effects of neem(Azadirachta indica) seed kernel extracts from different solvents on the predacious mitePhytoseiulus persimilis and the phytophagous miteTetranychus cinnabarinus

The effects of neem seed kernel extracts from different solvents on the predacious mitePhytoseiulus persimilis Athias-Henriot and the phytophagous miteTetranychus cinnabarinus (Boisd.) were compared. All extracts were much more toxic to the latter pest than to the former. Using the respective LC₅₀ for the two species, the toxicity index (LC₅₀ Phytoseiulus/LC₅₀ Tetranychus) was found to be 3 for the methanol, 4 for the ethanol, 23 for the acetone, and 58 for the pentane extract. The order of toxicity of the extracts (pentane > acetone > ethanol > methanol) was valid only forT. cinnabarinus. The EC₅₀s for reduction of fecundity were rather close for the two species.     

Species presence and density of tetranychid and phytoseiid mites in unsprayed and sprayed apple orchards in Northern Israel

Species presence and density of mixed populations of phytophagous tetranychid and predacious phytoseiid mites were studied in sprayed and unsprayed apple orchards in northern Israel during three growing seasons. Two species of phytophagous tetranychids, namely,Tetranychus cinnabarinus Boisduval andT. Urticae Koch, and two species of predatory phytoseiid mites —Typhlodromus athiasae Porath and Swirski andAmblyseius swirskii Athias-Henriot — were found. Predator density was lower than herbivore density in sprayed commercial orchards, but the reverse was true in unsprayed orchards. Contribution from the Agricultural Research Organization. No. 2855-E, 1989 series.     

Effects of agrochemical residues on four spider taxa: Laboratory methods for pesticide tests with web-building spiders

The susceptibility of web-building and hunting spiders from the tropics (Panama), Europe (F.R. of Germany) and the Middle East (Israel) to 30 pesticides (16 insecticides, 4 acaricides, 1 herbicide, 9 fungicides) was determined. Laboratory test methods for juvenile and adult web-building spiders are described.Philodromus sp. (hunting spider), was completely resistant to all substances;Argiope sp. (web-building spider),Linyphia sp. (web-building spider) andChiracanthium sp. (hunting spider) showed medium to high susceptibility. Insecticides affected spiders in a wide range of responses: from no mortality (most compounds of biological origin) and medium mortality (pyrethrin compounds, organophosphorus and carbamate compounds), to high mortality (cyclo compounds). To both groups of spiders (the hunting and web-building), most acaricides were highly toxic, whereas herbicides and fungicides were nontoxic.     

Tomato waste compost as an alternative substrate to peat moss for the production of vegetable seedlings

Different proportions of tomato waste compost (TWC) were combined with peat moss and vermiculite as growth substrates used to evaluate the quality of seedlings of economic vegetables, including tomato, hot pepper, cucumber and summer squash. The seeding substrates used were: (T0), vermiculite: peat moss: TWC (4: 1: 0, by weight), 0% TWC; (T1), vermiculite: peat: TWC (4: 0.75: 0.25), 5% TWC; (T2), vermiculite: peat: TWC (4: 0.5: 0.5), 10% TWC; (T3), vermiculite: peat: TWC (4: 0.25: 0.75), 15% TWC; and (T4), vermiculite: peat: TWC (4: 0: 1), 20% TWC. The best seedling response was recorded in substrate mixtures supplemented with 5% and 10% TWC, which hastened seed germination and improved seedling morphology. Since vegetable seedlings produced with TWC-amended substrate were of higher quality, compared to those produced exclusively on peat substrate, we suggest that TWC may be used to replace partially peat-based substrate used for vegetable transplants production in nurseries.     

Salt stress effects on enzymes activities involved in carbon metabolism and nitrogen availability of two Tunisian durum wheat varieties

Two varieties of durum wheat (Om Rabiaa and Karim), were analyzed and evaluated in the presence of increasing doses of NaCl (0, 100, 200 and 300?mM) in which we added different concentrations of nitrate (0.1, 3, 10?mM). The data obtained showed that presence of NaCl in the culture medium induces the increase of the salt accumulation levels (Na⁺, Cl^?) and reduces the levels of K⁺ and NO₃^? in the cultivar Om Rabiaa. In Karim variety, ions that have been heavily accumulated following exposure to NaCl are Na⁺ and K⁺ while low levels of NO₃^? and Cl^? have been detected. Those findings highlight the difference in the salinity tolerance of durum wheat cultivars also depending on nitrogen (N) availability, Karim cultivar being less sensitive to NaCl treatment than Om Rabiaa. These data also suggested a relationship between salt tolerance capacity and enhancement of nitrogen and carbon metabolisms enzyme activity.     

Genetic and phenotypic parameters for Aleutian disease tests and their correlations with pelt quality,reproductive performance,packed-cell volume,and harvest length in mink

Aleutian disease (AD), caused by the Aleutian mink disease virus (AMDV), is a major health concern that results in global economic losses to the mink industry. The unsatisfactory outcome of the culling strategy, immunoprophylaxis, and medical treatment in controlling AD have urged mink farmers to select AD resilient mink based on several detection tests, including enzyme-linked immunosorbent assay (ELISA), counterimmunoelectrophoresis (CIEP), and iodine agglutination test (IAT). However, the genetic analysis of these AD tests and their correlations with pelt quality, reproductive performance, packed-cell volume (PCV), and harvest length (HL) have not been investigated. In this study, data on 5,824 mink were used to estimate the genetic and phenotypic parameters of four AD tests, including two systems of ELISA, CIEP, and IAT, and their genetic and phenotypic correlations with two pelt quality, five female reproductive performance, PCV, and HL traits. Significances (P < 0.05) of fixed effects (sex, year, dam age, and color type), covariates (age at harvest and blood sampling), and random effects (additive genetic, permanent environmental, and maternal effects) were determined under univariate models using ASReml 4.1 software. The genetic and phenotypic parameters for all traits were estimated under bivariate models using ASReml 4.1 software. Estimated heritabilities (±SE) were 0.39 ± 0.06, 0.61 ± 0.07, 0.11 ± 0.07, and 0.26 ± 0.05 for AMDV antigen-based ELISA (ELISA-G), AMDV capsid protein-based ELISA, CIEP, and IAT, respectively. The ELISA-G also showed a moderate repeatability (0.58 ± 0.04) and had significant negative genetic correlations (±SE) with reproductive performance traits (from −0.41 ± 0.16 to −0.49 ± 0.12), PCV (−0.53 ± 0.09), and HL (−0.45 ± 0.16). These results indicated that ELISA-G had the potential to be applied as an indicator trait for genetic selection of AD resilient mink in AD endemic ranches and therefore help mink farmers to reduce the adverse effects caused by AD.     

Immunomodulatory effect of cimetidine in common carp (Cyprinus carpio L.)

The main indication of cimetidine is being H₂-receptor antagonist, but studies suggest that cimetidine may also act as a non-specific stimulant of cell-mediated immunity and immunomodulator. In order to determine the immunomodulatory effect of dietary intake of cimetidine in the common carp (100 ± 10 g), subjects were fed diets containing 0 (control), 50, 100 and 200 mg cimetidine kg^?1 of dry diet for a period of 6 weeks. TLC and NBT assays were significantly (P < 0.05) stimulated in cimetidine-supplemented groups displaying the highest value in 200 mg kg^?1 group. A decrease (P < 0.05) in cortisol and ACH50 value was recorded in fish treated with cimetidine. Serum protein, albumin and serum globulin levels were not significantly changed. The findings of the present investigation suggest that the incorporation of cimetidine in the diet of common carp enhances the non-specific immunity.     

Evaluation of cognitive loads imposed by traditional paper-based and innovative computer-based instructional strategies

Strategies of presenting instructional information affect the type of cognitive load imposed on the learner's working memory. Effective instruction reduces extraneous (ineffective) cognitive load and promotes germane (effective) cognitive load. Eighty first-year students from two veterinary schools completed a two-section questionnaire that evaluated their perspectives on the educational value of a computer-based instructional program. They compared the difference between cognitive loads imposed by paper-based and computer-based instructional strategies used to teach the anatomy of the canine skeleton. Section I included 17 closed-ended items, rated on a five-point Likert scale, that assessed the use of graphics, content, and the learning process. Section II included a nine-point mental effort rating scale to measure the level of difficulty of instruction; students were asked to indicate the amount of mental effort invested in the learning task using both paper-based and computer-based presentation formats. The closed-ended data were expressed as means and standard deviations. A paired t test with an alpha level of 0.05 was used to determine the overall mean difference between the two presentation formats. Students positively evaluated their experience with the computer-based instructional program with a mean score of 4.69 (SD=0.53) for use of graphics, 4.70 (SD=0.56) for instructional content, and 4.45 (SD=0.67) for the learning process. The mean difference of mental effort (1.50) between the two presentation formats was significant, t=8.26, p≤.0001, df=76, for two-tailed distribution. Consistent with cognitive load theory, innovative computer-based instructional strategies decrease extraneous cognitive load compared with traditional paper-based instructional strategies.     

Effects of modified pond management on limnological parameters in small‐scale aquaculture ponds in mountainous Northern Vietnam

In mountainous Northern Vietnam, traditional pond aquaculture is part of the integrated farming activity contributing to food safety and to income generation for small‐scale farmers of ethnic minorities. Traditional pond management consists of a polyculture of macro‐herbivorous grass carp with 3–5 other fish species that are cultured in small ponds with constant water flow through. The main limitations to production are species‐specific mass mortalities of grass carp, a poor feed base especially for all species but grass carp, and poor water quality. In this study, we compared the traditional pond management to a semi‐intensive pond management that was based on the traditional management system but included changes designed by researchers to increase fish production. The modifications consisted of water inflow control, supplemental fertilization and feeding, and a polyculture dominated by common carp. The changes in management significantly reduced the turbidity and increased oxygen supply, as well as the natural food base within the pond. These changes in pond management provide farmers with the possibility to improve their pond aquaculture scheme and overcome previous limitations.     

Assessing the effect of administering probiotics in water or as a feed supplement on broiler performance and immune response

1.?Two routes of probiotic administration in broiler farms, in water and in feed, were compared using 360 one-day-old male broiler chickens. Controls received no probiotics or antimicrobials. The water group received a probiotic preparation at a rate of 0·5 g/l, and the feed group received it at an inclusion rate of 1 g/kg.

2.?Performance of broilers in terms body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) improved when probiotic was provided via drinking water, compared to the control and feed groups. Probiotic administration reduced plasma cholesterol and triglyceride concentrations.

3.?Spleen (28 and 42 d) and bursa (42 d) relative weights were influenced by method of probiotic administration, which also improved T-cell dependent skin thickness response to phytohaemagglutinin (PHA) injection. The effect of challenge by dinitrochlorobenzene (DNCB) depended on the method of probiotic administration.

4.?The method of probiotic administration can influence the performance and immune competence of birds, and administration via drinking water appears to be superior to the more conventional in-feed supplementation method.