Showing papers by "CABI published in 2001"

The management of lowland neutral grasslands in Britain: effects of agricultural practices on birds and their food resources

Abstract: Summary 1The effects of agricultural intensification on biodiversity in arable systems of western Europe have received a great deal of attention. However, the recent transformation of grassland systems has been just as profound. 2In Britain, the management of grassland has changed substantially in the second half of the 20th century. A high proportion of lowland grassland is managed intensively. The major changes include a doubling in the use of inorganic nitrogen, a switch from hay to silage, and increased stocking densities, particularly of sheep. Structurally diverse and species-rich swards have been largely replaced by relatively dense, fast-growing and structurally uniform swards, dominated by competitive species. 3Most of these changes have reduced the suitability of grassland as feeding and breeding habitat for birds. 4The most important direct effects have been deterioration of the sward as nesting and wintering habitat, and loss of seed resources as food. Short uniform swards afford poor shelter and camouflage from predators, whereas increased mowing intensities and trampling by stock will destroy nests and young. Increased frequency of sward defoliation reduces flowering and seed set, and hence food availability for seed-eating birds. 5The indirect effects of intensification of management on birds relate largely to changes in the abundance and availability of invertebrate prey. The effects of management vary with its type, timing and intensity, and with invertebrate ecology and phenology, but, in general, the abundance and diversity of invertebrates declines with reductions in sward diversity and structural complexity. 6Low input livestock systems are likely to be central to any future management strategies designed to maintain and restore the ecological diversity of semi-natural lowland grasslands. Low additions of organic fertilizer benefit some invertebrate prey species, and moderate levels of grazing encourage sward heterogeneity. 7There is now a need to improve understanding of how grassland management affects bird population dynamics. Particularly important areas of research include: (i) the interaction between changes in food abundance, due to changes in fertilizer inputs, and food accessibility, due to changes in sward structure; (ii) the interaction between predation rates and management-related changes in habitat; and (iii) the impact of alternative anti-helminithic treatments for livestock on invertebrates and birds.

Social Behaviour in Farm Animals

Abstract: Why do animals live in groups? reproductive and parental behaviour effects on domestication chapters on cattle, pigs, domestic birds, sheep, horses, deer and fish individual strategies within groups humans as part of the social bond social cognition. (Part contents).

Host-plant mediated effects of root herbivory on insect seed predators and their parasitoids

Abstract: The effects of root herbivory on a tephritid seed predator (Terellia ruficauda) and its parasitoids were investigated. Soil fauna were manipulated by insecticide treatment; host plant (Cirsium palustre) phenology and the oviposition behaviour of both tephritid and parasitoids (Pteromalus elevatus and Torymus chloromerus) recorded. Although insecticide-treated (and hence reduced root herbivory) plants had larger flowerheads, population abundances of both tephritids and parasitoids were greater on thistle plants subjected to root herbivory. Percentage parasitism was similar in both treatments. Root herbivory is thought to enhance the nutrient quality of plants and this may have resulted in the tephritid preferentially feeding on thistles whose roots had been attacked. Parasitoids on these plants were probably affected by a combination of increased plant attractivity (as for the tephritids), smaller flowerheads aiding ovipositor entry and more tephritid hosts being present. This is the first study to show that root herbivores, through plant-mediated interactions, can affect seed herbivores and also, albeit indirectly through the host, natural enemy trophic levels.

Mycotoxin production from fungi isolated from grapes.

Abstract: L. A BRUNHOSA, R.R.M. P ATERSON, Z. K OZAKIEWICZ, N. L IMA A ND A. V ENAN C I O. 2001. Aims: In order to assess the potential for producing mycotoxins, fungi were isolated from wine producing grapes. Methods and Results: The isolates were identified and Penicillium expansum, the most well recognized mycotoxin producer, was analysed for mycotoxin production by TLC. Many of the strains produced patulin and/or citrinin, often depending on whether they were grown on a grape or yeast extract sucrose media. Conclusions: Citrinin was produced by all strains grown in the yeast extract sucrose medium, but only one strain (from 51) was able to produce this compound in grape juice medium. Patulin was produced in the yeast extract medium by 20 strains and in grape juice medium by 33 strains. Significance and Impact of the Study: The presence of mycotoxins in wine producing grapes is discussed. Grapes contamination with patulin seems not to contribute to wine contamination, and no ochratoxin producing fungi was identified.

Sequestration of host plant glucosinolates in the defensive hemolymph of the sawfly Athalia rosae.

Abstract: Interactions between insects and glucosinolate-containing plant species have been investigated for a long time. Although the glucosinolate–myrosinase system is believed to act as a defense mechanism against generalist herbivores and fungi, several specialist insects use these secondary metabolites for host plant finding and acceptance and can handle them physiologically. However, sequestration of glucosinolates in specialist herbivores has been less well studied. Larvae of the turnip sawfly Athalia rosae feed on several glucosinolate-containing plant species. When larvae are disturbed by antagonists, they release one or more small droplets of hemolymph from their integument. This “reflex bleeding” is used as a defense mechanism. Specific glucosinolate analysis, by conversion to desulfoglucosinolates and analysis of these by high-performance liquid chromatography coupled to diode array UV spectroscopy and mass spectrometry, revealed that larvae incorporate and concentrate the plant's characteristic glucosinolates from their hosts. Extracts of larvae that were reared on Sinapis alba contained sinalbin, even when the larvae were first starved for 22 hr and, thus, had empty guts. Hemolymph was analyzed from larvae that were reared on either S. alba, Brassica nigra, or Barbarea stricta. Leaves were analyzed from the same plants the larvae had fed on. Sinalbin (from S. alba), sinigrin (B. nigra), or glucobarbarin and glucobrassicin (B. stricta) were present in leaves in concentrations less than 1 μmol/g fresh weight, while the same glucosinolates could be detected in the larvae's hemolymph in concentrations between 10 and 31 μmol/g fresh weight, except that glucobrassicin was present only as a trace. In larval feces, only trace amounts of glucosinolates (sinalbin and sinigrin) could be detected. The glucosinolates were likewise found in freshly emerged adults, showing that the sequestered phytochemicals were transferred through the pupal stage.

Conservation implications of the link between biodiversity and ecosystem functioning

Abstract: The relationship between biodiversity and individual ecosystem processes is often asymptotic, saturating at relatively low levels, with some species contributing more strongly than others. This has cast doubt on arguments for conservation based on maintenance of the functioning of ecosystems. However, we argue that the link between biodiversity and ecosystem functioning is an important additional argument for conservation for several reasons. (1) Although species differ in importance to ecosystem processes, we do not believe that this argues for preservation of just a few species for two reasons: first, it is nearly impossible to identify all species important to the numerous systems and processes on which humans depend; second, the important species themselves may depend on an unknown number of other species in their communities. (2) Arguments for conservation based on ecosystem functioning are complementary to other utilitarian, ethical and aesthetic justifications. No single reason will convince all people or protect all species, however the combination produces a strong case for conservation of biodiversity. (3) Even if the relationship between biodiversity and ecosystem functioning is asymptotic at local spatial scales and in the short term, effects of biodiversity loss are likely to be important at larger temporal and spatial scales. (4) Initial arguments for the importance of biodiversity for ecosystem functioning were largely based on a precautionary approach (points 1-3). However, we are now moving to a scientific position based on accumulating experimental evidence. The future challenge is the integration of this scientific research with policy.

Short-term effects of canopy openness on insect herbivores in a rain forest in Guyana

Abstract: Summary 1. A before/after‐control/impact experiment (BACI) was used to examine the shortterm effects of canopy openness on insect herbivores foraging on the seedlings of five rain forest species in an unlogged forest in Guyana. During the first and second study years, insects were collected monthly from 250 sites, representing 9750 seedlings spread over a plot of 1 km 2 . At the onset of the second collecting year, half of the parent trees at the sites were felled, creating an average canopy openness of 26%. 2. Comparisons of the control and impact sites before and after the felling showed that overall insect abundance, particularly of psyllids, and species richness increased at the impact sites, whereas evenness decreased markedly. These responses were consistent with the prediction that intermediate disturbance promotes high diversity in tropical systems. 3. Twenty-nine per cent of insect species analysed showed a significant response to felling, with some populations doubling or halving at the impact sites after felling. The abundance of most species increased, although responses varied even between congeners. 4. A canonical correspondence analysis at the impact sites after felling indicated that most species responded to an increase in leaf production by seedlings, not to canopy openness per se . Species declining at the impact sites were more likely to feed indiscriminately on young and mature foliage and probably reacted to changes in microclimate. 5. The study illustrates the difficulty in identifying higher taxa, umbrella or indicator species that adequately integrate the responses of insect herbivores to forest disturbance. Because the integrity of insect communities in the understorey of this forest depends more on minimizing damage to plant resources than on canopy openness, we found some support for the conservation value of reduced impact logging in tropical wet forests.

Herbivory, litter and soil disturbance as determinants of vegetation dynamics during early old-field succession under set-aside

Abstract: Early-successional old fields are a major component of the European landscape. While a range of factors governing vegetation development in old fields has been identified, empirical and theoretical studies have tended to concentrate on plant competition as the dominant driving force behind succession. We studied the influence of three little researched, yet inter-related, factors on the early stages of an old-field succession: litter cover, soil disturbance and herbivory. Physical and chemical techniques were used to exclude large vertebrates and insects from experimental plots. These treatments had little effect on plant recruitment. A litter-removal experiment, nested within the exclusion treatments, revealed a significant inhibition of forb seedling germination by litter cover. However, the majority of seedlings died during the first month following emergence, whether or not litter was removed. A second experiment, involving the factorial combination of mollusc exclusion and soil disturbance, revealed that the response to disturbance was dependent on life-history characteristics of the plants. However, the dominant factor regulating community composition was seedling herbivory by molluscs. Molluscs caused high rates of forb seedling mortality and promoted the transition from a forb-dominated, to a grass-dominated community. Herbivory is often assumed to influence plant community dynamics through effects on competitive interactions. However, direct effects of herbivory, on the survival of seedlings, may be a significant factor structuring plant communities in ruderal, or other annual dominated systems.

Interactions between density-dependent processes population dynamics and control of an invasive plant species, Tripleurospermum perforatum (scentless chamomile)

Abstract: Tripleurospermum perforatum is an invasive weedy species which exhibits strong overcompensating density dependence. Interactions between density-dependent survival, probability of flowering and fecundity were modelled and their impact on the population dynamics were examined. When only fecundity was density-dependent, the dynamics were similar to those observed in the model containing all three density-dependent terms. Density-dependent survival was a stabilizing process when acting in combination with density-dependent fecundity and probability of flowering; removing density-dependent survival from the model produced two-point cycles. The addition of a seed bank was also stabilizing. Simulations of control strategies at different life-history stages indicated that full control would be difficult due to the strong over-compensating density dependence, with severe reductions in fecundity and late season survival necessary in order to reduce equilibrium seed density and biomass.

Developing cryopreservation protocols to secure fungal gene function.

Abstract: Protocols that involve a freezing process are frequently used for the preservation of fungi, but there have been few studies to assess the physiological and genetic stability of isolates after preservation. In this study, the effects of cryopreservation and lyophilisation on the viability, physiology and genetic stability of isolates of Metarhizium anisopliae, Fusarium oxysporum and Serpula lacrymans were examined. It was found that preservation regime influenced the characters of some of the test isolates. Secondary metabolite profiles and extracellular enzyme production can be affected by preservation. Polymorphism's were detected after PCR fingerprinting in replicates of 2 isolates of Metarhizium that had been preserved by cryopreservation and lyophilisation. The results indicated a need to improve existing preservation protocols. Research is being undertaken to develop novel cryopreservation regimes for recalcitrant micro-organisms. Biochemical and molecular techniques will be used to assess the effectiveness of preservation.

Territory density of the Skylark (Alauda arvensis) in relation to field vegetation in central Germany

Abstract: The Skylark (Alauda arvensis) is one of the most common birds in German farmlands. Recently populations declined rapidly in some regions. This new situation demands further research on the ecology and behaviour of this species. In particular, the effects of vegetation structure and field types on the settlement of Skylarks are still not completely understood. This study addresses these issues with reference to large, conventional fields in the Magdeburger Borde in central Germany. Territory mapping was applied in 1995 as a birdcensus technique in 3 types of fallow land and in 6 crops (25 observations each). The territory density was significantly influenced by the vegetation coverage and height. Skylarks avoided crops with dense and tall vegetation. The preferred vegetation coverage was 35–60 % and the preferred vegetation height was 15–60 cm. Fallow lands were the preferred breeding habitats in the whole breeding season (6.5 to 10.5 territories per 10 ha). Winter cereals and Winter RapeBrassica napus were important for newly arrived Skylarks in early spring. In spring the territory density in winter cereals was higher than in rape (3.0±0.4vs. 1.5±0.0 territories per 10 ha). Spring cereals were used for broods in spring (4.0±0.0 territories per 10 ha) and further in summer (7.0±1.4 territories per 10 ha). SunflowersHelianthus annuus and sugar beetsBeta vulgaris were used as breeding habitats only in summer. We estimated a mean density of 2.5 to 2.6 territories per 10 ha for a 5560 ha large agricultural area.

Euseius Finlandicus (Acari: Phytoseiidae) as a Potential Biocontrol Agent against Tetranychus Urticae (Acari: Tetranychidae): Life History and Feeding Habits on Three Different Types of Food

Abstract: Life history and reproductive parameters of the generalist predatory mite Euseius (Amblyseius) finlandicus (Oudemans) were studied in the laboratory at 25 ± 1°C, with a 16L:8D photoperiod and 60 ± 15% RH, to investigate its response to different food sources: an eriophyid mite Aceria sp., tulip pollen Tulipa gesnerana L., and two-spotted spider mite Tetranychus urticae Koch. Total developmental time of the immature stages was the shortest on eriophyid mites, followed by pollen, and then spider mites. Fecundity was highest on pollen (43.69 eggs; 1.63 eggs/female/day), then eriophyid mites (39.73 eggs; 1.37 eggs/female/day) and lowest on spider mites (18.16 eggs; 0.80 eggs/female/day). Intrinsic rate of increase (rm), net reproductive rate (Ro) and finite rate of increase (λ) followed the same pattern [pollen (0.168, 27.96 and 1.183, respectively), eriophyid mites (0.153, 20.81 and 1.167), spider mites (0.110, 9.44 and 1.119)]. Mean generation time (days) was the shortest on pollen (19.90), followed by eriophyid mites (20.02), and then spider mites (20.59). Average spider mite larvae consumed by E. finlandicus during immature stages were 9.18 for males and 11.85 for females. Adult E. finlandicus females consumed an average of 166.38 spider mite protonymphs during adult stage compared to an average of 66.55 by males. The number of prey protonymphs consumed per day by females was highest in the oviposition period, lower in the pre-oviposition period and the lowest in the post-oviposition period. The eriophyid mite as a prey recorded the shortest developmental time, while pollen as food recorded the highest oviposition rate in E. finlandicus. The potential of this predator as a biocontrol agent against T. urticae is discussed.

Fungi associated with Eichhornia crassipes (water hyacinth) in the upper Amazon basin and prospects for their use in biological control.

Abstract: Surveys were undertaken in 1998 and 1999 in the upper Amazon basin of Ecuador and Peru to collect and catalogue the mycobiota associated with water hyacinth in the river and lake systems. The results indicate that three groups of fungi, which occupy distinct niches on the plant, can be delimited: biotrophic fungi, colonising green leaf tissue, often without significant visible symptoms (e.g. Didymella and Mycosphaerella); necrotrophic fungi, causing prominent leaf lesions (e.g. Leptosphaeria, Colletotrichum, Myrothecium, Phaeoseptoria and Stagonospora); and fungi associated with and isolated from petioles previously invaded by coevolved insect natural enemies, such as Taosa and Thrypticus spp. (e.g. Acremonium, Cephalosporiospsis, Cylindrocarpon, Cylindrocladium and Stauronema). Some of these represent new host records, as well as undescribed taxa. A re-analysis of the mycobiota associated with water hyacinth worldwide reveals that most of the records originate from the USA and the Palaeotropics, where the plant is a major invasive species, and where, as a consequence, most research on its control has been concentrated. Fungal genera such as Alternaria and Cercospora, which traditionally have been favoured as biocontrol agents, seem to be absent or rare on E. crassipes in the Upper Amazon.

Development of a PCR test for the detection of Curtobacterium flaccumfaciens pv. flaccumfaciens.

Abstract: A chromosomal DNA library of the bacterial pathogen of bean, Curtobacterium flaccumfaciens pv. flaccumfaciens NCPPB 559 was constructed in the plasmid pGEM-7Zf(+). Several clones were identified that hybridised to all Curtobacterium flaccumfaciens pathovars including: C. f. betae, C. f. flaccumfaciens, C. f. oortii, C. f. poinsettiae and, in addition, to some strains of Clavibacter michiganensis subsp. insidiosus and Clavibacter michiganensis subsp. One of these clones (pPMP-26), after subsequent digestion with restriction endonucleases EcoRI/SacI, yielded a fragment of approximately 0.2 Kb (pPMP-26D) that hybridised specifically to C. f. flaccumfaciens and not to any of the other plant pathogenic members of the order Actinomycetales or any of the other prokaryotic bean pathogens tested. This fragment was subcloned and sequenced, analysis of the resultant 198 bp sequence showed that no significant homology existed with any other sequence currently deposited in public databases. Further analysis of these data facilitated the design of PCR primers which were subsequently tested against a wide range of plant pathogenic actinomycetes and other prokaryotic bean pathogens. Results show that these primers are highly specific for all strains of C. f. flaccumfaciens with no cross-reaction to strains from any other bacterial taxa tested.

Rice Sheath Blight — Pathogen Biology and Diversity

Abstract: Rhizoctonia solani Kuhn was originally reported causing sheath blight of rice in Japan at the beginning of this century (Miyake, 1910). However, rice sheath blight has developed into a major disease only during the past two decades. Nowadays, the disease is second only to, and often rivals, rice blast (Pyricularia oryzae) in terms of economic importance in many major rice-growing countries. The emergence of R. solani as a major rice pathogen has been attributed to the intensification of the rice-cropping system characterised by the development of new, short-statured, high-tillering, high-yielding varieties and an increase in nitrogen fertilisation inducing a favourable micro-climate for the pathogen. The rice sheath blight pathogen has been associated with isolates of one particular intraspecific group (ISG) of Rhizoctonia solani, anastomosis group (AG) 1 IA (Yamaguchi et al., 1984; Vijayan and Nair, 1985; Borthakur and Addy, 1988; Jones and Belmar, 1989), but diversity within this ISG appears to be much greater than was previously assumed (Liu and Sinclair, 1993). Detailed knowledge of pathogen characteristics at this taxonomic level is still lacking and has hampered understanding of the patho-systems.

A global strategy to defeat invasive species.

Abstract: In “black carp and sick cows” (Editorial, 13 Apr., p. [169][1]), Donald Kennedy illustrates that globalization of trade, travel, and transport can have unintended negative consequences, namely, the relocation and establishment of invasive species ([1][2]). He is justifiably concerned that there is too little awareness of this international threat and no general strategy for dealing with the invaders. In 1996, this same concern was voiced by representatives of 80 countries and the United Nations ([2][3]). This led The Scientific Committee on Problems of the Environment, The World Conservation Union, CAB International, and invasive species experts from a wide array of disciplines to establish the Global Invasive Species Program (GISP) in 1997. GISP's mission is to employ its scientific and technical expertise to increase the ability of all nations to minimize the spread and impact of invasive species. In its first phase of operations, GISP has produced four books ([3][4]) and designed a database for the world's worst invaders ( ) and a toolkit of best management practices. GISP's global strategy recommends actions that governments and other bodies can take to address the invasive species problem. Its recommendations informed the development of the United States' first national invasive species management plan, released by the National Invasive Species Council in January (available at ). GISP's studies indicate that prevention is more economical and feasible than controlling outbreaks of invasives. Thus, the improvement of prevention systems and their expansion to incorporate agricultural and environmental threats should be an international goal. Many invasive species have “lag periods” after introduction when small populations can be eradicated or contained; therefore, limited resources are best expended to detect and respond to newly established invasives. Ultimately, a nation's ability to address its invasive species problems is determined by its access to global information sources, the strength of its taxonomic capacity, and its willingness to cooperate with other countries. 1. [↵][5]“Invasive species” means an alien (non-native) species whose introduction does or is likely to cause economic or environmental harm or harm to human health. U.S. Executive Order 13112, 3 Feb. 1999. 2. [↵][6]1. O. T. Sandland 2. et al. , Ed. Norway/United Nations Conference on Alien Species (Norwegian Directorate for Nature Management and Norwegian Institute for Nature Research, Trondheim, Norway, 1996). 3. [↵][7]1. J.A. McNeely , Ed. The Great Reshuffling: Human Dimensions of Invasive Alien Species (World Conservation Union, Cambridge, MA, 2001) H. A. Mooney, R. J. Hobbs, Eds., Invasive Species in a Changing World (Island Press, Washington, DC, 2000);C. Perrings et al., Eds., The Economics of Biological Invasions (Edwar Elgar, Northampton, MA, 2000);C. Shine et al., A Guide to Designing Legal and Institutional Frameworks on Alien Invasive Species (IUCN, World Conservation Union, Bonn, Germany, 2000). [1]: /lookup/doi/10.1126/science.292.5515.169 [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: #xref-ref-1-1 "View reference 1 in text" [6]: #xref-ref-2-1 "View reference 2 in text" [7]: #xref-ref-3-1 "View reference 3 in text"

Host Range of Aphantorhaphopsis samarensis (Diptera: Tachinidae), a Larval Parasite of the Gypsy Moth (Lepidoptera: Lymantriidae)

Abstract: Aphantorhaphopsis samarensis (Villeneuve), a European tachinid, has been released in North America for classical biological control of the gypsy moth, Lymantria dispar (L.). This study examined the host range of A. samarensis. We used three approaches: (1) field collection and rearing of potential alternate or alternative hosts at European sites where A. samarensis was known to occur, (2) choice tests offering females of A. samarensis both gypsy moth and native North American species of Lepidoptera, and (3) host suitability tests in which we artificially inoculated European nontarget species with mature eggs of A. samarensis dissected from gravid females. In the field studies, we collected a total of 851 caterpillars, belonging to at least 54 species other than gypsy moth in 11 families, over several years, but none yielded A. samarensis, with the possible exception of a single larva of Lymantria monacha (L.) and the rusty tussock moth, Orgyia antiqua (L.), which yielded puparia resembling those ...

Exploitation of the Fecal Shield of the Lily Leaf Beetle, Lilioceris lilii (Coleoptera: Chrysomelidae), by the Specialist Parasitoid Lemophagus pulcher (Hymenoptera: Ichneumonidae)

Abstract: We investigated signal sources used by the parasitoid Lemophagus pulcher in locating and accepting larvae of its host, the lily leaf beetle, Lilioceris lilii. Olfactometer bioassays revealed that larvae with fecal shields, larvae without shields, the shield alone, and lily leaves damaged by L. lilii were all attractive to female parasitoids. In contact bioassays, L. pulcher females were attracted to shields and showed ovipositor probing independently of whether the larva underneath was L. lilii or a nonhost, suggesting that the shield plays a primary role in short-range host location and host acceptance by L. pulcher. The attractiveness of the shield is at least partly of a chemical nature, since shield extracts applied to dummies increased contact duration and induced ovipositor probing by L. pulcher. Another putative defense system of L. lilii, i.e., oral discharge which is emitted by disturbed larvae, was also attractive to experienced, but not to naive, female parasitoids. In all other tests, naive and experienced female L. pulcher responded to the same signal sources tested, suggesting that the host-selection behavior of this biological control candidate is governed largely by innate responses to host-associated cues.

Predators of Mesoplatys ochroptera in sesbania planted-fallows in eastern Zambia

Abstract: Mesoplatys ochroptera Stal (Coleoptera: Chrysomelidae) is a serious pest of the tropical legume sesbania (Sesbania sesban (L.) Merrill) widely used for soil fertility improvement in southern Africa. Surveys were conducted between October 1997 and June 1999 in order to identify the predators of M. ochroptera in sesbania fallows in eastern Zambia. The Heteroptera Afrius yolofa (Guerin-Meneville), Glypsus conspicuus (Westwood), Macrorhaphis acuta Dallas, Mecosoma mensor (Germar), Rhinocoris segmentarius (Germar), and Deraeocoris ostentans (Stal), the carabid beetle Cyaneodinodes fasciger (Chaudoir), the ants Tetramorium sericeiventre Emery and Pheidole sp., and the lacewing Mallada sp. were recorded as predators of M. ochroptera for the first time. The pentatomid bugs G. conspicuus, M. acuta and M. mensor were the most common predators in sesbania fallows. Adults and the different nymphal stages of the three species preyed on larvae, adults and occasionally on eggs of the beetle. In the insectary, the adults of G. conspicuus, M. acuta and M. mensor consumed a significantly higher number of larvae (p < 0.001) compared to adults of M. ochroptera under both free-choice and no-choice conditions. The voracity of the three species showed a positive response to prey density. The fifth instar nymphs showed variation in daily consumption of larvae, the highest number of prey being consumed two to three days after the fourth molt. These predators also attacked other pests associated with sesbania and crop plants. The potential role of the predators in the natural control of pests in agroforestry systems is discussed, with a review of their prey species.

Redescription of Steinernema longicaudum Shen & Wang (Nematoda: Steinernematidae); geographic distribution and phenotypic variation between allopatric populations

Abstract: Steinernema longicaudum Shen & Wang is redescribed based on a comparative morphological study of specimens from the type isolate from China, and two other isolates recovered from Korea and the USA. For the first and second generation female, the location of the vulva, shape of the vulval lips, and shape and length of the tail were newly observed diagnostic characters. A more detailed description of the morphology of the male spicules and gubernaculum, and the arrangement of the genital papillae is included. A description, based on scanning electron microscopy observations, of the lateral field pattern of the third-stage infective juveniles is also provided. Additionally, restriction fragment length polymorphism profiles based on the internal transcribed spacer region, and cross-breeding tests supplement the description of this species.

Species Concept in Sarocladium, the Causal Agent of Sheath Rot in Rice and Bamboo Blight

Abstract: Sarocladium is a genus of hyphomycetes resembling Verticillium and Gliocladium. It is the causal organism of sheath rot of rice and blight in bamboo. Sarocladium oryzae was once considered to be a minor disease of rice, but is becoming increasingly destructive and widely distributed. It infects rice plants at various stages of growth, entering through stomata or wounds, but is most destructive after booting, and frequently associated with the presence of insect damage or Pseudomonas infection. The management of sheath rot of rice by cultural, biological, and chemical methods has been reviewed (Ramabadran et al., 1990), although no effective control methods are currently available, seed treatment with fungicides such as Dithane M-45 and Benlate effectively eliminates seedborne inocula.

Biocontrol of Amaranthus spp. in Europe: state of the art

Abstract: Within European COST Action 816, a 5-year collaboration between scientists from 6 European countries has made an important contribution to the previously unstudied insect fauna associated with Amaranthus spp. in Europe. This provides a basis for future introductions of a non-native biocontrol agent into Europe. In addition, two promising microbial herbicides, based on the fungi Alternaria alternata and Trematophoma lignicola have been characterised. Further work on their use in integrated farming systems is required. The use of microbial herbicides in conjunction with new cropping systems, such as green cover crops or living mulch using Trifolium subterraneum is an approach which offers much potential.

Culture collections in the twenty-first century.

Abstract: Culture collections conserve the living tools for biotechnology. Without them there would be no reference organisms, and no stocks of crucial or rare microorganisms that are so valuable for biotechnology and biomedical research. The expertise that drives these collections is under threat, but the collections themselves may survive by pooling their knowledge.

Releases and first recovery of Lathrolestes ensator (Hymenoptera: Ichneumonidae) in North America, a parasitoid of Hoplocampa testudinea (Hymenoptera: Tenthredinidae)

Abstract: The European apple sawfly, Hoplocampa testudinea (Klug), is a pest of apple, Malus pumila Bork. (Rosaceae), in orchards. Introduced from Europe onto Long Island, New York, in 1939, it gradually invaded the New England states (Pyenson 1943). Downes and Andison (1942) also reported the apple sawfly on Vancouver Island in 1940. In 1979, H. testudinea was discovered for the first time in southern Quebec (Paradis 1980), after which it spread throughout the apple-growing areas of this province (Vincent and Mailloux 1988). There are no published records on any natural enemies of H. testudinea in North America.