Remzi Atlihan

Demographic Assessment of Plant Cultivar Resistance to Insect Pests: A Case Study of the Dusky-Veined Walnut Aphid (Hemiptera: Callaphididae) on Five Walnut Cultivars

ABSTRACT n To provide a comprehensive evaluation of walnut cultivar resistance to the dusky-veined walnut aphid, Panaphis juglandis (Goeze), we collected the life table data of this aphid reared on five cultivars of walnut (‘Akça I,’ ‘Chandler,’ ‘Fernette,’ ‘Fernor,’ and ‘Pedro’) under field conditions. The raw data of the developmental time, survival rate, and fecundity was analyzed using the age-stage, two-sex life table to account for the variable developmental rate and stage differentiation among individuals. Due to the species longer immature developmental time, shorter adult longevity, shorter reproduction period, and lower fecundity, the net reproduction rate (R0=5.9 offspring), intrinsic rate of increase (r=0.0983 d-1), and finite rate (&lgr;=1.1034 d-1) were the lowest when aphids were reared on the Fernor cultivar, while those reared on Akça I exhibited the highest population parameters (R0=18.0 offspring, r=0.2031 d-1, and &lgr;=1.2252 d-1). Based on the population characteristics, Fernor is a less favorable cultivar for the development and reproduction of P. juglandis. We also demonstrated the advantages of using bootstrapping for the analysis of standard errors of developmental time, longevity, fecundity, and other parameters as well. Our results indicated that demographic analysis of pest development, survival, and reproduction based on the agestage, two-sex life table offers a comprehensive assessment of pest growth potential on different crop cultivars.

Temperature-Dependent Development and Demography of Scymnus subvillosus (Coleoptera: Coccinellidae) Reared on Hyalopterus pruni (Homoptera: Aphididae)

Abstract The development, survival, and fecundity of Scymnus subvillosus (Goeze) (Coleoptera: Coccinellidae) were studied at 20, 25, 30, and 35°C, 60 ± 5% RH, and a photoperiod of 16:8 (L:D) h (5,000 lux) under laboratory conditions. The total developmental time from egg hatch to adult eclosion ranged from 22.6 d at 20°C to 10.6 d at 35°C. The developmental rates of the egg stage, the larval stage, and total preadult stage at different temperatures increased linearly with increasing temperature. The thermal summation of the egg stage, the larval stage, and the total preadult stage was 77.5, 145.8 and 300 degree-days (DD), respectively. The developmental threshold of the egg stage, the larval stage, and the total preadult stage was 7.4, 4.1, and 7.1°C, respectively. The life history raw data were analyzed using the age-stage, two-sex life table. The intrinsic rate of increase was 0.0845, 0.1138, 0.1395, and 0.0668 d−1 at 20, 25, 30, and 35°C, respectively. The net reproductive rate was highest at 25°C (R0 = 78.7), and lowest at 35°C (R0 = 4.7). The mean generation time was shortest at 35°C (T = 23.9 d). The life table data can be used for the projection of population growth and designing mass rearing programs. ÖZET Scymnus subvillosus (Goeze) (Coleoptera: Coccinellidae)’un dört farklı sıcaklık (20, 25, 30, ve 35°C), % 60 ± 5 orantılı nem ve 16 saat aydınlatmalı (5000 Lüx) laboratuvar koşullarında gelişme, canlı kalma oranı ve üremesi incelenmiştir. Yumurtadan ergine gelişme süresi 22.6 gün (20°C) ile 10.6 gün (35°C) arasında değişmiştir. Yumurta ve larva dönemleri ile toplam ergin öncesi dönemin gelişme oranı sıcaklıktaki artışla birlikte doğrusal olarak artmıştır. Yumurta, larva ve toplam ergin öncesi dönemlerin gelişmesi için gereksinim duyulan etkili sıcaklıklar toplamı sırasıyla 77.5, 145.8 ve 300 gün-derece, bu dönemlerin gelişme eşiği sıcaklıkları ise sırasıyla 7.4, 4.1, ve 7.1°C olarak hesaplanmıştır. Elde edilen verilerden yaşa bağlı, iki eşeyli yaşam çizelgesi analizi ile yaşam çizelgesi parametreleri oluşturulmuştur. Avcının kalıtsal üreme yeteneği değerleri 20, 25, 30, ve 35°C de sırasıyla 0.0845, 0.1138, 0.1395 ve 0.0668 gün−1 olarak bulunmuştur. En yüksek net üreme gücü değeri 25°C de (R0 = 78.7), en düşük ise 35°C de (R0 = 4.7) elde edilmiştir. En kısa ortalama döl süresi degˇeri 35°C de (T = 23.9 gün) elde edilmiştir. Bu çalışma sonucunda elde edilen yaşam çizelgesi verilerinin avcının populasyon gelişmesinin tahmininde ve kitle üretim programının düzenlenmesinde kullanılabileceği sonucuna varilmiştır.

Functional response of the coccinellid predator Adalia fasciatopunctata revelierei to walnut aphid (Callaphis juglandis)

The functional response types and parameters of 3rd and 4th instar larvae, and adult females and males of a coccinellid predator, Adalia fasciatopunctata revelierei (Mulsant) (Col.: Coccinellidae), were evaluated at five different densities of Callaphis juglandis (Goeze) (Hemiptera: Aphididae) in order to understand their role for the aphid’s biological control. Experiments were carried out in petri dishes at 25u2009±u20091°C, 60u2009±u200910% r.h. and 16L:8D photoperiod in a controlled temperature room. All tested stages exhibited a Type II response determined by a logistic regression model. The attack rate (α) and handling time (Th) coefficients of a Type II response were estimated by fitting a “random-predator” equation to the data. Although the estimates of α for all stages of A. fasciatopunctata revelierei tested were similar, the longest Th was obtained for 3rd instar larva because of the lower consumption rate at densities above 40 prey/day. Results indicated that the adult female has the highest predation of C. juglandis followed by 4th instar larvae, adult males and 3rd instar larvae. However, further field-based studies are needed to draw firm conclusions.

Reduced Fitness of the Colorado Potato Beetle (Coleoptera: Chrysomelidae) on Potato Plants Grown in Manure-amended Soil

Abstract Colorado potato beetle, Leptinotarsa decemlineata (Say), is the most important insect defoliator of potatoes worldwide. In this study, we conducted a series of no-choice assays comparing Colorado potato beetle reproduction and development on potato plants grown in manure-amended and synthetically fertilized soils. Manure-amended soil received annual applications of raw cow manure since 1991 and additional applications of cull potato compost and green manure between 1991 and 1998. Plants grown in manure-amended soil were inferior Colorado potato beetle hosts compared with plants grown in synthetically fertilized soil. The observed negative effects were broad in scope. Female fecundity was lower in field cages set up on manure-amended plots early in the season, although it later became comparable between the treatments. Fewer larvae survived past the first instar, and development of immature stages was slowed down on manure-amended plots. In the laboratory, first instars consumed less foliage from plants grown in manure-amended soils. These results show that organic soil management is associated with plant characteristics unfavorable for beetle reproduction and development, which should be taken into consideration when designing fully integrated crop management systems.

Linking Life Table and Predation Rate for Biological Control: A Comparative Study of Eocanthecona furcellata (Hemiptera: Pentatomidae) Fed on Spodoptera litura (Lepidoptera: Noctuidae) and Plutella xylostella (Lepidoptera: Plutellidae)

Abstract To better understand the predator–prey relationship and to compare predation rates, we studied the life table and predation rate of the predator Eocanthecona furcellata Wolff (Hemiptera: Pentatomidae) when reared on two major crucifer pests, Spodoptera litura (F.) (Lepidoptera: Noctuidae) and Plutella xylostella L. (Lepidoptera: Plutellidae). The net reproductive rate, intrinsic rate of increase, finite rate, and net predation rates of E. furcellata reared on P. xylostella were 292.4 offspring, 0.1389 d–1, 1.1490 d–1, and 644.1 third instars of P. xylostella, respectively. These values are significantly higher than those reared on S. litura, i.e., 272.3 offspring, 0.1220 d–1, 1.1298 d–1, and 863.1 third instars of S. litura. To evaluate the predation potential of E. furcellata fed on P. xylostella and S. litura, we combined both the growth rate and predation rate to calculate the finite predation rate (ω); our results showed that E. furcellata is an effective predator of both S. litura (ω = 1.6029) and P. xylostella (ω = 1.4277).

Biological features and life table parameters of the mealy plum aphidHyalopterus pruni on different apricot cultivars

Development, survival, reproduction rate, and population growth parameters of the mealy plum aphidHyalopterus pruni (Geoffroy) (Hom.: Aphididae) were evaluated on four different apricot cultivars (Tyrinte, Sakıt, Colomer, and Bebeco) under field conditions in the Van region of Turkey. Experiments were carried out on exterior leaves of trees, 1.5–2 m above the ground. Plexiglas clip-cells (25×6 mm) with the upper side covered by muslin were used in the experiments. The mealy plum aphid performed better on Tyrinte than on the other cultivars tested. The fastest development time (first instar to adult; 9.4 days), highest daily reproduction rate (2.6 offspring/aphid/day), and highest total fecundity (48.1 offspring/aphid) were obtained on Tyrinte. The intrinsic rate of increase — a good indicator of the growth potential of a population — of individuals fed on Tyrinte was significantly greater than that of individuals fed on cvs. Colomer and Bebeco. While mean generation times (To) of populations on different cultivars were close to each other, the net reproductive rate was the highest (29.45 offspring/aphid/generation) on Tyrinte and the population doubling time on Tyrinte was 18.7%, 25.2% and 26.3% faster than those of individuals on other cultivars tested. The results obtained in this study indicated that Tyrinte appeared to be the most susceptible to the mealy plum aphid among the cultivars tested.

Survival and Reproductive Strategies in Two-Spotted Spider Mites: Demographic Analysis of Arrhenotokous Parthenogenesis of Tetranychus urticae (Acari: Tetranychidae)

Abstract Tetranychus urticae Koch is a cosmopolitan pest whose rapid developmental rate enables it to produce colonies of thousands of individuals within a short time period. When a solitary virgin female colonizes a new host plant, it is capable of producing male offspring through the arrhenotokous parthenogenesis; once her sons mature, oedipal mating occurs and the female will produce bisexual offspring. To analyze the effect of arrhenotokous reproduction on population growth, we devised and compared separate life tables for arrhenotokous and bisexual populations of T. urticae using the age-stage, two-sex life table theory. For the cohort with bisexual reproduction, the intrinsic rate of increase (r), finite rate (λ), net reproductive rate (R0), and mean generation time (T) were 0.2736 d−1, 1.3146 d−1, 44.66 offspring, and 13.89 d, respectively. Because only male eggs were produced during the first 8 d of the oviposition period and the cohort would soon begin bisexual reproduction, it would be theoretically wrong to calculate the population parameters using the survival rate and fecundity of an arrhenotokous cohort. We demonstrated that the effect of arrhenotokous reproduction could be accurately described and evaluated using the age-stage, two-sex life table. We also used population projection based on life table data, quantitatively showing the effect that arrhenotokous reproduction has on the growth potential and management of T. urticae.

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 25xa0±xa01°C, 65xa0±xa010% 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 (Th) 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 Th (including digestion) were obtanined for the predator feeding on deutonmph. The lowest value of Th 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.

Fast Population Growth in Physogastry Reproduction of Luciaphorus perniciosus (Acari: Pygmephoridae) at Different Temperatures

Abstract Luciaphorus perniciosus Rack is one of the most serious pests of several cultivated mushroom species including Ganoderma lucidum (Fr.), Flammulina velutipes Karst., Auricularia polytricha (Mont.) Saac., Lentinus polychrous Lev., and Lentinus squarrosulus (Mont.) Singer in Thailand. Adult female Lu. perniciosus produce offspring inside their physogastric hysterosomas, with all embryos developing through to the adult stage while remaining in the abdomen. Once the abdomen ruptures, the female parent dies and the offspring consisting of mostly fertilized female adults along with a few male adults continue to emerge from the cadaver of the mother for a period of several days. This peculiar type of reproduction after the death of the mother is a special case for life table analysis and has not been discussed previously in demographic analyses. In this study, the life table data of this mite fed on Le. squarrosulus were collected at 25, 30, and 35 °C and analyzed by using the age-stage, two-sex life table. The standard errors of population parameters were estimated by using the bootstrap technique (200,000 bootstraps). At 25, 30, and 35 °C, females started reproduction at ages 9, 5, and 3 d, respectively; the net reproductive rates (R 0) were 192.27, 253.81, and 234.11 offspring. Due to their rapid development and high fecundity, the r values were as high as 0.4189, 0.8653, and 1.0892 d–1 at 25, 30, and 35 °C, respectively. Computer projection indicated that the mushroom mites Lu. perniciosus is capable of a threefold daily increase at 35 °C.

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 (20u2009mm in diameter and 10u2009mm 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.