Temperature-induced effects on development, reproduction, and predation of Harmonia axyridis fed on first instar larvae Spodoptera litura.

Since metabolism, survival, and reproduction in hexapods are closely related to temperatures; changes in the mean and variance of temperature are major aspects of global climate change. In the typical context of biological control, understanding how predator-prey systems are impacted under thermal conditions can make pest control more effective and resilient. With this view, this study investigated temperature-mediated development and predation parameters of the predator Harmonia axyridis against the potential prey Spodoptera litura. The age-stage, two-sex life table of the predator was constructed at four temperatures (i.e. 15, 20, 25, and 30°C) by feeding on the first instar larvae of S. litura. Our results showed that the mean generation time (T) decreased but the intrinsic rate of increase (r) and the finite rate of increase (λ) increased with increased temperature. The mean duration of the total preadult stage decreased with higher temperatures. The T and r were 70.47 d and 0.0769 d-1 at 15°C; 58.41 d and 0.0958 d-1 at 20°C; 38.71 d and 0.1526 d-1 at 25°C; and 29.59 d and 0.1822 d-1 at 30°C, respectively. The highest net reproductive rate (R0) and fecundity were obtained at 25°C. The highest λ (1.1998 d-1) and lowest T (29.59 d) were obtained at 30°C, whereas the maximum net predation rate (C0) was at 25°C. Total population and predation rates projections were the highest at 30°C. Based on these findings, we anticipate that biological control strategies for this predator release against S. litura should be attuned to warming scenarios to achieve better biocontrol functions.

Hormetic effects of thiamethoxam on Schizaphis graminum: demographics and feeding behavior.

In agroecosystems, insects contend with chemical insecticides often encountered at sublethal concentrations. Insects' exposure to these mild stresses may induce hormetic effects, which has consequences for managing insect pests. In this study, we used an electrical penetration graph (EPG) technique to investigate the feeding behavior and an age-stage, two-sex life table approach to estimate the sublethal effects of thiamethoxam on greenbug, Schizaphis graminum. The LC5 and LC10 of thiamethoxam significantly decreased longevity and fecundity of directly exposed adult aphids (F0). However, the adult longevity, fecundity, and reproductive days (RPd)-indicating the number of days in which the females produce offspring - in the progeny generation (F1) exhibited significant increase when parental aphids (F0) were treated with LC5 of the active ingredient. Subsequently, key demographic parameters such as intrinsic rate of increase (r) and net reproductive rate (R0) significantly increased at LC5 treatment. EPG recordings showed that total durations of non-probing (Np), intercellular stylet pathway (C), and salivary secretion into the sieve element (E1) were significantly increased, while mean duration of probing (Pr) and total duration of phloem sap ingestion and concurrent salivation (E2) were decreased in F0 adults exposed to LC5 and LC10. Interestingly, in the F1 generation, total duration of Np was significantly decreased while total duration of E2 was increased in LC5 treatment. Taken together, our results showed that an LC5 of thiamethoxam induces intergenerational hormetic effects on the demographic parameters and feeding behavior of F1 individuals of S. graminum. These findings have important implications on chemical control against S. graminum and highlight the need for a deeper understanding of the ecological consequences of such exposures within pest management strategies across the agricultural landscapes.

Impact of sublethal concentrations of flonicamid on key demographic parameters and feeding behavior of Schizaphis graminum.

Flonicamid is a novel systemic insecticide that efficiently controls sap-sucking insect pests. However, the impact of sublethal concentrations of flonicamid on key demographic parameters and the feeding behavior of greenbug, Schizaphis graminum has not yet been studied. In this study, we used the age stage, two-sex life table approach, and electrical penetration graphs (EPGs) to investigate the sublethal effects of flonicamid on the biological traits and feeding behavior of S. graminum. Bioassays showed that flonicamid possesses high toxicity to adult S. graminum with LC50 of 5.111 mg L-1 following 48 h exposure. Sublethal concentrations of flonicamid (LC5 and LC10) significantly decreased the longevity and fecundity of directly exposed parental aphids (F0), while the reproductive days were reduced only at LC10. The pre-adult stage and total pre-reproductive period (TPRP) increased in F1 individuals after exposure of F0 aphids to the sublethal concentrations of flonicamid. Furthermore, the adult longevity, fecundity and key demographic parameters (R0, r, and λ) were significantly reduced in progeny generation (F1). EPG recordings showed that the total duration of phloem sap ingestion and concurrent salivation (E2) decreased substantially in F0 and F1 aphids after exposure to LC5 and LC10 of flonicamid. Taken together, our results showed that the sublethal concentrations of flonicamid affect the demographic parameters and feeding behavior that ultimately suppress the population growth of S. graminum. This study provides in-depth information about the overall effects of flonicamid on S. graminum that might help to manage this key pest.

Transgenerational sublethal effects of abamectin and pyridaben on demographic traits of Phytonemus pallidus (Banks) (Acari: Tarsonemidae).

In addition to determining the lethal effects, identifying sublethal effects of a pesticide is crucial to understanding the total impact a pesticide may have on a pest population. We determined the sublethal effects the two pesticides, abamectin and pyridaben, have on the cyclamen mite, Phytonemus pallidus (Banks) (Acari: Tarsonemidae)-a major pest of strawberry. Demographic traits of the P. pallidus progeny (F1 generation) produced by parents (F0 generation) treated with a low lethal concentration (LC15) of abamectin and pyridaben were assessed using the age-stage, two-sex life table theory. The total longevity of the F1 generation (males = 10.78 days; female = 14.35 days) was the shortest in the progeny of the abamectin treated parents, differing significantly from the progeny of mites treated with pyridaben (males = 11.50 days, females = 15.63 days), and the control population (males = 13.50 days, females = 17.81 days). The intrinsic rates of increase (r) and the finite rates of increase (λ) of the progeny of abamectin (r = 0.0854 day-1, λ = 1.0891 day-1) and pyridaben (r = 0.0951 day-1, λ = 1.0997 day-1) treated parents were significantly lower than in the control mites (r = 0.1455 day-1, λ = 1.1567 day-1). The lowest fecundity (5.35 eggs/female), occurred in F1 female offspring of parents treated with LC15 concentrations of abamectin, which was significantly lower than in the pyridaben (6.11 eggs/female) and control treatments (11.45 eggs/female). Transgenerational sublethal effects of abamectin and pyridaben in P. pallidus can be effectively used to for optimizing IPM programs against this pest on strawberries.

Intergenerational Sublethal Effects of Flonicamid on Cotton Aphid, Aphis gossypii: An Age-Stage, Two-Sex Life Table Study.

Flonicamid is a novel systemic insecticide widely used against aphids. However, the intergenerational sublethal effects of flonicamid on cotton aphid, Aphis gossypii, have not been fully studied. This study aimed to evaluate the sublethal effects of flonicamid on the biological parameters of adult A. gossypii (F0) and its subsequent intergenerational effects on the offspring (F1 generation) through age-stage, two-sex life table analysis. The results of the bioassays indicate that flonicamid exhibits significant toxicity toward adult A. gossypii, as evidenced by an LC50 value of 0.372 mg L-1 after a 48-h exposure period. The longevity, fecundity, and reproductive days of adult cotton aphids (F0) were significantly decreased when treated with the sublethal concentrations of flonicamid. The pre-adult stage exhibited an increase, whereas the adult longevity, total longevity, and fecundity experienced a notable decrease in F1 aphids after the exposure of F0 aphids to sublethal concentrations of flonicamid. Furthermore, the key demographic parameters, including r, λ, R0, and RPd, showed a significant decrease, while the total pre-reproductive period (TPRP) experienced a significant increase in the F1 generation. Collectively, our findings indicate that sublethal concentrations of flonicamid impact the demographic parameters of A. gossypii, resulting in suppression of population growth. This study presents comprehensive information on the overall impact of flonicamid on A. gossypii, which could potentially aid in managing this major pest.

Exploring the efficacy of pyrethroid incorporated nets for the control of stored product moth species: immediate and delayed effects on Ephestia kuehniella and Plodia interpunctella (Lepidoptera: Pyralidae).

Insect pests pose a significant threat to stored commodities, necessitating the exploration of alternative pest management strategies. Long-lasting insecticide-incorporated nets (LLINs) have emerged as a promising tool, offering selectivity and reduced ecological impact compared to conventional chemical approaches. However, their efficacy against Ephestia kuehniella Zeller and Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), cosmopolitan stored product moth species, has remained underexplored. This study investigated the immediate and delayed effects of 2 commercial pyrethroid-incorporated nets, Carifend (0.34% α-cypermethrin) and D-Terrence (0.4% deltamethrin), on the adult and larval stages. Both LLINs demonstrated high efficacy in controlling E. kuehniella and P. interpunctella, with mortality rates reaching up to 100% depending on exposure and post-exposure durations. Particularly, rapid knockdown was observed with D-Terrence net inducing 100% of adults in P. interpunctella after 30 min exposure. LLINs achieved almost 100% immediate mortality rate against adults after just 1 day of exposure. In addition, immediate rates of affected individuals reached as high as 81% and 91% in E. kuehniella and P. interpunctella larvae, respectively, following just 5 h of exposure to the D-Terrence. Different responses were observed between the adult and larval stages, with larvae exhibiting higher tolerance and potential for recovery from the affected phase after short exposures. There were increasing mortality rates after greater exposure to LLIN. Findings highlight the potential of LLINs as a pest management tool in storage facilities against these important stored product moths. Understanding the responses between life stages and the significance of delayed effects is crucial for optimizing LLIN deployment strategies.

Cost-effectiveness evaluation of mass-rearing Cadra cautella (Lepidoptera: Pyralidae) based on harvest theory for sustainable alternative prey production.

Cadra cautella (Walker) (Lepidoptera: Pyralidae) is a pest in barn, and its eggs are often utilized as an alternative prey or as hosts for mass production of insect predators and parasitoids. To aid in developing a mass-rearing system for C. castella, the suitability of using an artificial diet based on brown rice flour and whole brown rice was compared using the age-stage, 2-sex life table. Compared with those reared on brown rice, the insects reared on an artificial diet had a shorter preadult period (32.08 vs 37.38 d), higher fecundity (468.14 vs 356.20 eggs/female), greater intrinsic rate of increase (0.1509 vs 0.1145 d-1), and higher net reproductive rate (199.28 vs 103.52 offspring). Small populations were required to rear the moth on an artificial diet to achieve the same daily production of C. cautella. Still, the food expense was only 60.2% of that of C. cautella reared on brown rice. Approximately 99.44% of the eggs in each rearing procedure could be supplied as alternative prey for predators, with the remainder served to maintain the colonies for subsequent batches. Only eggs laid within 6 d would be utilized to ensure the high quality of alternative prey for the mass production of predacious bugs. Additionally, a multifunctional device was designed for moth rearing and egg collection, reducing labor input and minimizing health risks for workers coping with inhaled scales. To encourage the production of natural enemies, a cost-effective diet for maintaining a sustainable colony, and a system for daily egg-harvesting of alternative prey were proposed.

Thiamethoxam-Induced Intergenerational Sublethal Effects on the Life History and Feeding Behavior of Rhopalosiphum padi.

Thiamethoxam, a second-generation neonicotinoid insecticide is widely used for controlling sap-sucking insect pests including Rhopalosiphum padi. The current study aimed to investigate the life-history parameters and feeding behavior of R. padi following treatments with sublethal concentrations of thiamethoxam. The lethal concentration 50 (LC50) value of thiamethoxam against adult R. padi was 11.458 mg L-1 after 48 h exposure. The sublethal concentrations of thiamethoxam (LC5 and LC10) significantly decreased the adult longevity, fecundity, and reproductive days in the directly exposed aphids (F0 generation). In the progeny R. padi (F1), the developmental durations and total prereproductive period (TPRP) were decreased while the adult longevity, fecundity, and reproductive days (RPd) were increased at both thiamethoxam concentrations. The demographic parameters including the net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were prolonged only at the LC5 of thiamethoxam. The EPG results indicated that the sublethal concentrations of thiamethoxam increases the total duration of non-probing (Np) while reducing the total duration of E2 in directly exposed aphids (F0). Interestingly, the E2 were significantly increased in the progeny generation (F1) descending from previously exposed parental aphids (F0). Overall, this study showed that thiamethoxam exhibited high toxicity against directly exposed individuals (F0), while inducing intergenerational hormetic effects on the progeny generation (F1) of R. padi. These findings provided crucial details about thiamethoxam-induced hormetic effects that might be useful in managing resurgences of this key pest.

Fitness costs of resistance to insecticides in insects.

The chemical application is considered one of the most crucial methods for controlling insect pests, especially in intensive farming practices. Owing to the chemical application, insect pests are exposed to toxic chemical insecticides along with other stress factors in the environment. Insects require energy and resources for survival and adaptation to cope with these conditions. Also, insects use behavioral, physiological, and genetic mechanisms to combat stressors, like new environments, which may include chemicals insecticides. Sometimes, the continuous selection pressure of insecticides is metabolically costly, which leads to resistance development through constitutive upregulation of detoxification genes and/or target-site mutations. These actions are costly and can potentially affect the biological traits, including development and reproduction parameters and other key variables that ultimately affect the overall fitness of insects. This review synthesizes published in-depth information on fitness costs induced by insecticide resistance in insect pests in the past decade. It thereby highlights the insecticides resistant to insect populations that might help design integrated pest management (IPM) programs for controlling the spread of resistant populations.

Laboratory-Induced Bifenthrin, Flonicamid, and Thiamethoxam Resistance and Fitness Costs in Rhopalosiphum padi.

The bird cherry-oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) is one of the most economically important pests of wheat crops worldwide. Thiamethoxam, bifenthrin, and flonicamid are extensively used insecticides for controlling this key pest. However, the indiscriminate use of chemical insecticides has led to the development of resistance in insects. In this study, we assessed the development of selection-induced resistance to bifenthrin, flonicamid, and thiamethoxam under controlled laboratory conditions. Additionally, we employed the age-stage, two-sex life table method to examine the fitness of R. padi. After ten generations of selection, bifenthrin-, flonicamid-, and thiamethoxam-resistant strains of R. padi were developed with resistance levels of 34.46, 31.97, and 26.46-fold, respectively. The life table analysis revealed a significant decrease in adult longevity and fecundity in these resistant strains compared to susceptible strain. Furthermore, the key demographic parameters such as net reproductive rate (R0) and reproductive days exhibited a significant reduction in all resistant strains, while the intrinsic rate of increase (r) and finite rate of increase (λ) were decreased only in resistant strains to bifenthrin and thiamethoxam. Taken together, these findings provide a comprehensive understanding of laboratory-induced insecticide resistance evolution and the associated fitness costs in R. padi. This knowledge could help to design resistance management strategies against this particular pest of wheat.

AgroEcoList 1.0: A checklist to improve reporting standards in ecological research in agriculture.

Many publications lack sufficient background information (e.g. location) to be interpreted, replicated, or reused for synthesis. This impedes scientific progress and the application of science to practice. Reporting guidelines (e.g. checklists) improve reporting standards. They have been widely taken up in the medical sciences, but not in ecological and agricultural research. Here, we use a community-centred approach to develop a reporting checklist (AgroEcoList 1.0) through surveys and workshops with 23 experts and the wider agroecological community. To put AgroEcoList in context, we also assessed the agroecological community's perception of reporting standards in agroecology. A total of 345 researchers, reviewers, and editors, responded to our survey. Although only 32% of respondents had prior knowledge of reporting guidelines, 76% of those that had said guidelines improved reporting standards. Overall, respondents agreed on the need of AgroEcolist 1.0; only 24% of respondents had used reporting guidelines before, but 78% indicated they would use AgroEcoList 1.0. We updated AgroecoList 1.0 based on respondents' feedback and user-testing. AgroecoList 1.0 consists of 42 variables in seven groups: experimental/sampling set-up, study site, soil, livestock management, crop and grassland management, outputs, and finances. It is presented here, and is also available on github (https://github.com/AgroecoList/Agroecolist). AgroEcoList 1.0 can serve as a guide for authors, reviewers, and editors to improve reporting standards in agricultural ecology. Our community-centred approach is a replicable method that could be adapted to develop reporting checklists in other fields. Reporting guidelines such as AgroEcoList can improve reporting standards and therefore the application of research to practice, and we recommend that they are adopted more widely in agriculture and ecology.

Evaluation of Lethal and Sublethal Effects of Methyl Benzoate on the Generalist Predator Orius laevigatus (Fieber).

Methyl benzoate (MBe), a volatile organic molecule, has been shown to have insecticidal effects on a variety of agricultural, stored products, and urban arthropod pests in recent investigations. However, the toxicity of MBe against nontarget organisms has rarely been investigated. This study investigated the lethal and sublethal effects of MBe on the generalist predator Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) via different exposure routes. This species is an important natural enemy of thrips, aphids, and mites in biological control programs globally. Acute toxicity bioassays conducted on O. laevigatus showed that the lethal median concentration (LC50) values of MBe for topical and residual toxicity were 0.73 and 0.94%, respectively, after 24 hr of exposure. Importantly, a sublethal concentration of MBe (LC30 = 0.51%) did not affect the survival and reproduction of O. laevigatus. In addition, prey consumption by O. laevigatus under different exposure conditions with varying densities of Aphis gossypii (Glover) (Hemiptera: Aphididae) adults demonstrated a good fit for a Type II functional response. The sublethal concentration of MBe did not affect the attack rate and handling time of O. laevigatus compared to untreated insects, nor did it affect the longevity and fecundity of O. laevigatus females. Thus, according to the International Organization for Biological Control, the sublethal MBe concentration for O. laevigatus is categorized as harmless and may be used in conjunction with this predator species for integrated control of many agricultural insect pests.

Effect of temperature on the life cycle of Harmonia axyridis (Pallas), and its predation rate on the Spodoptera litura (Fabricius) eggs.

Biological control is one of the strategies of pest control which is determined by the biological fitness and metabolic rates of the predator species used. Temperature and resource are important factors which influence the role of insects as biocontrol agents. Harmonia axyridis is a cosmopolitan and non-specific polyphagous predator. It can survive ecologically diverse environments and exploit multiple preys. This study investigated the effects of temperature on the population parameters of H. axyridis and its predation on the eggs of prey Spodoptera litura. For this purpose, an age-stage, two-sex life table of the predator was constructed at four constant temperatures, i.e. 15, 20, 25 and 30 °C, under laboratory settings of: 70 ± 5% RH, and 16:8 h (L: D) photoperiod. A computer simulation was then used to project the population and predation responses with respect to temperatures tested. We found that the development of larvae and adult (male/female) stages of H. axyridis decreased with colder temperatures (i.e., 15 and 20 °C) but increased with warmer temperatures (25 and 30 °C). The intrinsic rate of increase (r) and mean generation time (T) were 0.0662 d-1 and 79.84 d at 15 °C, 0.0843 d-1 and 64.90 d at 20 °C, 0.1067 d-1 and 48.89 d at 25 °C, and 0.1378 d-1 and 35.55 d at 30 °C, respectively. The mean duration of the total pre-adult stage was 44.26, 32.91, 20.63, and 15.39 d at 15, 20, 25, and 30 °C, respectively. At 30 °C. the finite rate of increase (1.1477 d-1) was the highest and the mean generation time (35.55 d) was the shortest. The net predation rate (C0) was 7935.54, 10,466.28, 10,139.38, and 7126.36 eggs at 15, 20, 25, and 30 °C, respectively. Population and predation projections were proportional to temperature. These findings are important for modelling the population responses of H. axyridis to climate change and tailoring integrated pest management strategies to altered climates.

Impact of Imidacloprid Resistance on the Demographic Traits and Expressions of Associated Genes in Aphis gossypii Glover.

Imidacloprid is one of the most widely used neonicotinoid insecticides to control sap-sucking insect pests, including Aphis gossypii. The intensive application of chemical insecticides to A. gossypii led to the development of resistance against several insecticides, including imidacloprid. Therefore, it is crucial to understand the association between imidacloprid resistance and the fitness of A. gossypii to limit the spread of the resistant population under field contexts. In this study, we used the age-stage, two-sex life table method to comprehensively investigate the fitness of imidacloprid resistant (ImR) and susceptible strains (SS) of melon aphids. Results showed that ImR aphids have prolonged developmental stages and decreased longevity, fecundity, and reproductive days. The key demographic parameters (r, λ, and R0) were significantly reduced in ImR strain compared to SS aphids. Additionally, the molecular mechanism for fitness costs was investigated by comparing the expression profile of juvenile hormone-binding protein (JHBP), juvenile hormone epoxide hydrolase (JHEH), juvenile hormone acid O-methyltransferase (JHAMT), Vitellogenin (Vg), ecdysone receptor (EcR), and ultraspiracle protein (USP) supposed to be associated with development and reproduction in insects. The results of RT-qPCR showed that EcR, JHBP, JHAMT, JHEH, and Vg genes were downregulated, while USP was statistically the same in ImR A. gossypii compared to the SS strain. Together, these results provide in-depth information about the occurrence and magnitude of fitness costs against imidacloprid resistance that could help manage the evolution and spread of A. gossypii resistance in field populations.

Functional Response of Harmonia axyridis to the Larvae of Spodoptera litura: The Combined Effect of Temperatures and Prey Instars.

Functional responses are central to predator-prey dynamics and describe how predation varies with prey abundance. Functional responses often are measured without regard to prey size (i.e., body mass) or the temperature dependence of feeding rates. However, variation in prey size within populations is ubiquitous, and predation rates are often both size and temperature-dependent. Here, we assessed functional responses of larvae and adult Harmonia axyridis on the 1st, 2nd, and 3rd instars of the prey Spodoptera litura across a range of temperatures (i.e., 15, 20, 25, 30, and 35°C). The type and parameters of the functional responses were determined using logistic regression and fitted to the Roger's random predator equation. The magnitude of predation varied with the predator and prey stage, but prey predation increased with warming and predator age. Predation by the female and 4th instar of H. axyridis on the 1st instar of prey was greater, followed by the 2nd and 3rd instar of prey S. litura. No predation occurred on the larger prey for the 1st, 2nd, and 3rd instars of H. axyridis. The larvae and adult H. axyridis produced a type II (hyperbolic) functional response curve across all temperatures and the three prey types they consumed. Space clearance rates, handling time, and maximum predation rates of H. axyridis changed with temperature and prey size, increasing with temperature and decreasing with prey size, suggesting more predation will occur on younger prey. This study indicates an interactive role of temperature and prey/predator size in shaping functional responses, which might complicate the planning of effective biocontrol strategies against this serious pest.

Demographic Characteristics and Population Simulation of Newly Invasive Fall Armyworm on Arachis hypogaea (Fabales: Fabaceae) and Dominant Green Manure Plant in Taiwan.

Spodoptera frugiperda (J.E. Smith) is a severe and fast-spreading pest of numerous agro-economic crops, including miscellaneous, vegetables, and green manure crops. Understanding pest ecology represents a core component in integrated pest management decision-making. In Taiwan, peanut (Arachis hypogaea L.) is an important miscellaneous crop, whereas sesbania (Sesbania roxburghii Merr.) is the most frequently used green manure crop. To improve the S. frugiperda management in Taiwan, the demographic characteristics and population simulation of this pest reared on peanut and sesbania leaves were analyzed using the age-stage, two-sex life table theory. The intrinsic rate of increase, finite rate of increase, and net reproductive rate of S. frugiperda were higher when reared on peanut (0.1625 d-1, 1.1764 d-1, 264.9 offspring) than on sesbania (0.0951 d-1, 1.0997 d-1, and 30.3 offspring). Population projection of S. frugiperda on peanut demonstrated that this crop is a more suitable host plant than sesbania. Yet, this suboptimal host still assures an increasing trend of more than 357-fold individuals in 75 d, from the initial cohort of 10 eggs. Our data suggest that green manure plants in fallowing fields may support the pest's survival all year round, and may be responsible for a successful establishment and unexpected outbreaks of this invasive pest on the neighboring crops in Taiwan. Our study thus highlights the importance of assessing the population dynamics and areawide pest management of an invasive polyphagous pest on a noneconomic crop to mitigate the potential risk of reinfestation and thus outbreaks.

Laboratory induced selection of pyriproxyfen resistance in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae): Cross-resistance potential, realized heritability, and fitness costs determination using age-stage, two-sex life table.

Pyriproxyfen is a biorational insecticide from IGR family, used worldwide against several economic pests. To evaluate the risk of pyriproxyfen resistance in dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae), a major concern for cotton producers, and to formulate strategies effective to tackle resistance, a field collected population was selected with pyriproxyfen under laboratory conditions using seed-dip method. A resistant strain designated as Pyr-SEL (G18) was developed after repeatedly selecting O. hyalinipennis with pyriproxyfen over eighteen generations. Thereafter, fitness costs, realized heritability (h2) and cross-resistance were investigated. As a result of selection, Pyr-SEL (G18) developed a very high level of resistance (resistance ratio = 464.23-fold) compared with the susceptible strain unselected over twenty generations Un-SEL (G20). The Pyr-SEL (G18) conferred strong cross-resistance to bifenthrin (146.59-fold), lambda-cyhalothrin (132.96-fold) and fenoxycarb (91.06-fold), whereas showed moderate cross-resistance to diafenthiuron (28.86-fold) and fipronil (22.73-fold). The h2 estimate was 0.16 in Pyr-SEL (G18). The developmental duration of O. hyalinipennis pre-adult prolonged, but traits of λ, r and R0 reduced in Pyr-SEL (G18) compared with the Un-SEL (G20). Also, the population projection obtained lower population size for Pyr-SEL (G18) than Un-SEL (G20). Fitness studies revealed that high resistance development to pyriproxyfen lowered the relative fitness of Pyr-SEL (G18) (Rf = 0.38) compared with the Un-SEL (G20). These findings may be practically valuable in tackling O. hyalinipennis resistance for better pest management.

Demographic Comparison of the Tetranychus urticae Koch. (Acari: Tetranychidae) Reared on Different Cultivars of Strawberry.

The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an important pest of strawberry (Fragaria × ananassa Duch.) grown in greenhouses and outdoors. In this study, we evaluated the resistance status of five common strawberry cultivars ('Aromas', 'Kurdistan', 'Missionary', 'Paros', and 'Queen Elisa') under laboratory conditions. The developmental times of the preadult and adult stages, total longevity, reproduction, and life table parameters were analyzed according to the age-stage, two-sex life table theory, which provides the most comprehensive description on the survival, stage differentiation, and reproduction of a population. Preadult development was the shortest on Kurdistan and longest on Aromas (17.70 d vs. 21.00 d). The greatest number of oviposition days occurred on Missionary (28.65 d), whereas the fewest were on Queen Elisa (21.58 d). The intrinsic rate of natural increase (r) and finite rate of increase (λ) varied among the cultivars. The highest values were found on Kurdistan (r = 0.1436d-1, λ=1.1544d-1), while the lowest values were on the Aromas cultivar (r = 0.1081d-1, λ=1.1141d-1). The longest mean generation time (T) of T. urticae occurred on Aromas. Based on the results of the present study, the cultivar Aromas was considered the most resistant to T. urticae and least favored strawberry cultivar for the development and reproduction of the mite. Demographic data of twospotted spider mite on these five strawberry cultivars can be used to improve our understanding of the population dynamics of the pest and thereby develop effective pest management strategies against T. urticae in both integrated and organic strawberry production.

Demography and Mass-Rearing Harmonia dimidiata (Coleoptera: Coccinellidae) Using Aphis gossypii (Hemiptera: Aphididae) and Eggs of Bactrocera dorsalis (Diptera: Tephritidae).

We compared rearing Harmonia dimidiata (F.) (Coleoptera: Coccinellidae) on four combinations of Aphis gossypii Glover (Hemiptera: Aphididae), and eggs of Bactrocera dorsalis Hendel (Diptera: Tephritidae), using the age-stage, two-sex life table. The four combinations were: both larvae and adults were reared on aphids; larvae were reared on aphids and adults were reared on fresh fruit fly eggs; larvae were reared on lyophilized fruit fly eggs and adults were reared on aphids; and larvae were reared on lyophilized eggs and adults were reared on fresh eggs. The highest intrinsic rate of increase (r = 0.1125 d-1) and net reproductive rate (R0 = 260.7 offspring) were observed when both larval and adult stages of H. dimidiata were reared on A. gossypii. When B. dorsalis eggs were used as rearing media for larvae, adults, or both, the values of r and R0 were significantly decreased. The lowest values (r = 0.0615 d-1 and R0 = 38.6 offspring) were observed when both larvae and adults were reared entirely on B. dorsalis eggs. Despite the lower r and R0 values, our results showed that B. dorsalis eggs could be considered as an adequate, less expensive alternative diet for rearing H. dimidiata because of the time and labor savings resulting from the ease of preparation and the ability to store the eggs for timely usage. The mass-rearing analysis showed that the most economical rearing system was to rear larvae on A. gossypii and adults on B. dorsalis eggs.

Within-Plant Distribution and Susceptibility of Hazelnut Cultivars to Mikomya coryli (Diptera: Cecidomyiidae).

The Mikomya coryli (Kieffer) (Diptera: Cecidomyiidae) is widespread in Europe and the most important cecidomyiid pest of hazelnut. Within-plant distribution, susceptibility of 18 Turkish hazelnut cultivars ('Aci,' 'Allahverdi,' 'Çakildak,' 'Cavcava,' 'Fosa,' 'Incekara,' 'Kalinkara,' 'Kan,' 'Karafindik,' 'Kargalak,' 'Kus,' 'Mincane,' 'Palaz,' 'Sivri,' 'Tombul,' 'Uzunmusa,' 'Yassi Badem,' and 'Yuvarlak Badem'), and the phenology of larvae of this pest in hazelnut leaves and involucres were assessed in 2014 and 2015 in Giresun (Turkey). Mikomya coryli distribution differed significantly within different parts of the hazelnut plant. The highest gall numbers of M. coryli were found in the middle part (0.70-1.40 m) of the plant in both years. Total gall numbers varied between years: 1,779 and 2,588 galls were counted in 2014 and 2015, respectively. Susceptibility to M. coryli damage varied significantly among the cultivars. The highest leaf gall densities and total numbers of galls were found on leaves and involucres of Allahverdi, Yuvaklak Badem, and Yassi Badem cultivars in both years. Mikomya coryli larvae were detected between April and June in the leaf galls. The number of larvae in the involucres changed between April and mid-June. Results of the within-plant distribution, M. coryli larval phenology, and cultivar pest-susceptibility analyses are presented to enable effective control of the pest as a part of hazelnut integrated pest management.