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It is important to use standard parameters for assessing the biological performance of natural enemies in biological programs. The predation parameters of Typhlodromus bagdasarjani Wainstein & Arutunjan (Acari: Phytoseiidae) fed on the immature stages of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), reared on four different host plants including cucumber (cultivar ʻNeginʼ), tomato (cultivar ʻIsabellaʼ), eggplant (cultivar ʻBellʼ) and watermelon (cultivar ʻCrimsonʼ) were determined under laboratory conditions at 25 ± 1 ℃, 60 ± 5% R.H. and a photoperiod of 16:8 (L:D) h. Predation data were analyzed using the CONSUME MSChart. The lowest and highest estimated values for the net predation rate (C0) were recorded on eggplant (35.12 prey/individual) and tomato (95.87 prey/individual), respectively. The lowest transformation rate from prey population to predator offspring (Qp) (12.76 prey/egg) was recorded on cucumber which was not significantly different from those obtained on the others. The highest value for the stable predation rate (ψ) was recorded on the cucumber (2.49 prey/predator) and the lowest amount was recorded on the watermelon (1.93 prey/predator). The finite predation rate (ω) for T. bagdasarjani on the abovementioned host plants was 2.73, 2.61, 2.03, and 2.04 (day-1), respectively. Our findings revealed the predation parameters of T. bagdasarjani fed on immature stages of T. urticae on four different host plants and will be helpful for its sustainable management in different agro-ecosystems. [ABSTRACT FROM AUTHOR]

The nature of spider mite counterattack and defensive behavior and their effects on predatory mites have only been investigated in social species. Here, we have examined the defensive success of Tetranychus urticae Koch (Acari: Tetranychidae) male individuals in the presence of Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) juveniles. We recorded the number of T. urticae eggs eaten (killed) within three days along with monitoring the predator (dead/alive) status. The defensive behavior of T. urticae male was considered as success when the predator had consumed less than 50% of the prey eggs and was killed at the end of the experimental period. Our main hypothesis was that introducing an additional male would increase the defensive success rate. Results showed that the success rate was significantly higher in the patches with two T. urticae male individuals compared to one. No significant difference were observed among the egg-eating (killing) rate within the three consecutive days of experiment in patches with one male, while in the treatments with an additional male, the egg killing rate of the third day was significantly higher than that on the first day. We also hypothesized that male T. urticae with significant higher rate of defensive success should be morphologically different in comparison with the defeated ones. We found no significant differences in the length of chelicera, first leg and body (length and width) between the successful versus defeated males. We concluded that T. urticae can attack the predator, but the weapon by which the success happens remained unclear. [ABSTRACT FROM AUTHOR]

This study was aimed to investigate the population dynamics and diversity indices of three invasive species; the twospotted spider mite (TSSM) Tetranychus urticae Koch (Acari: Tetranychidae), the silver leaf whitefly Bemisia tabaci Genn. (Hemiptera: Aleyrodidae), and the onion thrips Thrips tabaci Lindman (Thysanoptera: Thripidae) on four tested plants; Siberian (Russian) kale Brassica napus var. pabularia L., Italian (Tuscan) kale Brassica oleracea var. palmifolia L. (Brassicaceae), spearmint Mentha spicata L. and Saudi Mint Mentha longifolia L. (Lamiaceae); in addition to evaluating a proposed IPM protocol in two experimental sites (Om Saber, Beheira Governorate and Kom Oshim, Fayoum Governorate). The proposed IPM program consisted using predatory mites; Phytoseiulus persimilis Athias-Henriot, Amblyseius swirskii Athias-Henriot, and Cydnoseius negevi (Swirski & Amitai) (Acari: Phytoseiidae), a green pesticide, and an entomopathogenic compound. Samples were collected from tested plants for two seasons to calculate pest population dynamics, and diversity indices, before and after IPM treatments. The resulting data showed statistically significant fluctuation, population dynamics, abundance, distribution, and diversity indices of the three targeted pest species recorded on the four tested plants. The proposed IPM protocol resulted in a significant reduction percentage when A. swirskii was used compared to other tactics. It is discussed that abiotic and biotic factors together help in explaining why various pest species build their communities rapidly and increase their parameters that become above the Economic Injury Level (EIL). Such factors are hypothesized to affect the plant-arthropod, predatorherbivore, predator-predator, and tri-trophic interactions. The proposed protocol recommends the consideration of application timing and merging tactics together to get maximum efficiency. [ABSTRACT FROM AUTHOR]

Crude ethyl acetate extracts of six entomopathogenic fungi, Hirsutella species were screened against Tetranychus urticae Koch (Acari: Tetranychidae). In this study, all extracts presented potential to control eggs and adult female activities. Laboratory evaluation of the crude extracts of Hirsutella citriformis, H. guignardii, H. petchabunensis, H. satumaensis, H. saussurei and H. thompsonii showed slightly toxicity and median lethal concentration (LC50) values of 7,579.94, 8,910.38, 8,579.45, 5,055.96, 1,555.46 and 44,197.85 mg/L at 72 h after treatment against adult females of T. urticae, respectively. Related LC50 values that exhibited on eggs were 12,701.86, 30,922.72, 10,870.96, 12,635.56, 9,244.59 and 22,676.66 mg/L at 5 days after exposure. The most effective on T. urticae eggs and adult females is H. saussurei. Moreover, all extracts deceased the fecundity of T. urticae after being fed with mulberry leaf discs treated the crude extract of six species of Hirsutella under residual effect bioassay. The results suggest that the ethyl acetate extracts of Hirsutella citriformis, H. guignardii, H. petchabunensis, H. thompsonii, H. satumaensi and H. saussurei have the potential to be used for the control of T. urticae in the future. [ABSTRACT FROM AUTHOR]

Leaf domatia as a habitat-produced structure is considered to moderate the interaction intensity among guild parties. We studied whether domatia of sweet pepper (Capsicum annum) leaves could reduce the adverse effects of predation of a phytoseiid on behalf of an intraguild predatory mite on a phytoseiid intraguild prey, and a tetranychid extraguild prey. In the domatia-provided treatments where Amblyseius swirskii (Athias-Henriot) females were considered as predator, significantly fewer Phytoseiulus persimilis Athias-Henriot juveniles were killed, and eaten in comparison with the treatments without domatia. The predation rate of A. swirskii was affected by the domatia i.e. the number of eaten P. persimilis was significantly lower on patches with four domatia rather than those with no domatium, however, no significant difference was observed between those in patches with two, and four domatia. Both natural, and artificial domatia could reduce the predation rate on P. persimilis juveniles. When P. persimilis females were considered as predators, the number of A. swirskii killed juveniles was affected neither by presence nor by the number of leaf domatia. The number of eaten Tetranychus urticae Koch eggs/larvae in patches with either of the intraguild predator species was not affected by the presence, the number, and the type of domatia. We suggest that leaf domatia could affect the survival of phytoseiid predatory mites as the guild participants even when the highly aggressive intraguild predator, A. swirskii, enters such structures. [ABSTRACT FROM AUTHOR]

The suitability of eight pollen diets (wild almond, date palm, oak, pomegranate, pistachio, peach, damask rose, and walnut) and also Tetranychus urticae Koch as natural diet on life table of the Amblyseius swirskii (Phytoseiidae) was determined at 25 ± 1 °C, 60 ± 5% relative humidity and photoperiod of 16:8 h (L: D). Results showed that damask rose pollen was not accepted as food and did not support the development of A. swirskii beyond the protonymphal and deutonymphal stage. The highest and lowest values of the intrinsic rate of increase (r) and finite rate of increase (λ) belonged to the pistachio (0.192 and 1.212 day-1) and peach (0.022 and 1.023 day-1) pollen, respectively. The net reproductive rate (R0) values varied from 1.4 offspring for the peach pollen to 29.54 offspring for the pistachio. Furthermore, the highest and lowest fecundity rate was recorded on the pistachio (36.65 eggs/female) and peach (3.23 eggs/female) pollen, respectively. Measured life table parameters of A. swirskii reared on different diets revealed pistachio, and after that, date palm and pomegranate pollen grains to be the most suitable diets. These findings may introduce more suitable pollen diets for the rearing of this predatory mite. [ABSTRACT FROM AUTHOR]

The population abundance of Tetranychus urticae Koch and its naturally occurring phytoseiid mite, Amblyseius swirskii Athias-Henriot on four strawberry cultivars (029, Fortona, Markez and Wanter star) were studied during 2017/2018 and 2018/2019 seasons. In both studied seasons, the population of T. urticae was observed from mid-October, and still recorded until the beginning of May. The peaks of infestation appeared in February or March (according to the cultivar) then declined later until the end of the study. The predatory mite (A. swirskii) initially appeared in January 2018 and 2019, while its population's peaks were observed in March on the four cultivars. In the two studied seasons, 029 cultivar was infested with the maximum numbers of T. urticae followed by Markez and Fortona cultivars, while Wanter star cultivar had the lowest infestation. In the present study, as the foliar concentrations of alkaloids and phenolic compounds increased, the cultivar infestation with T. urticae decreased. In all cultivars, a positive correlation between the populations of A. swirskii and T. urticae was observed. The present work may be considered useful to develop a successful management program of T. urticae, a serious pest of strawberry. [ABSTRACT FROM AUTHOR]

Two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and silverleaf whitefly, Bemisia tabaci (Gennadius) (Hem.: Aleyrodidae) are among the most destructive pests under greenhouse conditions which is primirarily countered using chemical pesticides. Due to insecticidal and acaricidal effectiveness of Spiromesifen (Oberon®), agricultural producers extensively used this chemical to control both whitefly and spider mite populations. In the present study, effects of recommended concentration of Spiromesifen on some biological and behavioral attributes of predatory mite Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) feeding on different ratios of two-spotted spider mite and silverleaf whitefly were investigated. Different treatments were defined as 1 (150 immature stages of mite + 0 immature stages of whitefly), 2 (120 mite + 30 whitefly), 3 (90 mite + 60 whitefly), 4 (75 mite + 75 whitefly), 5 (60 mite + 90 whitefly), 6 (30 mite + 120 whitefly) and 7 (0 mite + 150 whitefly). According to the results, mortality percentage of adult individuals was not significantly affected by different ratios of prey. With increasing ratio of preys tested in experimental arena, feeding activity of predatory mite on both preys was increased. However, in the case of T. urtice, linear relation observed between the initial number of mite offered and number of mite eaten was more significant. Reproductive responses of female predators to different ratios of mixed preys had no specified trend. Furthermore, switching behavior was not detected in female predators. Our results have considerable role for increasing biological efficacy of A. swirskii in integrated management programs of different pests. [ABSTRACT FROM AUTHOR]

Laboratory experiments were conducted to investigate the influence of two pea cultivars, regular and sweet as substrates on biological aspects and life table analysis of two phytoseiid species, Cydnoseius negevi (Swirski & Amitai) and Neoseiulus californicus (McGregor) fed on nymphs of Tetranychus urticae Koch under laboratory conditions of 27 ± 1 ℃, 70–80 % RH and 16L:8D h photoperiod. The development was faster and reproduction of N. californicus was higher compared with C. negevi. The predatory mite N. californicus showed the highest fecundity when reared on sweet pea cultivar, while C. negevi exhibited the lowest fecundity when reared on regular pea cultivar. Rearing C. negevi on the two pea cultivars led to the greatest female longevity than that of N. californicus. Feeding capacity of females during oviposition period was the highest for N. californicus on sweet pea, but it was the lowest for C. negevi on regular pea cultivar. Life table analysis showed that the shortest mean generation time (T) for N. californicus (13.01 days) compared with C. negevi (14.65 days) on sweet pea cultivar. Also, the intrinsic rate of increase (rm) of N. californicus was 0.29 female/female/day, but the rm value was 0.24 female/female/day for C. negevi on sweet pea substrate. Therefore, it can be concluded that the two predatory mites, C. negevi and N. californicus, are efficient biological control agents against T. urticae on the two pea cultivars. [ABSTRACT FROM AUTHOR]