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In the Western Cape province of South Africa, codling moth (Cydia pomonella) is the most important lepidopteran pest of apples and pears. Currently an integrated pest management (IPM) strategy is followed. However, chemical control still plays an important role in the control of this pest. Entomopathogenic nematodes (EPNs) of the families Steinernematidae and Heterorhabditidae have been successfully utilized as biological control agents in classical, conservation, and augmentative insect pest management programmes. In this review different biological control options for control of codling moth are considered, with special emphasis on research being done on the biological control of codling moth using EPNs. To integrate nematodes into an IPM system, it is important to conduct research under local environmental conditions for a specific crop. Application of EPNs against codling moth will target the diapausing larval overwintering population above-ground. Especially for commercial application, the unique environmental conditions in the various production areas need to be assessed to allow for the effective use of various EPN species. Orchard application, onto trees poses its own unique challenges with regard to the inundative application of EPNs. Research on the use of EPNs to control codling moth and obstacles encountered in the success of codling moth control are discussed.
The genus Agabus (Dytiscidae) in North Africa is poorly studied. Agabus (Gaurodytes) ramblae was found for the first time in two localities in Tunisia (Sidi Bouzid and Tozeur governorates) and one in Libya (Yafran province). This is the first report of this species from Africa, which increases the number of Agabus species known from North Africa to 13. The known distribution of A. ramblae is discussed. An updated checklist of Agabus species occurring in the North Africa is provided.
Leucaena leucocephala (Lam.) de Wit (Fabaceae) was introduced to Ethiopia in the early 1980s. Even though this plant is not yet problematic, nor categorized as an invasive species in the country, there are several reports that place leucaena as an extremely damaging weed elsewhere, raising warning signs regarding the potential impacts of the plant in Ethiopia. The objective of this study was to make a preliminary assessment of the impact of a pre-dispersal seed feeding bruchid associated with L. leucocephala and determine its impacts on seed germination in Ethiopia. The study demonstrated that the bruchid Acanthoscelides macrophthalmus (Schaeffer) (Chrysomelidae) was present at all sites surveyed and damaged up to 44 % of seeds of L. leucocephala at the study sites. Damaged seeds showed reduced germination performance resulting in seedlings with weak, yellow and fragile root systems compared to healthy seeds. This is the first report on the presence of A. macrophthalmus in Ethiopia. Therefore, future studies need to focus on the level of infestations of the plant and the impacts of the plant across the country.
Knowledge of the life cycle of Hemijana variegata is important for sustainable utilization of this edible insect. The fecundity and survival of H. variegata were investigated under ambient conditions in the laboratory. Eggs were laid in clutches of between 180 and 490 eggs per clutch, and took an average of 8.45 days to hatch. Hemijana variegata has five larval instars. The first-instar larvae are unable to feed on older leaves, thus survival of the larvae requires that hatching be synchronized with leaf emergence of the host plant in the field. The duration of the pupal stage varied between 32 days and more than 119 days. This wide variation may be an adaptation to annual climatic fluctuations such as years with no rain or late rainfall. This strategy might ensure their survival in areas where droughts are often experienced. The larvae had the highest mortality rate, followed by the pupae and then the eggs, with survivorship rates of 30.12 % (larvae), 63.98 % (pupae) and 98.67 % (eggs). Pupal survivorship could be higher, as 24 % of the pupae had not emerged after two years when the experiment was terminated.
Damage caused by the fruit fly Bactrocera dorsalis (Hendel) (syn. B. invadens Drew, Tsuruta & White) (Diptera: Tephritidae) on mangoes in Senegal leads to production losses. A potential biological control agent against this pest is the weaver ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae). Senegalese mango-based orchards present a diversity in design and management practices that can influence the abundance of these two species in orchards. In this study we evaluated i) the ability of the O. longinoda ant to limit B. dorsalis damage in Senegalese orchards, and ii) variations in population abundance for these two species depending on orchard design and management practices. The study was conducted in Senegal in the Niayes area and the Thiès plateau. Fifteen orchards were sampled among three out of four kinds of orchards identified in this area: (1) ‘No-input mango diversified orchards’, (3) ‘Medium-input citrus-predominant orchards’ and (4) ‘Medium-input large mango- or citrus-predominant orchards’. In one of the orchards we measured infestation rates and numbers of fly pupae that developed from mangoes collected from trees (cv. Kent) ‘with’ and ‘without’ O. longinoda colonies over three harvesting periods (May, July and August) in 2013. The abundance of O. longinoda and B. dorsalis was measured for two months in the dry season and two others in the rainy season in the 15 orchards in 2012. The presence of O. longinoda on trees reduced the proportion of mangoes attacked by B. dorsalis as well as the number of pupae that developed from infested mangoes. The abundance of O. longinoda and B. dorsalis was negatively correlated. The abundance varied depending on the orchard design and management practices. O. longinoda abundance was greater in orchard types 1 and 3 than in type 4. Conversely, B. dorsalis abundance in the rainy season tended to be greater in orchard type 4 than in types 1 and 3. This study showed that O. longinoda is effective in limiting mango infestations by B. dorsalis. It also showed that the abundance of these two species was influenced by the orchard design and management practices. Therefore, using O. longinoda to control fruit flies is possible in Senegalese mango-based orchards by promoting weaver ant preservation.
Whitefly (Homoptera: Aleyrodidae) is among the most important crop pests around the world. Recent work has focused on obtaining basic ecological information about whiteflies for the development of non-chemical techniques to control these insect pests. In this research, a series of experiments were designed to clarify the ecological characteristics of whiteflies in Hebei Province in northern China in 2012. Two whitefly species, Trialeurodes vaporariorum (Westwood) and Bemisia tabaci (Gennadius) biotype Q, were investigated in the experimental greenhouses. The adults of these mixed whitefly populations displayed two activity peaks: one in the morning (09:00–11:00) and the other in the afternoon (15:00–16:00), with a tranquil period at night. The proportions of the two whiteflies at different leaf positions changed dramatically between the spring and autumn. The proportion of adults in the middle leaf position increased for both species in autumn compared to spring. The majority of T. vaporariorum moved downwards, whereas the B. tabaci moved upwards in autumn compared to their distributions in spring. The within-plant distribution of B. tabaci was more closely related to the leaf positions than leaf ages. In contrast, T. vaporariorum was more associated to leaf ages than leaf positions.
Two new species of Anacharis Dalman, 1823 from the Afrotropical Region are described: Anacharis afrotropica sp. n. and Anacharis rwenzori sp. n. Diagnostic characters and data about biology, distribution and affinities with other Anacharis species are given.
The black bean aphid, Aphis fabae Scopoli is a polyphagous aphid causing significant damage to several cultivated and uncultivated plants. In the present work, we have used COI barcoding to distinguish between three subspecies of A. fabae, frequently found in Tunisia, namely A. f. fabae, A. f. solanella and A. f. cirsiiacanthoidis. Results of our study revealed that COI barcoding was efficient to generate haplotypes discriminating A. f. fabae from the two remaining subspecies. Indeed, among seven haplotypes, identified and named H1–H7, five were found exclusively in A. f. fabae, one represented exclusively A. f. cirsiiacanthoidis, and one was shared by A. f. cirsiiacanthoidis and A. f. solanella. However, the differentiation of Aphis f. fabae from A. f. solanella and A. f. cirsiiacanthoidis was not further supported by a phylogenetic distinction, as it was revealed by neighbour-joining and maximum parsimony phylogenies. Such a coherent genetic structure of the A. fabae complex, not governed by the subspecies factor, as inferred from our present mitochondrial (mt)DNA data, is in agreement with previous analyses based on genomic DNA. Therefore, we hypothesize that the phenotypical and physiological processes having led to differentiation between subspecies would have arisen from weak selection pressures, thus resulting in little genetic change between subspecies. In combination with additional still-to-come data from additional markers, results of this study will be important to constitute a groundwork for pest integrated management.
Monitoring of the northern house-martin in northeastern Algeria recorded the first observation of this species in early February, whereas the greatest movements occurred around the beginning of March. Breeding activity of the northern house-martin usually started one month after their return from migration, apparently triggered by the availability of food resources. Our study on the feeding frequency to nestlings showed that although feeding visits were important in early nestling rearing, the highest values were recorded at the ages of 6–10 days. The number of prey brought to chicks was highest during May and lowest during August. Analysis of the diet of chicks revealed that it was composed mainly of 48 families representing eight orders of insects, with significant dominance of Homoptera throughout the breeding season.
The exotic tephritid Bactrocera invadens (syn. Bactrocera dorsalis) and the native Ceratitis species constitute serious pests and major impediment to Citrus production in Nigeria. Lack of accurate and reliable diagnostic methods independent of the life stages intercepted for both genera hampers implementation of appropriate early management programmes to avoid economic losses and delays in quarantine decision regarding these pests. We used a PCR amplification technique to successfully establish RFLP patterns of the COI coding gene to differentiate the exotic B. invadens from the native Ceratitis species infesting sweet oranges in Nigeria. The universal barcoding primer pair LCO1490/HCO2198 was used to amplify 658 bp-long fragment of the mitochondrial COI coding gene. The amplified fragment was analysed by automated direct sequencing and RFLP. Intraspecific variation in nucleotide sequences of B. invadens was very low with not more than 2 bp substitutions in four out of 31 individuals sequenced. Among the Ceratitis species intraspecific variation was also very low with at most 4 bp substitutions in few of the 32 individuals sequenced. The restriction enzymes Rsa I and Hsp92 II produced patterns that clearly and unambiguously separated B. invadens from Ceratitis spp. DNA barcoding was also used to confirm the identities of the tephritid species analysed. The molecular method established in this study will enhance easy monitoring, early detection of species involved, and implementation of appropriate management programmes that effectively reduce yield loses in Citrus production in Nigeria.
Aedes albopictus (Skuse) was first recorded in Nigeria in 1991 during a post epidemiological surveillance of yellow fever epidemics in Delta State. In this report, we present a map of the current distribution of Ae. albopictus and its possible epidemiological implications based on accessible records of mosquito fauna in Nigeria using electronic e-journal searching engines. We also report the results of a field study on population dominance between Aedes aegypti and Ae. albopictus in a woodland habitat in southwestern Nigeria between March and November 2002. Of over 100 accessible papers on mosquito fauna in Nigeria, only 18 have reported information on Ae. albopictus. Literature shows that Ae. albopictus became well established in southeastern Nigeria and then spread to other southern regions. There was no information about the species in northern Nigeria except Kano where a record of its breeding was reported. Data showed dominance of Ae. albopictus over Ae. aegypti in southeastern Nigeria but the reverse was observed during a field investigation at Ikenne farm settlement in southwestern Nigeria. Aedes albopictus was perhaps involved in the transmission of arboviral infections and Bancroftian filariasis in southern Nigeria. Data show that Ae. albopictus is well established in southern Nigeria but not in arid zones of the country. Its establishment and role as a vector of arboviral infections and Bancroftian filariasis in southern Nigeria should be a source of concern. The present report therefore serves as a baseline map for future epidemiological surveillance and the understanding of ecological distribution of Ae. albopictus in the country.
Several vectoring insects, such as aphids and white fly, harbour secondary bacterial endosymbionts. When an insect vectors a persistently transmitted plant virus, this virus should pass through the insect gut into the haemolymph. The secondary bacteria, however, may affect the movement, persistence and replication of the viruses, thereby influencing the vectoring efficacy or specificity of the insect in respect to these plant viruses. This issue, however, has not yet been fully investigated. Hence, the aim of this primary study is to investigate the effect of secondary bacterial endosymbionts of Sitobion avenae clones in respect of the vector specificity and transmission efficiency of barley yellow dwarf virus, as well as to highlight in general the role of secondary bacteria in virus transmission. The experiments were performed according to standard protocols using one virus strain, BYDV-PAV, and four S. avenae clones harbouring different bacterial and genetic profiles. We found that all tested clones were able to transmit the tested virus strain. Therefore, it can be concluded that the secondary bacterial endosymbionts may affect transmission efficiency of S. avenae but not their vectoring specificity. That said, the clones did not significantly differ in their efficiency of virus transmission. However, this study is initial evidence of the effect of secondary bacteria endosymbionts of aphids on virus transmission and further investigation is, therefore, still required.
Wax moth larvae (Galleria mellonella L.) and yellow mealworm larvae (Tenebrio molitor L.) were reared on five different diets respectively, to determine which diet resulted in the highest increase in insect larval weight. Wax moth eggs were placed on each diet and larvae that developed therefrom were weighed after 51 days. A diet containing 118 g wheat flour, 206 g wheat bran, 118 g milk powder, 88 g brewer's yeast, 24 g wax powder, 175 ml honey and 175 ml glycerol, produced the heaviest larvae, with an average weight of 0.19 g per larva. Mealworms were weighed 62 days after adult beetles were placed on the various diets. The heaviest larvae were produced on a diet consisting of wheat bran only, with each larva weighing, on average, 0.0154 g. Nematode production of Heterorhabditis zealandica and H. bacteriophora using wax moth, mealworm, codling moth (Cydia pomonella) and false codling moth (Thaumatotibia leucotreta) larvae were determined, as well as was the correlation between the weight of the host larvae and that of the nematode progeny produced. Wax moth larvae produced the highest number of H. zealandica and H. bacteriophora per g of host. The mean number of H. zealandica and H. bacteriophora infective juveniles produced were 1 459 205 and 1 898 512, respectively, per g of host. The mean number of H. zealandica produced per g of codling moth and false codling moth larvae was 57 582 and 192 867, respectively. Lower mean numbers were produced for codling moth and false codling moth larvae when using H. bacteriophora, with 39 653 and 97 652 nematodes produced per g of the respective hosts. A significant positive linear relationship existed between weight of wax moth larvae and that of mealworm and the number of nematodes produced. Using frozen hosts of wax moth larvae and mealworm, comparable reproduction of nematodes was only found with mealworm.
A preliminary checklist of butterflies collected in the Caldera de Lubá is presented. Of the 70 species cited, 14 represent the first records from Bioko (Graphium ucalegon ucalegon, Nepheronia argia argia, Pentila fidonioides, Cymothoe althea, Cymothoe capella, Cymothoe consanguis, Lachnoptera anticlia, Amauris vashti, Bicyclus golo, Bicyclus neustetteri, Coeliades forestan, Ceratrichia phocion camerona, Celaenorrhinus plagiatus and Semalea pulvina). From the results obtained after applying different diversity indices (richness, dominance, evenness) and accumulation functions, we can infer that the Rhopalocera of the Gran Caldera de Lubá constitute an extraordinarily diverse community of great evenness, lacking generally highly threatened taxa or species with a localized occurrence on Bioko and, collectively, the fauna is characterized by a highly even and stable structure. The results obtained can provide the tools to develop conservation measures in the future, as well as to strengthen the creation of Scientific Reserves used as genetic resources warehouse.
The cockroach, Blatta orientalis, is among one of the important domestic pests found in the semi-arid areas of Algeria. In this study, the insecticidal activity of spinosad, bioinsecticide, was tested against B. orientalis using different concentrations. Bioassays were done by topical application on newly emerged adult females under laboratory conditions. The results showed that the product exhibits a high level of toxicity with a dose-response relationship. The enzymatic analyses of the treated adults of B. orientalis with the determined LC50 dose revealed a neurotoxic activity of spinosad, with an inhibition of acetylcholinesterase and a stimulation of the detoxification system that is interpreted by the increase of glutathione-S-transferase activity. In other experiments the compound was applied at LC50 on a newly emerged females and its effect was investigated on reproduction during the first gonadotrophic cycle (0, 2, 4 and 6 days) and the ovarian protein contents. The results showed that spinosad reduced the number of oocytes per paired ovaries, the size of basal oocytes and the ovarian protein contents.
Four different thrips species; marigold thrips, Neohydatothrips samayunkur; western flower thrips, Frankliniella occidentalis; tomato thrips, Frankliniella schultzei and onion thrips, Thrips tabaci were recorded on marigold plants in the field. Tagetes erecta L. was grown in the experimental farm, Giza governorate, Egypt. The survey was carried out during mid-April to late July and from early September to late December 2013. Weekly samples were randomly selected and examined for the presence of the different thrips species. Identification of thrips species was based on morphological characters. Neohydatothrips samayunkur recorded the highest average numbers in both periods of survey, from mid-April to late July and from early September to late December 2013 (189.5 and 143.6 individuals/plant, respectively), while the lowest number was recorded for T. tabaci (4.6 and 5.9 individuals/plant). This is the first report of N. samayunkur in Egypt. Description of the recorded species is given as well as their seasonal abundance on marigold plants.
Lichenophanes szujeckii sp. n. is the second (after L. funebris Lesne, 1938) species of the genus described from Zambia. Besides the description, the paper presents a key to the identification of the representatives of Lichenophanes Lesne occurring in Zambia, together with remarks on the systematics and distribution of particular species.
Occurrence of the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in Ethiopia was confirmed following heavy infestation of tomato, Solanum lycopersicum L., in the Central Rift Valley (CRV) region of Ethiopia in February 2013. The pest wiped out tomato plantations, causing 100 % crop loss for some producers. This was despite the use of a variety of insecticides locally available to manage other vegetable insect pests. In this study, 10 insecticides from different insecticide classes including pyrethroids, organophosphates, spinosyns, insect growth regulators and diamides were screened for their efficacy against T. absoluta using a randomized complete block design with two different planting dates in 2013. The mean fruit infestation in the untreated control plot ranged between 54 and 76 %. In plots treated with diamide insecticides (chlorantraniliprole) fruit infestation was significantly lower with 2–6 % fruit damage followed by spinosyns (spinetoram and spinosad) with 30–35 % damage. A similar trend was observed in leaf damage severity. Mean marketable and total yield from the best performing treatment, Ampligo (a mixture of a diamide and a pyrethroid), were 18.4 and 31.9 t/ha, respectively. The corresponding marketable and total yields from the untreated plot were 3.2 and 13.5 t/ha. This corresponds to yield losses of 82.6 and 57.7 % in marketable and total yield, respectively. T. absoluta has the potential to develop pesticide resistance very quickly due to short generation time and high reproductive potential. Insecticides found effective need to be used judiciously including the rotation of effective insecticides from different classes. Future research on the management of this pest should focus on developing a biocontrol based integrated pest management system.
The two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) is a cosmopolitan pest of many greenhouse and field crops worldwide. Host plant quality affects the development, survival and fecundity of T. urticae. The life table parameters of T. urticae on three country bean varieties (Lablab purpureus L.), namely IPSA Seam 1, BARI Seam 1 and Kartica, were maintained at 25 ± 2 °C, 65 ± 5 % relative humidity (RH) and a photoperiod of 16:8 (L:D) in a growth chamber. The mean immature development time of T. urticae from egg to adult was significantly longer on IPSA Seam 1 than on the other two varieties. There were significant variations in fecundity and longevity which resulted in large differences on population growth parameters like the intrinsic rate of natural increase (rm), net reproductive rate (Ro), finite rate of increase (λ) and doubling time (tD). Kartica and BARI Seam 1 were the most suitable host for T. urticae with rm = 0.230 and 0.223 (offspring/female/day), respectively. The slowest population growth was observed on IPSA Seam 1 with rm = 0.197. The findings of the current study indicated that IPSA Seam 1 is a less suitable variety to two-spotted spider mite compared to the other two varieties. Furthermore, these results may lead to finding and screening process of comparatively resistant country bean varieties to be used in the management of T. urticae.
Since its detection in Kenya in 2003, the exotic fruit fly, Bactrocera dorsalis, has rapidly spread throughout sub-Saharan Africa. This study was conducted to predict the potential distribution of B. dorsalis in the southern African region using suitable environmental variables and some feral host plants. Presence data from surveillance information carried out in Mozambique and Swaziland up to 2013 were used for niche modelling to predict the potential geographical distribution of the pest in the southern African region. Prediction for its national distribution within Swaziland was also carried out using distribution data for eight feral host plants. Although variable between countries, predicted habitat suitability for the pest was potentially greater in the eastern parts of southern Africa, with response curves suggesting higher probability of the pest's occurrence in low altitude areas with moderate diurnal temperature and high precipitation during the wettest month of the year. Of the host plants considered, the pest's distribution was associated mainly with Ficus sycomorus. The model's prediction also suggested that human-associated activities, such as irrigation, could influence the distribution and establishment of the pest even in areas of low host-plant richness. Since the presence of B. dorsalis causes restrictions in international trade of its host plants, it is imperative that countries within the region continue surveillance programmes and coordinated strategies to reduce the impact of the pest.
Attagenus matamata Kadej & Háva sp. n. is described from South Africa. The habitus, antenna and genitalia are illustrated and compared with related species.
The impact of Bacillus thuringiensis and native Trichogramma turkistanica on the infestation rates of two lepidopterous pests, Virachola livia and Ectomyelois ceratoniae, was assessed in field experiments conducted in four pomegranate farms distributed in the Taif region of Saudi Arabia. Pomegranate trees were sprayed with B. thuringiensis spores, and indigenous T. turkistanica was inundatively released during the pomegranate fruiting season from April to September of 2014. The highest infestation rates with E. ceratoniae and V. livia in control and treated trees gradually increased until the end of the season, reaching 79, 54 and 22 % for E. ceratoniae, and 22, 16 and 7 % for V. livia in control, Bacillus-treated trees, and Trichogramma-treated trees, respectively. The mean percentages of fruits infested with E. ceratoniae or V. livia were significantly different between the untreated trees and both the trees treated with Trichogramma and those treated with Bacillus. Moreover, the trees treated with Trichogramma had a lower infestation rate by both E. ceratoniae and V. livia compared to the trees treated with Bacillus. The number of larvae collected from infested fruits varied from one to two larvae per fruit for both E. ceratoniae and V. livia. Use of Bacillus or native Trichogramma to control these pests can achieve high yields of Taify pomegranate of better quality.
The present study was conducted in Elkom Elakhdar village, Shebin El-Kom, Menoufia Governorate, during 2012 to determine the species composition and the occurrence frequency of dust mites collected from three rural houses of different development stages, as well as to determine the toxicity limits of different concentrations of three essential plant oils against two species of the family Pyroglyphidae, the main cause of allergies to humans. The results revealed 11 mite species belonging to five families (Pyroglyphidae, Chortoglyphidae, Glycyphagidae, Acaridae, and Cheyletidae). Of the total collected number of mites (5276) the most dominant species were the dust mites Dermatophagoides farinae (66.1 %), followed by D. pteronyssinus (23.3 %), while the rest of the species, Chortoglyphus arcuatus, Lepidoglyphus destructor, Glycyphagus domesticus, Gohieria fusca, Tyrophagus putrescentiae, Caloglyphus sp, Cheyletus malaccensis, Blomia sp. and Acarus siro ranged between 0.16 and 2.0 %. Regarding the effect of temperature on mite populations, temperature more than 25 °C in summer decreased the numbers of D. farinae and D. pteronyssinus. Toxicological tests of three essential plant oils against adult stages of D. farinae and D. pteronyssinus showed that lemon grass oil was more effective than geranium and thyme oils, with a mortality of approximately 100 % at 800 ppm concentration for both species. The LC50 of lemon grass was 228.992 ppm and 293.615 ppm against the two species, respectively. From these results it is recommended that application of control measures during summer when the mite population density is at its lowest and to use botanical oil extracts which can be effectively implemented in integrated pest management programmes.
The susceptibility of rhinoceros beetle larvae, Oryctes agamemnon, to different concentrations of Syzygium aromaticum cloves was studied under laboratory conditions. Two forms of cloves were applied, first as finely powdered flower buds and later as an essential oil. The clove powder concentrations used against the larvae were 1, 3, 5, 7 and 9 %, and the clove essential oil (CEO) was used at concentrations of 1, 2, 3, 4 and 5 %. The highest (68.5 %) and lowest (2 %) larval mortality were caused by 9 % and 1 % clove flower bud powder (CFBP), respectively. However, the CEO was more effective against the larvae of O. agamemnon than the powder. Mortalities ranged from 12.5 to 87.9 % at oil concentrations of 1 and 5 %, respectively. The results also showed that the two forms of cloves persist in the treated soil for 7 to 8 days. Additionally, the clove oil and powder have a residual effect in treated soil that provides sustainable protection for date palms against root borers. Accordingly, it was concluded that cloves in either powder or essential oil form are very promising for controlling Oryctes larvae. These results indicate that clove flower buds and essential oils are desirable tools for crop protection in the future, promoting environmentally friendly pest control strategies.
Based on the literature and new faunistic records, the diversity and distribution of the tiger beetles in Tunisia are summarized and discussed. In total, 15 species (one with two subspecies) are reported from the country. However, the occurrence of Cicindela maroccana maroccana is questionable, and should be confirmed by newer data. Checklists of tiger beetles are also provided for each Tunisian governorate. The highest diversity was recorded in the region adjacent to the Mediterranean Sea coastline. The area is mainly up to 100 m a.s.l. with salt marshes, strands of sandy sea beaches and river banks as main types of habitats occupied by Cicindelinae (14 species or 94 % of tiger beetle fauna). Mountainous and desert regions are characterized by much lower diversity (six species or 38% of fauna and two species or 13% of fauna, respectively). Cicindelinae occurring in these areas inhabit predominantly river banks and oases. In chorotype classification, Tunisian tiger beetles fall into six different groups including West Mediterranean species (50% of fauna), Maghreb endemics (19%), Mediterranean, North-African, Mediterranean-Westturanian and Afrotropico-Indo-Mediterranean species (each of them 6% of fauna). According to their phenology, the Tunisian tiger beetles may be divided into three main groups: 1) spring-active species (Cicindela campestris atlantis and all Neolaphyra taxa), 2) spring-summer-active species (Calomera littoralis littoralis, C. lunulata lunulata, Cassolaia maura cupreothoracica, Lophyra flexuosa flexuosa, Myriochila melancholica melancholica, Grammognatha euphratica euphratica), and 3) summer-active species (Calomera aulica aulica, Cylindera trisignata sciliensis and Cephalota spp.).
For two successive years, a survey was conducted of entomopathogenic fungi associated with two naturally infected predatory insect species on different plantations of the Nile Delta in northern Egypt. Adults of the eleven-spotted ladybird beetle, Coccinella undecimpunctata L. (Coleoptera: Coccinellidae), are frequently observed with infections of the entomopathogenic fungus Beauveria bassiana, which caused mortality of 4.1 % and 5.4 % in the adult ladybird beetle population sampled in July 2006 and 2007, respectively. However, mycosed individuals of the seven-spotted ladybird, Coccinella septempunctata, were rarely encountered. Adults of the syrphid fly Syrphus corollae (Diptera: Syrphidae) are also subject to infection with the entomopathogenic fungus Entomophthora syrphi. Data showed that E. syrphi caused mortality in syrphid fly adults at rates of 4.6 % in April to 0.2 % in June 2006, whereas mortality rates ranged from 6.1 % in April to 0.9 % in June 2007. Mycosed syrphid adults were always found in an elevated pssition (frequently near the tips of artichoke leaves). Two years of field monitoring revealed that both entomopathogenic fungi, B. bassiana and E. syrphi, fail to distinguish between their original hosts and the predatory insects that coexist in the same ecosystem.
Hessian fly, Mayetiola destructor (Say), is an endemic pest in Tunisia and is among the most destructive biotic stresses of commercial cereals. Genes in wheat that confer resistance to this insect provide the most efficient and economical means of crop protection. Yet, attempts to breed for resistant cereal genotypes are hampered by the periodic emergence of virulent pest biotypes that are unaffected by the plant's resistance factors in use. Therefore, it is crucial to undertake permanent surveys in order to establish baseline information on the status of germplasm resources. A survey of infestation was conducted during the growing season 2011/2012, over the four most important cereal-growing provinces of Tunisia (Béja, Jendouba, Kef and Siliana), which highlighted variation in the incidence and severity of attacks between regions and periods of the year. We recorded two intense outbreaks occurring in early March and late April, suggesting that eradication should be applied in the month of February to hinder the development of subsequent generations. Unlike this constancy in the insect biological rhythm, the genetics of its physiological interaction with the cereal host seems to be altered by mutations leading to the development of new virulent strains. When testing 25 cereal genotypes to infestation by Hessian fly in Béja, Jendouba and Kef, we found that the bread wheat cultivar ‘Salambo 80’ was susceptible. This genotype was resistant to Hessian fly in North Tunisia ten years before. In contrast to ‘Salambo 80’, bread wheat ‘Mahon 73’ was characterized by stable resistance across different infestation circumstances, indicating that it would provide a solution for breeding against the Hessian fly races currently prevailing in North Tunisia. The herein reported results represent an additional step of a long-term effort that should be maintained and updated to keep up with the co-evolutionary dynamics associating cereals to their feeding fly, and stay continuously alerted of biotype development.
The pea aphid, Acyrthosiphon pisum (Hemiptera: Aphidae), and the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), are two major pests that conjunct in their virulence pathways against hosts by settling a gene-for-gene interaction model. The most effective controlling method of these pests is the deployment of host resistance (R) genes, which strongly depends on both host and insect genotypes. MicroRNAs (miRs) are noncoding RNAs of ∼22 nucleotides inducing sequence-specific post-transcriptional gene silencing. The identification and analysis of miRs is nowadays a useful reverse genetics tool for studying insect virulence and host resistance pathways. in the present study, we utilized 15 virulence-regulatory miRs of the Hessian fly, Mayetiola destructor (Diptera: Cecidomyiidae), to search for homologies across 103 A. pisum mature miRs and 86 D. citri miR-like expressed sequence tags (ESTs), mined from several databases. Our results showed that reference miRs from M. destructor could be grouped with their most similar microRNA counterparts from A. pisum and D. citri within eight phylogenetic clades, and that seven of A. pisum miRs clustered with M. destructor ones at a similarity threshold of 90 %. Such structural similarities strongly suggest that different avirulence (Avr) genes from M. destructor, A. pisum and D. citri would be tightly regulated by a regulatory network including similar miRs. Our study offers a promising way to further explore the structural similarity between miRs toward their potential use in Integrated Pest Management (IPM).
In the article ‘Afrotropical Culicoides(Diptera: Ceratopogonidae): description of the hithertounknown male of C. walkedBoorman, 1979 from South Africa’ by K. Labuschagne, R. Meiswinkel and C.H. Scholtz that appeared in African Entomology23(1): 132–138 (March 2015), the number of paratypes of the senior synonym should have read as follows (not ‘59, same data…’, ‘29, same data…’ and ‘19, Makindu…’):
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