Lavandula gibsonii: A plant with insectistatic potential

Phytoparasitica - The plantLavandula gibsonii (fam. Lamiaceae) has been found to possess various insectistatic activities against several insect pests. Acetone extracts of the whole plant exhibit...     

Wheat root growth,grain yield and water uptake as influenced by soil water regime and depth of nitrogen placement in a loamy sand soil

Root growth, grain yield and water uptake by wheat in relation to soil water regime and depth of nitrogen (N) placement were studied in metallic cylinders filled with loamy sand soil. Root-length and -weight densities were greater under irrigated than under unirrigated conditions and they increased with deep placement as compared to surface mixing of fertilizer N. The differences were relatively larger in the deeper than in the upper soil layers and increased during later stages of plant growth. Under non-irrigated conditions, constant water table at 100 cm depth produced maximum root growth in the top 30 cm soil. Water uptake rate increased with increase in root density depending on root age and soil water status. Dry matter accumulation at different stages of plant growth and grain yield varied significantly with moisture regime and depth of N placement. Deep placement of fertilizer N under shallow water table and non-irrigated conditions caused greater root growth, better water utilization and a higher production.     

Reverse phase passive haemagglutination test for the detection of rinderpest antigen

Reverse phase passive haemagglutination [RPHA] test was applied for the detection of rinderpest antigen in various organs of rinderpest infected cattle. The results of RPHA were compared with counter immunoelectrophoresis [CIE] and single radial haemolysis [SRH] test. RPHA was as sensitive as CIE and SRH in detecting rinderpest antigen.     

Haemodynamics, blood gas and metabolic changes after anaesthesia with chloral hydrate and magnesium sulphate in camels (Camelus dromedarius)

The effects of chloral hydrate and magnesium sulphate (1:1, 10 per cent solution) were evaluated in six healthy adult camels. A dose of 1 ml kg-1 was used. These agents produced satisfactory anaesthesia with good muscle relaxation. The changes in the electroencephalogram showed that the anaesthetic effect lasted for 45 to 60 minutes. Tachycardia and hypotension were moderate and within safe limits. Electrocardiogram studies showed ST segment elevation and primary T wave changes. The acid-base status, blood gas tensions, haemoglobin concentration, blood glucose level and the plasma concentration of total protein, sodium, potassium and chloride were not altered.     

Resistance to blackrot disease (Xanthomonas campestris (Pam.) Dowson) in cauliflower

Of 200 genotypes of cauliflower screened for their reaction to blackrot disease (Xanthomonas campestris (Pam.) Dowson) ‘MGS-2⊕-3⊕’, ‘Pua Kea’ and ‘SN 445’, derived from Indian cauliflower cultivars, possessed a high degree of resistance. Neither ‘Snowball’ nor its relatives ‘Erfurt’ and ‘Alpha’ showed any resistance. For the plant breeder, soaking the seed in a bacterial suspension is the most useful screening-technique; less useful were the spraying of whole plants with a suspension and the severing of a leaf-tip beneath a suspension. There were positive and highly significant correlations between seed soaking and seedling reaction, seed soaking and adult plant reaction, and seedling reaction and adult plant reaction.     

The effect of inoculum size and betamethasone treatment on the course of infection with Dictyocaulus filaria in lambs

The effect of Betamethasone treatment on faecal larval production in lambs infected with Dictyocaulus filaria was studied. Four-to-six-month-old male lambs were infected with D. filaria at a dose of 75 larvae per kg body weight (L/kg) and subsequently treated with a total dose of 14 mg of Betamethasone, administered in divided doses, either during the early (day 5–15) or late (day 30–40) stages of infection. Faecal larval yields in treated animals during the period of patency were compared with those of un-treated controls and also with lambs infected with a dose of 150 L/kg.Higher worm establishment, as well as higher percentage survival of infected animals during patency, were associated with infections of 75 L/kg in comparison to 150 L/kg. Treatment with Betamethasone during the early stages of infection resulted in higher worm establishment but similar treatment given during the late stages of infection produced no such effects.The number of larvae per gram of faeces was higher in animals receiving infections of 150 L/kg in comparison to 75 L/kg. Treatment with Betamethasone, whether given during the early or late stages of infection, increased larval output in faeces of infected lambs. However, the output did not reach the levels shown by lambs given infections of 150 L/kg. The total estimated faecal larval yields for the period of patency were higher in the treated animals. The yields were much higher in animals treated during early stages of the infection.     

Influence of maternal antibody on efficacy of embryo vaccination with cell-associated and cell-free Marek's disease vaccine

Vaccination with turkey herpesvirus (HVT) of 18-day-old chicken embryos from a commercial source or from a cross (15 X 7) of two inbred lines induced better protection against early post-hatch challenge with virulent Marek's disease virus (MDV) than vaccination at hatch, despite the presence in embryos of maternally derived antibodies to HVT or to HVT and MDV. However, 50%-protective-dose (PD50) assays revealed that maternal antibodies in embryos reduced vaccine efficacy. The PD50 assays were conducted by vaccinating 15 X 7 embryos with serial dilutions of HVT at the 18th day of incubation. Embryonally vaccinated and unvaccinated chicks were challenged with MDV on the day of hatch. In the absence of maternal antibodies, the PD50 values in plaque-forming units for cell-associated and cell-free HVT were 57 and 328, respectively. In the presence of maternal antibodies, PD50 values for cell-associated and cell-free HVT were 105 and greater than 4,000, respectively.     

Evaluation of a modified-live virus vaccine administered in ovo to protect chickens against Newcastle disease.

The B1 strain of Newcastle disease virus (NDV-B1), which is nonpathogenic for newly hatched chickens, killed embryos when it was used to inoculate chicken eggs at embryonation day 18. Treatment of NDV-B1 with an alkylating agent, ethylmethane sulfonate (EMS) markedly reduced the pathogenicity of the virus for 18-day-old chicken embryos. Eggs inoculated with the modified virus (NDV-B1-EMS) hatched, and the virus was isolated from lungs and spleen of 1-day-old chickens. The hatched chickens developed antibody to NDV and were protected against challenge exposure (at 4 weeks of age) with a highly virulent GB-Texas strain of NDV. Presence of maternal antibody to NDV in embryonating eggs did not influence the protective ability of NDV-B1-EMS, which also induced protective immunity when administered to 4-week-old chickens. The 50% protective dose of NDV-B1-EMS in maternal antibody-negative and -positive embryos was calculated to be 10.77 and 17.70 embryo 50% lethal doses, respectively. Results of the study indicated that NDV-B1-EMS may be used as an embryo vaccine to protect chickens against Newcastle disease.