Explore the vast range of titles available.

▪ Abstract  Nonpathogenic rhizobacteria can induce a systemic resistance in plants that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). Rhizobacteria-mediated induced systemic resistance (ISR) has been demonstrated against fungi, bacteria, and viruses in Arabidopsis, bean, carnation, cucumber, radish, tobacco, and tomato under conditions in which the inducing bacteria and the challenging pathogen remained spatially separated. Bacterial strains differ in their ability to induce resistance in different plant species, and plants show variation in the expression of ISR upon induction by specific bacterial strains. Bacterial determinants of ISR include lipopolysaccharides, siderophores, and salicylic acid (SA). Whereas some of the rhizobacteria induce resistance through the SA-dependent SAR pathway, others do not and require jasmonic acid and ethylene perception by the plant for ISR to develop. No consistent host plant alterations are associated with the induced state, but upon challenge inoculation, resistance responses are accelerated and enhanced. ISR is effective under field conditions and offers a natural mechanism for biological control of plant disease.

Over recent years, there has been a growing interest in bacteria from the genus Anaplasma, especially the species A. marginale, A. ovis and A. phagocytophilum. Anaplasmosis, a disease caused by various species of Anaplasma, is an especially important issue for animal breeders. The main vectors of these bacteria are ticks, especially the genera Ixodes, Dermacentor, Rhipicephalus and Amblyomma. The genus Anaplasma includes obligate intracellular bacteria, parasitizing in the vacuoles of cells in eukaryotic hosts. A. marginale, A. centrale, A. ovis and A. bovis are obligate intracellular bacteria parasitizing in erythrocytes and monocytes of higher vertebrates, mostly ruminants. A. platys is mainly a pathogen of canines (displaying tropism to thrombocytes) and the species A. phagocytophilum (displaying tropism to granulocytes) is pathogenic to people and domestic animals. In this paper we present characteristics and differentiation of six species of the genus Anaplasma and their vectors in the world.

The efficacy of natural enemies in controlling pests under field conditions is largely correlated with their capacity to spread within infested crops. In this study the spatial dispersal of the California red scale parasitoid Aphytis melinus was evaluated in the field after augmentative releases. The experiment was conducted in 2007 in six 1-ha plots in a Sicilian citrus orchard under integrated pest management. A total of 180,000 A. melinus adults was released in each of three plots and the other plots were left as untreated control. The flight range of the parasitoid was evaluated, for 35 days after the release, on 16 trees per each plot, located at 20 and 40 m from the central release point using yellow sticky traps activated with Aonidiella aurantii sexual pheromone and by monitoring the percentage parasitism of the scale on fruits and twigs. The effects of the distance from the release point and density of susceptible stages of host on parasitoid dispersal were evaluated. The number of wasps captured during the whole trial was greater in the traps located 20 m from the release point than in those at 40 m and in the control plots. Aphytis melinus dispersed over distances less than 40 m based on both the lower percentage parasitism and numbers captured recorded at distances of 40 m. The results are discussed in the context of the biological control of California red scale in citrus orchards by means of wasp releases. In particular, the release points should be no more than 40 m apart for a quick and homogeneous colonization of the area treated.

Here, we present the ITS ribosomal DNA (rDNA) sequence data on 330 larvae of nematodes of the genus Anisakis collected from 26 different bony fish species from 21 sampling locations and different climatic zones. New host records are provided for Anisakis simplex sensu stricto (s.s.) and A. pegreffii from Anoplopoma fimbria (Santa Barbara, East Pacific), A. typica from Caesio cuning, Lepturacanthus savala and Katsuwonus pelamis (Indonesia, West Pacific), A. simplex s.s. from Cololabis saira (Hawaii, Central Pacific), A. simplex from Sebastolobus alascanus (Santa Barbara, East Pacific) and A. physeteris from Synaphobranchus kaupii (Namibia, East Atlantic). Comparison with host records from 60 previous molecular studies of Anisakis species reveals the teleost host range so far recorded for the genus. Perciform (57 species) and gadiform (21) fishes were the most frequently infected orders, followed by pleuronectiforms (15) and scorpaeniforms (15). Most commonly infected fish families were Scombridae (12), Gadidae (10), Carangidae (8) and Clupeidae (7), with Merluccius merluccius alone harbouring eight Anisakis species. Different intermediate host compositions implicate differing life cycles for the so far molecularly identified Anisakis sibling species.

Bluetongue is a non-contagious disease of domestic and wild ruminants caused by a virus within the Orbivirus genus of the family Reoviridae and transmitted by Culicoides biting midges. It is a reportable disease of considerable socioeconomic concern and of major importance for the international trade of animals and animal products. In the past, bluetongue endemic areas were found between latitudes 40 deg N and 35 deg S; however, bluetongue has recently spread far beyond this traditional range. This is in accordance with the extension of areas in which the biting midge Culicoides imicola, the major vector of the virus in the 'Old World', is active. After 1998 new serotypes of bluetongue virus (BTV) were discovered in Southern European and Mediterranean countries. Since 2006 BTV-serotype 8 has also been reported from the countries in Northern and Western Europe where Culicoides imicola has not been found. In such cases, BTV is transmitted by Palearctic biting midges, such as C. obsoletus or C. dewulfi, and the disease has thus spread much further north than BTV has ever previously been detected. New BTV serotypes have recently been identified also in Israel, Australia and the USA. This review presents comprehensive information on this dangerous disease including its history, spread, routes of transmission and host range, as well as the causative agent and pathogenesis and diagnosis of the disease. It also deals with relevant preventive and control measures to be implemented in areas with bluetongue outbreaks.

Predator searching efficiency increases in response to a variety of environmental cues associated with its prey. The sugary excretion of aphids (honeydew) has been found to act as a prey-associated cue for many aphid natural enemies. In the present study, the honeydew excreted by Acyrthosiphon pisum (Harris) was identified as an arrestant and a contact kairomone for young larvae and adults of a common predatory hoverfly, Episyrphus balteatus (De Geer) (Diptera: Syrphidae). First and second instar larvae increased their foraging behaviour in the honeydew-treated area. When plants were sprayed with crude honeydew, the speed of movement of female E. balteatus was significantly higher than in controls, resulting in a longer period of time spent on treated plants and laying eggs. We conclude that the honeydew excreted by A. pisum induces searching behaviour and acts as and arrestant not only for adults but also for young E. balteatus larvae.

Host-plant selection by phytophagous insects is largely determined by adult insects choosing the developmental location of offspring. Knowledge of natural selection leads to theoretical predictions about how adult behaviour might respond to host quality, the abundance of host-plants, adult egg-load, age and available search time, density-dependence, and stochastic effects. Debates about the value of simple adaptive models can only be settled by repeated testing and reformulation. The theoretical basis of adaptive host-selection is quite strong, but several challenges remain. Models are lacking which are both general enough to be applicable to a wide range of species, and easy to test. The role of variability in plant abundance and other stochastic forces requires clarification. Empirically, good field studies of the effect of host-plants on insect fitness are rare, but without them little progress can be made. The assessment of host-preference also requires attention. Quantitative tests of theory are rare, probably because general models do not encompass enough relevant natural history for each particular species. However much anecdotal and qualitative evidence seems to reflect adaptive predictions. A challenge for the future is to assess the adaptive value of particular mechanisms of host-selection, and to relate these to the predictions made in simple adaptive models.

We investigated the variation in body colour and its thermoregulatory function in Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae), a parasitoid wasp of Spodoptera and other free-living lepidopteran larvae. We show that the body colour of adult wasps darkens when cocoons are kept at low temperatures. The range in the variation in colour, however, differs for different parts of the body and among uniparental (thelytokous) strains. This melanism enables these wasps to attain a body temperature in sunshine up to 2 deg C. Moreover, this small gain in body temperature can markedly increase the flight activity of wasps at low ambient temperatures. We conclude that the variation in body colour that resulted from rearing the cocoons at different temperatures enable the wasps to adapt to changing thermal environments. The ecological significance of the difference in the degree of melanism of the different strains is discussed.

In this review, we test the hypothesis that abiotic stress increases the suitability of plants as food for herbivores. We conducted a meta-analysis that included 70 experimental studies in which insect performance was measured on woody plants subjected to water stress, pollution, and/or shading. Overall, plant stress had no significant effect on insect growth rate, fecundity, survival, or colonization density. We found great variation, however, in the magnitude and direction of insect responses among studies, most of which was related to insect feeding guild. In general, boring and sucking insects performed better on stressed plants, whereas plant stress adversely affected gall-makers and chewing insects. Reduction in performance of chewers was greater on stressed slow-growing plants than on stressed fast growers. Reproductive potential of sucking insects was increased by pollution but reduced by water stress. In some cases where sample sizes were small or the treatment periods short, apparent differences in insect responses to stress were probably artifacts due to inappropriate experimental design.

Muga silkworm is endemic to Assam and adjoining areas in North-Eastern India, and naturally produces golden silk. From time immemorial, many ethnic and tribal groups have produced muga silk. Muga silkworms are mostly wild unlike the mulberry silkworm, which is completely domesticated. The muga silkworm is a single species with little genetic variation among populations, survives harsh climatic conditions and is subject to various diseases, pests and predators. Due to the high incidence of disease and natural enemies, and variations in climatic conditions, the production of muga silk has recently declined dramatically. In order to improve the productivity of this silkworm it is important to have a better knowledge of both its host plants and biology. Lack of knowledge of its genetics and host plants is a major bottleneck. This paper reviews various aspects of muga silkworm culture, including the availability of different populations, and methods used to select for improvement in survival, cocoon yield, disease resistance, conservation and egg production.