Life table parameters of Iranian population, Tetranychus kanzawai (Acari: Tetranychidae) fed on soybean leaves 

2019 ◽  
Vol 24 (2) ◽  
pp. 231 ◽  
Author(s):  
Iman Hassanvand ◽  
Shahriar Jafari ◽  
Masoumeh Khanjani

The effects of six ambient temperatures (15, 20, 25, 30, 35 and 37.5ºC) on life table parameters of Tetranychus kanzawai Kishida (Tetranychidae) were studied under laboratory conditions on soybean (Glycine max (L.) Merrill). Total immature developmental time of females at the above-mentioned temperatures was 28.55, 16.34, 9.01, 6.96, 5.56 and 5.65 days, respectively. A linear and two nonlinear models of Lactin and SSI were fitted to developmental rate of immature stages of T. kanzawai to predict the developmental rate as a function of temperature, as well as to estimate the thermal constant (k) and critical temperatures. The estimated k for total immature developmental time of females and males was 134.58 and 126.74 DD, respectively. The estimated Topt and Tmax by Lactin model for overall immature stages were 36.20 and 40.70ºC, respectively. Intrinsic optimum temperature (TФ) and T1 (Topt) by SSI model for total immature stages was estimated to be 23.23 and 35.71ºC, respectively. Also the estimated TL and Th of SSI model for overall immature stage were 09.21 and 38.46ºC, respectively. The longest and shortest adult longevity was observed at 15°C (60.63 days), and 37.5°C (7.34 days), respectively. Mated females laid highest and lowest eggs at 25°C (237.96 eggs) and 37.5°C (30.54 eggs), respectively. The rm values ranged from 0.356 day-1 at 30°C to 0.089 day-1at 15°C. The highest value of R0 was 163.55 offspring female-1 at 25°C. The presented information in this study provided new perspective to better management of T. kanzawai on apple trees in Iran.

2020 ◽  
Vol 25 (3) ◽  
pp. 538-547 ◽  
Author(s):  
Azadeh Farazmand ◽  
Masood Amir-maafi ◽  
Remzi Atlihan

In this study, developmental time of Amblyseius swirskii Athias-Henriot feeding on immature stages of Tetranychus urticae Koch was evaluated at eight constant temperatures (15, 20, 25, 27.5, 30, 32.5, 35, and 37.5 °C) providing 60±5% RH and a photoperiod of 16 L: 8 D. Duration of the egg to adult developmental time decreased sharply with increasing temperature, except at 37.5°C. To describe the developmental rate of A. swirskii as a function of temperature, one linear and 9 nonlinear models (Logan-6, Logan-10, Lactin-1, Lactin-2, Briere-1, Briere-2, Analytis-3, Polynomial, and Equation-16) were fitted. The lower temperature threshold (T0) and the thermal constant (K) were estimated by the linear model for the total immature stage as 7.90 °C and 140.85 DD, respectively. Based on the Akaike Information Criterion (AIC) and R2adj, Polynomial, Analytis-3, Analytis-3, Logan-10 and Briere-2 were the best models for eggs, larvae, protonymphs, deutonymphs and total immature stages of A. swirskii, respectively. Our findings showed that development and predation of A. swirskii occurs in a wide range of temperatures. Therefore, this predatory mite could be applied in control of T. urticae in different weather conditions.


Author(s):  
Meritxell Pérez-Hedo ◽  
Carolina Gallego ◽  
Amy Roda ◽  
Barry Kostyk ◽  
Mónica Triana ◽  
...  

Abstract The predatory mirid Macrolophus praeclarus is widely distributed throughout the Americas, and is reported to prey upon several horticultural pest species. However, little is known about its biology, thermal requirements, crop odour preferences, phytophagy, and capability to induce defensive responses in plants. When five temperatures studied (20, 25, 30, 33 and 35°C) were tested and Ephestia kuehniella was used as prey, the developmental time from egg to adult on tomato, was longest at 20°C (56.3 d) and shortest at 33°C (22.7 d). The ability of nymphs to develop to adults decreased as the temperature increased, with the highest number of nymphs reaching the adult stage at 20°C (78.0%) and lowest at 35°C (0%). The lower and upper developmental thresholds were estimated at 11.2° and 35.3°C, respectively. The maximum developmental rate occurred at 31.7°C and the thermal constant was 454.0 ± 8.1 degree days. The highest predation rate of E. kuehniella eggs was obtained at 30°C. In Y-tube olfactory choice tests, M. praeclarus selected tomato, sweet pepper and eggplant odours more frequently than no plant control treatment. Macrolophus praeclarus feeding did not damage tomato plants compared to another zoophytophagous mirid, Nesidiocoris tenuis, which caused necrotic rings. The phytophagy of M. praeclarus induced defensive responses in tomato plants through the upregulation of the jasmonic acid metabolic pathway. The implications of the findings for using M. praeclarus in tomato biological control programmes in the Americas are discussed.


1974 ◽  
Vol 64 (2) ◽  
pp. 265-276 ◽  
Author(s):  
K. H. Lakhani ◽  
M. W. Service

AbstractFor three consecutive years the eggs, the immature stages and the emergent adults of Aedes cantans (Mg.) populations were sampled from a small woodland ditch in southern England with a view to constructing the life-table of the species. Estimates of the numbers of ‘viable’ eggs available for hatching and the size of the resultant adult population yielded an estimate of the probability of a ‘viable’ egg resulting in an adult. Estimating the mortality rates in different immature stages which occur simultaneously is known to be difficult. It was considered reasonable to rely on a generalised exponential survivorship model based on the assumption that the relative mortality rate during the duration of each instar of A. cantans is constant, but this rate may vary from instar to instar. The parameters of the model were estimated using experimental data on the duration and total incidences through regular sampling of different instars together with the estimate of the probability that a ‘viable’ egg would result in an adult. The survivorship picture thus obtained agreed closely with the survivorship pattern obtained using a graphical approach based on the construction of the stage-specific age distribution of the pre-adults, and then drawing a smooth curve through the age distribution to produce an approximation to the survivorship curve. Because mortality was similar in all three years, the three years' data were pooled to give estimates of the life-table parameters. These clearly showed that substantial population loss occurred in the first two larval instars of A. cantans.


2009 ◽  
Vol 62 ◽  
pp. 399-399
Author(s):  
A. Arbab ◽  
M.R. McNeill

Insect phenology models are widely used for decision support in pest management and more recently in risk assessments During the last two decades numerous linear and nonlinear models have been used to describe insect development rates and estimate various critical temperatures (CT) including optimal development temperature (Topt) maximum development temperature (Tmax) minimum development temperature (Tmin) and thermal constant (K) (eg day degree requirements to complete development) Using a database comprising more than 600 species from laboratory and field experiments the relationship between CT for the six main insect orders Coleoptera Diptera Hymenoptera Lepidoptera Homoptera and Hemiptera was compared There were no significant differences (P>005) between Topt and Tmax for all orders but Tmin and K showed significant (P


1992 ◽  
Vol 124 (5) ◽  
pp. 853-860 ◽  
Author(s):  
D.S. Yu

AbstractThe effects of photoperiod and temperature on the diapause of Aphelinus varipes (Focrster) from Kazakhstan and Apheiinus near varipes from Alberta, which both attack Russian wheat aphid, were studied in the laboratory. At 20 °C, 50% of A. varipes entered diapause when the photoperiod was between 12.5L:11.5D and 13L:11D whereas 50% of A. nr. varipes entered diapause when the photoperiod was around 14L:10D. Diapause induction was close to 100% at 11.5L:12.5D for both species. Maximum sensitivity to photoperiod occurred 2 days alter parasitization for A. varipes and 3 days after parasitization for A. nr. varipes. At 30 °C, the proportion of wasps entering diapause was reduced to 40 and 72% for A. varipes and A. nr. varipes, respectively. Exposing diapausing mummies to temperatures from 10 to −10 °C for 4–20 weeks shortened the postdiapause developmental time. Survival was lowered by exposing mummies to −10 °C for over 8 weeks. Postdiapause developmental rate was directly temperature dependent. The lower threshold and thermal constant for postdiapause development were estimated to be 10.3 °C and 189 degree-days (DD) for A. varipes and 7.41 °C and 204 DD for A. nr. varipes.


2017 ◽  
Vol 21 (1) ◽  
pp. 25 ◽  
Author(s):  
Sanjeev Kumar ◽  
Ch. Kontodimas

Cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is an important cotton pest in Punjab, India. Development of the immature stages (four instars in female and five in male) of P. solenopsis was observed at nine constant temperatures (15, 18, 20, 25, 30, 34, 35, 38, 40°C). Using the linear model, the lower temperature threshold (tmin) for development was estimated to be 4.93 and 2.95°C and the thermal constant (K) was 333.33 and 454.54 degree days for female and male, respectively. In addition, three nonlinear models (Lactin, Bieri-1 and 3rd order polynomial) were tested to describe the relationship between temperature and development rate and to estimate the upper developmental threshold (tmax) and the optimum temperature for development (topt). Our results proved that the Bieri-1 and Lactin models and provided the best fit (r2 = 93,4 – 99,9%) and estimated accurately all the three critical temperatures, ranged tmin = 5.06 – 5.25°C, topt = 33.55 – 33.60°C, tmax = 39.99 – 40.00°C, for the total development of females and tmin = 2.82 – 3.16°C, topt = 34.01 – 34.04°C, tmax =40.00 – 40.10°C, for the total development of males.


2010 ◽  
Vol 52 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Lucy Kananu Murungi ◽  
Aggrey Nyende ◽  
John Wesonga ◽  
Peter Masinde ◽  
Markus Knapp

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