scholarly journals Induction of dormancy in Lobesia botrana by long day and high temperature conditions

2017 ◽  
Vol 6 ◽  
pp. 7 ◽  
Author(s):  
Μ. Ε. Tzanakakis ◽  
Μ. Savopoulou-Soultani ◽  
C. S. Oustapassidis ◽  
S.C. Verras ◽  
Η. Hatziemmanouel
Keyword(s):  
High Temperature ◽  
Pupal Stage ◽  
Lobesia Botrana ◽  
Larval Diet ◽  
Northern Greece ◽  
Larval Stages ◽  
Laboratory Stock ◽  
Long Day ◽  
Summer Diapause ◽  
Typical Summer

Lobesia botrana (Denis and Schiffermueller) (Lepidoptera: Tortricidae) is known to enter a facultative autumnohibernal diapause-mediated dormancy in the pupal stage, when the embryonic and early larval stages are exposed to short-day photo-periods. Yet, in a laboratory stock originating from northern Greece and reared for years on an artificial larval diet, dormancy occurred also under a long-day photo-period. When the eggs were incubated at 30oC in the dark or at 26 oC under the natural daylength of August in northern Greece, and the larvae grew at L:D 16:8 and 25-26 oC, but not 20 oC, a substantial percentage of the pupae entered dormancy. This dormancy seems to be diapause-mediated. It is not known whether it is a typical summer diapause.

scholarly journals Effect of Leaves and Fruits Ethanolic Extract of Duranta repens on Mosquito Culex pipens pipens

2011 ◽  
Vol 8 (4) ◽  
pp. 870-876 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Life Cycle ◽  
Mortality Rate ◽  
High Mortality ◽  
Culex Pipiens ◽  
Ethanolic Extract ◽  
Pupal Stage ◽  
Fourth Generation ◽  
Larval Instars ◽  
Larval Stages ◽  
Biological Performance

The study aimes to investigate the effects of leaves & fruits ethanolic extract of Duranta repens L. on biological performance for all stages of life cycle of the mosquito Culex pipiens piepiens L., For this purpose the mosquitoes were reared in the laboratory till the fourth generation .Different concentrations of leaves (800,1000,1200,1400ppm) and fruits (800,1000,1200ppm) were tested on (eggs,larval stages,pupal stages and the adult stages). The results revealed that the extracts gave highest mortality rate for the eggs at(100%) compared with control,fruits extract shown highest mortality rate of the four larval instars (100%)at 1200ppm compared with leave extract at(80,50,33.33,20%).Also the extract caused a high mortality rate for pupal stage compared with fruits extract at(76.66,53.33%)respectively.Also ethanolic extract caused a 83.33,76.66% for male &femail. Developmental deformation was observed.. In conclusion, the findings of the present study indicate that the leaves &fruits extracts of Duranta repens L., , can be widely and effectively used in the control of mosquito.

Turions and dormancy states in Utricularia vulgaris

1979 ◽  
Vol 57 (24) ◽  
pp. 2740-2749 ◽  
Author(s):  
Robert D. Winston ◽  
Paul R. Gorham
Keyword(s):  
High Temperature ◽  
Dark Respiration ◽  
Starch Content ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Long Day ◽  
Response To Temperature ◽  
Late Stages ◽  
H 20 ◽  
Utricularia Vulgaris

Phenology and states of dormancy of Utricularia vulgaris were studied using plants and turions collected at intervals throughout the growing season of 1977 from a shallow eutrophic pond in central Alberta located at 53°25′ N, 113°46′ W. States of dormancy and the effects of photoperiod and temperature were determined by the potential for sprouting and subsequent apical growth under long-day (18 h, 20 °C), short-day (12 h, 20 °C), and high-temperature (16 h, 30 °C) conditions, with and without varying periods of chilling at 2–3 °C. Physiological changes associated with different states of dormancy such as frost hardiness, starch content, and dark respiration were also investigated. Turions were formed 1 month after summer solstice and entered a state of innate dormancy during which only a high-temperature treatment at 30 °C would induce sprouting. Plants from innately dormant turions that were forced to sprout and were then cultured at 20 °C invariably reentered dormancy by the production of new turions. Turions collected in the late stages of innate dormancy could withstand −8 °C but not −12 °C. As temperatures dropped and ice cover became continuous, turions entered an imposed state of dormancy during which immediate sprouting and continued vegetative growth occurred under all conditions. Starch content reached a maximum of 49 mg g−1 fresh weight during early innate dormancy and declined steadily thereafter. Dark respiration in response to temperature of plants obtained from turions collected during innate and imposed dormancy states differed above 25 °C but was similar below.

Flowering responses to vernalization and photoperiod in annual medics (Medicago spp.)

1975 ◽  
Vol 26 (5) ◽  
pp. 831 ◽  
Author(s):  
NM Clarkson ◽  
JS Russell
Keyword(s):  
High Temperature ◽  
Flowering Time ◽  
Vernalization Requirement ◽  
Vernalization Response ◽  
The Third ◽  
Long Day ◽  
Temperature Requirement ◽  
New Finding ◽  
Annual Medics

The three processes thought to control flowering times in annual medics (Medicago spp.) are a vernalization requirement, a long day requirement and a high temperature requirement. To examine the first two processes, seed of seven cultivars of six species was vernalized at 1�C for periods of up to 11 weeks, then grown to flowering under three photoperiods in a glasshouse. To study the third process, the time to flowering of selected treatments from this expcrirnent was compared with flowering data from plants grown in the field at a range of temperatures lower than in the glasshouse. Vernalization and photoperiod caused large shifts in flowering time but the effects varied widely among species. M. scutellata was almost insensitive to both factors but in M. rugosa acceleration of up to 91 days was caused by treatment. Vernalization and short dark periods were additive in accelerating flowering and largely able to substitute for each other. Species flowered almost simultaneously when given their most favourable conditions for flowering. High temperature accelerated flowering in all species studied. However, in species other than M. scutellata it was necessary for a vernalization requirement to be met before this effect was observed. A new finding was that the vernalization response in M. truncatula and M. littoralis was largely reversed after more than 7 weeks of vernalization. This suggests a previously undetected flowering mechanism in these species.

Hochelaga lettuce

2008 ◽  
Vol 88 (3) ◽  
pp. 551-553 ◽  
Author(s):  
Sylvie Jenni ◽  
George C Emery
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Organic Soil ◽  
Organic Soils ◽  
Physiological Disorder ◽  
Long Day ◽  
Lactuca Sativa L ◽  
Lettuce Breeding ◽  
Growing Conditions ◽  
Horticultural Research

Hochelaga is an early and heavy crisphead lettuce highly tolerant to bolting under long-day growing conditions (more than 13-h). Hochelaga is the first variety released by the Horticultural Research and Development Centre (HRDC) lettuce breeding program of Agriculture and Agri-Food Canada (AAFC), Saint-Jean-sur-Richelieu, Quebec. Very similar in appearance to Ithaca, the regional standard, Hochelaga is well adapted to organic soils. Hochelaga is more tolerant than Ithaca to rib discoloration, a physiological disorder caused by high-temperature growing conditions. Key words: Lactuca sativa L., crisphead lettuce, rib discoloration, bolting, heat stress, organic soil

PREVENTING AND TERMINATING PUPAL DIAPAUSE IN ATHRYCIA CINEREA (DIPTERA: TACHINIDAE)

1977 ◽  
Vol 109 (8) ◽  
pp. 1083-1090 ◽  
Author(s):  
H. G. Wylie
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Adult Emergence ◽  
Larval Parasite ◽  
Long Day ◽  
Pupal Diapause ◽  
Young Parent ◽  
Diapause Incidence ◽  
Athrycia Cinerea ◽  
Bertha Armyworm

AbstractPupal diapause in Athrycia cinerea (Coq.), a larval parasite of bertha armyworm, Mamestra configurata Walk., was usually prevented if the parasite larvae were reared at 25°C, but not if they were reared at 20°C. Mature larvae of the parasite were more sensitive than younger larvae to this temperature effect. Diapause incidence in A. cinerea at 20°C was not reduced by using only young parent females for oviposition; by rearing the parent females at a high temperature (25°C) and long day (16 h) prior to and during oviposition; by using host larvae that had been light-programmed for non-diapause; or by increasing the photoperiod, to which the parasite larvae were exposed, from 12 to 16 h. Termination of pupal diapause was accelerated by low temperature; at least 24 weeks at 2 °C were required to synchronize adult emergence.

SURVIVAL OF AEDES LARVAE IN CONSTANT AREA PONDS IN SOUTHERN ALBERTA (DIPTERA: CULICIDAE)

1983 ◽  
Vol 115 (2) ◽  
pp. 183-188 ◽  
Author(s):  
G. Pritchard ◽  
P. J. Scholefield
Keyword(s):  
Survival Rate ◽  
Low Temperatures ◽  
Pupal Stage ◽  
Mortality Rates ◽  
Water Levels ◽  
Daily Mortality ◽  
Larval Stages ◽  
Constant Area ◽  
Southern Alberta ◽  
Heavy Mortality

AbstractMosquito eggs were hatched by artificially flooding dry pond beds and estimates of population size were made through larval development for one population of Aedes spencerii, two of A. cataphylla, and three of A. vexans. Overall daily mortality rates were between 8 and 21% and survival to the pupal stage was generally less than 20%, even though water levels were maintained. Mortality appeared to be higher in early larval stages than in later larval stages. Predation was unimportant and survival rate may have depended on food supply or temperature or an interaction between the two. In normal ponds populations often suffer heavy mortality when ponds dry up before development is complete. A. cataphylla, a spring species, developed faster than A. vexans, a summer species, at low temperatures but more slowly at high temperatures.

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