REDUCED COLD-HARDINESS OF PEAR PSYLLA (HOMOPTERA: PSYLLIDAE) CAUSED BY EXPOSURE TO EXTERNAL WATER AND SURFACTANTS

David R. Horton; Tamera M. Lewis; Lisa G. Neven

doi:10.4039/ent128825-5

REDUCED COLD-HARDINESS OF PEAR PSYLLA (HOMOPTERA: PSYLLIDAE) CAUSED BY EXPOSURE TO EXTERNAL WATER AND SURFACTANTS

The Canadian Entomologist ◽

10.4039/ent128825-5 ◽

1996 ◽

Vol 128 (5) ◽

pp. 825-830 ◽

Cited By ~ 5

Author(s):

David R. Horton ◽

Tamera M. Lewis ◽

Lisa G. Neven

Keyword(s):

Low Temperatures ◽

Cold Hardiness ◽

Dilute Solutions ◽

Subzero Temperatures ◽

Pear Psylla ◽

External Water

AbstractOverwintering pear psylla, Cacopsylla pyricola (Foerster), were misted with water or with one of several dilute solutions of water and surfactant, and then exposed to a range of subzero temperatures for 24 h. Misted psylla had significantly greater mortality than unmisted controls. Increases in mortality occurred at temperatures as warm as −6°C, a temperature well within the range of conditions in the field. At extreme low temperatures (−18°C) there was virtually no mortality in the unmisted controls, whereas mortality approached or reached 100% in several of the misted groups. Temperatures necessary to kill 50% of insects estimated for topically treated psylla ranged between −2.6 and −12.7°C for surfactant-treated insects, and below −18°C for water-treated or control insects. The possibility of using surfactants and water for control of overwintering pear psylla is discussed.

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Parasites and low temperatures

Parasitology ◽

10.1017/s0031182000084614 ◽

1999 ◽

Vol 119 (S1) ◽

pp. S7-S17 ◽

Cited By ~ 14

Author(s):

D. A. Wharton

Keyword(s):

Life Cycle ◽

Cold Tolerance ◽

Low Temperatures ◽

Cold Hardiness ◽

Free Living ◽

Rate Of Growth ◽

Subzero Temperatures ◽

Growth Development ◽

Epidemiological Significance

SUMMARYLow temperatures affect the rate of growth, development and metabolism of parasites and when temperatures fall below 0°C may expose the parasite to the potentially lethal risk of freezing. Some parasites have mechanisms, such as diapause, which synchronise their life cycle with favourable seasons and the availability of hosts. Parasites of endothermic hosts are protected from low temperatures by the thermoregulatory abilities of their host. Free-living and off-host stages, however, may be exposed to subzero temperatures and both freezing-tolerant and freeze-avoiding strategies of cold hardiness are found. Parasites of ectothermic hosts may be exposed to subzero temperatures within their hosts. They can rely on the cold tolerance adaptations of their host or they may develop their own mechanisms. Exposure to low temperatures may occur within the carcass of the host and this may be of epidemiological significance if the parasite can be transmitted via the consumption of the carcass.

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EVALUATION OF ICE-NUCLEATING MICROORGANISMS FOR REDUCING THE SUPERCOOLING CAPACITY AND COLD-HARDINESS OF CACOPSYLLA PYRICOLA (HEMIPTERA: PSYLLIDAE)

The Canadian Entomologist ◽

10.4039/ent131715-6 ◽

1999 ◽

Vol 131 (6) ◽

pp. 715-723 ◽

Cited By ~ 4

Author(s):

Richard E. Lee ◽

Jacqueline D. Litzgus ◽

John A. Mugnano ◽

Marcia R. Lee ◽

David R. Horton ◽

...

Keyword(s):

Biological Control ◽

Pseudomonas Putida ◽

Pseudomonas Syringae ◽

Cold Hardiness ◽

Laboratory Studies ◽

Short Term ◽

Subzero Temperatures ◽

Pear Psylla ◽

Short Term Exposure ◽

Treatment Application

AbstractIn laboratory studies, suspensions of killed and live ice-nucleating microorganisms were used to decrease the supercooling capacity of the winter form of pear psylla, Cacopsylla pyricola (Foerster) (Hemiptera: Psyllidae). Dry, untreated adults supercooled extensively before they froze at −22.7 °C. Application of 1000 ppm of a preparation of the killed ice-nucleating bacterium, Pseudomonas syringae Van Hall 1902 (Pseudomonadaceae), significantly decreased the adults’ supercooling capacity causing some individuals to freeze at temperatures as high as −3.9 °C. Topical application of several live microorganisms also reduced the supercooling capacity of adults significantly; Pseudomonas putida (Trevisan 1989) was the most effective, causing more than 80% of C. pyricola adults to freeze at −15 °C or higher. Furthermore, the temperature of crystallization of adults treated with P. putida remained significantly higher than controls for at least lid post-treatment. Application of ice-nucleating microorganisms also reduced the capacity of adults to survive short-term exposure to high subzero temperatures comparable to a mild frost. Realization of this approach for biological control of pear psylla will require the development of methods for the delivery of microorganisms to overwintering adults under field conditions.

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Supercooling Points of Adult Dermacentor variabilis (Acari: Ixodidae) From a Population Near the Northern Distribution Limit

Journal of Medical Entomology ◽

10.1093/jme/tjaa223 ◽

2020 ◽

Author(s):

Matthew E M Yunik ◽

Neil B Chilton

Keyword(s):

Cold Hardiness ◽

Dermacentor Variabilis ◽

Subzero Temperatures ◽

Host Seeking ◽

Short Period ◽

Significant Difference ◽

Northern Distribution ◽

Dog Tick ◽

Provincial Park ◽

Established Population

Abstract The northern distributional limit of Dermacentor variabilis Say, the American dog tick, is expanding in Saskatchewan and Manitoba (western Canada). The ability of D. variabilis to continue to expand its range northwards will depend upon the ability of individuals within populations at the species distributional edge to withstand very low temperatures during winter. One component of cold hardiness is the supercooling point (SCP), the temperature below 0°C at which an individual freezes. In this study, the SCP was determined for 94 questing D. variabilis adults (44 females and 50 males) from an established population near Blackstrap Provincial Park in Saskatchewan. SCP values ranged from −18.2 to −6.7°C, with a median of −13.3°C. This suggests that host-seeking D. variabilis adults differ in their ability to survive exposure to subzero temperatures, for at least a short period of time, without freezing. The distribution of SCPs was bimodal, but there was no significant difference in SCP values between female and male ticks, and no relationship between SCP and tick body weight. It remains to be determined what factors contribute to the variation in SCP values among questing D. variabilis adults.

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Desiccation and low temperature attenuate the effect of UVC254 nm in the photobiont of the astrobiologically relevant lichens Circinaria gyrosa and Buellia frigida

International Journal of Astrobiology ◽

10.1017/s1473550414000470 ◽

2014 ◽

Vol 14 (3) ◽

pp. 479-488 ◽

Cited By ~ 6

Author(s):

T. Backhaus ◽

R. de la Torre ◽

K. Lyhme ◽

J.-P. de Vera ◽

J. Meeßen

Keyword(s):

Low Temperature ◽

Low Temperatures ◽

Photosynthetic Activity ◽

Real Space ◽

Fast Recovery ◽

Protective Mechanisms ◽

Subzero Temperatures ◽

High Viability ◽

Buellia Frigida ◽

Insight Into

AbstractSeveral investigations on lichen photobionts (PBs) after exposure to simulated or real-space parameters consistently reported high viability and recovery of photosynthetic activity. These studies focused on PBs within lichen thalli, mostly exposed in a metabolically inactive state. In contrast, a recent study exposed isolated and metabolically active PBs to the non-terrestrial stressor UVC254 nm and found strong impairment of photosynthetic activity and photo-protective mechanisms (Meeßen et al. in 2014b). Under space and Mars conditions, UVC is accompanied by other stressors as extreme desiccation and low temperatures. The present study exposed the PBs of Buellia frigida and Circinaria gyrosa, to UVC in combination with desiccation and subzero temperatures to gain better insight into the combined stressors' effect and the PBs' inherent potential of resistance. These effects were examined by chlorophyll a fluorescence which is a good indicator of photosynthetic activity (Lüttge & Büdel in 2010) and widely used to test the viability of PBs after (simulated) space exposure. The present results reveal fast recovery of photosynthetic activity after desiccation and subzero temperatures. Moreover, they demonstrate that desiccation and cold confer an additional protective effect on the investigated PBs and attenuate the PBs' reaction to another stressor – even if it is a non-terrestrial one such as UVC. Besides other protective mechanisms (anhydrobiosis, morphological–anatomical traits and secondary lichen compounds), these findings may help to explain the high resistance of lichens observed in astrobiological studies.

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Thermal Property Measurements on Biological Materials at Subzero Temperatures

Journal of Biomechanical Engineering ◽

10.1115/1.2895422 ◽

1991 ◽

Vol 113 (4) ◽

pp. 423-429 ◽

Cited By ~ 17

Author(s):

Xuemei Bai ◽

David E. Pegg

Keyword(s):

Thermal Conductivity ◽

Low Temperatures ◽

The Self ◽

Rabbit Kidney ◽

Kidney Cortex ◽

Low Viscosity ◽

Subzero Temperatures ◽

Liquid Samples ◽

Thermal Probes ◽

Low Ionic Strength

The self-heated thermistor technique was used to measure the thermal conductivity and thermal diffusivity of biomaterials at low temperatures. Thermal standards were selected to calibrate the system at temperatures from −10°C to −70°C. The thermal probes were constructed with a convection barrier which eliminates convection inside liquid samples of low viscosity, without affecting the conductivity and diffusivity results. Using this technique, the thermal conductivity and diffusivity of two organ perfusates (HP5 and HP5 + 2M glycerol), one kidney phantom (a low ionic strength gel), as well as rabbit kidney cortex have been measured from −10°C to −70°C.

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Flower cold hardiness: a potential determinant of the flowering sequence exhibited by bog ericads

Canadian Journal of Botany ◽

10.1139/b79-123 ◽

1979 ◽

Vol 57 (9) ◽

pp. 997-999 ◽

Cited By ~ 5

Author(s):

R. J. Reader

Keyword(s):

Low Temperatures ◽

Cold Hardiness ◽

Vaccinium Macrocarpon ◽

Southern Ontario ◽

Air Temperatures ◽

Insect Pollinators ◽

Cold Hardy ◽

Vaccinium Myrtilloides ◽

Potential Determinant ◽

Ledum Groenlandicum

In laboratory freezing trials, cold hardiness of six types of bog ericad flowers differed significantly (i.e., Chamaedaphne calyculata > Andromeda glaucophylla > Kalmia polifolia > Vaccinium myrtilloides > Ledum groenlandicum > Vaccinium macrocarpon) at air temperatures between −4 and −10 °C but not at temperatures above −2 °C. At the Luther Marsh bog in southern Ontario, low temperatures (−3 to −7 °C) would select against May flowering by the least cold hardy ericads. Availability of pollinators, on the other hand, would encourage May flowering by the most cold hardy species. Presumably, competition for insect pollinators has promoted the diversification of bog ericad flowering peaks, while air temperature, in conjunction with flower cold hardiness, determined the order in which flowering peaks were reached.

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Mechanism of freezing resistance in eco-dormant birch buds under winter subzero temperatures

Tree Physiology ◽

10.1093/treephys/tpz122 ◽

2019 ◽

Author(s):

Keita Endoh ◽

Seizo Fujikawa

Keyword(s):

Cold Hardiness ◽

Common Property ◽

Leaf Primordia ◽

Intercellular Spaces ◽

Freezing Resistance ◽

Cooling Rates ◽

Dormant State ◽

Sem Observation ◽

Subzero Temperatures ◽

The Common

Abstract Maximum freezing resistance is a component of winter survival and is associated with the eco-dormant state. Differential thermal analysis (DTA) has shown that changes of the freezing response of the dormant buds depend not only on species and bud type, but also on cooling rates. In order to clarify the freezing adaptation at the cellular level of eco-dormant buds in Japanese white birch, birch buds cooled at a rate of 0.2 °C min−1 and 5 °C day−1 were precisely examined by cryo-scanning electron microscopy (cryo-SEM). Freezing responses of floral dormant buds having female inflorescent primordia and leaf primordia with high-cold hardiness were assessed for extracellular freezing patterns by DTA. Cryo-SEM observation showed freezing of viscous solution filling intercellular spaces within buds and formation of extracellular ice in a random distribution within certain tissues, including green scales, leaf primordia and peduncles. The tissues producing extracellular ice had the common property that distinct intercellular spaces were present among cells having comparatively thick primary walls. In contrast, extracellular ice was not formed within flower primordium and parts of leaf primordium. These tissues had also the common property that no detectable intercellular spaces existed around the cells having thin primary walls. Cryo-SEM observation confirmed that all cells in tissues, regardless of whether extracellular ice was formed within tissues, and also regardless of differences in cooling rates, showed distinct cellular shrinkage by freezing. Recrystallization experiments by cryo-SEM confirmed that all freezable water in cells was eliminated by cooling at 0.2 °C min−1 at least to −30 °C. These results confirmed that all cells in birch buds responded to subzero temperatures through rapid equilibrium dehydration. In contrast to deep supercooling associated with extraorgan freezing of other freezing resistant buds of trees in an eco-dormant state, the mechanism of freezing resistance in eco-dormant birch buds is freezing adaptations by extracellular freezing.

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Cold-Hardiness, Habitat and Winter Survival of Some Orchard Arthropods in Nova Scotia

The Canadian Entomologist ◽

10.4039/ent96617-4 ◽

1964 ◽

Vol 96 (4) ◽

pp. 617-625 ◽

Cited By ~ 29

Author(s):

A. W. MacPhee

Keyword(s):

Nova Scotia ◽

Air Temperature ◽

Low Temperatures ◽

Cold Hardiness ◽

Winter Survival ◽

Kings County ◽

Winter Conditions ◽

Cold Hardy

AbstractIn Kings County, Nova Scotia, low temperatures in the coldest nights of winter can differ by as much as 10°F. from one area to another. This has an important bearing on winter survival of some arthropods. Overwintering sites of orchard arthropods range from exposed situations which remain at air temperature to well protected ones on the ground where temperatures rarely go below 20°F. The cold-hardiness of each of 24 species of arthropods was measured: seven were sufficiently cold-hardy to survive any winter conditions in Nova Scotia, five were less cold-hardy but overwinter in well protected sites and twelve had marginal cold-hardiness, their mortality varying with the winter and the locality.

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