Comparative effects of bark and peat based composts on the occurrence of vine weevil larvae and the growth of containerized polyanthus

A series of experiments was conducted to investigate the effect of inclusion of bark in potting composts on the numbers of vine weevil larvae on polyanthus plants. In 1989 more larvae were recovered from plants grown in peat compost than those grown in bark but these results were reversed when the study was repeated in 1990. Numbers of larvae also increased with higher ratios of bark:peat in composts but declined as the size fraction of bark used increased. The degree to which bark was composted did not appear to materially affect the numbers of vine weevil recovered. A strong, positive, relationship between larval numbers and foliage dry weight was found. Similarly, larval numbers were bigger with greater root development in bark composts. The results are discussed and it is suggested that the use of bark may promote more vigorous growth in polyanthus and thus enable plants to support more larvae.     

Black vine weevil (iOtiorhynchus sulcatus (F.)) oviposition on polyanthus plants outdoors in Northern Ireland

Vine weevil oviposition was monitored at a site in Northern Ireland from 1983-1986 by collecting eggs from sand layers on top of polyanthus plants. Oviposition started in May/ June and terminated in September/November. The mean oviposition period was 22.5 wk and this indicated that overwintering adults made a significant contribution to the total number of eggs laid. Viability of eggs was related to the numbers produced. The results are discussed in relation to meteorological data and it is concluded that the severity of a winter, as measured by the number of days with sub-zero mean temperatures, can influence both the numbers of eggs laid and the date on which oviposition commences.     

An evaluation of three insecticides as compost treatments for the control of vine weevil larvae in hardy-annual nursery stock

Three insecticides, Bacillus thuringiensis, chlorpyrifos and phorate, were tested as compost additives to control the larvae of Otiorhynchus sulcatus in hardy-annual nursery stock. In two experiments, one tested a range of doses (20-100 g a.i. m^-3 compost) in plants exposed to egg-laying adults for 20 weeks, and the other investigated the persistence of insecticidal activity. B. thuringiensis failed to control the larvae; phorate gave control up to early July but by August had also failed; chlorpyrifos-treated compost controlled larvae until mid-August and maintained partial control through September. Possible phytotoxic damage by chlorpyrifos is discussed.     

Electrical detection of subclinical mastitis

Abstract

Extract

Sir,— The work of Linzel et al.(2) Clarke, G. P. Y. and Oliver, J. 1977. Estimation of the prevalence of udder infection in dairy herds based on a single-quarter sample from each cow in the dairy herd. J. Dair. Res., 44: 195–199.  [Google Scholar] (3) Linzell, J. L. and Peaker, M. 1975. Efficacy of the measurement of the electrical conductivity of milk for the detection of subclinical mastitis in cows: Detection of infected cows at a single visit. Br. vet. J., 131: 447–460.  [Google Scholar] suggested that a high proportion of quarters showing subclinical infection could be detected by measuring the maximum absolute electrical conductivity of their foremilk. Consequently, it seemed worthwhile to evaluate the performance of a simple electrical conductivity meter ^{* *}AHI Mastitis Detector, AHI Plastic Moulding Co., Private Bag, Hamilton. , designed to be a rapid and reliable test for subclinical mastitis, against the more conventional tests.     

The effects of “holding” on some blood parameters in goats

One young male and five female goats aged from four months to mature fullmouthed were handled by stroking and raising the jugular vein intermittently for one minute each day for four days. A control group was kept in a similar pen out of sight of the test group for the four days and approached only when attended for pen cleaning and feeding. On the fifth day, heparinised blood samples were taken once hourly for a period of three hours by jugular venepuncture from both groups. After processing, the samples were examined for packed cell volumes, plasma and erythrocyte potassium and sodium concentrations. Analysis of variance of the data showed a significant (P<0.01) reduction in erythrocyte potassium concentration in the unhandled group (76.3 mmol/l to 74.2 mmol/l) from Time 0 to Time 1, and a similarly significant increase in levels in the handled group (73.7 mmol/l to 78.0 mmol/l) from Time 0 to Time 1. There was also a significant difference (P<0.05) in packed cell volumes between the unhandled and handled groups at Time 0 and Time 1 (28.6% v 25.2% and 27.6% v 25.0% respectively). There were no significant differences between the two groups in plasma sodium, plasma potassium or erythrocyte sodium.     

Energy Use Efficiency of Conventional versus Conservation Management Practices for Irrigated Potato Production in Southern Alberta

A 12-yr. (2000–2011) study was conducted in Alberta, Canada to compare the energy use efficiency (EUE) of conventional (CONV) and conservation (CONS) potato (Solanum tuberosum L.) management practices. Potato was grown in 3- to 6-yr. rotations which included dry bean (Phaseolus vulgaris L.), sugar beet (Beta vulgaris L.), soft wheat (Triticum aestivum L.), oat (Avena sativa L.), and timothy (Phleum pratense L.). CONS included compost application, reduced tillage, cover crops, and solid-seeded bean. Findings suggested that potato in 5-yr. CONS produced the highest EUE compared to the other CONS or CONV rotations. CONS can be used as a means of reducing the reliance on non-renewable energy inputs and improving overall EUE of potato production when less than 21% of the N content of compost applied was counted toward energy input use of potato production. At more than 21%, potato in the 4-yr. CONV became more favorable compared to potato in other rotations.     

Impact of field fungal contamination of barley on ensiling properties,nutritional quality and the microbiome of barley silage

Barley varieties of differing fungal disease resistance were grown in triplicate plots at Lacombe and Lethbridge, Alberta with the disease resistant variety (FR) sprayed with a foliar fungicide to maximize differences in field fungal disease. Both varieties were harvested at soft dough and ensiled in minisilos to assess differences in fungal contamination on ensiling properties, nutritional quality, aerobic stability and associated bacterial and fungal microbiomes. Data were analysed as repeated measures with the effect of treatment × time (duration of ensiling or aerobic exposure) included in the model. The percentage leaf area diseased by net form net blotch was higher (p < 0.05) in the untreated barley cv. Sundre (UN, 59.1% leaf area affected at Lacombe and 25.2% at Lethbridge) than in the FR barley cv. Chigwell (0.7% leaf area affected at Lacombe and 0.1% at Lethbridge). Fungal resistant barley had a lower (p < 0.01) acid and neutral detergent fibre content. Relative abundance of Xanthomonadales was higher (p = 0.02) for FR than UN, while Lactobacillales dominated the bacterial microbiome after 60 day of ensiling in both silages. Bacillales dominated both FR and UN after 21 day of aerobic exposure. Fungal resistant fresh barley forage had a tendency (p = 0.10) for a greater relative abundance of Pleosporales, while UN had higher (p < 0.01) Hypocreales. Mould counts were lower (p = 0.01) for FR than UN after 7 day of ensiling. Fungal resistant barley had minimal influence on the fungal community that contributed to the aerobic deterioration of barley silage.