Seasonal population fluctuation and life history in different temperatures of Myzus cerasi (Hemiptera: Aphididae) on cherry trees: a field and laboratory study.

This study determined the seasonal population fluctuation of Myzus cerasi (Fabricius) (Hemiptera: Aphididae) in cherry orchards and the effect of different temperatures on the life-history parameters of these aphids under laboratory conditions. Our field results showed that the population fluctuations and densities of M. cerasi on cherry trees were positively affected by the temperature increase between seasons. Also, our laboratory results showed that M. cerasi survived and reproduced at all temperatures tested under laboratory conditions. Female longevity was observed as 19.00 ±â€…2.38, 18.72 ±â€…0.49, and 12.59 ±â€…0.74 days, and fecundity was 10.14 ±â€…2.26, 9.36 ±â€…0.59, and 7.27 ±â€…0.84 offspring/female at 20, 25, and 30 °C, respectively. Although the highest net reproductive rate (R0) was observed numerically at 25 °C (7.80 offspring/female), there was no significant difference compared to 20 °C (7.10 offspring/female). The highest intrinsic rate of increase (r) and the highest finite rate of increase (λ) were calculated at 30 °C (0.15 ±â€…0.01 and 1.16 ±â€…0.01 day-1, respectively), and there was no significant difference compared to 25 °C. The mean generation time (T) of M. cerasi showed a significant difference at all temperatures tested and decreased from 22.59 ±â€…0.33 days at 20 °C to 12.78 ±â€…0.37 days at 30 °C. Consequently, our results revealed that the seasonal population fluctuation and the life history of M. cerasi in the field and laboratory conditions were affected significantly by different temperatures. Our data obtained in the field and the laboratory will contribute to the understanding of M. cerasi biology and to the management of the pest.

Do primary and secondary host plants affect aphid- parasitoid interactions in fruit orchards?

The aim of this study was to investigate how the primary (PHP) and secondary host plants (SHP) in the fruit orchards affect the interactions of aphids and their parasitoids in northwest Turkey during spring and summer 2020 and 2021. In total, 67 tritrophic aphid-parasitoid-host plant interactions, including new association records for Europe and Turkey, were obtained from 16 parasitoid species from the subfamily Aphidiinae (Hymenoptera: Braconidae) reared from 25 aphid species (Hemiptera: Aphididae) on 22 PHP and SHP in the fruit orchards. Also, we evaluated the effect of the PHP and SHP on the parasitoids, aphids and their interactions. We revealed that the species richness and the values of the biodiversity indices of the parasitoids and aphids were significantly higher on the SHP than the PHP. Similarly, the aphid-parasitoid interactions on the SHP showed greater diversity than the PHP. The results of this study clearly show that the interactions of parasitoids and aphids in the fruit orchards were more diverse on the SHP compared to the PHP.

Population Growth of Dysaphis pyri (Hemiptera: Aphididae) on Different Pear Cultivars With Discussion on Curve Fitting in Life Table Studies.

Population growth parameters of the Dysaphis pyri (Boyer de Fonscolombe) (Hemiptera: Aphididae) were evaluated on four different cultivars (Coscia, Ankara, Williams, and Santa-Maria) of pear (Pyrus communis L.) under field conditions in the Van region of Turkey. Aphids were kept on leaves of 10-yr-old pear trees in Plexiglas clip-cells (20 mm in diameter and 10 mm in height, with the upper side covered with muslin). For the description of the stage differentiation during population growth, we analyzed raw data of developmental time, survival, and fecundity using the age-stage, two-sex life table to take the variable developmental rate among individuals into account. Results indicated that the Coscia and Ankara cultivars are less favorable hosts for D. pyri because of the longer preadult developmental time, higher preadult mortality rate, and lower total fecundity on these cultivars. The intrinsic rate of increase (r), the net reproduction rate (R0), and the finite rate of increase (λ) values were lower on the Coscia and Ankara cultivars. We discussed the application of the Weibull function, polynomial model, and Enkegaard model in life table studies. Because these models are often inaccurate in describing survival and reproduction parameters, we suggest that their application in life table research should be reevaluated.

Consumption rate and functional response of the predaceous mite Kampimodromus aberrans to two-spotted spider mite Tetranychus urticae in the laboratory.

Prey stage preference of female Kampimodromus aberrans (Oudemans) (Phytoseiidae) at constant densities of different stages of Tetranychus urticae Koch (Tetranychidae), functional response types and parameters of the predator females to the varying densities of eggs, larvae, protonymphs and deutonymps of T. urticae were determined in order to establish its potential for the mite biological control. Experiments were conducted at 25 ± 1 °C, 65 ± 10% RH and 16:8 (L:D) photoperiod. Our results indicated that the predator consumed significantly more prey larvae than other prey stages. Functional response type of predator was determined by a logistic regression model. The predator exhibited a Type II response on all prey stages. The attack rate (α) and handling time (T ( h )) coefficients of a Type II response were estimated by fitting a "random-predator" equation to the data. The lowest estimated value α and the highest value of T ( h ) (including digestion) were obtanined for the predator feeding on deutonmph. The lowest value of T ( h ) were obtained for the predator feeding on prey larvae, but the attack rate value obtained on larva wasn't different than that obtained on egg and protonymph. According to our results, K. aberrans could be an efficient biological control agent of T. urticae at least at low prey densities. However, further field based studies are needed to draw firm conclusions.

Life history of hawthorn spider mite Amphitetranychus viennensis (Acarina: Tetranychidae) on various apple cultivars and at different temperatures.

Development duration and reproduction rate of hawthorn spider mite Amphitetranychus viennensis (Zacher) were carried out on five different apple cultivars (Amasya (local cultivar), Golden Delicious, Granny Smith, Starking Delicious and Starkrimson Delicious) at 25 degrees C, 65 +/- 10% RH and 16:8 L:D. In addition, the same parameters were determined on Golden Delicious leaves at three constant temperatures (20, 30 and 35 degrees C, 65 +/- 10% RH and 16:8 L:D) in the laboratory. A. viennensis showed a better performance on Golden Delicious than on the other apple cultivars. This was mainly due to a short development time (10.7 days), high daily egg production (5.2 eggs/female/day) and early reproduction peak. The highest intrinsic rate of natural increase (rm) was determined on the variety Golden Delicious (rm = 0.247/day), while the lowest one was observed on the variety Starking Delicious (rm = 0.215/day). The developmental periods of A. viennensis varied from 7.4 to 18.8 days at 35 and 20 degrees C for females, while it varied from 7.9 to 17.2 days at 30 and 20 degrees C for males. The development threshold of the eggs and pre-adult stages were 9.72 and 9.07 degrees C, total effective temperature was 72.99 and 185.18 degree-days, respectively. The mean generation time (To) of the population ranged from 16.13 days at 30 degrees C to 29.15 days at 20 degrees C. The net reproductive rate (R0) increased from 54.33 female/female at 20 degrees C to 78.34 female/female at 25 degrees C, and decreased to 75.71 female/female at 30 degrees C. The highest intrinsic rate of increase (rm) was reached at 30 C (rm = 0.268/day), the lowest one at 20 degrees C (rm = 0.136/day).