CONTRAST‐ENHANCED HARMONIC ULTRASONOGRAPHY OF MEDIAL ILIAC LYMPH NODES IN HEALTHY DOGS

Herein, we describe the normal contrast‐enhanced harmonic, color, and power Doppler ultrasonographic characteristics of the medial iliac lymph nodes in healthy dogs. Contrast‐enhanced harmonic ultrasonography of the medial iliac lymph nodes was performed on 14 healthy dogs after intravenous administration of the lipoprotein‐bound inert gas‐filled microbubble contrast media Definity^®. Time–pixel intensity curves were generated for 1‐min postinjection. Quantification of these curves was performed using Philips QLab software. Non‐contrast‐enhanced power and color Doppler examinations were performed in each node to assess vascular patterns subjectively. Normal lymph nodes exhibited a mean contrast wash‐in phase beginning at 6.3 s from the time of injection with mean peak pixel intensity at 12.1 s. Angioarchitecture was best visualized with contrast‐enhanced harmonic ultrasound compared with power and color Doppler. Normal lymph nodes in dogs have a central artery with a centrifugal and uniform branching pattern. Contrast‐enhanced harmonic ultrasonography is a noninvasive examination that demonstrates improved visibility of the intranodal architecture of healthy medial iliac lymph nodes in dogs compared with conventional, non‐contrast‐enhanced Doppler methods that may have future clinical applications.     

Yield and compensatory growth of lucerne following simulated winter-kill

Lucerne ( Medicago sativa L.) sown at 2·8-11·2 kg ha⁻¹ in spring was thinned in the autumn by digging plants from alternate 15- or 30-cm lengths of row. Both thinning treatments decreased the subsequent year stand density by 34%. Yields the following year were reduced by 24 and 17% for the 15- and 30-cm treatments respectively, and the next year by 10% for both treatments. Thinning effects were similar at all sowing rates. During the year following thinning, plants did not grow larger in response to the thinning. Thus, development of compensatory growth by lucerne plants following sudden stand thinning is slow.     

Growth of prairie grass (Bromus willdenowii) and tall fescue × perennial ryegrass (Festuca arundinacea×Lolium perenne) on the Appalachian Plateau of southern West Virginia, USA

The productivity and persistence of prairie grass ( Bromus willdenowii Kunth) cv. Grasslands Matua were compared with a similarly managed endophyte-free tall fescue × perennial ryegrass hybrid ( Festuca arundinacea Schreb. × Lolium perenne L.) cv. Johnstone. A field study was conducted on the Appalachian Plateau of southern West Virginia, USA (81°W, longitude; 38°N, latitude; 850m above sea level) for three consecutive years. Nitrogen totalling 0, 168, and 336 kg N ha⁻¹ year⁻¹ was applied to stands managed as hay. Annual herbage yields were similar for both species in year 1 (1989), but by year 3 (1991) Matua sown-grass yield was about 35% of first-year yields. Total herbage yield for Matua plots in the third year was similar to first-year yields owing to encroachment by non-seeded grasses and white clover ( Trifolium repens L.). Matua was susceptible to powdery mildew [ Blumeria graminis (DC) E. O. Speer] in this environment, and was similar in productivity (first year only) and nutritive quality to tall fescue × perennial ryegrass hybrid. Matua use may be limited to areas where low-temperature stress and resultant winter damage is unlikely to occur.     

Establishment of lucerne after maize in conservation tillage systems†

Extensive slug damage reported for lucerne ( Medicago sativa L.) establishment in grass sod and small grain fields when using conservation tillage prompted this 3-year study on establishing lucerne in maize ( Zea mays L.). Different crop residues were created by harvesting maize for grain and silage and including a silage+rye ( Secale cereale L.) winter cover crop treatment. Conventional tillage (ploughed in spring) following grain harvest was included as a control. In addition, a combination treatment of methiocarb bait broadcast on the surface and carbofuran granules applied in the furrow with the seed was compared with an untreated control. Finally, three planting dates, early and late April and late May, simulated the spring planting season. Planting lucerne in the different maize residues had a significant effect on lucerne yields, especially the silage+rye residue treatment, which caused the lowest lucerne yields. Highest yields of lucerne occurred when it was planted after silage, a treatment in which residue was minimal.
The earliest planting date gave the highest lucerne yields in the establishment year. Slugs did not reduce the establishment of lucerne in any maize residue, nor were lucerne yields affected by slug feeding. This was attributed to the low slug populations observed early in the growing season. Establishing and producing lucerne in maize residues was more successful in this study because of the lower slug populations than those usually encountered in grass sod or small grain residues.     

Harvest frequency effects on forage yield and quality of rapes and rape hybrids*

Spring-seeded rape requires approximately two-thirds of the growing season in the north-cast USA, to reach physiological maturity. Harvest frequency studies were conducted with rapes and rape hybrids in Pennsylvania to determine whether forage yields and/or quality can be improved with multiple harvests, and whether cultivars respond similarly to harvest management. Nitrogen was applied at 75 kg ha^?1 at seeding and 75 kg ha^?1 70 d after seeding. Additional fertilizer was applied according to soil test results. A split-split-block design was used. Harvest frequencies of 180, 90, 60, or 30 d were randomly assigned to blocks. Cultivars were randomized within each harvest frequency, with four replicates. Amount of regrowth of all cultivars after mid-August was highly variable, depending on weather. Foliar diseases and aphids lowered yields in different years. Cultivars differed in susceptibility to diseases and aphids as well as in morphology. Forage yields and crude protein yields of rape generally were highest with the 90-d harvest frequency, whereas crude protein concentration was highest with the 30-d frequency. Mean in vitro dry matter digestibility (IVDMD) values were high regardless of harvest frequency, cuttivar, or sampling date. Yield differences between cultivars generally were greatest with one harvest at 180 d; mean yield was highest for forage rapes, intermediate for winter oil rapes, and lowest for rape x Chinese cabbage hybrids. Under frequent harvesting, BLE rape and the rape x Chinese cabbage hybrid performances were exceptional as regards forage yield and quality.     

Comparative Efficacies of Next-Generation Insecticides Against Yellow Stem Borer and Their Effects on Natural Enemies in Rice Ecosystem

The efficacies of some next-generation insecticides against the rice yellow stem borer(YSB),Scirpophaga incertulas(Walk.), and their compatibilities with natural enemies were investigated during 2014 and 2015. Three newer insecticides, chlorantraniliprole 0.4% G, dinotefuran 20% SG, and methoxyfenozide 24% SC, and two commonly used insecticides, carbufuran 5 G and quinalphos 25 EC,were evaluated in the field for their efficacies against YSB and their non-target effects on natural enemies.Application of chlorantraniliprole 0.4% G at 10.96 kg/hm^2 resulted in the greatest reduction in YSB infestation(deadhearts and whiteheads) and greatest increase of yield compared to the untreated control plots, followed by methoxyfenozide 24% SC at 0.41 L/hm^2, dinotefuran 20% SG at 0.15 kg/hm^2,carbufuran 5 G at 10.96 kg/hm^2, and quinalphos 25 EC at 1.50 L/hm^2. All the insecticides reduced the numbers of predators viz., lady bird beetles, wolf spiders, carabid beetles, earwigs, green mirid bugs, and damselflies. Numbers of adults of the egg parasitoids Trichogramma sp., Telenomus sp. and Tetrastichus sp. were significantly reduced in insecticide-treated plots compared to untreated control plots. In all field trials, the harmful effects of the five insecticides were in the following rank order(least harmful to most harmful): chlorantraniliprole 0.4% G, carbufuran 5 G, dinotefuran 20% SG, methoxyfenozide 24% SC,and quinalphos 25 EC. On the basis of reduction in YSB infestation, increase in grain yield, and compatibility with natural enemies, chlorantraniliprole 0.4% G was proved to be the best of all the insecticides for YSB management system, although the study suggested minimizing its retail price for enhancement of cost effectiveness in farmers' fields.