Distribution and Potential Spread of Japanese Knotweed (Polygonum cuspidatum) in Canada Relative to Climatic Thresholds

2010 ◽  
Vol 3 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Robert S. Bourchier ◽  
Brian H. Van Hezewijk
Keyword(s):  
British Columbia ◽  
Minimum Temperature ◽  
Annual Precipitation ◽  
Suitable Habitat ◽  
Base Temperature ◽  
Japanese Knotweed ◽  
Degree Days ◽  
Southern Ontario ◽  
Degree Day ◽  
Daily Weather Data

AbstractJapanese knotweed (JK) is one of the most aggressive invasive plants known in the U.K., where its biology has been well-studied. It was introduced into Canada around 1900, but only recently has it become a serious concern in the province of British Columbia (BC). Climatic conditions, including annual degree days and mean-annual minimum temperatures at knotweed sites in British Columbia were modeled in BioSIM, using weather normals and long-term daily weather data, and compared to published thresholds (degree day = 2,505 DD, minimum temperature = −30.2 C, base temperature 0 C). The degree-day threshold was more limiting to JK in British Columbia than mean-minimum temperature (12.3% of province habitat was suitable for JK based on degree days compared with 26% for mean-minimum temperature). A new annual-precipitation threshold of 735 mm/year based on 95% of known knotweed sites in BC was identified. The best-fit logistic regression model included degree days and annual precipitation and predicted knotweed presence/absence with over 97% efficiency. Existing knotweed sites occupy just over half of the suitable habitat in BC, indicating there are still significant areas to be invaded. The limiting threshold for knotweed was reversed in Southern Ontario with between 35 to 53% of the habitat suitable based on minimum temperatures, whereas degree-day accumulations and annual precipitation were not limiting. Warmer temperatures from 2000 to 2008 resulted in an increase to 53% of the habitat in Southern Ontario being suitable for knotweed, compared to 35% when 1971 to 2000 weather normals were used. Different climatic thresholds among provinces might result in selection for different invasive knotweed genotypes. This could influence the success of biological control agents because of differential host suitability of knotweed genotypes. Habitat suitability maps generated will enable better targeting of knotweed surveys based on the risk of knotweed establishment.

scholarly journals Improving the Prediction of Processing Bean Maturity Based on the Growing-degree Day Approach

HortScience ◽  
2000 ◽  
Vol 35 (7) ◽  
pp. 1234-1237 ◽  
Author(s):  
Sylvie Jenni ◽  
Gaétan Bourgeois ◽  
Hélène Laurence ◽  
Geneviève Roy ◽  
Nicolas Tremblay
Keyword(s):  
Phaseolus Vulgaris ◽  
Prediction Model ◽  
Coefficient Of Variation ◽  
Developmental Stages ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Snap Bean ◽  
Degree Day ◽  
Common Base

Four snap bean (Phaseolus vulgaris L.) cultivars, Goldrush, Teseo, Labrador, and Flevoro, were grown in irrigated fields of southern Quebec between 1985 and 1998. Data on phenology collected from these fields were used to determine which base temperature would best predict time from sowing to maturity. The optimal base temperature was 0 °C for `Goldrush', `Teseo', and `Labrador' and 6.7 °C for `Flevoro'. Adjusting different base temperatures for intermediate developmental stages (emergence, flowering) did not improve the prediction model. All years for a given cultivar were then used to determine the base temperature with the lowest coefficient of variation (CV) for predicting the time from sowing to maturity. A common base temperature of 0 °C was selected for all cultivars, since `Flevoro' was not very sensitive to changes in base temperature. This method improved the prediction of maturity compared with the conventional computation growing-degree days (GDD) with a base of 10 °C. For the years and cultivars used in this study, calculating GDD with a base of 0 °C gave an overall prediction of maturity of 1.7, 1.5, 2.0, and 1.4 days based on average absolute differences, for `Flevoro', `Goldrush', `Teseo', and `Labrador', respectively.

scholarly journals Vernalization and Growing Degree-day Requirements of Thalictrum delavayi `Hewitt's Double'

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 501D-501
Author(s):  
Keith A. Funnell ◽  
Bruce R. MacKay ◽  
Ning Huang
Keyword(s):  
Cold Storage ◽  
Production Scheduling ◽  
Base Temperature ◽  
Cut Flower ◽  
Vernalization Response ◽  
Degree Days ◽  
Degree Day ◽  
Yield And Quality ◽  
Flower Yield ◽  
Natural Photoperiod

Vernalization and growing degree-day requirements of Thalictrum delavayi `Hewitt's Double' were determined to improve the production scheduling of this cut flower crop. Two-year-old crowns of T. delavayi `Hewitt's Double', lifted in the fall, were exposed to cold storage for 0, 3, 6, 9, 12, or 15 weeks at 8 ± 1°C. After storage, the containerized plants were grown at Massey Univ., Palmerston North (40°20.S) in a greenhouse heated at 15°C and vented at 20°C, under a natural photoperiod (11 h increasing to 13 h) plus a 4-h night interruption between 2200 and 0200 HR. As buds continued to develop during storage at 8°C, growing degree-days calculations were made over both storage and greenhouse forcing periods. All plants flowered, but T. delavayi `Hewitt's Double' nevertheless showed a quantitative vernalization requirement, being fully saturated after 6 weeks of cold storage at 8°C. With a base temperature of 0°C, time to flowering reduced from 3338 degree-days without vernalization to an average 2804 degree-days subsequent to the saturation of the vernalization response (6 to 15 weeks of vernalization). Flower yield averaged between three and five stems per plant, with stem lengths ranging between 140 and 200 cm. Differences in flower yield and quality among storage durations were minor and not commercially significant.

scholarly journals Growing Degree-day Requirements for Scheduling Flowering of Scadoxus multiflorus subsp. katharinae (Baker) Friis & Nordal

HortScience ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. 166-169 ◽  
Author(s):  
Keith A. Funnell
Keyword(s):  
Cold Storage ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Leaf Lamina ◽  
Degree Days ◽  
Vegetative Shoot ◽  
Degree Day

Containerized plants of Scadoxus multiflorus subsp. katharinae (Baker) Friis & Nordal were forced to anthesis under three environments of contrasting temperature. Flowering performance, growing degree-days (GDD) requirements for timing of anthesis, and the influence of cold storage (12 °C for 4 weeks) before forcing were evaluated. Total forcing time from the beginning of the experiment until anthesis decreased with warmer forcing environment, ranging between 129 and 86 days. Across all forcing environments, use of GDD was readily able to explain differences in time to anthesis resulting from both cold storage and forcing. Using a base temperature of 5 °C, GDD requirements between beginning of the experiment and anthesis was 1166 ± 124 GDD, emergence of the vegetative shoot and anthesis 1075 ± 118 GDD, and appearance of the tips of the leaf lamina and anthesis 883 ± 91 GDD. Using a base temperature of 11.5 °C, GDD requirements between appearance of tip of the involucre and anthesis was 180 ± 44 GDD, and the whole involucre being visible and anthesis 144 ± 42 GDD. In the next year, validation of the GDD requirements was achieved by subsequently forcing a second population of plants to anthesis for a specific date.

Evaluation of chitting to enhance earliness of potatoes grown in southern Ontario

1994 ◽  
Vol 74 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Alan W. McKeown
Keyword(s):  
Cold Storage ◽  
Potato Cultivars ◽  
The Other ◽  
Physiological Age ◽  
Degree Days ◽  
Southern Ontario ◽  
Degree Day ◽  
Lower Base ◽  
Low Degree ◽  
Rapid Accumulation

Potato cultivars Atlantic, Conestoga, Jemseg, Superior and Yukon Gold, grown for early markets and mid-season use in Ontario were evaluated for response to chitting in 1987 to 1989. Seed tubers were chitted at 8 °C commencing in January, for an average of 408, 284 or 172 degree-days (base 4 °C). Controls were stored at 4 °C. Plants emerged quicker from chitted seed and produced higher early yields than the controls. Approximately 260 degree-days of chitting was optimal for early yield of Jemseg and Superior. For maximum emergence, 318 degree-days was required for Jemseg. Commencing chitting before March did not increase yields for the other cultivars. Low degree-day requirements are likely the result of cold storage of seed prior to chitting, resulting in more rapid accumulation of degree-days and/or lower base temperatures for growth. Key words:Solarium tuberosum, cultivars, emergence, yield, physiological age

A unified degree day model describes survivorship of Copitarsia corruda Pogue & Simmons (Lepidoptera: Noctuidae) at different constant temperatures

2008 ◽  
Vol 99 (1) ◽  
pp. 65-72 ◽  
Author(s):  
N.N. Gómez ◽  
R.C. Venette ◽  
J.R. Gould ◽  
D.F. Winograd
Keyword(s):  
Survival Curve ◽  
The United States ◽  
Physiological Age ◽  
Alien Invasive Species ◽  
Temperature Threshold ◽  
Base Temperature ◽  
Survival Curves ◽  
Degree Day ◽  
Effects Of Temperature ◽  
Lepidoptera Noctuidae

AbstractPredictions of survivorship are critical to quantify the probability of establishment by an alien invasive species, but survival curves rarely distinguish between the effects of temperature on development versus senescence. We report chronological and physiological age-based survival curves for a potentially invasive noctuid, recently described as Copitarsia corruda Pogue & Simmons, collected from Peru and reared on asparagus at six constant temperatures between 9.7 and 34.5°C. Copitarsia spp. are not known to occur in the United States but are routinely intercepted at ports of entry. Chronological age survival curves differ significantly among temperatures. Survivorship at early age after hatch is greatest at lower temperatures and declines as temperature increases. Mean longevity was 220 (±13 SEM) days at 9.7°C. Physiological age survival curves constructed with developmental base temperature (7.2°C) did not correspond to those constructed with a senescence base temperature (5.9°C). A single degree day survival curve with an appropriate temperature threshold based on senescence adequately describes survivorship under non-stress temperature conditions (5.9–24.9°C).

scholarly journals Initial growth and development of southern sandbur based on thermal units

2014 ◽  
Vol 32 (2) ◽  
pp. 335-343 ◽  
Author(s):  
E.C.R. Machado ◽  
R.S.O. Lima ◽  
A.P.P. Silva ◽  
B.S. Marques ◽  
M.F. Gonçalves ◽  
...  
Keyword(s):  
Growth And Development ◽  
Dry Matter ◽  
Integrated Management ◽  
Base Temperature ◽  
Initial Growth ◽  
Agricultural Systems ◽  
Degree Days ◽  
Flowering Stage ◽  
Weed Biology ◽  
Best Fit

Availability of basic information on weed biology is an essential tool for designing integrated management programs for agricultural systems. Thus, this study was carried out in order to calculate the base temperature (Tb) of southern sandbur (Cenchrus echinatus), as well as fit the initial growth and development of the species to accumulated thermal units (growing degree days - GDD). For that purpose, experimental populations were sown six times in summer/autumn conditions (decreasing photoperiod) and six times in winter/spring condition (increasing photoperiod). Southern sandbur phenological evaluations were carried out, on alternate days, and total dry matter was measured when plants reached the flowering stage. All the growth and development fits were performed based on thermal units by assessing five base temperatures, as well as the absence of it. Southern sandbur development was best fit with Tb = 12 ºC, with equation y = 0,0993x, where y is the scale of phenological stage and x is the GDD. On average, flowering was reached at 518 GDD. Southern sandbur phenology may be predicted by using mathematical models based on accumulated thermal units, adopting Tb = 12 ºC. However, other environmental variables may also interfere with species development, particularly photoperiod.

scholarly journals Phenology, reproductive biology and growing degree days of the grapevine ‘Isabel’ (Vitis labrusca, Vitaceae) cultivated in northeastern Brazil

2016 ◽  
Vol 76 (4) ◽  
pp. 975-982 ◽  
Author(s):  
N. A. S. Nunes ◽  
A. V. Leite ◽  
C. C. Castro
Keyword(s):  
Reproductive Biology ◽  
Pollen Viability ◽  
Floral Biology ◽  
Climatic Conditions ◽  
Northeastern Brazil ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Vitis Labrusca ◽  
Degree Days ◽  
Inflorescence Development

Abstract Phenology and reproductive biology of cultivated species are important for the comprehension of the requirements for fruit and seed production and the management of pollinators. This study aimed to characterise the phenology, reproductive biology and growing degree days of the grapevine ‘Isabel’ (Vitis labrusca) in northeastern Brazil during January 2011 (P1), Augst 2011 (P2), April 2012 (P3) and August 2012 (P4). We recorded the duration (days) of the phenological stages, pruning (P), woolly bud (W), budburst (B), inflorescence development (ID), flowering (F), ripening (R) and harvest (H). We analysed the floral biology, the sexual system and the breeding system. We measured the growing degree days (GDD) required to reach the subperiods P-B, B-F and F-H. The periods P1, P2, P3 and P4 lasted for 116, 125, 117 and 130 days, respectively. The number of days of harvest were similar in the same dry (P1 and P3) and rainy (P2 and P4) periods. All the periods that we recorded were shorter than those observed in other regions of Brazil, which may be attributable to the mean temperature and carbohydrate metabolism. The flowers are green, hermaphroditic, with an odour of mignonette, low pollen viability and autogamous. The base temperature of 10°C was considered the most adequate for the subperiods as has been documented for other grape varieties in Brazil. Thus, temperature was also the most adequate for the cycles, presenting a smaller standard deviation (0.119, 0.147, 0.156 and 0.153 to P1, P2, P3 and P4, respectively) when compared to a base temperature of 12°C (0.122, 0.158, 0.165 and 0.160 to P1, P2, P3 and P4, respectively). The higher and the lower observed GDD were 1972.17 and 1870.05, respectively, both above the values recorded in other parts of Brazil for same variety. The phonological results, including knowledge of growing degree days, are important to the planning of cultures at the study site and in other regions that have similar climatic conditions and make it possible to pre-determine the harvest.

Dispersal, home-range size, and habitat use of an endangered land snail, the Oregon forestsnail (Allogona townsendiana)

2012 ◽  
Vol 90 (7) ◽  
pp. 875-884 ◽  
Author(s):  
A.B. Edworthy ◽  
K.M.M. Steensma ◽  
H.M. Zandberg ◽  
P.L. Lilley
Keyword(s):  
British Columbia ◽  
Home Range ◽  
Habitat Use ◽  
Land Snail ◽  
Home Range Size ◽  
Dispersal Distance ◽  
Land Snails ◽  
Dispersal Ability ◽  
Suitable Habitat ◽  
Maximum Displacement

Terrestrial molluscs have declined globally, often as a result of habitat loss and fragmentation. Many land snails are poor dispersers and exist in isolated habitat patches. The Oregon forestsnail ( Allogona townsendiana (I. Lea, 1838)) coincides with the most densely populated region of British Columbia and is listed as endangered in Canada. To investigate the dispersal distances and habitat-use patterns of Oregon forestsnails, we tagged and tracked 21 adult snails at Langley, British Columbia, for up to 3 years (2005–2008). The maximum daily dispersal distance for a snail was 4.5 m and the maximum displacement that we observed for a snail was 32.2 m during 3 years. Snails occupied home-range areas of 18.4–404.4 m2, often overlapping both forest and meadow habitat. Their home-range sizes were smaller in habitats with high availability of stinging nettle ( Urtica dioica L.), which may be an indicator of high-quality habitat. Our results suggest that the Oregon forestsnail is a relatively sedentary species with limited dispersal ability in its adult stage. Although Oregon forestsnails are likely unable to colonize suitable habitat independently, remnant forest–meadow mosaic patches such as our study site provide valuable habitat for Oregon forestsnail, which are supplementary to large tracts of intact forest where most of their populations are found.

scholarly journals Extreme Minimum Temperature Zones of British Columbia

2014 ◽  
Author(s):  
D W McKenney ◽  
J H Pedlar ◽  
K Lawrence ◽  
P Papadopol ◽  
K Campbell ◽  
...  
Keyword(s):  
British Columbia ◽  
Minimum Temperature ◽  
Extreme Minimum Temperature

scholarly journals Pengaruh Suhu terhadap Perkembangan Pradewasa Parasitoid Eriborus argenteopilosus Cameron (Hymenoptera: Ichneumonidae)

2012 ◽  
Vol 13 (3) ◽  
pp. 250
Author(s):  
Novri Nelly ◽  
Trimurti Habazar ◽  
Rahmat Syahni ◽  
Damayanti Buchori
Keyword(s):  
Survival Rate ◽  
Temperature Effect ◽  
Development Time ◽  
Degree Days ◽  
Degree Day ◽  
Adult Parasitoid ◽  
Different Temperatures ◽  
Lepidoptera Pyralidae

Temperature effect on development time of the preadult parasitoid Eriborus argenteopilosus Cameron(Hymenoptera: Ichneumonidae) were studied to know development time, degree days and survival rate.Crocidolomia pavonana (Fabricius)(Lepidoptera: Pyralidae) larvae was exposed to E. argenteopilosus female andreared at four different temperatures i.e 160C, 200C, 250C and 300C. Data were analyzed using anova and linearregression to calculate degree day. At 200C E. argenteopilosus showed the highest degree day and survival rate(18.67 %), while at 300C nothing adult parasitoid emergenced. Degree day to development time of parasitoid attemperature 200C i.e fase egg-adult: 300.05; egg-pupae 173.35; pupae-adult 171.

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