Dimethoate insecticide application seldom reduces silvertop incidence in grass seed fields on the Canadian Prairies

2021 ◽  
Author(s):  
J. J. Soroka ◽  
Bruce D. Gossen
Keyword(s):  
Seed Yield ◽  
Perennial Grass ◽  
Strong Support ◽  
Field Studies ◽  
Kentucky Bluegrass ◽  
Extensive Study ◽  
Residue Management ◽  
Grass Species ◽  
Insecticide Application ◽  
Grass Seed

Many arthropods have been reported (but none confirmed) as causal agents of sterile seed heads in perennial grass seed fields, known as silvertop or white head. Field studies to identify the arthropods that cause silvertop were conducted in five perennial grass species at seven sites in Saskatchewan, Canada over several years. The effect timing of insecticide application in spring – early, mid or late – and of post-harvest residue management – mowing, close mowing with straw removed (scalping), and burning – on subsequent arthropod populations, silvertop incidence and seed yield were assessed. Samples of grass tillers and sweep net collections were taken regularly, and the arthropods collected were identified to family level and counted. Arthropod populations from sweep samples varied among sites and dates in number and taxon composition, but no arthropod assemblage was consistently associated with silvertop in any grass species. Thrips were the most numerous arthropods on tillers at all sites. Insecticide application often temporarily reduced arthropod populations, but reduced silvertop incidence at only 1 of 15 site-years, and increased seed yield at only 1 of 17 site-years. Scalping or burning did not reduce silvertop incidence but often increased healthy seed head numbers and seed yield relative to mowing, the standard treatment. The majority of Kentucky bluegrass fields had extremely low seed yields unrelated to silvertop or arthropod levels. This extensive study, across a range of grass species and management regimes, provides strong support for the conclusion based on previous work that arthropod pests are not the sole cause of silvertop.

scholarly journals Effects of Irrigation and Nitrogen Fertilization on Seed Yield, Yield Components, and Water Use Efficiency of Cleistogenes songorica

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 466
Author(s):  
Qibo Tao ◽  
Mengjie Bai ◽  
Cunzhi Jia ◽  
Yunhua Han ◽  
Yanrong Wang
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Seed Yield ◽  
Yield Components ◽  
Perennial Grass ◽  
Yield Component ◽  
Path Coefficient ◽  
Grass Seed ◽  
Significant Difference ◽  
Use Efficiency

Irrigation and nitrogen (N) are two crucial factors affecting perennial grass seed production. To investigate the effects of irrigation and N rate on seed yield (SY), yield components, and water use efficiency (WUE) of Cleistogenes songorica (Roshevitz) Ohwi, an ecologically significant perennial grass, a four-year (2016–2019) field trial was conducted in an arid region of northwestern China. Two irrigation regimes (I1 treatment: irrigation at tillering stage; I2 treatment: irrigation at tillering, spikelet initiation, and early flowering stages) and four N rates (0, 60, 120, 180 kg ha−1) were arranged. Increasing amounts of both irrigation and N improved SY, evapotranspiration, WUE, and related yield components like fertile tillers m−2 (FTSM) and seeds spikelet−1. Meanwhile, no significant difference was observed between 120 and 180 kg N ha−1 treatments for most variables. The highest SY and WUE was obtained with treatment combination of I2 plus 120 kg N ha−1 with four-year average values of 507.3 kg ha−1 and 1.8 kg ha−1 mm−1, respectively. Path coefficient and contribution analysis indicated that FTSM was the most important yield component for SY, with direct path coefficient and contribution coefficient of 0.626 and 0.592. Overall, we recommend I2 treatment (three irrigations) together with 120 kg N ha−1 to both increase SY and WUE, especially in arid regions. Future agronomic managements and breeding programs for seed should mainly focus on FTSM. This study will enable grass seed producers, plant breeders, and government program directors to more effectively target higher SY of C. songorica.

scholarly journals Growth and Physiological Traits Associated with Drought Survival and Post-drought Recovery in Perennial Turfgrass Species

2010 ◽  
Vol 135 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Qi Chai ◽  
Fang Jin ◽  
Emily Merewitz ◽  
Bingru Huang
Keyword(s):  
Cell Wall ◽  
Drought Stress ◽  
Osmotic Adjustment ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Physiological Traits ◽  
Grass Species ◽  
Cell Wall Elasticity ◽  
Drought Recovery ◽  
Drought Survival

The objective of this study was to determine physiological traits for drought survival and post-drought recovery upon re-watering in two C3 perennial grass species, kentucky bluegrass [KBG (Poa pratensis)] and perennial ryegrass [PRG (Lolium perenne)]. Plants were maintained well watered or exposed to drought stress by withholding irrigation and were then re-watered in a growth chamber. KBG had significantly higher grass quality and leaf photochemical efficiency, and lower electrolyte leakage than PRG during 20 days of drought. After 7 days of re-watering, drought-damaged leaves were rehydrated to the control level in KBG, but could not fully recover in PRG. KBG produced a greater number of new roots, while PRG had more rapid elongation of new roots after 16 days of re-watering. Superior drought tolerance in KBG was associated with osmotic adjustment, higher cell wall elasticity, and lower relative water content at zero turgor. Osmotic adjustment, cell wall elasticity, and cell membrane stability could play important roles in leaf desiccation tolerance and drought survival in perennial grass species. In addition, post-drought recovery of leaf hydration level and physiological activity could be associated with the accumulation of carbohydrates in leaves and rhizomes during drought stress and new root production after re-watering.

Residue management increases seed yield of three turfgrass species on the Canadian prairies

2002 ◽  
Vol 82 (4) ◽  
pp. 687-692 ◽  
Author(s):  
B. D. Gossen ◽  
J. J. Soroka ◽  
H. G. Najda
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Poa Pratensis ◽  
Creeping Bentgrass ◽  
Kentucky Bluegrass ◽  
Residue Management ◽  
Row Spacing ◽  
Seeding Rate ◽  
Canadian Prairies ◽  
The Impact

Little information is available on the management of turfgrass species for seed production in the Canadian prairies. The objective of these studies was to assess the impact of residue management and row spacing on seed yield under irrigation. A factorial experiment was seeded at Saskatoon, SK, in 1993 to assess the impact of burning or scalping (very close mowing with residue removal) vs. mowing, and 20- vs. 40-cm row spacing on seed yield of Kentucky bluegrass (KBG) (Poa pratensis), creeping red fescue (CRF) (Festuca rubra subsp. rubra) and creeping bentgrass (CBG) (Agrostis palustris). Also, a residue management trial on KBG was seeded at Brooks, AB, in 1993. At Saskatoon, yield was higher at 20-cm spacing across all three species in 1994, but spacing had no impact on winter survival, stand density, tiller growth or yield in subsequent years. Burning and scalping consistently resulted in earlier spring green-up, a higher proportion of fertile tillers, and higher seed yield than mowing. Even with residue management, yield declined after one harvest in CBG and CRF, and after two harvests in KBG. At Brooks, residue management had a similar impact on yield of KBG. A second trial at Brooks examined the impact of row spacing (20, 40, 60 cm) and seeding rate (0.5 to 6 kg seed ha-1) on KBG. Seed yield was highest at 40-cm spacings in 1994, at 60 cm in 1995, and at 40 to 60 cm in 1996. Seeding rate did not have a consistent effect on yield. We conclude that a combination of residue management and 20- to 40-cm spacings provide the highest, most consistent seed yields for these turfgrass species in this region. Key words: Burning, clipping, turfgrass, seed production, row spacing, Poa, Festuca, Agrostis

Influence of post-harvest residue management and cultivar on tiller dynamics and seed yield in timothy

1994 ◽  
Vol 74 (3) ◽  
pp. 507-513 ◽  
Author(s):  
M. H. Entz ◽  
S. R. Smith Jr. ◽  
D. J. Cattani ◽  
A. K. Storgaard
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Phleum Pratense ◽  
Residue Management ◽  
Cultivar Differences ◽  
Grass Species ◽  
Compensatory Mechanisms ◽  
Burn Treatment ◽  
Post Harvest ◽  
Harvest Residue

Timothy (Phleum pratense L.) is a bunch-type cool season perennial grass species grown in Manitoba primarily for seed production. The objectives of this study were to determine the effect of post-harvest residue management (straw removal-SR, straw and stubble removal-SSR and fall burning-Burn) on tiller production, yield components and seed yield of five timothy cultivars (Basho, Climax, Goliath, Hokuo and Salvo), and to better understand the association between yield components and final seed yield in timothy crops grown in the dry subhumid region of the Canadian prairies. Two experiments were conducted over four production seasons at Arborg, MB and one production season at St. Claude, MB. Tiller number per m2 in spring (TS) and at harvest (THV) were measured in 1990 at St. Claude and in 1990 and 1991 at Arborg. Residue management (RM) treatment ranking for TS was Burn < SR < SSR, but tiller senescence and compensatory mechanisms resulted in equivalent THV values across all RM treatments. The number of seed-bearing tillers m−2 at harvest was also unaffected by RM. Seed yield was unaffected by RM in all instances, except at Arborg in 1989 where a significant RM × cultivar interaction was observed. The basis of the interaction was the greater sensitivity of Hokuo to the Burn treatment. Cultivar differences for seed yield were relatively consistent over years and between the two experiments, with Climax always ranking in the high yielding group and Salvo with the low yielding group. Based on analysis of yield components, it appeared that RM most affected early season growth (i.e. TS), while cultivar most affected later season growth (fertile tillers per unit area, seed yield per fertile tiller (SYFT)). Seed yield differences were most closely associated with SYFT (r2 = 0.97**) across cultivar treatments. Key words: Burning, straw removal, harvest index, yield components, forages

scholarly journals Native Perennial Grasses in Highway Medians: Pre- and Postplant Techniques for Establishment in a Mediterranean Climate

2008 ◽  
Vol 1 (4) ◽  
pp. 368-375
Author(s):  
Stephen L. Young ◽  
Victor P. Claassen
Keyword(s):  
Plant Density ◽  
Perennial Grass ◽  
Field Studies ◽  
Perennial Grasses ◽  
Species Selection ◽  
Grass Species ◽  
Native Plant ◽  
Grass Establishment ◽  
Grass Growth ◽  
Native Perennial Grass

AbstractWithin highway rights-of-way, native perennial grasses provide desirable services to support natural and human constructed ecosystems. However, native perennial grass establishment in annual grass dominated roadsides of semiarid and Mediterranean climates of the western United States requires specific cultural and chemical management treatments to control weeds. In 2004, field studies were conducted in Sacramento Valley, California to determine the effect of herbicide, disc cultivation, and species selection on native perennial grass establishment and annual weed persistence. Perennial grass species mixes common to drier and wetter upland areas in northern California were drill seeded at two sites (I-5 North and I-5 South) that had been burned in 2003 and received weed control (i.e., herbicide, cultivation, mowing) in spring 2004. Herbicides were the most important treatments for native perennial grass establishment and weed reduction. Native perennial grass species persistence was largely unaffected by cultivation or native plant accessions at these sites. Native perennial grass density increased at I-5 North in the second year of growth (2006) resulting in a plant density totaled across all herbicide regimes of 3.9 plants m−1 compared to 2.5 plants m−1 at I-5 South. Vigorous native perennial grass growth in the more fertile and less droughty soils of I-5 North helped to limit annual weeds through competition, which is anticipated to reduce the need for chemical and mechanical control in years following early establishment.

Root biomass and shoot to root ratios of perennial forage crops in eastern Canada

2002 ◽  
Vol 82 (4) ◽  
pp. 731-737 ◽  
Author(s):  
M. A. Bolinder ◽  
D. A. Angers ◽  
G. Bélanger ◽  
R. Michaud ◽  
M. R. Laverdière
Keyword(s):  
Root Biomass ◽  
Perennial Grass ◽  
Field Studies ◽  
Climatic Conditions ◽  
Grass Species ◽  
Eastern Canada ◽  
Forage Crops ◽  
Significant Difference ◽  
Peak Standing Crop ◽  
Perennial Legume

Shoot to root ratios (S:R) at peak standing crop are commonly used to estimate the annual crop residue C inputs to the soil from the root biomass left in the soil at harvest. However, root biomass has often been neglected in field studies and estimates of S:R for many commonly grown forage species are not available. Our objective was to determine root biomass and S:R of seven perennial grass species and two perennial legume species under eastern Canadian soil and climatic conditions. Root biomass in three soil layers (0–15, 15–30 and 30–45 cm) was measured shortly after the second harvest in the first (1995) and second (1996) year of production. Two harvests of aboveground DM were taken each year. The total root biomass (0–45 cm) in the second year of production (average of 1437 g m-2) was twice that measured in the first year of production (average of 683 g m-2). This temporal variation was mainly explained by the increase of root biomass in the 0- to 15-cm layer. The proportion of total root biomass (0–45 cm) in the 0- to 15-cm layer increased from 54 to 71% while that in the 15- to 30-cm layer decreased from 37 to 21%; the proportion of roots in the 30- to 45-cm layer remained constant at about 10% in both years. The S:R of alfalfa for the 0- to 15-cm depth was significantly higher than that for most of the grasses. No significant difference in S:R was observed among grass species. Recognizing that S:R may vary with locations and climatic conditions, our results suggest that average S:R of about 1.30 (values ranged from 1.01 to 1.72) in the first production year and 0.60 (values ranged from 0.43 to 0.87) in the second production year could be used as a first approximation to estimate the amount of root biomass left in the soil to a depth of 45 cm from forage crops in eastern Canada. The S:R of forage crops, particularly grasses, were lower than those of annual crops such as small-grain cereals and corn. Key words: Forage, annual C inputs, soil organic matter, root biomass, shoot to root ratios

Silvertop in perennial grass seed production: Effects of type and timing of biotic stresses

2021 ◽  
Author(s):  
Julie Soroka ◽  
Bruce D. Gossen
Keyword(s):  
Seed Production ◽  
Poa Pratensis ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Development Stage ◽  
Perennial Grasses ◽  
Grass Species ◽  
Biotic Stresses ◽  
Seed Harvest ◽  
Bromus Riparius

Seed production of perennial grasses is an important industry in Canada, but many fields exhibit high proportions of sterile heads with characteristic symptoms in a condition known as silvertop. In a 3-yr field study, biotic stress treatments were applied to caged plots of Kentucky bluegrass (<i>Poa pratensis</i>) and meadow bromegrass (<i>Bromus riparius</i>) to assess their effects on silvertop incidence. Treatments were: 1) control, 2) addition of grass-feeding insects, primarily grass plant bugs (Miridae), 3) inoculation with <i>Fusarium poae</i> spores, 4) both insects and spores, and in one year, 5) mechanical piercing of seed heads above the last node. Additionally, cores of the two grass species were potted and removed from the field in spring in each of 2 years. After 2-, 4-, and 6-wk intervals in a cold room at 4° C to stagger plant development stage, the five treatments were applied to caged plants of both grasses, which were maintained in a greenhouse until seed harvest. In both studies, the numbers of healthy seed heads, percentage of heads with silvertop, and seed weights were determined. In the field, stress treatments infrequently and inconsistently affected silvertop levels. Regression showed that the relationship between silvertop and seed yield, although significant, explained little of the variability in yield. Silvertop developed in all treatments in the greenhouse; treatments had no effect on silvertop levels, which were highest in plants treated at the R1 (boot) growth stage. This suggests that the boot stage of the two grass species is most vulnerable to silvertop occurrence.

Phytophagous arthropods and silvertop levels associated with post-harvest residue treatments in three turfgrass species grown for seed

2005 ◽  
Vol 85 (1) ◽  
pp. 213-224 ◽  
Author(s):  
J. J. Soroka ◽  
B. D. Gossen
Keyword(s):  
Seed Production ◽  
Poa Pratensis ◽  
Creeping Bentgrass ◽  
Kentucky Bluegrass ◽  
Residue Management ◽  
Grass Species ◽  
Festuca Rubra ◽  
Agrostis Palustris ◽  
Red Fescue ◽  
The Impact

Silvertop, which is characterized by whitish, completely sterile seed heads produced on green tillers, is a common symptom in many perennial grasses. A 3-yr study of creeping bentgrass (Agrostis palustris), Kentucky bluegrass (Poa pratensis) and creeping red fescue (Festuca rubra subsp. rubra) grown for seed production was conducted at Saskatoon, Saskatchewan, to investigate the cause(s) of silvertop, the impact of residue management strategies on silvertop incidence, and the impact of silvertop on seed yield. Three residue management practices were applied in the fall of the first harvest year and again the next fall, as follows: (i) burned after harvest; (ii) clipped to 1–2 cm in height and the residue removed; or (iii) mowed to 20 cm and the residue retained. Arthropods in each plot were collected weekly from May until July by sweep sampling, counted, and identified to family level or lower, and the incidence of seed heads with and without silvertop were assessed. The majority of arthropods were thrips, leafhoppers, plant bugs, mites, or grass-dwelling flies. Grass species and residue treatment strongly affected the number of reproductive tillers and levels of silvertop. Levels of silvertop were lowest in creeping bentgrass in all 3 yr of the study, while they were similar for Kentucky bluegrass and creeping red fescue. Mown plots had fewer reproductive tillers, fewer heathy seed heads, and higher levels of silvertop than burned or clipped plots. However, arthropod species composition was generally similar across grass species and residue treatments. This indicates that a specific arthropod taxon may not be a critical factor in silvertop expression. The relationship between the number and composition of arthropods found and incidence of silvertop is discussed. Key words: Festuca rubra subsp. rubra, Poa pratensis, Agrostis palustris, seed production, arthropods, silvertop

Root growth, appearance and disappearance in perennial grasses: Effects of the timing of water stress with or without defoliation

2002 ◽  
Vol 82 (3) ◽  
pp. 539-547 ◽  
Author(s):  
A. C. Flemmer ◽  
C. A. Busso ◽  
O. A. Fernandez ◽  
T. Montani
Keyword(s):  
Water Stress ◽  
Root Growth ◽  
Perennial Grass ◽  
Field Studies ◽  
Perennial Grasses ◽  
Grass Species ◽  
Phenological Stage ◽  
Semiarid Environments ◽  
Tussock Grasses ◽  
Different Levels

The effects of early and late defoliations were evaluated under different levels of soil water content on root growth, appearance and disappearance in Stipa clarazii Ball. S. tenuis Phil., and S. gynerioides Phil. Field studies were conducted in 1995. 1996 and early 1997. Stipa clarazii and S. tenuis are two important palatable perennial tussock grasses in temperate, semiarid rangelands of central Argentina. where S. gynerioides is one of the most abundant, unpalatable perennial grass species. We hypothesized that (1) root growth is reduced after defoliation at any phenological stage in S. clarazii and S. tenuis in comparison to undefoliated controls, (2) root growth. and root appearance and disappearance in all three species decrease as plant water stress increases, and (3) root growth associated with water stress in S. clarazii and S. tenuis is reduced comparatively less when plants are water-stressed earlier than later, or for a longer period of time during the growing season. Our results led us to reject hypothesis 1 and to accept hypotheses 2 and 3. Maintenance of root growth after defoliation in S. clarazii and S. tenuis would allow these species a greater soil exploration and resource finding to sustain regrowth in their native, semiarid environments. Key words: Root growth, appearance and disappearance, perennial grasses, water stress, defoliation, Stipa species

Afterripening Requirements and Optimal Germination Temperatures for Nuttall's Alkaligrass (Puccinellia nuttalliana) and Weeping Alkaligrass (Puccinellia distans)

Weed Science ◽  
2007 ◽  
Vol 55 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Catherine S. Tarasoff ◽  
Daniel A. Ball ◽  
Carol A. Mallory-Smith
Keyword(s):  
Incubation Temperature ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Grass Species ◽  
Puccinellia Distans ◽  
Dry Storage ◽  
Seed Harvest ◽  
High Level ◽  
Moisture Conditions ◽  
Embryonic Dormancy

In the Grande Ronde Valley of eastern Oregon, two perennial grass species in the genusPuccinellia, weeping alkaligrass and Nuttall's alkaligrass, are weeds of Kentucky bluegrass grass-seed production fields. Weeping alkaligrass is introduced from Eurasia, whereas Nuttall's alkaligrass is native to the region. These two species were studied to determine dormancy attributes and optimal temperature conditions for seed germination. Results from the current studies indicate that both species have a high level of embryonic dormancy immediately following seed harvest, which is primarily eliminated through dry storage (afterripening) and an incubation temperature of 20 C. Following adequate afterripening, a prechill treatment of 5 d at 5 C had an inconsistent effect on germination of weeping alkaligrass (P = 0.012 in 2002, 0.156 in 2003) and improved germination of Nuttall's alkaligrass over both years (P < 0.0001). The afterripening requirement for weeping alkaligrass was more than 90 d, whereas Nuttall's alkaligrass required more than 180 d. Following adequate afterripening, both species had rapid and well-synchronized germination at fluctuating day/night temperatures of 30/10 C given unlimited moisture conditions. Given these results, it is unlikely that seeds of either species would germinate in eastern Oregon during the summer months. The data predict a long viability period under dry storage for both species. Weeping alkaligrass and Nuttall's alkaligrass should exhibit a rapid, well-synchronized germination in the spring as observed in the field.

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