Diapause Termination, Developmental Threshold and Thermal Requirements of Eggs of the Maple Aphid,Periphyllus californiensisShinji

2002 ◽  
Vol 7 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Chuan-Chan Wang ◽  
Kimito Furuta
1983 ◽  
Vol 115 (4) ◽  
pp. 387-392 ◽  
Author(s):  
R. M. Trimble

AbstractThe timing of diapause termination and the thermal characteristics of postdiapause development were compared in six Ontario populations of the spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.). The populations studied were from the major apple growing areas which are located in four climatically different zones. Pupae of all populations collected in the fall and stored under simulated overwintering conditions had terminated diapause by the end of January. Pupae overwintering under natural conditions had also terminated diapause by this time. Significant population differences occurred in the postdiapause developmental threshold (t0) and thermal constant (K). Simulating postdiapause development and emergence of the six populations using the 1981 temperature records from one location resulted in a 9-day difference between the earliest and latest mean emergence times. The implications of these results for pest management are discussed.


2017 ◽  
Vol 48 (1) ◽  
Author(s):  
Taciana Melissa de Azevedo Kuhn ◽  
Alci Enimar Loeck ◽  
Marcos Botton

ABSTRACT: The thermal threshold and thermal requirements of Neopamera bilobata were determined, and the number of generations that this species may produce in the main strawberry-producing regions of Brazil was estimated. In a climate chamber (70±10% RH and 12h photophase) at 16, 19, 22, 25, 28, or 30±1°C, the development of 120 eggs was monitored until the adult stage, at each temperature. Nymphs were maintained in individual cages and fed on strawberry fruits of the cultivar Aromas. The mean duration and viability of the egg and nymph stages were calculated by estimating the lower and upper developmental thresholds and the thermal constant, and this information was used to estimate the number of generations per year in different strawberry-producing regions of Brazil. The egg-to-adult duration decreased as temperatures increased, up to 28°C (93.4, 83.2, 43.9, and 31.4 days at 19, 22, 25, and 28°C, respectively). Viability of nymphs was highest between 22 and 28°C. At 30°C, the egg-to-adult duration increased (36 days), while the viability decreased (11.11%). The lower egg-to-adult developmental threshold was 15.2°C and the thermal constant was 418.4 degree-days. Calculating the number of generations indicated that the largest number (5.1 generations yr-1) was obtained for the municipality of Jaboti, Paraná, and the smallest for Caxias do Sul, Rio Grande do Sul (1.9 generations yr-1). Our findings demonstrated that important strawberry-producing regions in Brazil are suitable for the development of N. bilobata.


1977 ◽  
Vol 109 (11) ◽  
pp. 1469-1474 ◽  
Author(s):  
Fred H. Schmidt

AbstractStorage of diapausing larvae of Choristoneura viridis and C. occidentalis at low temperature (2°C) appeared to be sufficient stimulus to terminate diapause. Reactivation at 25°C occurred sooner and was more synchronous with longer storage at 2°C. Highest survival was obtained after storage of 20 to 22 weeks for both C. viridis and C. occidentalis. Intraspecific and interspecific reactivation rates were compared by analysis of covariance, using the model ln Y = a + B ln X , where Y = larval emergence in days at 25°C and X = storage in weeks at 2°C. Intraspecific sex differences were not significant, indicating that protandry observed in this laboratory in both species must be due to some other factor. C. viridis had substantially less stringent thermal requirements for diapause termination than C. occidentalis. Diapause in the two species is discussed.


Author(s):  
Andrew Z. Boeckmann ◽  
Zakaria El-tayash ◽  
J. Erik Loehr

Some U.S. transportation agencies have recently applied mass concrete provisions to drilled shafts, imposing limits on maximum temperatures and maximum temperature differentials. On one hand, temperatures commonly observed in large-diameter drilled shafts have been observed to cause delayed ettringite formation (DEF) and thermal cracking in above-ground concrete elements. On the other, the reinforcement and confinement unique to drilled shafts should provide resistance to thermal cracking, and the provisions that have been applied are based on dated practices for above-ground concrete. This paper establishes a rational procedure for design of drilled shafts for durability requirements in response to hydration temperatures, which addresses both DEF and thermal cracking. DEF is addressed through maximum temperature differential limitations that are based on concrete mix design parameters. Thermal cracking is addressed through calculations that explicitly consider the thermo-mechanical response of concrete for predicted temperatures. Results from application of the procedure indicate consideration of DEF and thermal cracking potential for drilled shafts is prudent, but provisions that have been applied to date are overly restrictive in many circumstances, particularly the commonly adopted 35°F maximum temperature differential provision.


Author(s):  
Yingchao Ji ◽  
Guohua Li ◽  
Chenggang Zhou ◽  
Shuyan Yin

Abstract Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.


Author(s):  
Razieh Shabani Kordshouli ◽  
Andrzej Grzywacz ◽  
Kamran Akbarzadeh ◽  
Kamal Azam ◽  
AliMohammad AliMohammadi ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document