Insecticide resistance management and integrated mite management in orchards: can they coexist?

At the core of an integrated pest management program for Pennsylvanian apple orchards is an integrated mite management program that is based on a natural enemy, the coccinellid Stethorus punctum punctum (LeConte). The program relies upon the principles of ecological selectivity (e.g. chemical selection, timing, dose and method of application) for the organophosphate and carbamate insecticides. During the last 20 years the tufted apple bud moth (TABM), Platynota idaeusalis (Walker), a direct pest of apple, has developed resistance to these two chemical classes. In an effort to address this growing resistance problem, an intensive research program was initiated in 1986 on how to manage insecticide resistance in TABM while preserving the integrity of the integrated mite management program. One aspect of this research program is the investigation of biochemical and genetic approaches to resistance, including an analysis of detoxification mechanisms, effects of host plant allelochemistry on resistance and detoxification enzyme activities, reversion, gene flow and the isolation and characterization of a gene for glutathione transferase from TABM. Management approaches that have been developed and successfully implemented include pheromone mating disruption, parasitoids, ground-cover management including insecticides, Bacillus thuringiensis Berl. products and insect growth regulators. Resistance management options for TABM are presented. ©1997 SCI     

The isolation of leptospira serotypes copenhageni and ballum from healthy calves

Abstract

Extract

Bovine Leptospirosis was first recognized in New Zealand in 1950 (Anon., 1951 Anon. N.Z. Department of Agriculture Annual Report 1950–51 1951 28 28  [Google Scholar]). Since then the infection has become widespread, particularly during wet spring and summer months (Anon., 1973 Anon. N.Z. Ministry of Agriculture and Fisheries , Research Division Annual Report 1972–73 1973 (in press)  [Google Scholar]). In calves, infection with serotype pomona frequently gives rise to haemoglobinuria and general malaise, while symptoms such as loss of condition and pendulous abdomens which appear suddenly and are followed by sudden death have been associated with copenhageni infections (Dodd and Brackenridge, 1960 Dodd, D. C. and Brackenridge, D. T. 1960. Leptospira icterohaemorrhagiae AB infection in calves. N.Z. vet. J., 8: 71–76. [Taylor &; Francis Online] , [Google Scholar]).     

The use of dimensional analysis in a study of drop retention on barley

Dimensional analysis was used to simplify an experimental investigation of the relationship between the variables thought to be involved in the retention process. Equipment was developed for applying drops of known size at a range of velocities to glasshouse-grown barley leaves. This enabled experiments to be carried out to determine the velocity at which drops of a given size were retained on a leaf. Expressions were developed relating the groups of variables thought to affect retention. From these expressions, a graph was produced which can be used to predict the retention behaviour over the experimental range investigated. For example, if drops (100-400 μm diameter) of water containing a surfactant are applied at their terminal velocitres to the leaves, it is predicted that (a) smaller drops will be retained better than larger drops, and (b) larger drops will be retained if the surface tension of the spray liquid is reduced.     

Effects of landscape-scale broadleaved woodland configuration and extent on roost location for six bat species across the UK

Although forest fragmentation can greatly affect biodiversity, responses to landscape-scale measures of woodland configuration in Europe have been examined for only a limited range of taxa. Almost all European bat species utilise woodland, however little is known about how they are affected by the spatial arrangement of woodland patches. Here we quantify landscape structure surrounding 1129 roosts of six bat species and a corresponding number of control locations across the UK, to examine associations between roost location and landscape composition, woodland proximity and the size of the nearest broadleaved woodland patch. Analyses are performed at two spatial scales: within 1 km of the roost and within a radius equivalent to the colony home-range (3–7 km). For four species, models at the 1 km scale were better able to predict roost occurrence than those at the home-range scale, although this difference was only significant for Pipistrellus pipistrellus. For all species roost location was positively associated with either the extent or proximity of broadleaved woodland, with the greatest effect of increasing woodland extent seen between 0% and 20% woodland cover. P. pipistrellus, Pipistrellus pygmaeus, Rhinolophus hipposideros, Eptesicus serotinus and Myotis nattereri all selected roosts closer to broadleaved woodland than expected by chance, with 90% of roosts located within 440 m of broadleaved woodland. Roost location was not affected by the size of the nearest broadleaved patch (patches ranged from 0.06–2798 ha ± 126 SD). These findings suggest that the bat species assessed here will benefit from the creation of an extensive network of woodland patches, including small patches, in landscapes with little existing woodland cover.     

青海盐湖资源开发与可持续发展研究

通过对青海盐湖资源储量、开发利用现状的调查,总结了目前所存在的问题并寻找出盐湖资源可持续发展的评价指标体系。初步界定青海盐湖资源开发处于可持续发展初期阶段。     

Effects of disturbance and habitat loss on papyrus-dwelling passerines

Throughout the world, but particularly in tropical regions habitat loss and disturbance are considered detrimental to biodiversity. We examine the effects of disturbance by harvesting, burning and habitat fragmentation on six bird species associated with papyrus (Cyperus papyrus) swamps. The presence or absence of these species was verified in 93 wetlands in southern Uganda between June and August 2003. Disturbance was estimated directly by observation and indirectly from examining vegetation structure. Habitat fragmentation was quantified by delineating swamps on Landsat ETM images and applying ‘Fragstats’ to calculate relevant patch metrics. The occurrence of all six species was affected positively by increased swamp size, but birds were more likely to occur in small swamps at high altitude. The shape and proximity of swamps to neighbouring wetlands had little effect on occurrence. As altitude, habitat fragmentation and disturbance were correlated, determining avian responses to disturbance was problematic. However, the occurrence of all species was affected by disturbance, often showing unimodal responses, if disturbance was not considered in conjunction with habitat fragmentation. When the effects of habitat fragmentation and disturbance were analysed together, only the occurrences of papyrus yellow warbler and white-winged warbler were affected (positively) by disturbance. Results suggest that papyrus-dwelling passerines, except papyrus gonolek, are tolerant of low intensities of disturbance, a novel finding in the tropics. We recommend that policy-makers do not prohibit harvesting, thus generating good will and encouraging rural householders to comply with additional conservation policy.     

Death and Transfiguration of a Triple Junction in the South Atlantic

Three major lithospheric plates-Antarctic, South American, and African-meet in the South Atlantic near Bouvet Island where the Mid-Atlantic Ridge (MAR), the Southwest Indian Ridge (SWIR), and the American Antarctic Ridge converge toward a fast evolving triple junction. A major magmatic pulse has recently built a new, swollen segment of the SWIR (Spiess Ridge) that is propagating toward the MAR at a rate of 4 to 5 centimeters per year, disrupting a former ridge-ridge-ridge (RRR) triple junction. A new triple junction will be established about 70 kilometers to the north when the propagating SWIR/Spiess segment will impact with the MAR, probably within the next 1 million years. The American Antarctic Ridge will take advantage of the MAR/SWIR duel by capturing an approximately 70-kilometer stretch of MAR, whereas the Antarctic plate will increase its size.     

Potential impacts of a recent and rapidly spreading coloniser of Australian freshwaters: Oriental weatherloach (Misgurnus anguillicaudatus)

Abstract –  Oriental weatherloach ( Misgurnus anguillicaudatus ), a benthic freshwater fish species native to East Asia, was first recorded in Australian freshwater systems in 1984. Although this species is widely established around the world, very little is known about its potential impacts as an invader. We gathered field data to parameterise a mesocosm experiment investigating the impacts of Oriental weatherloach in Southeastern Australia. During this experiment, Oriental weatherloach caused significant reductions in macroinvertebrate numbers and biomass. Additionally, Oriental weatherloach were associated with elevated ammonia, nitrate/nitrite (NO _x ), and turbidity levels. Because of issues involved in scaling up mesocosm experiments we are not able to conclusively determine that Oriental weatherloach are having large impacts in natural systems. Our results come from mesocosms designed to mimic natural conditions, however, and they thus indicate that ecological impacts may be occurring, and underline the need for further research and control.     

Limitations of metabolic activation systems used with in vitro tests for carcinogens

Important differences between the metabolic activation of 7,12-dimethylbenz[a]anthracene in intact cellular systems and in liver homogenates suggest that the use of homogenates in conjunction with short-term assays for carcinogens could yield misleading results.