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The effectiveness of predators in suppressing prey populations is known to be influenced by the predator-prey release ratio. The efficacy of Neoseiulus cucumeris (Oudemans) against Frankliniella occidentalis (Pergand) in the presence or absence of Tetranychus urticae Koch and Phytoseiulus persimilis Athias-Henriot on rose plants was evaluated in the present study. The decrease of F. occidentalis populations was compared at the six predator:prey ratios of 1:2, 1:5, 1:10, 1:20, 1:50, and 1:100 in the laboratory, and at the three release rates of 20, 40, and 100 predators per m2 in microcosm conditions. The plants without predators were considered as controls. All treatments with the release of N. cucumeris resulted in a significant decrease in F. occidentalis larval population compared to the control. The most suppression (84.5%) of F. occidentalis larvae was observed in the release rate of 100 adults of N. cucumeris per m2 in 30 days after the release of the predator. Predator ratios of 1:2 and 1:5 of N. cucumeris: F. occidentalis resulted in a 94.6 and 93.4% decrease in F. occidentalis larvae after 24 hours, respectively. The presence of T. urticae (as a competitor herbivore) and P. persimilis had no effect on the efficiency of N. cucumeris in the suppression of F. occidentalis. The dense webs of T. urticae decreased the efficiency of N. cucumeris at predator:prey ratios of 1:5 and 1:10 more than1:2. This study showed that the release of 100 adults of N. cucumeris per m2 would be sufficient to control F. occidentalis larvae on rose plants. Moreover, we demonstrated that higher release rates of N.cucumeris are needed when T. urticae’s dense webs are present.

In this research, functional responses of Amblyseius swirskii Athias-Henriot preying on different Tetranychus urticae Koch nymphal densities (2, 4, 8, 16, 32, 64, and 128) were studied at eight constant temperatures (15, 20, 25, 27.5, 30, 32.5, 35 and 37.5°C) in a circular Petri dish (3-cm diameter × 1-cm height) under lab conditions. At all temperatures, the logistic regression showed a type II functional response. A nonlinear relationship was found between temperature and attack rate and the reciprocal of handling time. The reciprocal of handling time decreased exponentially with increasing temperature. In contrast, the attack rate grew rapidly with increasing temperatures up to an optimum, showing a decreasing trend at higher temperatures. In order to quantify the functional response of A. swirskii over a broad range of temperatures and to gain a better estimation of attack rate and handling time, a temperature-settled functional response equation was suited to our data. Our model showed that the number of prey consumed increased with rising prey density. Also, the predation rates increased with increasing temperatures but decreased at extremely high temperatures. Based on our model, the predation rate begins at the lower temperature threshold (11.73°C) and reaches its peak at upper temperature threshold (29.43°C). The coefficient of determination (R2) of the random predator model was 0.99 for all temperatures. The capability of A. swirskii to search and consume T. urticae over a wide range of temperatures makes it a good agent for natural control of T. urticae in greenhouses.

In this study, temperature-dependent oviposition model of Amblyseius swirskii Athias-Henriot fed by Tetranychus urticae Koch as prey was developed. In order to obtain data for the model, the longevity, fecundity and survivorship of adult females of A. swirskii were recorded at seven different temperatures (15, 20, 25, 27.5, 30, 32.5 and 35 °C) all at 60±5% RH and a photoperiod of 16:8h (L; D) in growth chamber. The longevity of females decreased with increasing temperature; the maximum at 15°C (84±3.24 days) and the minimum at 32.5°C (22.48±0.31 days). The female adult developmental rates (1/median longevity) was described by Sharpe and DeMichele model (r2=0.99). The highest and the lowest fecundity were observed at 25°C (22.63±0.76 eggs/female) and 15°C (9.4±0.67 eggs/female), respectively. The oviposition model comprised of three functions: temperature-dependent fecundity, age-specific cumulative oviposition rate and age-specific survival rate. The best model of temperature-dependent fecundity was described by a non-linear equation (extreme value function) (r2=0.98). Similarly, the best model of age-specific cumulative oviposition was described by the two-parameter Weibull function (r2=0.94). Eventually, the best model of age-specific survival rate was described by sigmoid function (r2=0.97). Amblyseius swirskii has ability to control pests such as thrips, whiteflies and two-spotted spider mites and can grow even in low temperatures. Therefore, this mite can be active at the beginning of spring season. Temperature-dependent oviposition model of A. swirskii can determine optimal temperature for mass-rearing and predict seasonal population dynamic of this predatory mite in greenhouses. Finally, the greenhouse data can validate this model in future.

The effect of seven constant temperatures (15, 20, 25, 27.5, 30, 32.5, and 35 ± 1°C) on developmental time of Tetranychus urticae Koch on cucumber leaf discs was determined under laboratory conditi...

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.

Herbivores' host plant resistance may also affect performance of their predators. The effect of susceptible ('Yellow') and resistant ('Roulette') rose cultivars on demographic parameters of the two-spotted spider mite (TSSM), Tetranychus urticae Koch and its predators Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) was determined under laboratory conditions. The obtained data were analyzed using the two-sex life table theory. The development rate of different life stages of TSSM and its predators on the susceptible and resistant rose cultivars were significantly different. Total development time of juvenile stages of TSSM and A. swirskii on the resistant cultivar was longer than that on the susceptible one, although no significant differences were obtained in the case of P. persimilis. By using the two-sex life table, the intrinsic rate of increase (r) of TSSM on the susceptible and resistant cultivars was 0.205 and 0.143 day-1, respectively. In addition, the net reproductive rate (R0) of TSSM on the susceptible and resistant cultivars was 26.46 and 11.47 eggs per individual, respectively; however, the mean generation time (T) of TSSM on these cultivars was 15.92 and 16.92 days, respectively. Furthermore, the value of the intrinsic rate of increase (r) in P. persimilis on the susceptible and resistant cultivars was 0.217 versus 0.163 day-1as well as in A. swirskii on the mentioned cultivars was 0.147 versus 0.117 day-1, respectively. There was no significant difference between the values of the net reproductive rate (R0) in P. persimilis on the susceptible and resistant rose cultivars, but in A. swirskii the value of this parameter on the susceptible cultivar was significantly higher than that on the resistant one. The mean generation time (T) in both predators on the resistant cultivar was longer than the susceptible one. In conclusion, resistance of the rose cultivar negatively affected the population growth parameters of TSSM and its both predators.

This review discusses mostly recent advances related to the fundamental and applied knowledge of mite families for the control of pests in Iran. There are several mite families (more than 20) related to pests that the focus has been mostly on mites of the family Phytoseiidae because of their important role in biological control of mite and insect pests. Hence, this family has been the subject of intensive studies about biology, behaviour, ecology and interactions with other natural enemies and recently efforts are doing for mass rearing of some species of this family. Among other Mesostigmata, a few representatives of the family Laelapidae appear to be suitable for augmentative releases. Efficacy of some other mesostigmatic mites (e.g. Parasitidae, Macrochelidae, Blattisociidae) have to be more studied regarding to their biological and behavioral traits. In Prostigmata, some tydeoids are predators and also can play their role as alternative prey. Species of the family Stigmaeidae could be potentially useful in orchards. Some families like Anystidae have a limited value as effective biocontrol agent. Some other prostigmatic families in the country require more study such as Trombidiidae, Erythraeidae, Podapolipidae and Acarophenacidae. Fundamental researches including faunistic, and also bioecological studies are necessary to find more promising biocontrol agents.

Predation rate is basic to any investigation of prey–predator interaction. The predation rate of Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) fed on the two-spotted spider mite (TSSM), Tetranychus urticae Koch, reared on the susceptible (Yellow) and resistant (Roulette) rose cultivars was determined under laboratory conditions at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16:8 (L:D) h. The value of total prey consumption in different life stages of both predators was higher on TSSM reared on the resistant rose cultivar than those on the susceptible one. In addition, the value of total prey consumption in different life stages of P. persimilis was higher than A. swirskii on both susceptible and resistant rose cultivars. The net predation rate (C0) of both predators on TSSM reared on the resistant rose cultivar was higher than those on the susceptible one. The stable predation rate (ψ) on the susceptible and resistant rose cultivars was 2.50 and ...

This study was carried out on the ability of predatory thrips Scolothrips longicornis Priesner to feed on 2 phytoseiid species and vice versa. Also the effect of predation of Neoseiulus californicus (McGregor) on Typhlodromus bagdasarjani Wainstein and Arutunjan and vice versa was evaluated. The larvae, prepupae, and pupae of thrips and the eggs, larvae, and protonymphs of phytoseiids were selected as intraguild prey. The intraguild predation (IGP) among S. longicornis and 2 phytoseiid species was unidirectional and in favor of phytoseiids, i.e., S. longicornis was not able to feed on larval stages of 2 phytoseiids. However, N. californicus and T. bagdasarjani fed on the 1st instar larvae (1.39 and 0.80 per day), 2nd instar larvae (0.87 and 0.55 per day), prepupae (0.51 and 0.48 per day), and pupae of thrips (0.51 and 0.49 per day, respectively). Both phytoseiids fed on eggs, larvae, and protonymphal stages of each other. Females of N. californicus consumed more phytoseiid larvae (2.49 per day) than T. bagdasarjani, which consumed 1.08 N. californicus larvae per day. When Tetranychus urticae was presented as an extraguild prey, intensity of IGP between 2 species of phytoseiids and on larval stages of S. longicornis reduced significantly. Therefore, it is concluded that (i) IGP existed among the 3 examined species and lack of feeding of S. longicornis on 2 phytoseiid species can be justified by its feeding type (monophagy), (ii) N. californicus was much more prone to IGP than was T. bagdasarjani.

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most economically important pests on a wide range of crops over the world. This study was carried out to evaluate the efficacies of two predatory mite species, Neoseiulus californicus (McGregor), an introduced species in Iran, and Typhlodromus bagdasarjani Wainstein & Arutunjan, a native species, as biocontrol agents of Te. urticae. The functional response and mutual interference of these two phytoseiid mites were determined under laboratory conditions at 25°C, 65% RH and a photoperiod of 16 h light:8 h dark. The functional response of the two predator species to eggs or nymphs of Te. urticae was type II. The highest attack rate (0.0936 h–1) and the lowest handling time (1.6451 h) were recorded for N. californicus on eggs and the lowest attack rate (0.0473 h–1) and the highest handling time (2.399 h) were estimated for T. bagdasarjani on nymphs of Te. urticae. Nicholson's model and linear regression were used to determine the per capita ...

The lifetime functional response and predation rate of Amblyseius swirskii Athias-Henriot on eggs of the two-spotted spider mite, Tetranychus urticae Koch were determined under laboratory conditions using cucumber leaf discs. Densities of 2, 4, 8, 16, 32, 64 and 128 prey were offered to 3, 4, 5, 6, 7, 12, 17, 22 and 27-day-old A. swirskii individuals. Based on the logistic regression, the functional response of twelve-day-old A. swirskii was type III, while the other ages showed type II. The Rogers model was used to estimate searching efficiency (a) and handling time (Th). The longest handling time (1.387±0.315 h) was observed in the protonymphal stage, while the shortest handling time and highest maximum attack rate (T/Th) were estimated at the age of seven-days (0.396±0.057 h and 60.67 prey/day, respectively). In the functional response experiments, results of the highest prey density used (128 eggs) showed that the highest number of prey consumed by A. swirskii individuals aged twelve and seventeen-days old (35.6 and 43.1 eggs, respectively). It is concluded that A. swirskii could be an efficient biological control agent of T. urticae at the middle-age of its life and at higher prey densities.

This study was carried out on the ability of predatory thrips Scolothrips longicornis Priesner to feed on 2 phytoseiid species and vice versa. Also the effect of predation of Neoseiulus californicus (McGregor) on Typhlodromus bagdasarjani Wainstein and Arutunjan and vice versa was evaluated. The larvae, prepupae, and pupae of thrips and the eggs, larvae, and protonymphs of phytoseiids were selected as intraguild prey. The intraguild predation (IGP) among S. longicornis and 2 phytoseiid species was unidirectional and in favor of phytoseiids, i.e., S. longicornis was not able to feed on larval stages of 2 phytoseiids. However, N. californicus and T. bagdasarjani fed on the 1st instar larvae (1.39 and 0.80 per day), 2nd instar larvae (0.87 and 0.55 per day), prepupae (0.51 and 0.48 per day), and pupae of thrips (0.51 and 0.49 per day, respectively). Both phytoseiids fed on eggs, larvae, and protonymphal stages of each other. Females of N. californicus consumed more phytoseiid larvae (2.49 per day) than T. bagdasarjani, which consumed 1.08 N. californicus larvae per day. When Tetranychus urticae was presented as an extraguild prey, intensity of IGP between 2 species of phytoseiids and on larval stages of S. longicornis reduced significantly. Therefore, it is concluded that (i) IGP existed among the 3 examined species and lack of feeding of S. longicornis on 2 phytoseiid species can be justified by its feeding type (monophagy), (ii) N. californicus was much more prone to IGP than was T. bagdasarjani.

In microcosm set-ups we investigated whether combined releases of the predatory thrips Scolothrips longicornis Priesner and two phytoseiid species, Neoseiulus californicus (McGregor) and Typhlodromus bagdasarjani Wainstein & Arutunjan provide better biological control of Tetranychus urticae Koch on cucumber plants than releases of each predator species alone. Results showed that control of T. urticae populations was equivalent under all predator combinations as in single predator release, indicating that no additive or synergistic effects among three predatory species had occurred in the control of the prey. In addition, the densities of each predator species under different combinations were similar, indicating that the three predators did not prey on each other during the observation period. Overall, our results showed that all three predator species are effective predators of T. urticae under microcosm conditions and suggest that they can be used in combination without decreased efficacy through intraguild predation.

Cannibalism is an important factor in biology and ecology of many species of insects and mites. The structure and dynamics of populations of predators used in biological control programs might be affected by cannibalism. The objective of the present study was to determine cannibalism by adult females of the generalist phytoseiids, Neoseiulus californicus (McGregor) and Typhlodromus bagdasarjani Wainstein & Arutunjan and the specialist predatory thrips, Scolothrips longicornis Priesner. The experiments were conducted under laboratory conditions at 25°C, 65% RH and a photoperiod of 16h light: 8h dark. The larval stages, prepupae and pupae of the thrips and the immature stages (eggs, larvae and protonymphs) of the phytoseiids were used as prey. For this purpose, two types of experiments were carried out. In the first experiment, cannibalism of N. californicus, T. bagdasarjani and S. longicornis on their immatures were studied in the absence of the two-spotted spider mite (TSSM), Tetranychus urticae ...