CAUSAL AGENTS OF SILVER TOP AND OTHER TYPES OF DAMAGE TO GRASS SEED CROPS

1967 ◽  
Vol 99 (6) ◽  
pp. 660-670
Author(s):  
D. A. Arnott ◽  
I. Bergis

AbstractStudies during 1962–64 showed that the mites Siteroptes graminum (Reut.) and Aceria tulipae Keifer, thrips, and the fungus, Fusarium poae (Pk.) Wr., were not causal agents of silver top in the Peace River region, and indicated leafhoppers were probably not involved. The fact that silver top is controlled with insecticides, but not with miticides, constituted strong evidence for insects as causal agents. In 1963, extensive examination of grasses with silver top revealed minute, inconspicuous punctures, 0.01 to 0.04 mm in diameter through leaf sheaths which were typical of chose made by insects with piercing and sucking mouthparts such as plant bugs. In 1964, attempts to produce silver top by infesting grass plants with plant bugs, leafhoppers, and spittlebugs were unsuccessful for reasons in-explainable. Non-appearance of silver top in either infested or uninfested plants, however, indicated the causal agent was not present in the plants or attached soil when collecred from fields in mid-May. Further studies in 1965 showed that grasses affected by silver top were infested with the plant bugs Stenodema trispinosum Reut., S. vicinum (Prov.), Litomiris debilis Uhl., Capsus simulans Stal., and Trigonotylus ruficornis (Geof.). Experimental infestation of plants with these bugs showed that they fed on stems by puncturing through leaf sheaths and so damaging stem tissue as to cause silver top. In 1966, examination of grasses with silver top from southern Alberta, Saskatchewan, and Oregon revealed punctures in leaf sheaths opposite areas of stem injury, indicating that plant bugs probably cause silver top in these regions.

2008 ◽  
Vol 88 (3) ◽  
pp. 439-446 ◽  
Author(s):  
N. A. Fairey

In order to address a paucity of information, a study was conducted in the Peace River region of northwestern Canada to determine the effects on seed production of creeping red fescue (Festuca rubra L. var. rubra) of six water treatments [natural precipitation and 100, 125, 150, 175 and 200% of the average, cumulative, long-term precipitation (LTP) of 459 mm yr-1] in combination with four N-fertilization regimes (zero + 102, 34 + 68, 68 + 34, and 102 + zero kg ha-1 N for the first + second crops, respectively). The 2-yr seed yield exceeded 2900 kg ha-1 when N was supplied to just one of the two seed crops, viz. with 150 to 200% LTP when N was applied only to the first seed crop, and with 125 to 150% LTP when N was applied only to the second seed crop. Under the prevailing, long-term, moisture environment at the study site (100% LTP), total seed yield over two production years was greatest (2136 kg ha-1) with 68 + 34 kg ha-1 N. The effects of the water and N treatments on seed yield were not associated with the mass of root organic matter recovered after the harvest of the second seed crop. These results confirm, and begin to quantify, numerous visual observations in the Peace River region that seed yields of creeping red fescue are restricted by insufficient precipitation. Key words: Creeping red fescue, Festuca rubra, grass seed production, nitrogen fertility, water, soil moisture


2001 ◽  
Vol 81 (2) ◽  
pp. 265-271 ◽  
Author(s):  
N. A. Fairey ◽  
L. P. Lefkovitch

A field study in the Peace River region of north-western Canada evaluated the effect of seeding rate on the seed yield and quality of perennial ryegrass (Lolium perenne L.) in the year after establishment with a grain companion crop. Each of two sites was sown with 70 kg ha–1 barley (Hordeum vulgare L.) and under-sown, in 30-cm rows, with three cultivars (All*Star, Barclay and Repell) of diploid perennial ryegrass at seeding rates of 150, 300, 600, 1200, 2400 and 4800 viable seeds m–2. During the establishment year of the perennial ryegrass, the grain yield of the barley companion crop was comparable to commercial yields for the region. Time of seed maturity, seed yield and thousand-seed weight of perennial ryegrass were not significantly (P ≤ 0.05) affected by the seeding rate, but were by cultivar. There was a significant (P ≤ 0.01) seeding rate × cultivar interaction for fertile tiller density and specific seed weight. Seed dockage differed significantly (P ≤ 0.001) among cultivars (16.7–27.9%) and increased with seeding rate (19.8–24.2%), and the germination capacity of the harvested seed was unaffected by seeding rate or cultivar. Grass seed yield was positively associated with fertile tiller density for each cultivar (r = 0.454***, n = 72 for All*Star; r = 0.364***, n = 72 for Repell; and r = 0.719***, n = 72 for Barclay). Compared with the other cultivars, Barclay matured 13 –15d later, had the lowest density of fertile tillers (1330 m–2), the highest seed dockage (27.9%) and the lowest seed yield (345 kg ha–1). All*Star had the highest seed yield (774 kg ha–1), the lowest seed dockage (16.7%), and the highest thousand-seed weight (1.55g). Repell was intermediate in seed yield (633 kg ha–1) but similar to All*Star, rather than Barclay, in other characteristics. The later maturity, creeping habit and prostrate stature of Barclay may have reduced its ability to produce fertile tillers and seed as efficiently as the other two cultivars at this northern latitude. In the Peace River region, there is potential for under-seeding a spring grain crop with perennial ryegrass for the production of successive harvests of grain and grass seed, provided the cultivar of perennial ryegrass is adequately adapted for seed production. The seeding rate for the perennial ryegrass is not particularly critical and 150–300 viable seeds m–2 should be adequate for diploid perennial ryegrass grown in rows with a grain companion crop. Key words: Perennial ryegrass, Lolium perenne L., grass seed production, grass seed quality, seeding rate, grain companion crop


2003 ◽  
Vol 1 (1) ◽  
pp. 67-74
Author(s):  
D. T. Fairey ◽  
N. A. Fairey ◽  
L. P. Lefkovitch ◽  
J. A. C. Lieverse

AbstractThe agri-climatic adaptation of an alfalfa variety in North America is categorized by its Fall Dormancy Rating (FDR1 = dormant to FDR9 = non-dormant). Presently, only relatively dormant, winter-hardy varieties (FDR1–4) are grown for seed and herbage at the northern latitudes of western Canada. However, there is considerably greater demand for seed of varieties that have FDR ≥ 4. A study was conducted in the Peace River region of north-western Canada to determine the relationship between FDR and seed production of alfalfa with FDR ≥ 4. Trials were established in each of two consecutive years with four varieties representing each of six FDR categories, FDR4–9. Growth characteristics were determined for two successive years of seed crops for each year of establishment. Seed yield (as a percentage of that for FDR4) was 84, 52, 40, 29 and 39% for FDR5 to FDR9, respectively, whereas total biomass at seed maturity was 89,73, 73, 57 and 57% for FDR5 to FDR9, respectively. Seed yield was more sensitive to changes in FDR than total biomass. Short rotations of specific alfalfa varieties with FDR ≥ 4 could be an option for seed growers in the northerly latitudes of western Canada, provided greater financial compensation is given for higher FDR varieties, and provided genetic drift can be retained within acceptable limits.


Blue Jay ◽  
1994 ◽  
Vol 52 (2) ◽  
Author(s):  
Norbert G. Kondla ◽  
Edward M. Pike ◽  
Felix A. H. Sperling

2021 ◽  
pp. 1-15
Author(s):  
Amanda Jorgensen ◽  
Maya L. Evenden ◽  
Owen Olfert ◽  
Jennifer Otani

Abstract Wheat midge, Sitodiplosis mosellana Géhin (Diptera: Cecidomyiidae), is an invasive pest of wheat, Triticum spp. (Poaceae), in North America and is found in all wheat-growing regions of the world. Wheat midge biology, particularly post-diapause emergence of adults, varies with geographic region. The biology of wheat midge has not previously been examined in the northernmost area of its range in Canada – the Peace River region of Alberta. Wheat midge adult emergence was compared in situ to two phenological models of wheat midge emergence developed in other geographic regions. In-field adult emergence did not match the published phenological models. In the Peace River region, adults emerged later than are predicted by both models and precision for both models was low. With the Saskatchewan model, accumulated rainfall that was more than 110 mm in May and early June delayed emergence, whereas accumulated rainfall that was less than 43 mm during that period caused earlier than predicted emergence. Multiple peaks of wheat midge emergence, up to 20 days apart, were observed at some sites, supporting the Jacquemin model depicting “waves” of emergence. Including differences in soil temperature accumulation related to precipitation and optimising the model temperature thresholds would improve accuracy of the current Canadian phenological model in the Peace River region.


1962 ◽  
Vol 42 (2) ◽  
pp. 183-190 ◽  
Author(s):  
B. D. Owen ◽  
A. Reddon ◽  
F. Whiting

Ninety-two sows and two hundred and sixteen pigs were employed in four gestation-lactation and three growing-finishing experiments to determine the adequacy of barley grown on the Grey Wooded soils of the Peace River region in northwestern Canada, as a source of riboflavin, pantothenic and nicotinic acid in swine rations. Vitamin B12 was assessed as a dietary essential in the all-plant rations. In the gestation-lactation experiments sow gains during gestation were greater in the B-vitamin supplemented lot and a trend toward heavier weaning weights of pigs was evident. Vitamin supplementation increased the level of vitamin B12 in sow’s milk collected 1 week post-partum and of both riboflavin and pantothenic acid collected 1 week and 6 weeks post-partum. Nicotinic acid content of sows’ milk was unaffected by supplementation. There was a highly significant decrease in riboflavin level in both control and supplemented lots between 1 and 6 weeks following parturition. The decrease was greatest in the unsupplemented lot.B-vitamin supplementation did not affect growing period gains or pig carcass quality in the growing-finishing experiments. However, certain significant growth responses were noted in the finishing period.The data indicate that the basal rations employed contained adequate riboflavin, pantothenic and nicotinic acid to support normal gestation, lactation and growth in Yorkshire swine.


1960 ◽  
Vol 40 (1) ◽  
pp. 204-206 ◽  
Author(s):  
T. C. EDMONDS ◽  
C. H. ANDERSON

not available


1961 ◽  
Vol 41 (2) ◽  
pp. 261-267 ◽  
Author(s):  
C. R. Elliott ◽  
C. H. Anderson ◽  
B. D. Owen

Yields of herbage, animal gains, carrying capacity and TDN production were determined for three pasture swards grown on a Grey Wooded soil (Albright-Hythe series) in the Peace River region of northern Alberta over the period 1953 to 1956 inclusive. Sheep were used as grazing units. Fertilizer treatments of nil, ammonium phosphate (11-48-0) at 300 pounds per acre and ammonium nitrate (33-0-0) at 100 pounds per acre were applied annually to pastures of creeping red fescue, creeping red fescue-alfalfa and bromegrass-alfalfa.Productivity obtained with unfertilized grass-legume mixtures was almost double that for unfertilized grass grown alone. Increased production attributable to alfalfa was also obtained, although to a lesser degree, where fertilizers were used. Pastures of creeping red fescue seeded alone and with alfalfa responded markedly to applications of nitrogen while responses to phosphorus were negligible. Conversely, bromegrass-alfalfa pastures responded strongly to applications of phosphorus and only slightly to nitrogen.


1959 ◽  
Vol 39 (4) ◽  
pp. 505-511 ◽  
Author(s):  
P. Pankiw ◽  
C. R. Elliott

Pollination studies involving zero, one and three colonies of honey bees per acre, on commercial alsike clover fields ranging in size from 15 to 75 acres, were conducted in 1954, 1955, and 1957 in the Hinton Trail district of the Peace River Region of Alberta. These studies indicated that in large fields one colony of honey bees per acre is sufficient to pollinate alsike clover, consideration being given to competition of other crops and to the climatic conditions. The influence of competing crops was such that 65- to 75-acre fields, with one colony per acre, were similar in honey bee populations and seed production to 15- to 20-acre fields with three colonies per acre. Competing plant species accounted for 15 to 36 per cent of the pollen collected by honey bees. Fields with the higher populations of pollinators matured earlier than fields deficient in pollinators. A population of 3400 honey bees per acre (0.7 bee per sq. yd.) throughout the flowering period resulted in seed sets up to 82 per cent and seed yields to 375 lb. per acre. Check fields, where no honey bees were supplied, ranged in production from 29 lb. per acre, with a low native pollinator count, to 293 lb. where a pollinator equivalent of 1300 bumble bees per acre was observed. Bumble bees worked alsike clover at the rate of 28.6 florets per minute, as compared to 20.0 for leaf-cutter bees and 18.7 for honey bees.


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