite, practically no adult flies emerged. At 50%, more than 80% of the adults did not emerge and the pupal period was prolonged. The sex ratio of the adults was not affected after the contact of the pupae with the neem cake. The estimated lethal concentrations to kill 50% and 90% of the population were 30.6% and 51.6%, respectively. Conclusion. The neem seed cake has contact actions against the larval-pupal stage of C. capitata. Neem seed cake in the pupation substrate can cause high mortality when its concentration is 50% or more, and it prolongs the delay of the pupal period of C. capitata.

Introduction. Green mould, Penicillium digitatum (Pers.: Fr.) Sacc., causes economically important postharvest disease in citrus. Materials and methods. Ethiopian plant extracts of Acacia seyal (Del. Var. Seyal) and Withania somnifera (L.) Dual were used to test the control of green mould in wound-inoculated fruit, stored for 21 d at 7 °C and at > 85% RH. The chemical compositions of the two extracts were determined using high-performance chromatography. Thereafter, freshly harvested (naturally infected) fruit were subjected to different postharvest treatments and stored for 50 d to investigate the effects of the two plant extracts on fruit quality parameters. Treatments included (pre-wax + leaf extracts), (wax + leaf extracts incorporated into wax, Citrosol A®), (leaf extract alone), (fruit washed in chlorinated water at 5.25%), (untreated fruit) and (commercially treated fruit). Results. Extracts of A. seyal and W. somnifera reduced the incidence of green mould by 56.1% and 50%, respectively, in wound-inoculated fruit. A. seyal extract contained a high concentration of gallic acid (60.3 mg·mL–1) whilst W. somnifera contained low concentrations of caffeic acid (8.7 mg·mL–1), salicylic acid (6.3 mg·mL–1) and 3,4 dihydroxy benzoic acid (3.8 mg·mL–1). Green mould was absent in naturally infected fruit subjected to (pre-wax + leaf extracts), (wax mixed with leaf extracts) and (leaf extracts) treatments. (Pre-wax + leaf extracts) and (wax mixed with leaf extract) treatments significantly reduced weight loss; retained firmness and colour; and they maintained eating qualities and a maturity index (SSC/TA) similar to commercial treatment. Conclusion. Both extracts of A. seyal and W. somnifera showed potential to be used as an alternative in combined applications with wax application under low temperature storage to replace synthetic fungicides, to ultimately control green mould and retain overall fruit quality.

Introduction. Penicillium digitatum is a commercially important postharvest pathogen of citrus that is responsible for significant annual global losses. Strains of the fungus, which exhibit strong resistance to widely used synthetic fungicides, are of major concern to the industry. The aim of the study was to investigate the antifungal activities of polar extracts and compounds from Lippia species, indigenous to South Africa, against a Guazatine®-resistant strain of P. digitatum.Materials and methods. In vitro tests were done by incorporating the compounds and plant extracts into Malt Extract Agar at concentrations ranging from (0.2 to 1.0) mg·mL–1. An in vivo (curative) assay was conducted using the checkerboard technique on ‘Valencia’ oranges. Results and discussion. A strong correlation between the in vitro and in vivo results was observed. All the compounds and extracts were able to inhibit fungal growth at concentrations above 0.6 mg·mL–1. Verbascoside was the most active compound, while extracts of Lippia javanica and Lippia rehmannii caused significant inhibition of mycelial growth. The observed activity was largely ascribed to the presence of verbascoside in the plant extracts. Conclusion. Polar extracts of Lippia species have potential as environmentally friendly alternatives for the control of P. digitatum on citrus.

The infectivity and pathogenicity of three native entomopathogenic nematodes (Heterorhabditis (HNI 0100 and sp-CIAT) and Steinernema (SNI 0198)) were evaluated in third instar larvae of Phyllophaga menetriesi (Blanchard) under laboratory conditions. Concentrations of 7000 and 13,000 infective juveniles per millilitre were applied to the coleopteran larval host (individuals) that had been placed in plastic cups with 40 g of sterile sand at 5.8% (w/w) moisture. The evaluations were done 5 and 10 days after treatment. It was observed that both the percentage of infectivity (74.5%, n = 247), measured in terms of percentage of penetration and the percentage of pathogenicity (10.5%, n = 247) of the three native nematodes were significantly different due to the treatments. Steinernema had the highest values of infectivity (>80%), but no pathogenicity. In contrast, the treatments with Heterorhabditis, despite having the lowest degree of infectivity (52.9%), had the highest mortality values (31.6%). Therefore, the Heterorhabditis strains were considered to be the most promising as biological control organisms within an integrated pest management programme due to their higher degree of pathogenicity. Nevertheless, different strains and species of native nematodes should be evaluated in all the developmental stages of the pest.

Introduction. Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) can be considered important rhizospheric beneficial microorganisms. Their use as biocontrol strategies against soilborne pathogens such as nematodes should be taken into account. However, optimal management of soil microbiota communities is not easy because of the high specificity involved in these types of interactions. The aim of our study was to determine whether the combined inoculation of two AMF species and a Bacillus consortium based on three strains previously described as PGPR in other crops were able to reduce nematode infection and damage on papaya. Materials and methods. Papaya seedlings were inoculated with two AMF isolates (Glomus mosseae or G. manihotis) at the beginning of the nursery phase. Once the mycorrhizal symbiosis was established, a Bacillus consortium was applied. Nematode inoculum was applied 20 d after transplanting to individual pots. Plants were harvested 160 d after nematode inoculation. Results. In terms of plant development and nutrition, benefits due to AMF inoculation persisted in the presence of PGPR. However, the effect of dual inoculation was different, depending on the Glomus species. This positive effect was also evident in plants with nematode. Meloidogyne infection was significantly reduced in mycorrhizal plants. However, the addition of PGPR does not seem to improve the results of AMF single treatments in terms of nematode infection. Conclusion. Dual application of AMF and PGPR must be considered for papaya threatened by the root-knot nematode, although a previous screening should be done in order to select the best microbe combination to optimise results.

Introduction. Au Maroc, le parasitoïde A. melinus constitue l’agent de lutte biologique le plus efficace contre les pullulations d’A. aurantii, ou pou de Californie, insecte très nuisible à l’agrumiculture marocaine. Or, cet hyménoptère est présent naturellement dans la région du Tadla, grande région agrumicole du centre du Maroc (325 295 ha). De ce fait, la protection intégrée des agrumes contre A. aurantii pourrait constituer une possibilité de lutte prometteuse par rapport à la seule lutte chimique raisonnée. Note étude a été un préalable à la mise en place d’une stratégie de lutte intégrée sur agrumes au Tadla par la surveillance du pou de Californie et de son principal parasite A. melinus. Matériel et méthodes. Nos expérimentations ont été conduites en 2000 et 2001 dans un verger non traité, constitué d’un mélange de variétés d’agrumes. L’évolution de la dynamique des populations d’A. aurantii et d’A. melinus a été suivie et les périodes d’abondance des stades réceptifs vivants du ravageur coïncidant avec les périodes d’activité de son parasitoïde ont été repérées. Résultats. Dans la région du Tadla, le pou de Californie a présenté quatre générations par an, une génération printanière (avril–mai), une génération estivale (juin–juillet) et deux générations automnales (octobre et novembre–décembre). Les stades du ravageur susceptibles d’être parasités par A. melinus ont été observés tout au long de l’année. L’analyse de ces stades a révélé deux périodes (printanière et automnale) particulièrement favorables à la ponte des femelles du parasitoïde. Ses populations se sont révélées importantes dès le début de l’automne et jusqu’à la fin du printemps suivant. Conclusion. Des lâchers d’A. melinus effectués durant l’automne, l’hiver et le printemps pourraient donc être efficaces.

Laboratory experiments were conducted to investigate the effect of diet on the biology and prédation capacity of the phytoseiid mite Amblyseius zaheri Yousef & El-Brolossy. The predatory mite was able to develop and reproduce when fed on nymphs of the twospotted spider mite Tetranychus urticae Koch, nymphs of the citrus brown mite Eutetranychus orientalis Klein, motile stages of the eriophyid mite Eriophyes dioscoridis Soliman & Abou-Awad, eggs of the scale insect Parlatorio ziziphus Lucas, nymphs of the whitefly Bemisia tabaci (Genn.) and pollen grains of date palm, Phoenix dactylifera. The predatory mite's development was fastest on a diet of nymphs of Er. dioscoridis. All of the diets led to a female-biased progeny, which was most pronounced in predators fed on date palm pollen. The results are discussed in light of the biological control capacity of the phytoseiid mite.

—Native to the Caribbean islands and Central America, the spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae), has spread to North America, South America, Asia, Africa, Australia and several Pacific islands. A total of 62 natural enemies, including 8 parasitoids, 53 predators and one fungal pathogen, are known to attack the whitefly in different countries. Of the parasitoids, the accidentally or deliberately introduced aphelinids Encarsia sp., Encarsia (?) haitiensis Dozier and E. guadeloupae Viggiani provide control of A. dispersus in many countries. The exotic coccinellid predator Nephaspis oculata Wingo also plays an important role in reducing the whitefly's populations. However, the A. dispersus remains a pest in some countries in the absence of parasitoids. This article reviews current information on biological control of A. dispersus in different countries/states, in particular India, the Pacific islands, Hawaii and countries in West Africa.

—Infochemicals play an important role in the biology of many insect species. An understanding of their role in plant-herbivore-carnivore interactions can be used in the development of tools for the enhancement of environmentally benign alternatives to synthetic pesticides. This review discusses how chemical information mediates ecological interactions between organisms and the role of infochemicals in integrated pest management. Infochemicals can be used in pest monitoring and in pest control, through mating disruption, mass trapping and to aggregate herbivores at delivery sites for biological control agents. Particular emphasis is placed on the potential of using pheromones and kairomones in the management of the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), a pest in plantations of East African highland banana and plantain in most banana-growing regions of the world. Cosmopolites sordidus produces an aggregation pheromone that attracts both males and females. This pheromone has been identified and synthesised and is being recommended as an effective agent in the trapping and control of the weevil. The synergism between banana plant extracts (kairomones) and the synthetic pheromone in attracting C. sordidus should be better exploited. Future research areas that can provide information for the development of an infochemical-based trapping system for the management of C. sordidus are discussed.

The effects of temperature on the development of Orius albidipennis (Reuter) (Hemiptera: Anthocoridae), reared on its prey, Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), were studied in the laboratory. Nymphal mortality was 87, 48 and 38 % at 20, 25 and 30 °C, respectively. With the exception of first-instar nymphs, percentage mortality was lowest at 25 °C. Pre-oviposition period and longevity decreased with an increase in temperature. Mean daily and total fecundity were 2.1 and 76.4 respectively at 25 CC. The mean developmental period from oviposition to adult eclosion was 27.7, 14.1 and 10.9 days at 20, 25 and 30 °C respectively. There was a linear relationship between temperature and developmental rate (1/day) of O. albidipennis. Lower thermal thresholds were 13.8, 13.5, 12.7, 15.0, 13.8 and 12.5 °C for eggs and nymphal stages 1 to 5, respectively, with the corresponding average degree-day requirement of 46.9, 42.6, 33.3, 29.2, 26.1 and 51.4 days, respectively. The implications of these results for biological control of thrips are discussed.

Introduction. Au Cameroun, les tentatives de lutte chimique contre Trioza erytreae, psylle des agrumes, ne permettent pas de maîtriser le niveau élevé des pullulations de ce ravageur dans les vergers. La lutte biologique serait la voie la plus prometteuse pour limiter ses populations dans le pays. Matériel et méthodes. Le parasitisme du psylle a été étudié sur des bourgeons d'agrumes parasités. Les larves momifiées du psylle ont été collectées, dans un verger de la région de Yaoundé, sur des agrumes isolés et sur une rutacée endémique, Clausena anisata. Ces momies ont été suivies au laboratoire et les hyménoptères qui en sont sortis ont été identifiés. Résultats. Le parasitisme global a été de 15 % environ. L'inventaire des espèces d'hyménoptères parasitoïdes de T. erytreae a montré la présence de parasitoïdes primaires : Psyllaephagus pulvinatus (36,3 %), Tamarixia dryi (3,5 %), P. secus (3,3 %), Psyllaephagus sp. (0,6 %), P. chiangamus (0,6 %), Bethylidae (genre et espèce non connus) (0,4 %) et Coccophagus pulvinariae (0,03 %) et des hyperparasitoïdes : Aphidencyrtus (Syrphophagus) cassatus (45,3 %), Tamarixia sp. (6,8 %), Tetrastichus sp. (1,5 %), Marrieta javensis (0,2 %), Physcus sp. (0,2 %), Aphanogmus sp. (0,2 %) et Cheiloneurus cyanonotus (0,1 %). Discussion. La faune des parasitoïdes de T. erytreae est aussi riche au Cameroun qu'en Afrique du Sud. Certaines espèces sont signalées sur ce psylle pour la première fois : Aphanogmus sp., Tamarixia sp., Psyllaephagus chiangamus, Psyllaephagus sp., Psyllaephagus secus et l'espèce non décrite de Bethylidae. Conclusion. La présence naturelle de parasitoïdes primaires de T. erytreae au Cameroun est un atout intéressant pour démarrer, dans ce pays, une lutte biologique contre cet important ravageur des agrumes.

Chilo partellus (Swinhoe) was first recorded in South Africa in 1958 and became a major pest of maize and grain sorghum. It has invaded the main maize producing areas in the Highveld Region, gradually competitively displacing the indigenous Busseola fusca (Fuller). Between 1980 and 1993 two egg, seven larval and two pupal parasitoids were introduced for biological control of Ch. partellus. Cotesia flavipes Cameron (Braconidae), Paratheresia claripalpis van der Wulp (Tachinidae), Tetrastichus howardi (Olliff) (Eulophidae) and Xanthopimpla stemmator Thunberg (Ichneumonidae) were released and recovered from the field. Recoveries were made up to a few weeks after releases but parasitoids failed to survive the winter and establish. The harsh winter conditions in the release sites, the long larval diapause period of Ch. partellus, lack of synchronisation between the development of the parasitoids and that of their host larvae, and absence of alternative host plants were identified as the main obstacles for the parasitoids establishment. It is concluded that the prospects of achieving any degree of biological control of stemborers in the Highveld Region with parasitoids from the tropics are poor. A parasitoid from a temperate zone of the USA, Macrocentrus grandii Goidanich (Braconidae), was introduced recently into South Africa and is currently reared on Ch. partellus in quarantine. Macrocentrus grandii stays dormant in its diapausing host, Ostrinia nubilalis (Hubner), during winter to emerge in spring. Because of its ability to diapause in winter it is hoped that after releases, M. grandii will establish on Ch. partellus in the Highveld Region of South Africa.

Field surveys carried out in Mozambique showed that two indigenous cereal stemborers, Busseola fusca Fuller (Lepidoptera: Noctuidae), Sesamia calamistis Hampson (Lepidoptera: Noctuidae) and one exotic stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), are the main pests of maize and sorghum in the country. Busseola fusca was abundant at high altitudes (> 800 m) and Ch. partellus was abundant at low altitudes (< 800 m). Sesamia calamistis occurred at all elevations but in low numbers. Of the three stemborers, Ch. partellus was the most widespread and abundant pest of maize followed by B. fusca. Therefore, a programme was initiated to introduce the exotic parasitoid Cotesia flavipes Cameron (Hymenoptera: Braconidae) to increase natural suppression of Ch. partellus populations. Cotesia flavipes was introduced into southern Mozambique for the first time in November 1996. Additional releases were subsequently carried out in several places in southern and central Moz imbique from 1998–2000. The parasitoid was recovered from all localities sampled 1 to 3 years after its introduction, indicating that this exotic parasitoid had established in the southern and central regions of Mozambique.

A study was conducted at Katumani, Kiboko and Ithookwe, in the semi-arid Eastern Province of Kenya for four seasons (short rains 1996-long rains 1998), to confirm the major stemborers of maize, and to introduce and monitor the colonisation of Cotesia flavipes Cameron (Hymenoptera: Braconidae) in these stemborers. About 6750 adults of Cotesia flavipes were released at each site, from ‘release stations’, starting one week after plant emergence and repeated fortnightly up to harvest. Pre-release parasitism of the stemborers was determined, for two seasons prior to release of Co. flavipes, during the season of release and one season after the release of this parasitoid. Parasitism was assessed from developmental stages of the stemborers recovered through destructive sampling of 100 plants, starting one week after plant emergence. This was repeated weekly at Katumani, and fortnightly at Kiboko and Ithookwe until harvest. The stemborers recovered from maize were Chilo partellus, Sesamia calamistis, Cryptophlebia leucotreta and Busseola fusca in descending order of abundance, with Ch. partellus being the most widespread stemborer. Cotesia flavipes parasitised and successfully colonised Ch. partellus and S. calamistis in the three sites during the season of release and one season post-release of the parasitoid. Parasitism by Co. flavipes ranged from 7.14–25.80 %. The colonisation rate of Co. flavipes in the two major stemborers in the semi-arid Eastern Province of Kenya suggests the high potential of this parasitoid in regulating populations of stemborers that attack maize in this region.

Studies were conducted in two districts of eastern Uganda from 1997 to 1999 to introduce and monitor the establishment of an exotic parasitoid, Cotesia flavipes Cameron (Hymenoptera: Braconidae), for the control of the stemborer Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), and also to determine the stemborer species complex in maize and sorghum. The study confirmed the presence of four important stemborers, two pyralids Ch. partellus and Eldana saccharina Walker and two noctuids, Busseola fusca Fuller and Sesamia calamistis Hampson. Chilo partellus was dominant, constituting 53–88% of stemborers four d followed by B. fusca at 8–37 %. The most abundant local parasitoid was the larval parasitoid Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae). The pupal parasitoids Pediobius furvus Gahan (Hymenoptera: Eulophidae) and Dentichasmias busseolae Heinrich (Hymenoptera: Ichneumonidae) were also recorded. Parasitism of Co. sesamiae on Ch. partellus ranged between 0 and 13.1 %. The introduced Co. flavipes was recovered from all sites in four consecutive seasons (between 1998 and 1999) causing parasitism of between 4 and 32.9 % on Ch. partellus. Cotesia flavipes was also recovered from the indigenous stemborers B. fusca and S. calamistis. This study indicates that Co. flavipes has established in eastern Uganda.

Using examples from surveys to collect natural enemies of the indigenous African sugarcane borer Eldana saccharina Walker throughout Africa, insight is given into what factors should be investigated should biological control of other indigenous African stemborers be considered. Indigenous host plant range, parts of indigenous and crop hosts attacked, types of natural enemies found in these different niches and natural enemy attack strategies are all important factors to consider when planning redistribution of indigenous natural enemies from one part of Africa to another. This knowledge is important when choosing the correct natural enemy for mass rearing and release into the affected crop, and can be used to manage the crop habitat, using the indigenous tritrophic systems identified, to increase crop diversity and thus effectiveness of indigenous natural enemies.

Studies to determine the relative abundance and distribution of stemborer species and their associated parasitoids in maize and sorghum were carried out during the 1995–1996 and 1999–2000 cropping seasons on Unguja and Pemba, the two main islands of Zanzibar. Three stemborer species were found on both islands in maize and sorghum, with the exotic species Chilo partellus (Swinhoe) (Crambidae) being the most abundant and widely distributed species, accounting for 75.3 % of stemborer attack. It was followed by Sesamia calamistis Hampson (Noctuidae) and Ch. orichalcociliellus Strand (Crambidae). Stemborer abundance was significantly higher in Pemba (1.47 ± 0.20) than Unguja (0.85 ± 0.05). Overall stemborer density in Zanzibar, during the period of study, was 1 03 ± 0.08 stemborers per plant. Stemborer infestation was significantly higher during the short rainy season than long rainy season but it did not vary between maize and sorghum or coral rag and plantation areas. The indigenous parasitoids recorded included ten larval parasitoids: Bassus sp., Chelonus sp., Cotesia sp., Cotesia sesamiae (Cameron), Cotesia ruficrus (Haliday), Dolichogenidea sp., Dolichogenidea aethiopica Wilkinson, Dolichogenidea polaszeki Walker, Megaselia sp. and an unidentified Tachinidae. Among these, the braconid Co. sesamiae was the most common parasitoid, attacking all the stemborer species and recorded from 85.2 % of parasitised larvae. However, parasitism was low— 3.9 % on Unguja and 1.9 % on Pemba. In addition, the efficiency of Co. sesamiae was reduced by two hyperparasitoids—Aphagnomus fijiensis Ferrière and Elasmus sp. Seven pupal parasitoids were recorded, namely Dentichasmias busseolae Heinrich, Brachymeria sp. Westwood, Brachymeria olethria Waterston, Pediobius furvus Gahan, Psilochalcis soudanensis Steffan, Syzeuctus ruberrimus Benoit and an unidentified Chalcididae. The differences in species diversity between the two islands are discussed in the context of the equilibrium theory of biogeography and the geographical size. Classical biological control of the introduced stemborer Ch. partellus using the exotic parasitoid Co. flavipes to supplement the indigenous parasitoids in population regulation is proposed as a potentially useful option for Zanzibar.