Monitoring and treatment of Fascioloides magna in semi-farm red deer husbandry in Croatia

The presence of American liver fluke (Fascioloides magna) in Croatian wild ruminant species was detected for the first time in January 2000. At the same time, the problem of adequate parasitological monitoring and treatment appeared in the captive deer population. Quarantine and health screening protocols, as well as migration and transportation influence had to be evaluated in red deer husbandry. Non-invasive methods were introduced to estimate the prevalence of F. magna in the semi-farm rearing system. Coprological analysis has been performed on 264 faecal samples. The most effective antiparasitic treatment was implemented on herd and individual treatment. Treatment was extended to the free-ranging population of deer in the same region.     

Winter annual grassy weeds increase over‐winter mortality in autumn‐sown wheat

Over‐winter mortality, that is, winterkill, reduces cereal crop competitive ability and yield. While management and environmental variables are known to affect winterkill, the extent to which weeds contribute to increased winterkill is largely unknown. Winter annual weeds may increase winterkill through resource competition and by increasing incidence of and damage from plant pathogens that cause winterkill. We evaluated the impact of summer annual (Avena fatua) and winter annual (Bromus tectorum) weeds on the over‐winter survival rate of winter wheat over three winters, during which plots were covered with snow. Pink snow mould (Microdochium nivale), a winterkill pathogen known to infect B. tectorum and winter wheat, was common in wheat stands. In weed‐free treatments, mortality rates were initially near zero, but increased by nearly 45% in each subsequent winter, presumably due to an increase in snow mould disease in continuously cropped winter wheat. Whereas A. fatua infestation had no impact on crop survival rates, winter wheat survival in B. tectorum‐infested plots was 50% less than the weed‐free control in the second and third years of this study. Among B. tectorum‐infested plots, winter wheat over‐winter survival declined with increasing weed seed produced in the previous summer. Overall, this study demonstrated that winter annual weed infestations can reduce crop stand densities below replanting thresholds by reducing fall‐sown cereal winter survival. The effects of winter annual weeds on winter wheat may be meditated by increased proliferation of snow mould disease.     

The response of commercial cucurbit rootstocks to (a)virulent isolates of Meloidogyne incognita

Journal of Plant Diseases and Protection - Meloidogyne incognita is the predominant root-knot nematode (RKN) species infecting cucurbit plants. It causes galling on the roots of plants and...     

The distribution of olive fruit fly captures with McPhail traps within an olive orchard

The spatial distribution of olive fruit flyBactrocera (Dacus) oleae (Gmelin) (Diptera: Tephritidae) field captures with McPhail traps within an experimental orchard was evaluated. Contour maps were constructed to examine the patterns in the 3-year trapping data. Captures varied widely inside the olive orchard, with traps suspended on wild olive trees exhibiting the poorest performance. Favorable microclimate, created by a standing water pool, appeared to be responsible for increased trap captures during the hot summer months. The positive role of the olive tree fruit load is also discussed. http://www.phytoparasitica.org posting Feb. 2, 2003.     

Infection of Tomicus piniperda (Col., Scolytidae) with Canningia tomici sp. n. (Microsporidia, Unikaryonidae)

Canningia tomici sp. n. (Microsporidia, Unikaryonidae) infects the midgut epithelium, the gut muscules, Malpighian tubules, connective tissues, adipose tissues and the gonads of the pine shoot beetle, Tomicus piniperda (L.) (Coleoptera, Scolytidae). The infection is present in populations of Tomicus piniperda in Europe and in the United States. Uninucleate oval single spores occur in two sizes: 2.8±0.4× 1.4±0.4m and 3.8±0.3×2.0±0.2m. The polar filament of this microsporidium is fixed subapically in a flat anchoring disc. The thick posterior lamellae of the binary polaroplast are asymmetric due to the lateral fixation of the polar filament.     

Isolation and characterization of novel soilborne lytic bacteriophages infecting Dickeya spp. biovar 3 (‘D. solani’)

Nine bacteriophages infecting Dickeya spp. biovar 3 (‘Dickeya solani’) were isolated from soil samples collected in different regions in Poland. The phages have a typical morphology of the members of the order Caudovirales, family Myoviridae, with a head diameter of c. 90–100 nm and tail length of c. 120–140 nm. In host range experiments, phage ?D5 expressed the broadest host range, infecting members of all Dickeya spp., and phage ?D7 showed the narrowest host range, infecting isolates of Dickeya dadantii and ‘D. solani’ only. None of the phages was able to infect Pectobacterium spp. isolates. All phages were prone to inactivation by pH 2, temperature of 85°C and by UV illumination for 10 min (50 mJ cm^?2). Additionally, phages ?D1, ?D10 and ?D11 were inactivated by 5 m NaCl and phage ?D2 was inactivated by chloroform. Phages ?D1, ?D5, ?D7 and ?D10 were characterized for optimal multiplicity of infection and the rate of adsorption to the bacterial cells. The latent period was 30 min for ?D1, 40 min for ?D5, 20–30 min for ?D7 and 40 min for ?D10. The estimated burst size was c. 100 plaque‐forming units per infected cell. The bacteriophages were able to completely stop the growth of ‘D. solani’ in vitro and to protect potato tuber tissue from maceration caused by the bacteria. The potential use of bacteriophages for the biocontrol of biovar 3 Dickeya spp. in potato is discussed.     

Fates of Setaria faberi and Abutilon theophrasti seeds in three crop rotation systems

Weed seeds in and on the soil are the primary cause of weed infestations in arable fields. Previous studies have documented reductions in weed seedbanks due to cropping system diversification through extended rotation sequences, but the impacts of different rotation systems on additions to and losses from weed seedbanks remain poorly understood. We conducted an experiment in Iowa, USA, to determine the fates of Setaria faberi and Abutilon theophrasti seeds in 2‐, 3‐ and 4‐year crop rotation systems when seed additions to the soil seedbank were restricted to a single pulse at the initiation of the study. Over the course of the experiment, seedlings were removed as they emerged and prevented from producing new seeds. After 41 months, seed population densities dropped >85% for S. faberi and >65% for A. theophrasti, but differences between rotation systems in the magnitude of seedbank reductions were not detected. Most of the reductions in seedbank densities took place from autumn through early spring in the first 5 months following seed deposition, before seedling emergence occurred, suggesting that seed predation and/or seed decay was important. For S. faberi, total cumulative seedling emergence and total seed mortality did not differ between rotation systems. In contrast, for A. theophrasti, seedling emergence was 71% lower and seed mortality was 83% greater in the 3‐ and 4‐year rotation systems than in the 2‐year system. Results of this study indicate that for certain weed species, such as A. theophrasti, crop rotation systems can strongly affect life‐history processes associated with soil seedbanks.     

Biological control in Hungary: present situation and possibilities1

Biological control has already achieved certain results in Hungary, especially against soil-borne fungi and glasshouse pests. Nevertheless, experience has shown that locally found biological agents, however effective, could not be developed into registered, ready-for-sale plant protection products because of the lack of companies willing to invest. Biological control in Hungary is therefore limited to the conservation of natural antagonistic flora and fauna and to the application of imported biopesticides and bioagents, which are subject in Hungary to a registration procedure similar to that for chemical plant protection products. Current work includes the development of an anti-nematode product from a local strain of Arthrobotrys oligospora, application techniques for a local mirid Dicyphus hyalinipennis against insect pests, studies with native and imported strains of the nematodes Steinernema and Heterorhabditis against soil-borne insect pests, and introduction techniques for the chrysomelid Zygogramma sutularis against the weed Ambrosia elatior.     

Assessment of cytoplasmic effects of cytoplasmic male-sterile lines in upland cotton

Paired A- and B-lines, cytoplasmic male-sterile (CMS)-lines and main-tainer lines, respectively, were crossed with R-lines (restorer) to produce A × R, R × B and B × R hybrids, which were used in 1993 and 1996 to predict the performance of three lypes of CMS cotton lines available in China. A significant difference in yield and yield components was revealed between paired A × R and B × R hybrids. This difference was greatly influenced by both CMS cytoplasm and the interaction between cytoplasm and nuclear genotypes. It is suggested that there are detrimental effects of CMS cytoplasm on yield and yield components. General combining ability of near-isogenic CMS lines was also affected by this negative effect. The detrimental effect was closely related to an increased number of immature seeds per boll, which might be caused by partial female sterility associated with CMS cytoplasm. The possibility of developing specific combinations of CMS Upland × Upland restorer hybrids that express enough heterosis for yield to overcome the detrimental effect of the CMS cytoplasm is discussed.     

U and sr isotopes in ground water and calcite, yucca mountain, nevada: evidence against upwelling water

Hydrogenic calcite and opaline silica deposits in fault zones at Yucca Mountain, Nevada, have created considerable public and scientific controversy because of the possible development of a high-level nuclear waste repository at this location. Strontium and uranium isotopic compositions of hydrogenic materials were used to test whether the veins could have formed by upwelling of deep-seated waters. The vein deposits are isotopically distinct from ground water in the two aquifers that underlie Yucca Mountain, indicating that the calcite could not have precipitated from ground water. The data are consistent with a surficial origin for the hydrogenic deposits.