Success of nursing ide (Leuciscus idus, L.) fry related to the period of feeding with live food

The ide Leuciscus idus (Linnaeus 1758) belongs to autochthonous, less frequent and vulnerable fish species in the frame of ichthyofauna of the Czech Republic. It was the reason for testing the possibility of captive breeding and production of fry in a controlled environment. The goal of this paper was to find the optimal transfer time of ide larvae from live food (Artemia salina nauplii) to dry starter feed providing good survival and growth. At the end of the experiment, high values of cumulative survival (in percentages) and individual weight (in milligrammes) were found for ide fry in groups D (90.6%, 178.6 mg; 15 days A. salina + 10 days starter feed), A (89.9%, 169.9 mg; A. salina only) and C (88.6%, 160.4 mg; 10 days A. salina + 15 days starter feed). Significantly lower values of the given parameters were found in group B (57.1%, 92.6 mg; 5 days A. salina + 20 days starter feed), and the lowest ones were in group E (29.8%, 75.6 mg; starter feed only). Mean values of the level of ontogenesis at the end of the experiment in fry of A–E groups were analogous to length and weight growth. Groups D, C and A consisted of juveniles only (J1, J2), and groups B and E consisted of larvae and juveniles (L4, L5, L6, J1, J2). Condition and production parameters [Fulton’s coefficient of condition (FWC), total length (TL), weight (w), specific growth rate (SGR), food conversion ratio (FCR), cumulative survival] and relationships between basic lengths TL, fork length (FL) and standard length (SL) were evaluated.     

Control of the Whitefly Trialeurodes vaporariorum Westw. (Homoptera, Aleyrodidae) on tomato by the new insecticide Acetamiprid

The efficacy of a new class of insecticide (chloronicotinyl) Mospilan 20 SP (a.?i. acetamiprid), compared with Lannate 90 SL (a.?i. methomyl) and Applaud WP 25 (a.?i. buprofezin), in glasshouse control of whitefly (Trialeurodes vaporariorum) on tomatoes, was investigated. All investigated insecticides significantly decreased the number of whitefly larvae, compared with untreated plots where population density grew during the trial. Based on statistical analysis, efficacy of all insecticides on whitefly larvae were in the same category. Some differences occurred 7 days after the third treatment. Deposited egg number was significantly different between checks and each insecticide plot. Efficacy of investigated insecticides, evaluated according to deposited egg number, was also good and in the same category.     

Fungicide sensitivity of populations of wheat powdery mildew (Erysiphe graminis f.sp. Tritici) in Central Europe in 1993

In 1993 we observed the sensitivity of wheat powdery mildew populations (Erysiphe graminis DC f.sp. tritici Marchal) from the Czech Republic, Austria, Hungary and Slovakia to the fungicides triadimenol, tebuconazole, propiconazole, flutriafol and fenpropimorph. The highest resistance value was shown to triadimenol, which attained a mean resistance factor (MRF) of 29 (expressing how many times the population is more resistant than are standard sensitive isolates) in the mildew population from the Czech Republic. The mildew populations from eastern Slovakia and eastern Hungary, populations geographically isolated from the other populations, showed very high sensitivity to all fungicides tested. There was most sensitivity to fenpropimorph (smallest MRF values) compared with the other fungicides. Cross-resistance was established among all triazoles used, but not between triazoles and fenpropimorph. Sensitivity of wheat powdery mildew populations from Central Europe to these fungicides is considered adequate, and the development of resistance has shown a decreasing tendency in recent years.     

A Natural Population of Recombinant Plum Pox Virus is Viable and Competitive under Field Conditions

The isolate BOR-3, collected in Slovakia in 1996, was recently identified as a natural recombinant between an M and D type of Plum pox virus (PPV). Biological assays demonstrated its capacity to be aphid- and graft-transmitted to various Prunus spp. hosts. A study was carried out to determine the further presence of PPV recombinants in two epidemiologically distinct areas – Slovakia and France. Tools based on PPV-M and D subgroup typing, targeting P3–6K₁, CI and CP regions of the PPV genome were used for recombinant identification. Closely related recombinant variants were detected in different Prunus spp. during a survey conducted in Slovakia in 2001, but not within a set of selected PPV isolates from France collected between 1985 and 2001. Sequence analysis of the (Cter)NIb–(Nter)CP region of 10 recombinant isolates from Slovakia showed their high homology, reaching more than 98%. All the recombinant isolates shared the same recombination breakpoint situated in the C terminus of the NIb gene. Our study demonstrates that the PPV recombinants are viable and competitive with conventional PPV-M and D isolates. The present work indicates that the occurrence of recombinants within PPV isolates might be more common than previously assumed.     

Quantitative real-time PCR assay for rapid detection of Pseudomonas amygdali pv. lachrymans in cucumber leaf rinse

Journal of Plant Diseases and Protection - Pseudomonas amygdali pv. lachrymans (Pal) is a bacterium that causes angular leaf spot disease of cucumbers. There is no direct protection against this...     

The effects of metribuzin on early life stages of common carp (Cyprinus carpio)

Metribuzin belongs to the triazine group of herbicides, which are frequently used in agriculture. The aim of this study was to assess the impact of metribuzin on growth and development of early life stages of fish. Subchronic toxic effects of metribuzin at concentrations of 0.9, 4, 14, and 32 mg/L on embryos and larvae of common carp (Cyprinus carpio) were investigated during a 30 day toxicity test under experimental conditions. Exposure to metribuzin at 32 mg/L was associated with increased mortality. Negative effects on total body length, weight, and inhibition of specific growth rate were induced by all experimental concentrations. Length and weight parameters were the most sensitive. The negative impact of metribuzin was observed in the highest tested concentration beginning on day 6 of exposure. Retardation of early ontogeny was associated with concentrations ?4 mg/L. Histological examination revealed changes in liver and caudal kidney after 30 days exposure to 32 mg/L. Based on growth parameters, development, and histological examination, the Lowest Observed Effect Concentration (LOEC) value was 0.9 mg/L.     

Comparative analysis of genetic diversity in Prunus L. as revealed by RAPD and SSR markers

RAPD and SSR markers were used for genetic diversity evaluations among 15 genotypes selected from the genus Prunus L. Altogether 40 RAPD primers and 21 primer pairs designated for microsatellite loci were applied on the whole group of genotypes.     

Microsporidia in aquatic microcrustacea: the copepod microsporidium Marssoniella elegans Lemmermann, 1900 revisited

Marssoniella elegans Lemmermann, 1900, a parasite of ovarial tissues of the copepod Cyclops vicinus Uljanin, 1875, was studied as a representative of aquatic-clade microsporidia which form "heteroinfectious spores" (spores not infective to the original host as opposed to "homoinfectious spores" which are infective for the original host) and which thus should require an alternate host. Several structural characters of this microsporidian are similar to those of copepod morphs of microsporidia infecting mosquitoes. However, small subunit ribosomal DNA phylogeny indicates that caddis flies (Insecta, Trichoptera) might be the alternate hosts of Marssoniella. Ultrastructural data obtained are used to redefine the genus Marssoniella Lemmermann, 1900 and its type species Marssoniella elegans.     

Analysis of tissue culture-derived variation in pea (Pisum sativum L.)-preliminary results

Summary The possibility of producing agronomically-useful somaclones via organogenesis and somatic embryogenesis from callus cultures of pea (Pisum sativum L.) was studied. Organogenic calli were induced from immature leaflets on MSB medium with NAA and BAP. Embryogenic calli were derived either from immature zygotic embryos (using 2,4-D) or from shoot apices (using picloram) of aseptically-germinated seedlings.The seed progenies (T₁ to T₃-generation) of primary regenerants were grown in field conditions and their phenotypic variation was evaluated and compared with control, non-tissue culture-derived plant material. In addition, electrophoretic analyses of selected isoenzyme systems and total proteins have been done. The results do not show dramatic changes in qualitative and quantitative traits. The evaluation of at least two future generations (T₄, T₅) is planned.Abbreviations BAP 6-benzylaminopurine - IBA indole-3-butyric acid - MSB medium (mineral salts after Murashige & Skoog, 1962, vitamins after Gamborg et al., 1968) - NAA -naphthalene-acetic acid, picloram-4-amino-3,5,6-trichloro picolinic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - ORG organogenesis - SE somatic embryogenesis