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Fruit-piercing moths are a sporadic pest of citrus, especially in the Eastern Cape Province of South Africa, where the adults can cause significant damage in outbreak years. However, growers confuse fruit-piercing moths with fruit-sucking moths that do not cause primary damage. In this study we trapped these moths during the 2013–2015 growing seasons. A large number of diverse fruit-feeding moths were collected through weekly sampling in citrus orchards in the Eastern Cape and northern Limpopo provinces. Twenty-three species of fruit-feeding moth were trapped. However, only two were fruit-piercing species, capable of causing primary damage, namely Serrodes partita (Fabricius) (Erebidae) and Eudocima divitiosa (Walker) (Erebidae). Surprisingly S. partita, which has been reported as the main fruit-piercing moth pest of citrus in South Africa, comprised only 6.9 % of trap catches. The categorisation of moths as fruit-piercing or fruit-sucking (causing secondary damage) was confirmed by examining the morphological structures (tearing hooks and erectile barbs) of these moths’ proboscides. This study has shown that in non-outbreak seasons, S. partita comprised only a small percentage of fruit-feeding moths in citrus orchards. However, growers may misidentify the harmless fruit-sucking species as fruit-piercing species, and thus overestimate the density of fruit-piercing moths.
Acorn burial and consumption by geotrupid dung beetles is an interesting trophic interaction recently reported for Iberian Thorectes and North American Mycotrupes species. In Iberian Thorectes species, this interaction provides not only ecophysiological and reproductive advantages to the beetles but also more effective dispersal for Quercus acorns. The genus Thorectes is particularly diverse in the Iberian Peninsula and North Africa, where most species of the genus occur. Due to the high diversity of Thorectes in North Africa, especially in Morocco, where Quercus forests are widely distributed, we investigated whether acorn burial and consumption by Thorectes beetles also occurred in this region. For this, field sampling was conducted in northern Morocco by searching for beetles buried and consuming acorns within 1 m2 quadrats in areas where Thorectes species and Quercus forests occur jointly. Three beetle species (T. distinctus, T. laevigatus and T. trituberculatus) were found consuming buried acorns of Q. suber in the field. Most of the beetles were found feeding on acorns, while only 20% were found in dung-provisioned burrows. These results suggest that acorns constitute the staple food of some North African Thorectes species. In addition, we found T. trituberculatus and T. distinctus burrows and nests provisioned with oak leaf litter. Burrows and nests provisioned with Quercus litter also suggest a tighter interaction of Thorectes beetles with oaks. Feeding and nesting with relatively predictable and abundant resources in oak forests, such as acorns and leaf litter, may be especially important to explain the diversification and success of flightless Thorectes species in Mediterranean ecosystems such as those of the Iberian Peninsula and North Africa.
A study focusing on the population structure of Euphyllura olivina (Costa, 1839) (Hemiptera: Aphalaridae) in olive groves of three regions of Kabylia (Algeria). We identified, for the first time, the existence of colour polymorphism in this olive tree pest. Two different forms have been identified in three distinct groves both in 2014 and 2015. The morphological variations affect different parts of the adult body of both sexes, including the abdomen and the terminalia.
Hypotrigona species are difficult to identify morphologically. Here, we show that nest sites and nest architecture can be used to discriminate three Hypotrigona species found in Kenya. Hypotrigona gribodoi, H. araujoi and H. ruspolii colonies from Kakamega forest and H. gribodoi from Mwingi, were collected and placed in a meliponiary at the International Centre of Insect Physiology and Ecology (ICIPE). The following parameters were recorded: nest sites, internal nest entrances, external nest entrance colour and size, sizes (in terms of volume) of brood cells, honey and pollen pots, arrangement of brood cells and presence or absence of involucrum (cerumen covering brood). It was found that nest sites are specific to species. Hypotrigona gribodoi nests mostly in crevices in mud walls while H. ruspolii and H. araujoi nest in cavities in specific tree species, mainly in indigenous forests. The colour of external nest entrances varies between the species. H. araujoi’s is yellowish brown, H. gribodoi’s is white or cream while that of H. ruspolii is dark brown. There is an internal nest entrance in H. gribodoi, which is absent in the other two Hypotrigona species. Brood cells are clustered in H. gribodoi and H. ruspolii whereas H. araujo's form vertical semi comb-like layers. The area of the apical opening of the entrance tube and volumes of brood cells, honey and pollen pots differ significantly between the three Hypotrigona species. Therefore, nest sites and nest architecture can be used to discriminate three Hypotrigona species. Furthermore, the study indicates that conservation of indigenous forests, the main habitat for H. araujoi and H. ruspolii is important for their conservation.
Melon fruit flies are economically important pests of cucurbit vegetables. The development and survival of melon fly was compared at six constant temperatures ranging from 16 to 36 °C and two carbon dioxide levels (380 and 570 ppm) under laboratory conditions. Temperature below 20 °C and above 32 °C proved less favourable for growth and development of melon fruit fly. It exhibited normal growth and development at 24 °C. Temperatures above 24 °C caused mortality of 19.07 % and up to 100 % at 36 °C. But, levels of elevated carbon dioxide did not elicit varied response to growth and development in four generations studied and confirmed.
The male of the rare South African bethylid species, Tuberepyris codex Azevedo & Mugrabi, is discovered, described and illustrated. The conspecific gender association is established based on the high level of morphological congruence between the newly collected male and the known female specimen, facilitated by the unusually low level of sexual dimorphism for this subfamily. Both the male and female have the R and 1Cu cells completely fused in the forewing, a diagnostic character of this species, and a unique character within the genus.
Knowledge of the ecology of the red palm mite, Raoiella indica Hirst, is still fragmentary in South America since it was only recently introduced from East Asia. Gathering intra-plant distribution and population fluctuation data could contribute to developing more efficient sampling methods for R. indica. Taking this into consideration, studies were carried out to determine spatial temporal distribution of R. indica in three commercial plantations in the state of Falcón, in Venezuela. Higher mite numbers were registered on middle and lower leaf portions collected from middle or lower plant strata, suggesting that sampling should be allocated to these canopy areas on coconut trees. The R. indica population showed to be negatively associated with rainfall. In 2010, population levels of R. indica were higher than in 2011 (maximum 7 mites/cm2); this was probably a function of lower rainfall values for that year. In 2011, the highest population levels were reached between April and July, coinciding with the lowest rainfall values over that year. Relating to this population spike, the Amblyseius largoensis population showed a numerical response in relation to R. indica density; this predator species does not appear to be exerting bio-control on the mite pest population.
Transgenic Bt cotton with insect resistance was introduced for commercial cultivation in India in 2002 (Barwale et al. 2004). Bt cotton expressing Cry1Ac is mainly toxic to the bollworm complex (Helicoverpa armigera, Pectinophora gossypiella, Earias insulana and E. vittella). The rapid adoption of Bt cotton technology in India imposes a strong selection pressure on the target pest with a risk of resistance development to Cry toxins including Cry2Ab following the introduction of dual gene BG-II cotton in 2006. Spotted bollworm, Earias insulana infests the cotton crop during the early season as a shoot borer and damages fruiting bodies during mid-season crop growth. Efficacy of Bt cotton hybrids BG-II (Cry1Ac + Cry2Ab) and Bt (Cry1Ac) through leaf (90–95-day-old crop) and square (80–85-day-old crop) bioassay under laboratory conditions, recorded 97–100 % mortality on leaves of BG-II, 93 % on Bt and 1.3–5.4 % on non Bt against 1-day-old larvae of Earias insulana. Observed mortalities on plant squares were 94–100 % in BG-II, 91 % in Bt and 1.3–5.6 % in non-Bt genotypes. Frequency of resistance alleles in field populations of Earias insulana to Cry1Ac protein by using F2 screening procedure was also undertaken. In the present study on F2 screening on 266 isofemale lines of Earias insulana collected from Sirsa (Haryana), Sriganganagar (Rajasthan) and Mansa (Punjab) during 2013–14, 2014–15 and 2015–16, no alleles could be detected conferring major resistance to Cry1Ac in the population of Earias insulana from all three locations. However, evidence for partial resistance alleles in F2 generation of two isofemale lines from Sirsa (Haryana) population was recorded during 2013 but could not be reconfirmed.
To investigate the contribution of surface-exposed loops (loops 1, 2 and 3) in the toxicity of Cry1Ab against Helicoverpa armigera larvae, three loop-replaced Cry1Ab mutants were prokaryotically expressed in Escherichia coli BL21 (DE3). Proteolytic processing of Cry1Ab toxins with trypsin indicated that the replacement of each surface-exposed loop caused no damage to toxin stability. Results of in vitro binding and competition assay indicated that, similarly to the native Cry1Ab toxin, the mutants retained almost the same binding affinity and specificity with brush border membrane vesicles (BBMV) of H. armigera. Nevertheless, H. armigera larvae fed with each loop-replaced Cry1Ab mutant showed less growth inhibition in comparison with those fed with native Cry1Ab toxin. The most significant decrease in toxicity was observed from larvae fed with loop 2-replaced Cry1Ab mutant, with a c. 12-fold increase in the weight of tested larvae relative to that of larvae fed native Cry1Ab toxin. The results demonstrate that the replacement of three surface-exposed loops located in domain II of Cry1Ab toxin may result in a certain reduction in the toxicity. Relative to loop 1 and loop 3, loop 2 seem to play a more important role in generating toxicity of Cry1Ab against H. armigera larvae.
The carob moth, Ectomyelois ceratoniae (Zeller), is a polyphagous pest in hot and dry climates, such as the Mediterranean region, and occurs on citrus in South Africa, however, its pest status is not known. The aim of this research was to investigate its seasonal activity patterns and damage potential on citrus crops, in comparison to a pest of phytosanitary concern and one it can be confused with in the larval stage, the false codling moth, Thaumatotibia leucotreta (Meyrick). The study was carried out over 20 months in two regions, one with predominantly citrus and one with mixed agricultural production. Carob moth activity patterns indicated two periods of activity (summer and early spring), with damage taking place in citrus during autumn, close to harvest. The results showed that there were no significant differences in carob moth trap catches between the two study sites (F1,4 = 0.00661, P = 0.94) and no significant differences in wild false codling moth catches between the two study sites (F1,4 = 1.2960, P = 0.32). While traps in both regions caught carob moths in equal abundances, damage only occurred in the region dominated by citrus crops. Assessing pest status, relative to the false codling moth, indicated that carob moth is not currently a major economic pest.
The brown cocoa mirid, Sahlbergella singularis (Hemiptera: Miridae), causes cocoa yield loss of about 30 % to 70 % in Cameroon. The pathogenicity of six indigenous isolates of Beauveria bassiana (BIITAC) and Metarhizium anisopliae (MIITAC) to the fourth and fifth nymphal stages of S. singularis was evaluated under laboratory conditions. Two methods of inoculation were tested at various conidial concentrations: (1) immersing the pod in 200 ml of the suspension for 3 min (ingestion method) and (2) immersing each insect in 1 ml of the suspension for 5 s (immersion method). Tween® 80 at 0.1 % (v/v) was used as a control. After 14 days from initial exposure to conidia, corrected mortality ranged from 35 to 100% for immersion and from 16 to 94.3% for ingestion. Mortalities due to fungi isolates were significantly different from that of their control (P < 0.05). The effect of immersion was more significant than that of ingestion, and mortalities increased with increasing spore concentration. Mycelial outgrowth and sporulation after seven days on some of the dead insects, kept on humidified filter paper in dark conditions, demonstrated that death was due to fungal infection (mycosis). Based on pathogenicity results, LC50, LT50 and LT90 fungal outgrowth, B. bassiana isolates BIITAC10.3.3, BIITAC6.2.2, MIITAC6.2.2 and the M. anisopliae isolate MIITAC11.3.4 could be selected for their virulence, and advanced to field trials for the development of microbial control.
The area-wide spatio-temporal distribution of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) trap catches was investigated in the regions of Elgin/Grabouw, Villiersdorp and Vyeboom, collectively known as EGVV, Western Cape, South Africa. The primary fruit crops planted in EGVV include various varieties and cultivars of pome fruit, stone fruit, citrus, wine grapes and berries. Fruit fly trapping data from four consecutive seasons were sourced from a centralised database managed by a non-profit company, which operates an area-wide integrated pest management (AW-IPM) programme, incorporating the sterile insect technique (SIT) for C. capitata fruits flies, within EGVV. Mean trap catch between regions and seasons was compared. The spatio-temporal variation of mean trap catch was also investigated. A geographic information system (GIS) was used to symbolise and map mean trap catch per trap location. There was no significant difference in the mean trap catch between regions. Significant differences did occur between some seasons in Villiersdorp and Vyeboom but not in Elgin/Grabouw. The spatial distribution of trap catches between seasons varied greatly, indicating no definitive pattern. However, traps with the highest seasonal trap catch occurred mostly in the southeastern parts of each region and traps with lower levels were distributed mostly in the northwestern parts of each region. The results suggest a relationship between the geographic characteristics of EGVV and the abundance and distribution of C. capitata. It is recommended that an in-depth spatio-temporal analysis be carried out to better understand the geographical distribution of trap catches in the study area.
Populations of Tetranychus urticae Koch (Acari: Tetranychidae), and its predatory mite, Agistemus exsertus Gonzalez (Acari: Stigmaeidae), were determined on four soybean varieties, namely, Giza 22, 35, 82 and 111, during the 2016 season, and in addition some biological aspects of both species were studied. The results obtained revealed that Giza 35 variety was the most susceptible variety with significant difference between the mean numbers of T. urticae compared with other varieties. The mean rate of infestation was 11.89 individuals/25 cm2 of leaves, while the mean number of T. urticae was 7.11 and 3.54 individuals/25 cm2 of leaves for Giza 111 and Giza 82 without significant difference. Giza 22 recorded the lowest mean number of T. urticae, 1.53 individuals/25 cm2. The population dynamics of T. urticae showed that infestation increased gradually from mid-June reach its maximum at the end of July, and then decreased gradually at the beginning of August, reaching its minimum number at the beginning of September before harvest time. As for A. exsertus, data showed that the mean number of A. exsertus was the highest on Giza 35 (2.46 individuals/25 cm2) followed by Giza 22 (2.13 individuals/25 cm2), but Giza 82 and Giza 111 mean numbers were 1.99, and 1.91 individuals/25 cm2. Life cycle of tetranychid males was the shortest when reared on Giza 35 with significant difference with other varieties. As for females the shortest life cycle was when reared on Giza 35 with significant difference with Giza 22 which recorded the longest life cycle for males and females, respectively.
The grey flesh fly Parasarcophaga argyrostoma plays a role in human cutaneous wounds and eye myiasis as well as it acts as a parasitoid of various animals. The present study aimed to investigate the efficacy of methoprene on the adult performance and natality of this fly. Five dose levels (10.0, 5.0, 1.0, 0.1 and 0.01 μg/larva) of methoprene was topically applied onto the early last instar larvae and prepupae. The adult emergence of flies was completely blocked at the highest dose, regardless of the time of treatment. At other dose levels, the adult eclosion was partially blocked. Survival of the adult flies was adversely affected by the toxic potency of methoprene. Only at doses of 5.0 and 1.0 μg/larva, some morphologically deformed flies were observed. The total longevity of adult females was remarkably shortened in a dose-dependent course. Topical application of methoprene onto either last instar larvae or prepupae resulted in a considerably prolonged pre-larviposition period, but significantly shortened larviposition period. Topical treatment of either last instar larvae or prepupae with methoprene led to dramatic reduction in natality, in a dose-dependent course.
There has been a recent increase in new records of insects from the subtropical parts of South Africa that have expanded their historical ranges to now include the biologically and climatically atypical southwestern Cape region at the tip of the African continent. Suggested mechanisms include climate change, provision of previously absent nutriments and direct transport of individuals via human activities. Here we summarise previous reports of fruit chafer beetles (Scarabaeidae: Cetoniinae: Cetoniini) invading the southwestern Cape region, provide additional data on their distributions and provide data for additional taxa that have now also been newly recorded in the region. The newly reported species Pachnoda sinuata sinuata probably naturally occurs in the region but has gone unnoticed due to specialised habitat requirements and morphological similarity to a widespread generalist. Some taxa are very recent arrivals while others have been known from the region for a long time, but all are experiencing noticeable population increases in urban and agricultural areas. We propose that these species likely dispersed from their native ranges to the southwestern Cape via direct transport of colonised nursery stock and their recent increases in population size are consistent with what is expected when founder populations overcome barriers to reproduction. All of the new arrivals are well-adapted to transformed landscapes in the subtropics and do not occupy natural vegetation in the newly invaded ranges, strengthening the hypothesis that pre-adaptation to human settlements aid biological invasions of otherwise unsuitable bioregions in South Africa. As many additional species are pre-adapted to transformed biotopes in subtropical areas, one would expect that additional species will colonise the southwestern Cape in the future with unknown economic, ecological and evolutionary consequences.
There are few studies on the effects of copper chlorophylline (Cu-chl) and magnesium chlorophylline (Mg-chl) on the cellular level, physiological parameters and DNA damage to Culex pipiens larvae. These parameters may be conducive to larval death as a result of photosensitisation reaction after feeding on these photosensitisers and being exposed to light. This study focuses on the impact of Cu-chl and Mg-chl on ultrastructural damage and cellular alteration, immune parameters and DNA damage. The results showed a significant change in the phenoloxidase activity as a function of photosensitiser concentrations. The ultrastructure of midgut tissues revealed obvious damages in different cellular levels. There was no significant effect on DNA. So, it can be concluded that Cu-chl and Mg-chl caused C. pipiens larvae death via the physical damage of larval tissues, and the direct effect on biochemical and physiological parameters of larval viability. Healthy DNA molecules, after the larval treatment, reflected no chance for the undesired mutation of the sublethal concentration of Cu-chl and Mg-chl.
Native ants are the oldest example of biological control agents used in tropical tree crops. Unfortunately, intensification of agricultural practices has led to a simplification of habitat and subsequent loss of native ant biodiversity. This paper describes an evaluation of the ants present in a Rwandan coffee plantation. The plantation was unshaded, intensively managed and regularly treated with pesticides. No herbicides or fertilisers were used, although the area had been mulched. Only five ant species were found in the plantation (Pheidole megacephala, Lepisiota depressa, Nesomyrmex angulatus and Camponotus (Myrmosericus) spp. (2 spp.). Pheidole megacephala dominated the plantation and occurred on 94 % of trees, while L. depressa, C. (Myrmosericus) spp. and N. angulatus each occurred on 13 % or less of trees. Pheidole megacephala and L. depressa were negatively associated, whereas C. (Myrmosericus) spp. were positively associated with L. depressa. Association between the coffee pests and ant species was not significant. We conclude that intensification of coffee production in this plantation and domination by P. megacephala has contributed to the low diversity of ants present and that those species that do occur there are not particularly efficient at reducing pest densities.
The facultative blowfly species, Lucilia sericata (Meigen) and Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae) largely handicap sheep production practices, resulting in immense economic devastation. Through simultaneous mechanical and chemical activity, the larvae largely cause physical damage to the wool and meat. Over the past few decades, myiasis has predominantly been controlled with the use of various synthetic chemicals, in addition to various sheep husbandry practices. However, an increased development of chemical resistance has been noted. With this, the aim of the study was to evaluate and compare various plant extracts for the potential use in the management of Lucilia spp. Through use of inverted funnel choice tests, the repellent action of the plant extracts was assessed. With a commercial citronella spray employed in the control, similarly high repellency was observed with treatments of Zanthoxylum sp. and Eucalyptus camaldulensis. With a minimum of 80 % pesticidal action required for test solutions to be considered successful, both plant extracts implicated potential action against the flies. The phytochemical secondary metabolic properties of the plant extracts were analysed with thin layer chromatography (TLC). Qualitative TLC was employed to differentiate the organic compound profiles of each plant extract, while various spray reagents were utilised to identify specific properties of various chemical groups. Those possibly contributing to the repellent results obtained included triterpenoids, alkaloids, essential oils, coumarin drugs, saponin drugs and flavonoids. With positive management potential and a basic phytochemical evaluation, further investigation into the use of these plant extracts against Lucilia spp. is advised.
Parasitism is a hostile relationship that helps greatly in the development and evolution of many creatures in their race for survival. Chewing lice of nestlings of the osprey Pandion haliaetus (L.) have been studied in Farasan Island, Saudi Arabia. All previous chewing lice records from this bird have also been reviewed. Four species of chewing lice are previously known to infest P. haliaetus. The nestlings of the osprey in Farasan were only infested by Colpocephalum turbinatum Denny, 1842. This species of chewing lice is recorded herein for the first time from the Kingdom of Saudi Arabia and its distributional pattern is very characteristic among three different avian orders (Accipitriformes, Columbiformes, and Strigiformes). Colpocephalum turbinatum was found mainly on terrestrial birds of the order Columbiformes and it may be transferred to predatory birds in the other two orders, but the presence of this parasite on some aquatic birds of prey like osprey may indicate that the ancestors of these birds were terrestrial hunters that acquired this louse from their prey such as doves and pigeons before their transference to aquatic life. The pattern of chewing lice distribution through their host populations and habitats may reveal some important ecological and evolutionary events that happened to their hosts in the past.
Mantophasmatodean insects have been widely recorded in Cretaceous and Eocene amber. Although rare, Mantophasmatodeans are famous for a quite widespread occurrence in the Baltic area until the Eocene extinction, living in a Tertiary flora commonly associated with forested ecosystems. Close relatives are still alive in southern Africa, like those belonging to the Mantophasma genus, probably one of the most intriguing living fossils in the world. Some nymphs were collected in a Namibian plateau east of the Erongo Complex and carefully cultivated in a laboratory. Our main purpose was to investigate the entire life cycle of these Namibian living fossils to share novel insights in the palaeoclimate of Baltic Eocene. We unravelled the adult morphology and the postembryonic development of these intriguing insects, commonly called heelwalkers, and performed a comparison of the morphometric, ecological and ethological data between our specimens and the living species described so far in literature. Furthermore, we analysed the vibrational male–female communication of these primitive insects. The robust evidence provided here supports some controversial recent palynological assessments of the Eocene and show that the Baltic landscape was much more open than commonly thought.
The size of harvester termite Hodotermes mossambicus (Hagen) (Isoptera: Hodotermitidae) populations on the clay-rich red-soils of semi-arid grasslands in southwestern Zimbabwe in any particular dry season was found to be strongly influenced by the annual rainfall received the preceding rainy season. The size of the termite population of the antecedent dry season also had an important influence. Populations were found to build up over successive dry years and crashed following a season of substantially above average rainfall to fall further after the next rainy season which was also above average. Termite populations and foraging activity also fluctuated considerably within seasons. There was an increase as the dry season progressed but foraging fell dramatically at the end of the season and remained at low levels throughout the summer months. Foraging was confined to degraded patches in the red-soil veld mosaic in the early dry season with expansion into the other grass communities occurring in the late dry season. Fluctuations in harvester termite populations had a marked effect on the extent of the foraging area and hence on the amounts of grass cover remaining in the degraded, ecotone and sound veld communities of the red-soil mosaic at the end of the dry season. Termite foraging activities serve to maintain the grass sward in a vigorous condition by preventing excessive accumulation of dead foliage on ungrazed sites and they had an important influence on the botanical changes which occurred within each grass community of the mosaic. The main effect was to favour those grass species such as Heteropogon contortus and Themeda triandra, that are intolerant of excessive top-hamper (standing dead grass) and litter accumulation.
Weekly ovitrap surveys were conducted from February 2013 to May 2015 in Pointe des Lascars and Panchvati, two villages in Mauritius, as part of a study investigating the possible use of the sterile insect technique (SIT) to control Aedes albopictus mosquitoes, the sole vector of Chikungunya and Dengue virus in the country. A high presence of this species was noted in both villages with 64 to 100 % of ovitraps being positive for eggs throughout the year. Monthly ovitrap productivity did not differ significantly between the two villages (t49 = –1.19, P >0.05), indicating their suitability to be used as paired sites. An important but unstable population of Ae. albopictus was also noted on the outskirt of Panchvati. The overall ovitrap productivity (for the three sites together) was highest from December to March (ranging from 101 to 272 eggs/ovitrap/week) and lowest from July to September (ranging from 13 to 126 eggs/ovitrap/week). Sterile releases could hence be initiated during the months of July to September when Ae. albopictus is at its lowest incidence and after ensuring that the species is still reproductively active during the low season. Moreover, before sterile males are released in Panchvati, the establishment of a buffer zone around the village must be contemplated to prevent the migration of feral females from the outskirt region. Ovitrap positivity and ovitrap productivity in both villages were positively correlated with temperature, relative humidity and rainfall while temperature was the major significant factor influencing oviposition, thereby highlighting the possibility of using meteorological variables to construct predictive models of vector incidence in the region.
The heredity of autogeny in Culex pipiens from northern coast, Alexandria, Egypt, was investigated. Parental females laid more autogenous egg rafts than F1, F3, and F4 females. No significant difference was found in the autogeny rate when F3 female mosquitoes from an autogenous colony mated with males either from an autogenous or anautogenous colony. Similarly, when F3 males from an autogenous colony mated with females either from an autogenous or anautogenous colony, statistically comparable autogeny rates were recorded. However, when females from an anautogenous colony were allowed to mate with males from an autogenous colony, the autogeny rate was statistically higher than that when females from an autogenous colony mated with males from an anautogenous colony. Molecular analysis using ISSR was suitable for detecting polymorphic banding patterns between autogenous and anautogenous specimens of mosquitoes. The ISSR technique succeeded in showing 13 different molecular markers which can be relied upon in distinguishing between populations. Molecular distances among populations were low, ranging between 0.114 and 0.284. On the other hand, cluster and principal coordinate analyses showed that anautogenous specimens were contiguous in one group and separate from autogenous specimens. The ISSR technique is therefore able to detect genetic differentiation among the studied populations, and to distinguish between autogenous and anautogenous mosquitoes from the northern coast of Egypt.
The family Pipunculidae has a potential value for biological pest control, as most pipunculid species are endoparasitoids of the hemipteran suborder Auchenorrhyncha. In the present study, all known Egyptian taxa of the family Pipunculidae (big-headed flies) are systematically catalogued. Old World synonymies, type localities, world distributions by biogeographic realm(s) and country, Egyptian localities and dates of collection are provided. A total number of 24 species belonging to four genera and two tribes has been catalogued.
The South African avocado industry is export-oriented, with approximately 3.0 % of international market share and with a five-year mean annual production of 118 000 t from 17 500 ha. Feeding by thrips results in fruit scarring and corky tissue development, making the fruit unsuitable for export. The study aimed to identify the spectrum of thrips in avocado flowers and more importantly, to confirm the identity of the thrips species responsible for damaging fruit. Thrips were collected from flowering panicles and identified using taxonomic keys. Frankliniella occidentalis (Pergande), Scirtothrips aurantii (Faure), Thrips gowdeyi (Bagnall), Thrips pusillus (Bagnall), Thrips tenellus (Trybom), Haplothrips gowdeyi (Franklin), Haplothrips bedfordi (Jacot-Guillarmod) and Megalurothrips sjostedti (Trybom) were consistently collected from May to September 2018. The minute size of thrips warranted a pre-season trial to determine the best netting material to contain thrips. Insect screen (149 µm), nylon netting (250 µm), chiffon (210 µm), voile (250 µm), organza (500 µm), tea filter paper (74 µm) and coffee filter paper (53 µm) were evaluated. The experiment was laid out as a randomised complete block design with six replications and the trials repeated twice. Only coffee filter paper and tea filter paper contained at least 85 % of the thrips and were therefore chosen for thrips exclusion trials. Surveillance by fruit sampling was undertaken to determine the natural host status of avocado to thrips. Avocado fruitlets were randomly sampled and incubated under laboratory conditions. Scirtothrips aurantii (Faure) (the South African citrus thrips) emerged from fruitlets and was sustained on that fruit to adulthood. This is the first study to demonstrate that avocado is a natural host to this pest in South Africa.
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