A groundnut pest occurring in South Africa and widely reported as Aproaerema modicella (Deventer) has recently been identified by mtDNA CO1 analysis as Aproaerema simplexella (Walker), a strain native to Australia. Two experiments were conducted during 2011–2012 growing season at five sites in South Africa. The first experiment examined the preference of A. simplexella between groundnut, soya bean, lucerne, pigeon pea and lablab (common known host crops for A. modicella). The second experiment examined the effect of cypermethrin on the control of the pest on soya bean and groundnut at two sites. Among the host crops tested, soya bean was the most preferred by the pest followed by groundnut at all sites. The pest was also observed on pigeon pea at all sites, but the infestation was very low. Lucerne was observed as the less preferred host for this species. No infestation was observed on lablab bean across the sites. Spraying cypermethrin in groundnut and soya bean reduced infestation in both crops to very low levels. In the unsprayed plots, the high infestation levels significantly reduced crop yields.

Applications of Madex® (granulovirus) against the codling moth, Cydia pomonella, which targets neonate larvae before or during their initial entry into fruit, provide selective control of this key apple pest. Differences in the efficacy of Madex® treatment against C. pomonella larvae were observed in an experimental orchard in northern Italy on two apple tree cultivars, ‘Golden Delicious’ and ‘Red Chief’. The intensity of egg-laying by the moth may vary from one cultivar to another. The composition of a metabolite blend on the leaf surface consisting of glucose, fructose, sucrose, sorbitol, quebrachitol and myo-inositol is one of the factors that could explain these variations. Our hypothesis was therefore that variations in the efficacy of Madex® could be related to variations in egg numbers, itself related to the composition of metabolites on the leaf surface of each cultivar. Differences in egg-laying (number and localization) were recorded on the two cultivars, ‘Golden Delicious’ and ‘Red Chief’, untreated or treated with the larvicide. Madex® had the same efficacy on both cultivars in terms of the reduction of fruit damage due to larval feeding. Surprisingly, the effect of Madex® on reducing damage seemed less tied to a lethal effect of the larvicide on the larvae than to egg-laying reduction, the latter being linked to changes in chemical signals of the leaf surface induced by applications of Madex®. This observation was verified by experiments on egg-laying on an artificial substrate. When the active metabolite blends mimicking the corymb leaf surface compositions of each cultivar (untreated and treated with Madex®) were applied to nylon cloth egg-laying substrates, significant reductions in acceptance (% of egg-laying females) and egg-laying stimulation (number of eggs per egg-laying female) were observed. The reduction of eggs on ‘Red Chief’ could be primarily explained by a drastic effect on egg-laying stimulation, whereas the reduction on ‘Golden Delicious’ was partly due to a lower acceptance. The number of eggs laid naturally differs from one apple tree cultivar to another. The effects of reduced egg-laying caused by applications of Madex® were due to biochemical changes in surface blends, depending on the cultivar.

Sex ratio distortion in the tropical butterfly Acraea encedon is caused by infection with a male-killing bacterium of the genus Wolbachia. Severely female-biased populations with extremely high bacterial prevalences were previously reported in A. encedon. In this paper, we describe a study in which the spatial variations and the temporal changes in the population sex ratio and the prevalence of the male-killing Wolbachia were thoroughly investigated in the wild populations of Acraea encedon in Uganda between 2005 and 2007. The two parameters were found to vary extensively over space and time, indicating that the male-killer is highly dynamic. Both the female-bias and the Wolbachia prevalence were lower than that recorded in the literature.

This paper describes a new species of the genus Rhombognathus in the family Halacaridae (Acari: Prostigmata) under the name of Rhombognathus accrue sp. n. The material examined in the present study was collected at Labadi Beach on the coast of Accra in Ghana. Mites were recovered from small algae of the order Gigartinales in the phylum Rhodophyta on several rocks on the shore less than 0.5 m depth. Rhombognathus accrae is characterized by 1) dorsal plates ornamented with areolae, 2) anterior epimeral region with two adjunctive setae and posterior epimeral region with one adjunctive seta, 3) five perigenital and four subgenital setae in the female, 4) nine or 10 perigenital setae on each side of the genital foramen and four subgenital setae in the male, 5) telofemora I-IV with 4/3, 4/3, 3/0, 3/0 dorsal/ventral setae, genua I-IV with 5, 5, 3, 3 setae, 6) narrow palmate accessory process with about seven teeth. This is the first record of the genus from West Africa. A key to the African species of Rhombognathus is provided.

The effect of temperature, ultraviolet (UV) radiation and sunlight on the pathogenicity, yield and DNA genome pattern of the entomopathogenic virus SpliMNPV to the Egyptian cotton leafworm Spodoptera littoralis (Boisduval) was studied. The viral pathogenicity in terms of larval mortality, and yield in terms of polyhedral inclusion bodies/g larval body weight, significantly increased with the increase of temperature; with optimal temperature of 30 °C for viral yield. However, the pathogenicity significantly decreased with the increase of the exposure period, under the stress of both UV radiation and sunlight, in case of non-shielded exposed viral samples. In contrast, sunlight and UV had no significant effect on the viral pathogenicity in shielded exposed samples. The viral yield significantly decreased with the increase of the exposure period to UV radiation. The same pattern also held true for the exposure to sunlight in case of non-shielded exposed samples without using a UV filter. The viral DNA genome pattern was not affected under the stress of temperature, UV-radiation (shielded samples), sunlight using a UV filter (shielded or non-shielded samples), and sunlight without using a UV filter (shielded samples). Whereas, the intensity of the viral DNA, in non-shielded samples, decreased gradually with the increase of the exposure period to UV radiation and sunlight without using a UV filter.

In this study the life-history of Oomyzus sokolowskii (Kurdjimov), a parasitoid of the diamondback moth (DBM) Plutella xylostella (L.) as characterized. The life cycle, adult size, fecundity, ovigeny, parthenogenesis, host age preference and host-searching behaviour by parasitoid females were studied under laboratory conditions. Oomyzus sokolowskiiapos;s life cycle lasted 15. 6 days. Sexual dimorphism was recorded, with females being bigger than males. The species is synovigenic. The parasitism rate was significantly different between mated and unmated females, which implied that mating stimulated the behaviour of parasitism. Thelythokous parthenogenesis was not recorded. Females could parasitize all larval stages and pre-pupae, but the parasitism rate was higher in the fourth larval stages of DBM. The host-seeking behaviour was influenced by host spatial patchiness; O. sokolowskii females performed better when they were placed in a 7 cm3 oviposition box. This study gives a better understanding of the life history traits of O. sokolowskii, which has been neglected in the biological control of DBM in tropical regions. The study suggests the use of O. sokolowski as a promising candidate for the management of DBM in cabbage in combination with other IPM strategies.

A study was done to compare the production efficiency, in terms of total wet and dry larval yield and average weight of larvae of Musca domestica, reared at a constant temperature and nutrient supply but with increased larval density per unit of feed supplied. Wet weight yield increased with increased stocking density at a rate of 16.74 g/0.1 g eggs added while dry weight yields increased at a rate of 2.75 g/0.1 g eggs added. At the maximum rate tested, (6.318 eggs/g wet feed) no decrease in rate was observed and it is therefore concluded that the maximum wet and dry yields will be obtained at rates even higher than 6.318 eggs/g wet feed. Average larval weight was significantly influenced by density with the maximum observed at 3.159 eggs/g wet feed with a constant decrease up to 5.002 eggs/g wet feed and no significant differences observed at higher densities. It was thus concluded that, for the purpose of mass rearing larvae of M. domestica for biomass conversion, larval density as expressed per unit of nutrient supplied could be increased to levels of above 6.318 eggs/g wet feed but, for the production of breeding stock densities, should be maintained at levels of 5.002 eggs/g wet feed or lower.

The analysis, by gas chromatography coupled with mass spectrometry, of the essential oils extracted from six conifers showed that the monoterpene family is predominant and that the major component was pinene. In contact tests, at a dose of 50 µl essential oil/50 g of seed, all essential oils affected very significantly the longevity, fecundity and emergence of Callosobruchus maculatus (Coleoptera: Bruchidae). In inhalation tests, after 24 h of exposure at a dose of 37.5 µl essential oil, Cupressus sempervirens originating from Algeria and Tunisia caused 100 % mortality in adults of C. maculatus. In repulsivity tests, Tetraclinis articulata of Tunisian origin was very efficient at a rate of 94 %. There was no secondary effect on Vigna unguiculata seeds treated with the highest doses (50 and 75 µl of essential oils), as evidenced by weight and germination capacity.

Charipinae material from Africa deposited in the Natural History Museum of London, Canadian National Collection of Insects and the United States National Museum of Natural History (Smithsonian Institution) has been revised. A total of 275 specimens have been examined and 16 species have been determined. They belong to four genera: Alloxysta, Apocharips, Dilyta and Phaenoglyphis. Eight Alloxysta species are here recorded for the first time from Africa: Alloxysta arcuata (Kieffer, 1902), Alloxysta brevis (Thomson, 1862), Alloxysta castanea (Hartig, 1841), Alloxysta citripes (Thomson, 1862), Alloxysta mullensis (Cameron, 1883), Alloxysta pilipennis (Hartig, 1840), Alloxysta postica (Hartig, 1841) and Alloxysta victrix (Westwood, 1833); five of them from the Afro tropical Region. New records are established for some species previously known from this region. Diagnoses for the new Alloxysta records are given; their main diagnostic features are shown in different plates. Dilyta camerounensis Lebel & Modeste, 2007 is considered as nomen dubius. A key to African Charipinae is also given.

Soil arthropods cause kernel and pod damage and can lower yields of peanut (Arachis hypogaea L.) in Ghana, West Africa. On-station and on-farm experiments were conducted during 2007 and 2008 at Kwadaso and Hiawoannwu, respectively, using an improved peanut cultivar/line RRR-ICGU 88709 in a soil arthropod pests management trial. The trial included four treatments, i.e. chlorpyrifos (Dursban™) insecticide as a standard, three levels of granulated sugar as baits, and an untreated control. Soil arthropod pests observed in peanut plots during both years from the two locations were white grubs, millipedes, symphilids, termites, earwigs, and red ants while predators included centipedes and black ants. Termites and red ants were the predominant arthropod pests and predatory black ants (Hymenoptera: Formicidae) exceeded that of centipedes (Myriapoda: Chilopoda) in the two trial locations. The proportion of unfilled pods was high in the two locations during both years. Generally, the population of centipedes was lower than that of black ants. Damage caused by arthropods to pods or kernels in the sugar-baited plots across the two locations were low and differed significantly from the non-baited plots. Chlorpyrifos-treated plots recorded the highest yield followed by the high rate of sugar baits and the lowest yield being the low rate of sugar among the treatment plots. Data generated in this study have shown that sugar-baits may be effective in suppressing pest populations of peanut and may provide a better refuge for the natural enemies and could be recommended as an option for pest management in peanut production.

The bruchid, Callosobruchus analis L., is a common storage insect pest of leguminous pulses including lentil (Lens culinaris Medikus). This study was conducted to document relative resistance and susceptibility differences among the eight lentil genotypes against C. analis. Feeding preference, weight lost after feeding, frass weight obtained, reproduction and development time of the bruchid pest, thickness of the outer seed coat and percentage germination were measured to determine the reaction of lentil genotypes. The results showed that none of the genotypes screened was completely free from bruchid infestation. Seeds of genotype AEL-49/20 were least infested and displayed relatively tolerant response; conversely, genotype AEL-23/40 harboured the maximum infestation and was highly susceptible. The remaining six genotypes, Matiary-S, AEL-57/50, M-85, ICARDA-8, AEL-28/40 and M-93 were categorized as intermediate (moderate resistant or moderate susceptible) to the attack of bruchids. Significant (P ≤ 0.05) variations existed among the lentil genotypes with respect to seed coat thickness (from 19 to 39 µm), playing an important role in imparting resistance. Germination test of tolerant genotype AEL-49/20 showed 91 % emergence potential. The results emphasize the importance of resistance development to maximize the protection of L. culinaris against C. analis.

Although endoparasitoids are widely used for biological control of Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) throughout the world, current methods do not allow for easy estimation of parasitism levels. I investigated the potential of using ratios of parasitoid cocoons to infestations to develop a simple and practical method of estimating parasitism levels in the field. Crop infestations by the pest and densities of its endoparasitoids' cocoons were recorded at weekly intervals over six consecutive years on unsprayed cabbage. In order to establish if there was a relationship between parasitism levels and ratios of parasitoid cocoons to infestations, samples of host larvae and pupae were collected every week during scouting for rearing in the laboratory. The majority of parasitoid cocoons belonged to the larval endoparasitoid Cotesia vestalis (Haliday) (Hymenoptera: Braconidae), which was the major mortality factor of P. xylostella. Total parasitism levels were positively related to ratios of parasitoid cocoons to infestations. Crop infestation by P. xylostella was low during periods of high parasitism (≥50 %) than during low parasitism (< 50 %), and 50 % parasitism corresponded with 20 % ratio of parasitoid cocoons to infestations. This study shows that ratios of parasitoid cocoons to infestations can be used to estimate background parasitism levels.

Andrena haemorrhoa (Fabricius, 1775) is recorded for the first time in Algeria. In this paper, a new subspecies, Andrena haemorrhoa messaadensis subsp. n., is described. Andrena haemorrhoa, which is able to live north of the polar circle, can also survive in a hot and dry region in North Africa. Characteristics of the study area are provided. The sample site and the morphology related to the description of female Andrena haemorrhoa messaadensis is illustrated.

The clearwing moth, Monopetalotaxis candescens, is a major root-boring pest of cultivated ‘rooibos’, Aspalathus linearis, in South Africa. Neonates penetrate the tap root at the base of the stem within a few hours of hatching, presenting a brief window for control of an otherwise highly cryptic pest. Several systemic and contact/stomach insecticides as well as the entomopathogenic fungus, Nomuraea rileyi, were evaluated from 2005–2012 on 6–8-month-old plantations of A. linearis. A strategy based on prophylactic applications of a contact/stomach insecticide (active ingredient: Esfenvalerate) during early to midNovember resulted in > 97 % control. This level of control was realized following delivery of 10 ml aliquots of a 0.4 % concentration of the chemical to the stem-base of individual plants. Attempts at biological suppression of M. candescens with N. rileyi proved unsuccessful. Commercial-scale application of the chemical was possible through the development of an automated measured-dose applicator (vehicle-mounted) consisting of multiple nozzle-lines carried/directed individually by operators. The stem-directed application strategy developed here implies reduced chances of the chemical coming into contact with leaves (and twigs) to be harvested early in the following year, minimum environmental pollution and/or little to no impact on beneficial insects residing on the plant.

Laboratory studies were conducted to investigate the toxic, growth-inhibiting and antifeedant/deterrent effects of neem derivatives on spotted bollworm and its effects on the parasitism potential and adult emergence of Trichogramma chilonis. Neem oil at 1, 1.5 and 2 % and neem seed water extract at 3 % concentrations not only significantly killed more spotted bollworm larvae but also reduced the number of surviving larvae that pupated. However, neem oil and neem seed water extract at 1 % did not affect adult emergence in the tested insect. Neem oil at 1.5 and 2 % and neem seed water extract at 3 % significantly reduced the number of larvae on treated leaves. Percentage parasitism of bollworm eggs by T. chilonis was significantly reduced when they were placed on leaves treated with 2 % neem oil, Polytrin-C® (40 % profenofos 4 % Cypermethrin) and 3 % neem seed water extract, but adult emergence of T. chilonis was not affected by any of the neem treatments. Similarly, the F₁ progeny parasitized the bollworm untreated eggs normally and the emergence of F₂ progeny was not affected by neem treatments. However, Polytrin-C® significantly reduced parasitism of the bollworm eggs by T. chilonis and adult emergence of the parasitoid.

False codling moth, Thaumatotibia leucotreta (Meyrick, 1913) (Lepidoptera: Tortricidae), is an important pest on citrus in South Africa. Several new insecticides were screened for their potential negative impacts on T. leucotreta's reproduction through topical insecticide applications and detached fruit bioassays. Detached fruit bioassays showed that the registered standard concentration of Delegate^® 20 g/1001 and DPX-HGW86 35 ml/1001 caused females to oviposit significantly fewer eggs (P = 0.0016) than the controls. The same was found for the registered concentration of Coragen^®(P < 0.0001). Topical insecticide trials showed that only concentrations of Coragen^®, at the registered field rate and above had an effect on the moths’ reproductive output (P <0.0001). Alsystin^® and Meothrin™, which were used as industry standards, did not negatively affect the reproductive output of the moths during topical or detached fruit bioassay trials. This study helps to better understand the importance of the application mode, i.e. directly on moths or fruit and implies secondary benefits to some insecticide applications.

The effect of manure application and host plant spacing on the infestation level and damage of Thrips tabaci in onion were investigated under field conditions and in cage experiments. Manure applications before and at transplanting were used in a factorial combination with three levels of plant spacing as treatments. Plots with no manure application were included as controls. In field experiments, significantly fewer number of adults and nymphs of T. tabaci per plant were recorded in plants grown in soil with manure applied before transplanting at a rate of 20 t/ha. Plants grown without manure application harboured significantly higher numbers of T. tabaci at 45 days after transplanting and late growth stages. Plots that received manure application before transplanting (20 t/ha) with 20 × 30 cm and 20 × 25 cm spacing showed markedly reduced mean thrips counts per plant, and had significantly higher leaf size compared to those transplanted with manure application (20 t/ha) and at 20 × 30 cm plant spacing. The extent of damage incurred on onion plants by natural infestation of T. tabaci was mostly mild at 15 and 30 days after transplanting and intermediate damage was recorded on plants at 45 days and late growth stages. On the other hand, plants in plots without manure application and 20 × 20 cm and 20 × 25 cm spacing showed markedly reduced leaf size and had intermediate damage at 15 and 30 days after transplanting and sustained severe attack as the crop matures. In cage experiments, significantly lower mean number of larvae and adults were recorded from pots with manure application before transplanting followed by at transplanting manure application as compared to plots with no manure application. This study illustrated that optimum organic manure application at the appropriate time had an effect on the infestation level of onion thrips. Therefore, manure application three months before transplanting was found to be the critical period for optimum plant growth and had the lowest onion thrips infestation.

Surface contact toxicity of clove, Syzygium aromaticum L. Merr. & Perry, and rosemary, Rosmarinus officinalis L., oils were investigated against the American cockroach, Periplaneta americana (L.), in the laboratory. Both clove and rosemary oils showed variable mortality percentages according to concentration, exposure time and stage of the insect. Clove oil exhibited stronger toxic effects than rosemary oil. First instar nymphs were more sensitive than the fourth instars followed by adults. Clove oil induced highly significant contact toxic effects against P. americana nymphs and adults after 4, 24 and 48 h exposure. First and fourth instar nymphs were more sensitive to clove oil (LC₅₀ values of 0.0001 and 0.0077 µl/cm², respectively) than rosemary oil (LC₅₀ values of 1.92 and 2.25 µl/cm²) after 24 h, respectively. Regarding adults, the effect of both oils was very weak after 48 h exposure. Adults of P. americana were the least sensitive to clove and rosemary oils, recording LC₅₀ values 1.5375 and 6.09 µl/cm², respectively. In continuous exposure tests, LT₅₀ values correlated negatively with concentrations. Clove oil had lower LT₅₀ values than rosemary oil. For clove oil the lowest LT₅₀ values ranged between 14.10 and 4.85 h in case of the first instar at low concentration level of 0.0005–0.0020 µl/cm² and 20.00 to 5.00 h for adults at high concentration level of 2.0–3.0 µl/cm². While the LT₅₀ was high for the fourth instar nymphs and ranged from 43.67 to 26.68 h at moderate concentrations, 0.002–0.010 µl/cm², respectively. For rosemary oil the highest LT₅₀ values were 115.03-97.00 h for adults followed by 32.76-8.86 h for the fourth instar nymphs and 25.45-5.62 h for first instars at the same concentrations level, 2–4 µl/cm², respectively. Clove and rosemary oils may be used as promising botanical insecticides against P. americana.

The survival of Apis mellifera Linnaeus, 1758 adults under laboratory conditions is not ensured only by a well-balanced diet during the larval stage and the first days after emergence; their population density in each experimental unit also affects the longevity of these insects, In this context, where statistical techniques allow considering random effects, fixed and different, covariance structures are interesting to build models that add information to bees confined to the laboratory. The goal of this paper was to study bee mortality in an experiment with different densities in each experimental unit observed over time. The statistical analyses used a mixed model with a covariance structure AR(1) and concluded that the average mortality rate for the bees is less progressive when considering densities with 50 individuals in each experimental unit.

The cuticular hydrocarbons of the fourth-instar larvae of Culex pipiens aged one and six days were analysed by gas chromatography and gas chromatography-mass spectrometry. The effect of an insect growth regulator (halofenozide = RH-0345) on the cuticular hydrocarbons was evaluated using newly moulted fourth-instar larvae of C. pipiens, at the lethal concentrations (LC₅₀ = 12.58 and LC₉₀ = 28.58 µ/l). A previous study revealed that RH-0345 is toxic to larvae of C. pipiens by induction of precocious larval moulting. Several cuticular hydrocarbons (CHCs) were identified and many of the other compounds remained unknown. Our data show that the CHC classes consisted of n-alkanes (C23-C29) and differed quantitatively between larval ages. Significant quantitative differences in the distribution of the hydrocarbons of different chain lengths were observed. Amounts of the CHCs of the treated larvae were shifted towards longer-chain alkanes compared to untreated larvae. Typically, treatment with halofenozide decreased significantly the amounts of the major cuticular hydrocarbons of the larvae for the two lethal concentrations, at day 1 and 6. These results provide background data for further studies on the possible role of mosquito cuticular hydrocarbons in chitin synthesis and to better understand the physiological action of halofenozide.

The larvicidal effectiveness of slow-release tablet formulations of the chitin synthesis inhibitor Dudim^® (diflubenzuron) and the bioinsecticide Natular™ (spinosad) against mosquito larvae of Aedes aegypti (L.) has been evaluated. The results showed that the test formulations provided long-term residual control against the larvae. Effective control giving 90–100 % inhibition of adult emergence was achieved for 10 weeks post-treatment for diflubenzuron and 7 weeks for spinosad. In addition, larval treatments with slow-release diflubenzuron formulations led to a marked prolongation in the time needed for blood meal digestion and a reduction in the reproductive potential of adult survivors. On the other hand, larval treatments with slow-release formulations of spinosad tablets affect neither the time of blood meal digestion nor the reproductive capacity of mosquito adults that emerged from surviving larvae.

A list of insect visitors of plum was established during the 2009 and 2010 flowering period for an orchard in Constantine. Four orders of insects were encountered on flowers: Hymenoptera, Diptera, Lepidoptera and Coleoptera. The last three orders made very few visits. The honeybee was the most abundant visitor in both years, representing 79 % and 78 % of recorded visits. Foraging honeybees visited on average nine flowers per minute and 27 flowers per tree, and flights were most frequent between adjacent trees of different rows (56 %). Only the flowers that received between three and five honeybee visits yielded fruit and the percentages of fruits formed were similar (31.6 % and 30.4 % in 2009 and 2010, respectively).

The Arabian rhinoceros beetle, Oryctes agamemnon arabicus (Burmeister, 1847), is an invasive species, introduced to Tunisia from the United Arab Emirates and causing serious damage to date palm trees in southern Tunisia. Considering the economic importance of this pest, it is necessary to understand the genetic diversity within and among its populations and investigate its dispersal mode. In the present study, the mitochondrial gene encoding the cytochrome oxidase subunit I (COI) was used to analyse the extent of genetic variation between samples of O. agamemnon arabicus, collected from geographically distant locations in Tunisia. A 505 bp DNA fragment, resulting from PCR amplification, was sequenced. Representative sequences were aligned, revealing nine polymorphic sites that identified eight haplotypes. Haplotype diversity (Hd) and Tajima's D neutral test were 0.707 and -0.043, respectively, indicating a low level of mtDNA variability. The calculated gene flow value was Nm = 0.47, indicating a high amount of gene flow occurring between populations from Tozeur and those from Kebili, although both departments are separated by the Chott-El-Jerid salt lake. The presence of common haplotypes between Tozeur and Kebili as well as the clustering pattern obtained by the NJ method confirmed this result. Based on these facts and considering the limited flight of O. agamemnon arabicus and its slow reproduction, it is likely that its expansion in Tunisia was facilitated mainly by human transportation of infected offshoots.