Effectiveness of Combined Use of Mineral Oil and Insecticide Spray in Reducing <Emphasis Type="Italic">Potato Virus Y</Emphasis> (PVY) Spread under Field Conditions in New Brunswick,Canada

In the 2014 and 2015 crop seasons, the efficacies of different types, rates and combinations of mineral oil and insecticide foliar sprays for reducing Potato virus Y (PVY) spread were tested in controlled field trials in New Brunswick (NB), Canada. Experimental plots were planted with certified PVY-free Goldrush, supplemented with known virus-infected seed to raise PVY inoculum to 2.3% and 3% at the beginning of the 2014 and 2015 seasons, respectively. Treatments consisted of mineral oil-only sprays at different application rates, insecticide-only sprays of differing numbers, and several combined mineral oil and insecticide spray regimes, all compared to a no-spray control treatment. PVY spread to 18% (2014) and 22% (2015) of initially virus-free plants in no-spray control plots, with significant reductions observed in PVY spread in several treatments. Greatest PVY reductions, as low as 4% (2014) and 12% (2015), were in combined mineral oil and insecticide spray treatments, followed by oil-only sprays; while insecticide-only sprays did not significantly reduce PVY spread. As well as measuring PVY spread to marked test plants and randomly collected post-harvest tuber sample from the plots, exhibited similar treatment pattern for PVY incidence. Multiple logistic regression modeling confirmed the relative efficacy of combined oil and insecticide sprays for reducing PVY spread, while accounting for variable inoculum and aphid factors. Modeling also highlighted the importance of planting low-PVY seed initially, and of early application of foliar sprays. Local best management practice recommendations for reduction of in-field PVY spread were discussed.     

The coat proteins and putative movement proteins of isolates of Prunus necrotic ringspot virus from different host species and geographic origins are extensively conserved

A complete sequence for the RNA 3 of Prunus necrotic ringspot virus (PNRSV) is described (Genbank Accession U57046). Primers from this sequence were used to amplify both the movement protein and coat protein genes of 3 other isolates of PNRSV originating from different host species and geographic locations. Comparisons of these sequences with those of other published sequences for PNRSV and the closely related apple mosaic virus (ApMV) showed that both the movement proteins and coat proteins of isolates of PNRSV are extensively conserved irrespective of either the original host or the geographic origin. The movement protein and coat protein of ApMV and PNRSV are sufficiently conserved to suggest that these two viruses may have evolved from a common ancestor. The amino acid sequence of the two coat proteins shows areas of similarity and difference that would explain the serological continuum reported to occur among isolates of these two viruses. Nevertheless, the movement protein and coat protein of the two viruses are sufficiently different so that ApMV and PNRSV should be considered to be distinct viruses.     

Pheasant ataxia: a new condition in pheasant poults

Between 1995 and 1997 a neurological condition in pheasant poults from 24 sites in England and Scotland was investigated. Affected birds showed varying degrees of ataxia and incoordinated movements and, in severe cases, recumbency, but generally remained alert with their heads held upright. The condition characteristically affected poults from seven weeks of age and the incidence on any one site was low. No significant bacteria were isolated consistently from brain tissue. The condition was characterised histologically by a non-suppurative meningoencephalitis, in which lesions were found predominantly in the cerebellum in 61 of 81 samples examined (75.3 per cent). A non-suppurative myelitis was recorded in 16 of 20 spinal cords examined. No lesions were recorded in peripheral neural tissue and lesions were rare in other tissues. The condition appeared not to have been recorded previously in pheasants. A viral aetiology was suspected but Newcastle disease virus was not involved.     

Use of quicklime to increase oyster seed production

A single application of quicklime (calcium oxide), spread at a rate of 6.75 metric tons/ha, was used to prepare dormant oyster setting beds for spat production. Of 2 000 ha in Long Island Sound, Connecticut, U.S.A., 1200 ha had sufficient shells to cover at least 75% of the bottom. However, these shells had a continuous fouling organism layer that would prevent significant oyster setting. Many beds had predator populations of sea stars (Asterias forbesi) and oyster drills (Urosalpinx cinerea and Eupleura caudata). Quicklime cleans the shells by killing fouling organisms, and also controls sea stars and embryonic oyster drills.When the supply of clean shells for annual spreading on the setting beds is limited, use of the quicklime method prepares greater quantities of shells for possible oyster set.     

Cowdria ruminantium infection in the mouse: a review

The current knowledge of the pathogenicity, clinical signs and mortality of artificial infections by syringe inoculation of Cowdria ruminantium in laboratory and wild strains of mice is reviewed. It is concluded that a wide spectrum of pathogenicity for mice exists in stocks of the organism.     

TENOSYNOVITIS IN CHICKENS

An adenovirus was isolated from the tendon fluid of broilers and meat breeders with clinical tenosynovitis. The viral infection was in many cases accompanied by a staphylococcal infection. The significance of the adenovirus is not yet known, although initial transmission studies indicate that it may play a role in the tendon thickening process.     

Effects of Stem-Injected Plant Growth Regulators, with or without Sucrose, on Grain Production, Biomass and Photosynthetic Activity of Field-Grown Corn Plants

Study of plant growth regulators (PGRs) through conventional foliar application or tissue culture or other organic materials has limitations. No previous study has examined the effects of long-term continuous addition of PGRs, with or without sucrose, to field-grown corn ( Zea mays L.) plants. A field study was conducted to determine the effects on corn plant growth and productivity during the grain-filling period of a continuous supply of PGRs, with or without sucrose, using a recently developed injection technique to deliver pressurized solutions through syringe needles sealed to the stem with latex. Our four PGRs (IAA, ABA, ethephon and salicylic acid) and a distilled water control, and two levels of sucrose (150 g l⁻¹ and a distilled water control) were injected into corn plants for 42 consecutive days during the grain-filling period. The plants injected with solutions not containing sucrose took up 42 ml more than those injected with sucrose-containing solutions. Corn plants injected with salicylic acid (SA) produced 9 % more grain yield than plants injected with no PGRs. The combination of SA and sucrose increased the photosynthetic rate by 42 % when compared with distilled water. Injection of ethephon resulted in an 11 % reduction in grain yield. Neither IAA nor ABA altered plant photosynthesis or productivity. Sucrose injection increased the dry weight of injected internodes and stover, and induced partial stomatal closure, although without any measurable effect on net photosynthetic rate. This study showed that stem injection makes possible the study of changes in plant physiology during grain-filling due to the effects of PGRs and metabolites administered continuously over protracted periods of time. It also demonstrated a previously undocumented stimulation of plant photosynthesis and grain yield by SA.