Propagation of Plants by Root Cuttings: II. Seasonal Fluctuation of Capacity to Regenerate from Roots

Some species regenerate readily from root cuttings at any time of year, whereas cuttings of other species show a well-marked seasonal fluctuation in capacity to grow. In the latter a high proportion of successes is possible only if cuttings are taken in the “ on ” season. In the “ off ” season for raspberry, not only do root cuttings fail but whole root systems, severed and left undisturbed in situ, also die. The regenerative capacity of (a) root cuttings, and (b) severed roots left in situ, has a bearing on the degree of control, which can be obtained by tillage, of weed species which are able to regenerate from roots left in the ground.     

Effects of supplemental dietary tannins on the performance of white‐tailed deer (Odocoileus virginianus)

Tannins are natural and nutritionally significant components of the diets of browsing ungulates. In trials on supplemented pastures and in drylots, we estimated dry matter intake (DMI), weight gain, and urea N, potassium, cortisol and creatinine in urine of captive white‐tailed deer fed pelleted diets that differed only in the respective quebracho tannin (QT) content. The low control, medium and high QT rations were 3.6, 63 and 152 g/kg DM respectively. There was no tannin‐free pellet option. Trials were divided into winter pasture, restricted choice and spring growth. In winter pasture trial on pasture using QT, deer reduced QT intake relative to that expected under random foraging. This aversion was also apparent during the spring growth trial. While DMI in the winter pasture trial remained similar among treatments (p > 0.05), averaging 130 g/kg^0.75/day, deer gained more weight (p < 0.05) when given a choice that included the high QT ration. During subsequent spring growth, DMI and weight gains generally exceeded those of the winter period. Unlike the winter pasture trial, weight gains in spring growth trial were higher (p < 0.05) in the low‐control QT treatment. In the restricted choice trial, weight gain was again higher (p < 0.05) for deer fed a low‐control QT diet. The urea N/creatinine ratio of deer fed the low‐control QT diet (0.0357) was over three times that of deer fed the high QT diet (0.0107). Neither potassium/creatinine nor cortisol/creatinine ratios were affected by diet (p > 0.05). Collectively, these results suggest that although deer do not avoid tannins, and even ingested up to 5% under the choice options in these trials, the effect of tannins on deer performance may vary by season as well as by foraging opportunities.     

Ecotoxicological Study of Insecticide Effects on Arthropods in Common Bean

Arthropods are an important group of macroorganisms that work to maintain ecosystem health. Despite the agricultural benefits of chemical control against arthropod pests, insecticides can cause environmental damage. We examined the effects of one and two applications of the insecticides chlorfenapyr (0.18 liters a.i. ha-1) and methamidophos (0.45 liters a.i. ha-1), both independently and in combination, on arthropods in plots of common bean. The experiment was repeated for two growing seasons. Principal response curve, richness estimator, and Shannon–Wiener diversity index analyses were performed. The insecticides generally affected the frequency, richness, diversity, and relative abundance of the arthropods. In addition, the arthropods did not experience recovery after the insecticide applications. The results suggest that the insecticide impacts were sufficiently drastic to eliminate many taxa from the studied common bean plots.     

Ecosystem services of geoduck farming in South Puget Sound,USA: a modeling analysis

Provisioning and regulatory ecosystem services of Pacific geoduck clam (Panopea generosa) culture were simulated for an intertidal shellfish farm in Eld Inlet, South Puget Sound, Washington, USA. An individual geoduck clam growth model was developed, based on a well-established framework for modeling bivalve growth and environmental effects (AquaShell?). Geoduck growth performance was then validated and calibrated for the commercial farm. The individual model was incorporated into the Farm Aquaculture Resource Management (FARM) model to simulate the production cycle, economic performance, and environmental effects of intertidal geoduck culture. Both the individual and farm-scale models were implemented using object-oriented programming. The FARM model was then used to evaluate the test farm with respect to its role in reducing eutrophication symptoms, by applying the Assessment of Estuarine Trophic Status (ASSETS) model. Farm production of 17.3 t of clams per 5-year culture cycle is well reproduced by the model (14.4 t). At the current culture density of 21 ind m^?2, geoduck farming at the Eld Inlet farm (area: 2684 m²) provides an annual ecosystem service corresponding to 45 Population-Equivalents (PEQ, i.e. loading from humans or equivalent loading from agriculture or industry) in top-down control of eutrophication symptoms. This represents a potential nutrient-credit trading value of over USD 1850 per year, which would add 1.48% to the annual profit (USD 124,900) from the clam sales (i.e. the provisioning service). A scaling exercise applied to the whole of Puget Sound estimated that cultured geoducks provide a significant ecosystem service, of the order of 11,462 PEQ per year (about USD 470,600) in removing primary symptoms of eutrophication, at the level of the whole water body. The modeling tools applied in this study can be used to address both the positive and negative externalities/impacts of shellfish aquaculture practices in the ecosystem and thus the trade-offs of the activity.     

Rabies Vaccination: Higher Failure Rates in Imported Dogs than in those Vaccinated in Italy

The current European Union (EU) legislation decrees that pets entering the EU from a rabies‐infected third country have to obtain a satisfactory virus‐neutralizing antibody level, while those moving within the EU require only rabies vaccination as the risk of moving a rabid pet within the EU is considered negligible. A number of factors driving individual variations in dog vaccine response have been previously reported, including a high rate of vaccine failure in puppies, especially those subject to commercial transport. A total of 21 001 observations collected from dogs (2006–2012) vaccinated in compliance with the current EU regulations were statistically analysed to assess the effect of different risk factors related to rabies vaccine efficacy. Within this framework, we were able to compare the vaccination failure rate in a group of dogs entering the Italian border from EU and non‐EU countries to those vaccinated in Italy prior to international travel. Our analysis identified that cross‐breeds and two breed categories showed high vaccine success rates, while Beagles and Boxers were the least likely to show a successful response to vaccination (88.82% and 90.32%, respectively). Our analysis revealed diverse performances among the commercially available vaccines, in terms of serological peak windows, and marked differences according to geographical area. Of note, we found a higher vaccine failure rate in imported dogs (13.15%) than in those vaccinated in Italy (5.89%). Our findings suggest that the choice of vaccine may influence the likelihood of an animal achieving a protective serological level and that time from vaccination to sampling should be considered when interpreting serological results. A higher vaccine failure in imported compared to Italian dogs highlights the key role that border controls still have in assessing the full compliance of pet movements with EU legislation to minimize the risk of rabies being reintroduced into a disease‐free area.     

Identification and determination of mecarbam and its major degradation products in water and crops

Methods have been developed for the analysis by gas-liquid chromatography and thin-layer chromatography of mecarbam and a number of its degradation products which result from oxidation and/or partial hydrolysis. In acid solution, mecarbam was found to be relatively stable but it decomposed more readily under alkaline conditions to give O, O-diethylhydrogen phosphorodithioate by fission of thesulphur-carbon bond. At pH 9.2, the half-life at room temperature was about 44 h. For residue analysis, a clean-up procedure with Florisil was found to be preferable to one which employed alumina, as the latter caused cleavage of the ethoxycarbonyl group under certain conditions. Field trials with olives, oranges and pears showed that the parent pesticide, mecarbam, was the only significant detectable residue at any stage from treatment to harvesting, and that it tended to concentrate in the oil-containing portion of the crop. Low levels of O, O-diethyl S-methylcarbamoylmethyl phosphorodithioate were also detected in residues from lucerne and from bean plants, and it was shown that this samemetabolite could be formed photolytically on filter paper or (morerapidly) on dock leaves. S-(N-Ethoxycarbonyl-N-methylcarbamoylmethyl) O, O-diethyl phosphorothioate was detected only in bean plants and then, at a level of less than 0.1 mg kg^?1.     

Quantitative measures of disease in broiler breeder chicks of different major histocompatibility complex genotypes after challenge with infectious bursal disease virus

Criteria for evaluating genetic differences in resistance and susceptibility to infectious bursal disease (IBD) within a commercial broiler breeder line of chickens were compared. Line A broiler breeder chickens were challenged with graded doses of Animal and Plant Health Inspection Service (APHIS) strain IBD virus (IBDV) and evaluated at 2 time points, 3 days postinoculation (PI) and 10 days PI. Measures obtained at both time points included bursa to body weight, bursa histology, bursa lymphocyte count, and percentage of T cells in the bursa. Furthermore, viral load in the bursa was determined 3 days PI and anti-IBDV antibody titers, 10 days PI. A dose of 50 50% embryo infective dose caused IBD in about half the line A birds at the 10-day time point, and this dose was chosen for further studies. The data were analyzed for correlation among the various measures. Comparison of the 3-day- and 10-day-PI bursa lymphocyte counts indicated that birds challenged with low doses of virus suffered lymphocyte depletion at the 3-day time point, but many or all (depending on the dose) recovered by the 10-day time point. With a viral dose that caused bursal atrophy in about half the birds by 10 days PI, families segregating for 2 major histocompatibility complex (MHC) haplotypes were compared in terms of resistance to IBD. Results indicated that there was no difference among the 3 MHC genotypes in incidence of IBD by any of the disease measures.