Beech leaf disease symptoms caused by newly recognized nematode subspecies Litylenchus crenatae mccannii (Anguinata) described from Fagus grandifolia in North America

Symptoms of beech leaf disease (BLD), first reported in Ohio in 2012, include interveinal greening, thickening and often chlorosis in leaves, canopy thinning and mortality. Nematodes from diseased leaves of American beech (Fagus grandifolia) sent by the Ohio Department of Agriculture to the USDA, Beltsville, MD in autumn 2017 were identified as the first recorded North American population of Litylenchus crenatae (Nematology, 21, 2019, 5), originally described from Japan. This and other populations from Ohio, Pennsylvania and the neighbouring province of Ontario, Canada showed some differences in morphometric averages among females compared to the Japanese population. Ribosomal DNA marker sequences were nearly identical to the population from Japan. A sequence for the COI marker was also generated, although it was not available from the Japanese population. The nematode was not encountered in Fagus crenata (its host in Japan) living among nematode‐infested Fagus grandifolia in the Holden Arboretum, nor has L. crenatae been reported in American beech in Japan. The morphological and host range differences in North American populations are nomenclaturally distinguished as L. crenatae mccannii ssp. n. from the population in Japan. Low‐temperature scanning electron microscopy (LT‐SEM) demonstrated five lip annules and a highly flexible cuticle. Females, juveniles and eggs were imaged within buds with a Hirox Digital microscope and an LT‐SEM. Nematodes swarmed to the tips of freshly cut beech buds, but explants could not be maintained. Inoculation of fresh nematodes from infested leaves or buds to buds or leaves of F. grandifolia seedlings resulted in BLD leaf symptoms. Injuring dormant buds prior to nematode application, in fall or spring, promoted the most reliable symptom expression. The biogeography and physiology of anguinid nematode leaf galling, and potential co‐factors and transmission are discussed.     

EPPO Contingency Exercise Workshop for a Forestry Pest,Zlatibor, Serbia, 2018‐11‐27/29

An EPPO Contingency Planning Workshop for a Forestry Pest was held in Zlatibor, Serbia, between 27 and 29 November 2018. In total, 55 experts from 21 EPPO member countries attended the 3‐day workshop. Participants were split into four groups for the exercise and each group acted as an ‘outbreak management team’ for a scenario based on the finding of a quarantine pest for forestry. Only when the exercise had started were participants informed that the outbreak scenario centred around the fictitious discovery of pinewood nematode (Bursaphelenchus xylophilus) in the Tara National Park in Serbia. As the scenario developed, each team had to organize themselves to manage a number of issues designed to mimic the development of an outbreak over the first month following its detection. It was clear from the feedback from participants that that contingency planning workshop was a valuable exercise for EPPO to conduct and participants highlighted the importance of it to prepare themselves for real‐life situations.     

Optimal allocation of limited water supplies for Russet Burbank potatoes

Water shortages in many potato-producing regions have increased the demand for information on irrigating potatoes with limited water supplies. Field studies were conducted at Aberdeen, Idaho in 1988 and 1989 to determine the optimal allocation of limited water supplies for Russet Burbank potatoes. Irrigation amounts equal to 60 or 80% of estimated seasonal evapotranspiration (ET) were applied using various patterns of water allocation. Irrigation deficits were either partitioned evenly over the entire tuber bulking period, or were imposed during two of three designated growth stages (early, mid or late bulking) corresponding to the periods from 0 to 3, 3 to 6, and 6 to 9 weeks after tuber initiation, respectively. A well-watered, 100% ET check was included for comparison. Total yield reductions were greater when irrigation deficits were imposed during the early-mid and midlate bulking sequences than when they were imposed evenly over the entire tuber bulking period or during the early-late bulking sequence. Results relating U.S. No. 1 yields to seasonal water allocation patterns were similar to those for total yield. However, U.S. No. 1 yield reductions were proportionately greater. Irrigation deficits imposed during the early-mid bulking sequence resulted in the lowest specific gravities and the highest percentages of dark ends.     

Zone-subsoiling effects on potato yield and grade

Soil compaction and erosion are problems in many Pacific Northwestern potato fields. We wanted to determine if zone-subsoiling would reduce these problems and improve potato yields and or grade without adversely impacting other production practices. Studies were conducted in Southern Idaho at six locations over two years on different soils and with different irrigation methods to assess the effects of zone-subsoiling immediately after planting on tuber yield and grade. Reservoir-tillage comparisons were made at three locations where sprinkler water application rates were higher than soil infiltration rates. Russet Burbank was represented by eight location-years and Russet Norkotah by two. Zone-subsoiling consistently improved tuber grade or increased tuber size. The biggest improvement was under furrow irrigation. Zone-subsoiling also tended to increase total yield in eight of ten location-years. Reservoir-tillage improved yield and grade, but zone-subsoiling did not without reservoir-tillage when water application rates were high. At no location did zone-subsoiling significantly decrease tuber grade or yield. Zone-subsoiling had no appreciable effects on hill configuration or seed-piece dislocation. Surface cracking and “water piping” occurred under furrow irrigation but were not significant problems. Results were similar for both cultivars. Additional studies will be needed to successfully incorporate zone-subsoiling into commercial production practices     

Insulin response to glucose in estrous and diestrous obese and lean heifers

This study determined if the insulin and glucose responses to glucose infusion in obese (n = 4) and lean (n = 4) Holstein heifers were affected by stage of the estrous cycle. Glucose (.35 g/kg) was infused within 2 min into the jugular veins of heifers during diestrus (d 15) and at the subsequent estrus (d 0). Concentrations of insulin and glucose were determined in jugular venous serum obtained from blood samples collected at 60, 45, 30, 15 and 1 min before and at 2.5, 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, 120, 140, 160, 180, 210 and 240 min after glucose. Mean (+/- SE) pretreatment concentrations of glucose (mg/100 ml) in obese (68 +/- 1.9) and lean (71 +/- 2.5) heifers were unaffected by body condition and stage of the cycle. Mean (+/- SE) pretreatment concentrations of insulin (microU/ml) were unaffected by stage of the cycle but were higher (P less than .05) in obese (33 +/- 3.6) than in lean (18 +/- 2.7) heifers. Body condition affected the insulin response with greater absolute concentrations (P less than .01) and total (P less than .005) response areas of insulin in obese than in lean heifers. Kinetics of the injected glucose were unaffected by body condition and stage of the cycle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of naloxone on ad libitum intake and plasma insulin, glucose, and free fatty acids in maintenance-fed sheep

The dose-dependent effects of naloxone on feed intake, and plasma chemicals (insulin, glucose, FFA) purportedly involved in feed intake regulation, were determined in 16-hr fasted sheep that were lean and chronically fed maintenance. Dorset ewes (n = 5) were treated with 0 (saline), 0.3, 1 or 3 mg/kg of naloxone in a generalized randomized block experiment with at least 7 d between successive doses. Feed intakes and plasma insulin, glucose and FFA were determined frequently during 24 hr of ad libitum intake after each naloxone treatment. The 0.3, 1 and 3 mg/kg doses of naloxone reduced (P less than 0.01) the 4-hr feed intake by 30, 40, and 60% respectively, whereas the initial feed intake (10 min) was decreased (P less than 0.05) 45% only by 3 mg/kg naloxone. However, total 24-hr intakes were similar across all doses because intakes between 4 and 24 hr of feeding in sheep treated with 0.3 (839 g), 1.0 (802 g) and 3.0 (1330 g) mg/kg naloxone exceeded (P less than 0.01) that in saline-treated sheep (391 g). Feeding-induced changes in plasma insulin, glucose and FFA concentrations were independent of naloxone treatment, suggesting that endorphinergic control of feed intake may not involve coincidental changes in plasma insulin, glucose and FFA levels which are thought to play a role in systemic regulation of appetite in animals. The endorphinergic regulation of appetite in sheep may involve the central nervous system, rather than peripheral opiate mechanisms that utilize blood-borne signals. Further, the ability of naloxone to suppress appetite in sheep appears inversely related to the duration of fasting or severity of negative energy balance.     

The role of indigenous wild, semidomestic, and exotic birds in the epizootiology of velogenic viscerotropic Newcastle disease in southern California, 1972-1973.

During an epornitic of velogenic viscerotropic Newcastle disease (VVND) in southern California, free-flying wild birds, captive and free-ranging semidomestic birds, and exotic birds were collected from the quarantine area to determine their role in the epizootiology of the disease. The VVND virus was isolated from 0.04% of 9,446 free-flying wild birds, 0.76% of 4,367 semidomestic birds, and 1.01% of 3,780 exotic birds examined. Three house sparrows and 1 crow directly associated with infected poultry flocks were the only free-flying wild birds from which VVND virus was isolated. Among semidomestic species, ducks, quail, chukars, pheasants, peafowl, pigeons, and doves were found to be infected. Psttacines, pittas, and toucans accounted for 92% of the VVND virus isolations from exotic birds. In addition, domestic Newcastle disease virus (NDV) was isolated from 0.29% of the free-flying wild birds, from 1.65% of the semidomestic birds, and from 0.19% of the exotic birds collected. Hemagglutination-inhibition against domestic NDV was demonstrated in 0.24% of 3,796 wild bird serums, 8.28% of 2,004 semidomestic bird serums, and 3.90% of 231 exotic bird serums tested. Although few free-flying wild birds were infected with VVND virus in this epornitic, the isolation of domestic NDV strains from free-flying wild ducks and mourning doves suggests the potential for transportation of NDV over long distances by migratory birds.