Tree-hole breeding mosquitoes in Israel

Multan is a vast city expanding day by day by engulfing agricultural lands that leads to poor hygienic conditions. Such conditions help in proliferation of arthropod vectors and vector borne diseases including mosquito borne diseases. With the present scenario of climate change and anthropogenic activities, natural breeding habitats of mosquito species are being destroyed or lost resulting in shift of oviposition behavior from natural breeding sites to artificial ones. Tree holes are considered as one of preferred natural habitats for many species of mosquitoes. Some mosquito species may prefer particular tree species for egg laying while others may prefer some other tree species. Most controlling activities against mosquitoes involve artificial habitat destruction, while natural sites especially tree holes are overlooked due to lack of knowledge. Considering this scenario, the present study was planned to check population of mosquitoes in tree holes at various habitats in urban and rural areas of Multan. Trees having holes were selected on different urban and rural sites. A total 213 mature trees were visited on different selected sites and only 25 trees with holes were found. Data was collected on fortnightly basis; the collected specimens were brought to laboratory for identification purpose. Results of this study have shown that a total of 1008 mosquito larvae of three species; Aedes albopictus, Culex quinquefasciatus and Culex vagans, were collected from the tree holes. Highest population of mosquitoes collected from mango tree holes which covered 40% of total mosquito population. Species Aedes albopictus comprises 51% of total collected population with highest numbers while Culex vagans found in least numbers and covered 16% of total mosquito population.

Roger Kitching’s bookcould be regarded asthe first field guide tothe fascinating worldof life in ephemeralbodies of water.Phytotelmata,aquatic organismsliving in containers ofplant origin, whichrange from flatworms to crustaceans toaquatic larvae of insects and frogs, occurnot only in tree holes, bamboo internodesand basins of buttressed trees, but also inbromeliad tanks, palm fronds and otherwatertight axils of leaves and floral bract,and even in the highly acidic fluid in thepitchers of pitcher plants. How unique arethe assemblages of such organisms inphytotelm and do they function as acommunity, showing the emergentcharacters, such as stable food webs, thatare seen in other communities?This book presents evidence andtantalizing facts about the speciesdiversity, trophic relations and evolution ofphytotelmata. Based on his own extensivework, Kitching constructs species-basedfood webs of the saprophagous and thepredatory animals found in tree holes andpitcher plants, and examines global,continental and regional patterns in theseand others reported in the literature.Disregarding microbes, rotifers andnematodes, he singles out competition andpredation as the key forces that structurethe phytotelm community and shows howbiogeographical and ecological factorsinfluence the pattern and process inthese communities.A drawback to this approach is that it isentirely binary in linking species (havingor not having a connection) and suffersfrom a lack of quantitative information onthese links. It is difficult to assess the rolesof individual species in these habitatsbecause nutrient input will differdepending on both the host plant and thenature of its container (pans or rot holes).All species of saprophytes need to beknown and their competitive andcomplementary functions in nutrient andenergy consumption worked out toproduce comprehensive food webs forthese systems. However, the top-downeffects of predators are easier to assessand here an experimental approach can beused to manipulate the food-webstructure. Not surprisingly, impacts ofpredators are more dramatic in smallerphytotelm units than in larger ones, butnot all predators, even those occurring inhigh density, have a keystone role incontrolling the overall food-web structure.Since 1960 (Ref. 1), ecologists havefocused on the analysis of food webs inmicrocosms, such as small springs,decaying logs and cowpats. This was anattempt to produce an accurate descriptionof the entire community in a semi-closedsystem so that all species present in thatsystem could be accounted for in terms ofenergy transfer and trophic relations. ThisLindeman-style approach to ecosystemanalysis

The bryophyte vegetation in twenty-eight hectare plots in forests of S-Chile between 38° and 42°S and sea level and the forest line has been studied. Since bryophytes are fully dependend on atmospheric water and nutrient supply, they are good indicators of ecological conditions, especially for humidity. Therefore cover of epiphytic bryophytes, percentage of hepatics, composition of life forms and phytomass of epiphytic bryophytes were used as parameters. Cover and phytomass of epiphytic bryophytes as well as percentage of hepatics show moderate values in the lowlands, peak values in the montane belt (400-800m) and low values in the high montane to subalpine forests. This zonation corresponds with the composition of life forms and is attributed to a higher humidity in the montane belt. Life forms characteristic for the lowlands and submontane belts are pendants, those for the montane belt are wefts and tails, and those for the high montane and and subalpine belts are mats and cushions. The same zonation is found in New Zealand at comparable latitudes. The altitudinal differences are much stronger than the latitudinal ones. Compared with similar transect studies in New Zealand, there is a comparable zonation based on bryphytes. The percentage of hepatics as a good indicator of humidity, is – both in Chile and New Zealand - higher in the transects along the coast with higher precipitation, lower in transects in the inland with less precipitation, and increasing with altitude. Compared with tropical rain forests, the “mossiness” of temperate rain forests expressed by phytomass of epiphytic bryophytes per hectare, cover and percentage of hepatics is comparable to tropical rain forests above 2000 m, which is the corresponding elevation with regard to the mean annual precipitation. In Chile, however, there is a distinct decrease of “mossiness” in the high montane and subalpine forests, which is attributed to special climatological conditions, whereas bryophytes reach maximum cover and phytomass in the tropical high montane and subalpine forests. A comparison with montane forests in Europe in 48°N reveal, that phytomass and percentage of hepatics is distinctly less than in the true rain forests of the southern hemisphere.

From 1972 to 1977 a large laboratory effort was devoted to determining data on efficacy, safety, environmental impact (on nontarget organisms), and some preliminary field work using several isolates of Bacillus sphaericus. The B. sphaericus strains were found to be specific in their mosquito larvicidal activity, not causing mammalian toxicity nor apparent perturbation of the environment. During this period several fermentation and industrialization problems were investigated so that by 1978, using new strains and cultures, it was possible to have prepared kilogram amounts of an active dry stable powder, of strain 1593, for field evaluation. These field evolution. These field evaluations are presently still in progress. Control has been seen particularly against Culex, Anopheles, and Psorophora species, with some what less control aganst Aedes species. Unlike the agriculturally oriented Bacillus thuringiensis candidates, B. sphaericus bacterial cell, which is digested in the larval midgut (within a peritrophic membrane), releasing a toxin as early as 15 min after ingestion. Subsequent death of the larva ensues. Recent evidence suggests that applied B. sphaericus powder will survive in aquatic situations (ditches, ponds, and tree holes) for at least nine month. Comparisons of the B. sphaeicus strains with recently isolated strains of B. thuringiensis (var. israelensis), the latter being particularly active against Aedes species, indicates that they may be useful complements of each other in overall mosquito control strategies. The recent isolation of several new strains of B. thuringiensis, from WHO‐CCBC accessions from Roumania, indicate that although the B. thuringiensis isolate is a rare event when compared to the occurrence of B. sphaericus isolates (they usually occur together in accessions from which B. thuringiensis is isolated), several new useful strains of B. thuringiensis should be anticipated. The longevity of the B. thuringiensis strains in the wild has not yet been investigated.

BackgroundFailure in detecting naturally occurring breeding sites of Aedes mosquitoes can bias the conclusions drawn from field studies, and hence, negatively affect intervention outcomes. We characterized the habitats of immature Aedes mosquitoes and explored species dynamics along a rural-to-urban gradient in a West Africa setting where yellow fever and dengue co-exist.MethodologyBetween January 2013 and October 2014, we collected immature Aedes mosquitoes in water containers in rural, suburban, and urban areas of south-eastern Côte d’Ivoire, using standardized sampling procedures. Immature mosquitoes were reared in the laboratory and adult specimens identified at species level.Principal findingsWe collected 6,159, 14,347, and 22,974 Aedes mosquitoes belonging to 17, 8, and 3 different species in rural, suburban, and urban environments, respectively. Ae. aegypti was the predominant species throughout, with a particularly high abundance in urban areas (99.374%). Eleven Aedes larval species not previously sampled in similar settings of Côte d’Ivoire were identified: Ae. albopictus, Ae. angustus, Ae. apicoargenteus, Ae. argenteopunctatus, Ae. haworthi, Ae. lilii, Ae. longipalpis, Ae. opok, Ae. palpalis, Ae. stokesi, and Ae. unilineatus. Aedes breeding site positivity was associated with study area, container type, shade, detritus, water turbidity, geographic location, season, and the presence of predators. We found proportionally more positive breeding sites in urban (2,136/3,374, 63.3%), compared to suburban (1,428/3,069, 46.5%) and rural areas (738/2,423, 30.5%). In the urban setting, the predominant breeding sites were industrial containers (e.g., tires and discarded containers). In suburban areas, containers made of traditional materials (e.g., clay pots) were most frequently encountered. In rural areas, natural containers (e.g., tree holes and bamboos) were common and represented 22.1% (163/738) of all Aedes-positive containers, hosting 18.7% of the Aedes fauna. The predatory mosquito species Culex tigripes was commonly sampled, while Toxorhynchites and Eretmapodites were mostly collected in rural areas.Conclusions/significanceIn Côte d’Ivoire, urbanization is associated with high abundance of Aedes larvae and a predominance of artificial containers as breeding sites, mostly colonized by Ae. aegypti in urban areas. Natural containers are still common in rural areas harboring several Aedes species and, therefore, limiting the impact of systematic removal of discarded containers on the control of arbovirus diseases.

Low winter temperatures induce an increase in the soil-to-trunk hydraulic resistance of field-grown olive trees resulting in a significant disturbance of their water relations. A disturbance of water relations in response to chilling have long been observed in potted plants growing under controlled conditions, but information is lacking for field plants. The aim of this study was to assess the effects of winter low temperatures on the water relations of mature olive trees. To this end, water potential, sap flux density, soil temperature and meteorological data were monitored in a hedgerow olive orchard near Córdoba, southern Spain, throughout two consecutive winters. Water stress symptoms were found in terms of midday Ψ, despite adequate water supply and low evaporative demand. These effects were associated with changes in the soil-to-trunk hydraulic resistance (R root), which increased by December–January to much higher values than those previously reported in the literature, particularly in the year of higher fruit load. The contribution of viscosity (η) to the observed R root dynamics was almost negligible as deduced from measurements of soil temperature, so the high winter values of R root were likely to have originated from other causes such as reductions in membrane permeability and root growth. The findings of this work raise new major issues that deserve further research such as the impact of the winter water stress on stomatal conductance and photosynthesis rates in mature olive trees.

Living specimens of Megarhinus brevipalpis were transported from southern Natal to Johannesburg to establish an insectary-bred colony. The natural habitat of these predatory mosquitos consisted of small isolated patches of sub-tropical forest, in which the rainfall is 40–50 ins. (102–127 cm.) with a mean winter temperature of 64°F. (17·7°C.) and an annual range of 27°–33°F. (15°–18°C). The breeding places were leaf axils of Strelitzia nicolai (a plant resembling a wild banana), small rot holes in trees and larger ones in Strelitzia stumps. The larvae were collected from leaf axils with an apparatus consisting of a rubber bulb to which were attached lengths of glass and rubber tubing.The insectary was a room 9 ft.×8 ft. 6 ins. and 9 ft. high which was kept at tropical heat and humidity. Mating of the adults was observed, copulation being effected while at rest or in flight. Oviposition was usually accomplished in flight but also while at rest on the surface of the water. In the summer time two females, which were tested, laid about 85 eggs each during the month following emergence from the pupa, six or seven days elapsing after emergence before the first oviposition. In the middle of the winter, oviposition (with later generations) became very irregular in spite of the temperature and humidity remaining constant. The adults, which were comparable to those of the natural habitat, were fed on sugar solution, honey and fruit juice. One bred out as a gynandromorph.When given an abundant supply of larvae of laboratory bred Aëdes aegypti, the life-cycle of M. brevipalpis was normally : egg (incubation), less than two days ; larva, 11–20 days (average 14·5 days) ; pupa, five days. This does not include a small number of exceptional cases in which the life as a fully grown larva was abnormally prolonged (in one case nearly four months) for reasons which are not absolutely clear. The larvae killed from 100 to 200 or more Aëdes larvae during the normal larval life, but many of these were not eaten when the brevipalpis were in the late fourth instar. By a special technique they were also induced to eat dead tissues including minced pork brawn, minced maggots and minced flies. Except for the latter these were not satisfactory foods although there was slow development.Fourth-instar larvae were kept out of water for three to four weeks (without food), in a damp atmosphere, and afterwards when fed most of them developed normally, but pupation was sometimes suspended for a considerable time. They have been sent by post (out of water) in tubes with damp cotton wool and filter paper.The egg differed from that of other Megarhinus species in having a crown of projections at one end with a cup-like structure in the centre. The exochorion had roughly hexagonal cells but without numerous tubercles as in other species.First-instar larvae remained in the egg-shell after hatching when the eggs-were out of water but on a damp surface and in a saturated atmosphere. They survived like this for up to six days or about the same time as the larvae survived in tap water if there was no food. When liberated in water the head of the first-instar larva was comparatively small with the mouth parts folded in. Within two hours of liberation in water the head enlarged considerably and the mouth parts came into position ; the larva was then ready to catch its Culicine prey. When in water containing dead leaves, these larvae survived from a few days to over four weeks and some grew to the third instar without any Culicine food.Cannibalism was investigated. Fourth-instar larvae did not attack each other readily ; they devoured smaller larvae of their own species and small to medium size larvae resorted to cannibalism, particularly in the absence of Culicine prey. There was evidence that fourth-instar Aëdes aegypti occasionally ate first-instar Megarhinus.The discussion traces attempts which have been made in certain Pacific islands, notably Hawaii and Fiji, to use Megarhines for biological control of disease-carrying mosquitos. M. brevipalpis has a shorter life-cycle than the species introduced into these islands and the conclusion reached is that laboratory breeding, to enable large numbers to be released in certain areas, would be a suitable adjunct to a programme of general control, in this part of the world. Airmail consignments of larvae are being sent to Hawaii with the object of starting a laboratory colony there.

Olive trees are known for their capability to endure and recover from low stem water potentials (Ψstem < -6 MPa) and even maintain substantial gas exchange under such conditions. In the current experiment, we tested the physiological responses of mature olive trees in-situ while enduring such Ψstem under field conditions for seven months of rainless Israeli summer. To characterize olive trees' seasonal response to drought, we followed the annual patterns (a measurement day once a month) of Ψstem, gas exchange, osmotic adjustment, and hydraulic conductance of mature bearing olive trees that were disconnected from irrigation. We found that through the dry summer, the trees gradually dehydrated to a minimum of -8.1 MPa in October. An increase of 1320 mmol/kg in the leaf osmotic concentration through the summer was part of the tree's acclimation to the low Ψstem. Surprisingly, despite the low Ψstem that have probably led to substantial xylem cavitation, the trees maintained stomatal conductance of at least 0.023 mol m-2 s-1 and positive assimilation throughout the year. Following the winter rains, the plants recovered their Ψstem, gas exchange, and hydraulic conductance to maximal values. The results demonstrate olives' remarkable ability to tolerate Ψstem while maintaining above minimal gas exchange and producing fruits.

The distribution of isopod species along a 70 km transect through northern Israel is described. The transect started from the Mediterranean seashore through Mt. Carmel and the Gilboa Mts. to the Jordan Valley. The habitats ranged from grassland, macqui to woodland in the Mediterranean region, onto grassland in the semi-arid region. Thirty isopod species were found, of these only one species was common to all the regions, and two species were found in four out of five regions. The largest number of species inhabited the mountainous habitats of Mt. Carmel and the Gilboa Mts: 20 and 14 species, respectively. Twelve species were found in the Coastal Plain; five of these were found exclusively there. Two of the four species found in the Jordan Valley were characteristic of that semi-arid region. Beta-diversity was found to be low in most cases and especially in the comparison between Mediterranean and semi-arid habitats.

Due to the expansion of olive oil cultivation around the world and the increasing effects of climate change, Olea europaea (L:) cultivation must deal with ever higher temperatures and drought conditions, with productivity and virgin olive oil (VOO) quality issues. At the same time the demand for premium quality products with high nutraceutical value, chemical and organoleptic characteristics related to specific areas of cultivation is steadily rising. Within this framework a deep knowledge of the olive variety with regards to environment interaction is necessary to achieve VOO production and qualitative standards required by the market. Rainfed adult olives (cv Bosana) cultivated in five typical areas of north and central Sardinia (Italy) were the subject of a three-year study, with the aim to investigate the influence of pedoclimatic variability on olive and olive oil characteristics. Physical and chemical attributes of fruits (morphometric features, firmness, pH, titratable acidity, sugar content, moisture, and oil yield) and VOO (fatty acid and sensory profile) were analysed at harvest and related to monthly weather data (precipitation, maximum, average, and minimum temperatures) of the whole fruit development period and soil composition. Monthly maximum temperatures were the most relevant variables. However, the role of each meteorologic variable was specific per olive and olive oil parameters and their relevance varied according to the period of the season. An emblematic example is that the maximum temperatures during summer months reduced oil yield and improved oleic acid concentration, but during the following months, the same variable exerted an opposite effect. This suggests the presence of a maximum temperature threshold in the olive fruits, for lipogenesis processes. Meteoclimatic conditions during maturation were the principal element responsible for VOO sensory profile: high precipitation and low thermal amplitude promoted an attribute’s intensities.

Lake Kinneret is a 168-km2 lake located in northern Israel. It provides about 50% of the drinking water consumed in this arid country. To manage correctly this vital water resource, it is essential to understand the various hydrometeorological processes that affect its water budget and, in particular, its evaporation. The complexity of the terrain in this region (varying from ≈2800 m to ≈−410 m within a short distance), combined with different types of soil and ground covers surrounding the lake, results in complicated microscale and mesoscale atmospheric motions, including sea, lake, and land breezes, as well as anabatic and katabatic winds. The Regional Atmospheric Modeling System (RAMS), a state-of-the-art nonhydrostatic model with two-way interactive multigrid nesting and four-dimensional data assimilation capabilities, was used, together with observations collected near the western and eastern shores of the lake, to study these processes. It was configured with two nested grids centered in the middle of the lake: 1) a coarse grid with 4 km × 4 km grid elements representing a 264 km × 240 km domain including Mount Hermon, the Dead Sea, the Golan Heights, and the Mediterranean coast; and 2) a fine grid with 1 km × 1 km grid elements covering a 42 km × 50 km domain. Two three-day periods in the summers of 1992 and 1993, during which hydrometeorological observations were available, were simulated. To account for synoptic conditions, the National Centers for Environmental Prediction–National Center for Atmospheric Research mandatory-level reanalyses produced every 6 h for these periods were assimilated by the model. The strength and timing of the various atmospheric motions that develop in that region and their interactions significantly affect the hydrometeorological processes of the lake, which are subject to important diurnal and spatial variations of wind intensity and direction, temperature, humidity, and fluxes. Since these processes have a strong feedback on the lake hydrodynamics and thermal structure, it is concluded that the development of a coupled lake–atmosphere model is needed to provide good estimates of lake evaporation when lake water surface temperatures are not available. Here, it is demonstrated that RAMS performs properly, given the particular complexity of the Lake Kinneret system and the uncertainty inherent in observations above turbulent water.

Different methods have been devised to analyze vulnerability to cavitation of plants. Although a good agreement between them is usually found, some discrepancies have been reported when measuring samples from long-vesseled species. The aim of this study was to evaluate possible artifacts derived from different methods and sample sizes. Current-year shoot segments of mature olive trees (Olea europaea), a long-vesseled species, were used to generate vulnerability curves (VCs) by bench dehydration, pressure collar and both static- and flow-centrifuge methods. For the latter, two different rotors were used to test possible effects of the rotor design on the curves. Indeed, high-resolution computed tomography (HRCT) images were used to evaluate the functional status of xylem at different water potentials. Measurements of native embolism were used to validate the methods used. The pressure collar and the two centrifugal methods showed greater vulnerability to cavitation than the dehydration method. The shift in vulnerability thresholds in centrifuge methods was more pronounced in shorter samples, supporting the open-vessel artifact hypothesis as a higher proportion of vessels were open in short samples. The two different rotor designs used for the flow-centrifuge method revealed similar vulnerability to cavitation. Only the bench dehydration or HRCT methods produced VCs that agreed with native levels of embolism and water potential values measured in the field.

Most of olive orchards growing in Spain receive excessive applications of N fertilizers (primarily soil application) without any criterion, contributing to groundwater (NO3- leaching) and atmospheric pollution. The experiment was conducted in order to study the effect of the amount and method (soil vs. soil and foliar) of urea application on leaf N concentration, yield, fruit size, tree growth, and oil content of mature olive trees (Olea europaea L.) cv. Picual. After six years of experiment, the results indicate that increasing the amount of N applied annually from 0 to 1 kg of N per tree did not result in an increase of yield, oil content or vegetative growth. However, leaf N concentration was higher when N was applied to both soil and leaves rather than only soil. Results support the hypothesis that annual applications of N fertilizer to olive orchards are not necessary in order to obtain good productivity and growth when leaf N is above the deficiency threshold. Also, N use efficiency seems to increase when urea is applied to leaves.

Leaf chlorosis, severe defoliation and wilt associated with root rot were observed on mature olive trees cv. Nera di Gonnos in an experimental orchard at Mirto Crosia (Calabria, southern Italy). An oomycete was consistently isolated from rotten roots of symptomatic olive trees. It was identified as Phytophthora bilorbang by morphological characters and sequencing of Internal Transcribed Spacer (ITS) regions of ribosomal DNA (rDNA). Pathogenicity was verified by inoculating potted two-month-old rooted cuttings of Olea europaea var. Nera di Gonnos in a soil infestation trial. P. bilorbang was re-isolated from roots of symptomatic, artificially inoculated olive cuttings to fulfill Koch’s postulates. This is the first report of P. bilorbang on O. europaea L. and on a species of the Oleaceae family worldwide.

6-Benzylamino purine (BA) solutions at 100, 200 or 400 ppm, applied to self-pollinated flowers of the partly self-incompatible olive ( Olea europaea , L. cv. Chalkidikis) at full bloom, increased the set of normal seeded fruits in young potted trees, in the greenhouse. In mature orchard trees, only concentrations at 400, 600 or 800 ppm were effective. Applications of BA to open-pollinated flowers failed to increase fruit-set. BA applied to unpollinated flowers did not induce the formation of normal fruits and did not increase the number or size of smaller parthenocarpic fruits. The use of 2-naphthoxyacetic acid (2-NOA) and potassiumgibberellate (KGA 3 ), after self-pollination of the flowers, did not affect the set of normal seeded fruits.