Amblyseius Swirskii Athias-Henriot Research Articles

The impact of different concentrations of nano-capsulated Aleppo oak extraction on the biological performance of Amblyseius swirskii (Acari: Phytoseiidae)

Essential oils have demonstrated promising results in controlling mites. However, their impact on predatory mites, which are widely used in pest management programs, remains uncertain. In the present study, the effects of 1, 2 and 3 (g a.i. L-1) of nano-capsulated Aleppo oak extraction on the biological parameters of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) were investigated under laboratory condition. Based on the results, the pre-adult period of the predator was significantly longer in the 2 (g a.i. L-1) concentration (6.66 days) compared with the control and the 1 (g a.i. L-1) concentration. Additionally, the total lifespan in the control group (39.42 days) was significantly longer than the treatment with a 3 (g a.i. L-1) concentration (31.50 days). The total fecundity in the 2 (g a.i. L-1) concentration (47.60 eggs/female) was significantly higher than the other treatments, indicating a positive effect of this botanical pesticide at the concentration recommended by the manufacturer on the reproductive system of the predatory mite. No significant differences were observed among the different treatments and the control group in terms of population growth parameters (GRR, R0, r, and λ). Only the mean generation time (T) showed a significant difference, with the longest period being recorded in the 2 (g a.i. L-1) concentration (15.44 ± 0.21), which was significantly longer than the control and the 1 (g a.i. L-1) concentration. The lack of significant differences in population growth parameters between the treatments indicates that nano-capsulated Aleppo oak extraction is safe for use along with the predatory mite A. swirskii.

Residual effect of commonly used insecticides on key predatory mites released for biocontrol in strawberry.

Florida is the second largest producer of strawberries in the United States. However, the production system faces numerous challenges, especially Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) infestations. Management of this pest involves applying insecticides and use of predatory mites, particularly Amblyseius swirskii Athias-Henriot, Neoseiulus cucumeris Oudemans, and Neoseiulus californicus McGregor (Mesostigmata: Phytoseiidae). Strawberry growers in Florida are concerned about the compatibility of the commercial formulations of insecticides used in strawberry pest management with predatory mites. This study assessed the residual effect of commercial insecticides used in strawberry production on the survival, feeding, and oviposition of the 3 predators. Using Munger cells, predators were exposed to commercial formulations of spinetoram, cyantraniliprole, azadirachtin + pyrethrin, Beauveria bassiana, Cordyceps javanica, capsicum, garlic, and canola oil extracts, and water control. There was a gradual decline in the survival and feeding of predatory mites when exposed to all insecticides. Spinetoram had the highest impact on the survival and feeding of all predators compared to other insecticides, while C. javanica had the lowest impact. Cyantraniliprole and azadirachtin + pyrethrin significantly reduced predator survival after 72h of exposure, whereas capsicum, garlic, and canola oil extracts caused a similar reduction after 96h. All predators consumed low proportions of S. dorsalis across all treatments. Oviposition was low in all treatments, with no discernable variation among treatments. These results highlight the potential of using entomopathogenic fungi in conjunction with A. swirskii, N. cucumeris, and N. californicus for the management of S. dorsalis and T. urticae in strawberries.

The impact of different photoperiod regimes on vital life traits of Amblyseius swirskii and Neoseiulus cucumeris (Acari: Phytoseiidae).

Environmental factors, such as photoperiod can play an important role in the development and performance of predatory mites. The influence of five photoperiod regimes (0: 24, 8: 16, 12: 12, 16: 8, and 24: 0h; Light: Dark) on the population parameters of the predatory mites, Amblyseius swirskii Athias-Henriot and Neoseiulus cucumeris (Oudemans) was studied under the laboratory conditions at 25°C and 25 ± 1°C, 65 ± 5% RH. Regarding A. swirskii, the longest and shortest total pre-adult and total preoviposition periods (TPOP) were in the photoperiod of 12L:12D and 16L:8D, respectively. The oviposition days, adult longevity, total life span, fecundity, gross reproductive rate (GRR), and net reproductive rate (R0) of the predator had no significant difference in all photoperiods tested. The intrinsic rate of increase (r) and the finite rate of increase (λ) in 16L:8D photoperiod had no significant difference with the other photoperiods tested except 12L:12D. Regarding N. cucumeris, the shortest total pre-adult and TPOP were in full darkness. The oviposition days and fecundity were significantly higher in 16L:8D than the others. The value of R0 in 16L:8D was significantly higher than 8L:16D. The highest values of the parameters r and λ were observed in full darkness, which had no significant difference with 16L:8D and 24L:0D. According to the results, the photoperiod regime had a more significant influence in terms of development and reproduction on N. cucumeris than A. swirskii, and 16:8 (L: D) h photoperiod was recognized as the proper regime for their rearing.

The potential application of Czenspinskia transversostriata in biological control.

Phytoseiid predatory mites are one of the most important groups of biocontrol agents, commonly used in biological control. The ability to produce these predatory mites economically, at high density on cheap factitious food sources, is a major contributor to their success. Astigmatid mites are the most widely used factitious food for this purpose. In this study, we investigated the potential application of the leaf-dwelling astigmatid mite Czenspinskia transversostriata (Oudemans) (Acari: Winterschmidtiidae) as a prey mite in biological control. We tested whether C. transversostriata is a suitable food source for the predatory mite Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae), both in the laboratory and on cucumber plants. Based on a reproduction trial, C. transversostriata proved to be an equally good food source compared to both pollen of Typha angustifolia L. (Poales: Typhaceae) and a frequently used prey mite Carpoglyphus lactis L. (Acari: Carpoglyphidae). In a pre-establishment trial on cucumber plants, populations of A. swirskii reached equally high densities when supplemented with C. transversostriata, compared to C. lactis. Lastly, we show that C. transversostriata is capable of feeding and reproducing on powdery mildew growing on cucumber plants, thereby slowing down the development of the pathogenic fungus. Results derived from this study show that C. transversostriata may have multiple potential applications in biological control programs.

Field efficacy of a biopesticide and a predatory mite for suppression of Scirtothrips dorsalis (Thysanoptera: Thripidae) in strawberry.

Chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) has emerged as a severe invasive pest of strawberry Fragaria × ananassa Duchesne in the United States. The objective of this study was to assess the field efficacy of a biopesticide and thrips predator, Amblyseius swirskii Athias-Henriot for S. dorsalis management in field grown strawberry compared to synthetic insecticide applications that are current industry standard (spinetoram) conducted at UF/IFAS GCREC, FL during 2021-2022 and 2022-2023 in a 2-year field study. The following treatments were applied in the field: (1) biopesticide, capsicum oleoresin extract + garlic oil + canola oil application at maximum label rate; (2) predatory mite of thrips, A. swirskii released at 30 predators per plot; (3) spinetoram applied at maximum label rate; and (4) biopesticide applied 24 h before release of A. swirskii. A control plot with no insecticide or predatory mite releases was maintained. Results show that the capsicum extract can be used for management of S. dorsalis, especially during the latter stages of strawberry field season when resistance to spinetoram is high. The field performance of A. swirskii was variable and extensive research is needed to highlight factors affecting field performance of predatory mites for thrips management.

Sublethal effects of a spiromesifen and abamectin combination on Tetranychus urticae (Acari: Tetranychidae) and its predators Phytoseiulus persimilis and Amblyseius swirskii (Acari: Phytoseiiidae).

The two-spotted spider mite, Tetranychus urticae Koch (TSSM), is an important cosmopolitan pest of agricultural crops that is often managed in greenhouses by augmentation of predatory mites in combination with acaricides. Here we examined the transgenerational effects of low lethal concentrations of a widely-used acaricide, Oberon Speed® (a combination of spiromesifen and abamectin), on the life history traits and population growth of T. urticae and two of its predators, Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). The concentrations employed corresponded to the LC10, LC20 and LC30 values estimated for TSSM protonymphs 48h post-exposure in a topical bioassay, which yielded an LC50 value of 207.2ppm. Parental exposure of TSSM to all three low concentrations increased the total developmental time of progeny; both the LC20 and LC30 treatments reduced adult longevity and number of oviposition days, but only the LC30 treatment increased the preoviposition period. Similarly, both the LC20 and LC30 treatments significantly reduced life table parameters (r, R0, λ, and GRR), and increased generation time (T) and population doubling time (DT). Although maternal exposure to the acaricide had various impacts on progeny life history, A. swirskii was less affected than P. persimilis, suggesting the former species would be more compatible for integration with Oberon Speed® for control of T. urticae in greenhouse vegetable production.

Life table parameters of Amblyseius largoensis, Amblyseius swirskii and Proprioseiopsis lenis (Acari: Phytoseiidae) fed on eggs and larvae of Frankliniella occidentalis.

The immature development and reproduction of the predatory mites Amblyseius largoensis (Muma), Proprioseiopsis lenis (Corpuz and Rimando), and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) were investigated using both thrips eggs and first instars of the western flower thrips, Frankliniella occidentalis Pergande, as prey in a controlled laboratory environment at 25°C and 60% relative humidity. When provided with thrips eggs as food, A. largoensis exhibited a notably shorter immature development period for both males (7.05 days) and females (6.51 days) as compared with A. swirskii (8.05 and 7.19 days, respectively) and P. lenis (8.10 days and 7.05 days, respectively). Amblyseius largoensis also displayed a higher oviposition rate (2.19 eggs/female/day) than A. swirskii and P. lenis (1.79 and 1.78 eggs/female/day, respectively). Moreover, it exhibited the highest fecundity (25.34 eggs/female), followed by P. lenis (24.23 eggs/female) and A. swirskii (22.86 eggs/female). These variations led to A. largoensis having the highest intrinsic rate of increase (rm) at 0.209, followed by A. swirskii at 0.188, and P. lenis at 0.165. However, when the predatory mites were provided with first instars of F. occidentalis, A. swirskii demonstrated a faster immature development period for both males (7.67 days) and females (7.59 days) as compared with P. lenis (9.00 days and 7.86 days, respectively) and A. largoensis (8.47 days and 8.61 days, respectively). While the oviposition rates of P. lenis (1.92 eggs/female/day) and A. swirskii (1.90 eggs/female/day) were similar when feeding on this prey, A. largoensis produced fewer eggs (1.83 eggs/female/day). Further, A. swirskii exhibited the highest fecundity (31.93 eggs/female), followed by A. largoensis (25.71 eggs/female) and P. lenis (23 eggs/female). Consequently, the intrinsic rate of increase (rm) on thrips first instars was highest in A. swirskii (0.190), followed by A. largoensis (0.186), and P. lenis (0.176). In summary, our findings indicate that in terms of life history parameters A. largoensis performs optimally when feeding on thrips eggs, whereas A. swirskii performs best when preying on the mobile first instars of the thrips. These insights into the dietary preferences and reproductive capabilities of the studied predatory mite species have important implications for their potential use as biological control agents against F. occidentalis in agricultural settings.

Side Effects of Some Insecticides and Acaricides on Different Beneficial Insects in Laboratory Conditions

Side effects studies are important for the development of Integrated Pest Management (IPM) strategies, especially due to the adverse impacts of broad-spectrum pesticides on natural enemies. This study was conducted to evaluate the side effects of commonly used pesticides on Chilocorus bipustulatus L. (Coleoptera: Coccinellidae), Anagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae), and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) under laboratory conditions. The results revealed varying mortality rates among the natural enemies, with Abamectin exhibiting the highest mortality rates of 65.00%, 71.50%, and 78.75% respectively. Spirodiclofen (S1) showed the lowest mortality rate of 17.50% for C. bipustulatus, while Buprofezin (B) and Spirodiclofen (S2) showed rates of 18.78% and 18.93%, respectively for A. pseudococci. For A. swirskii, Spirodiclofen (S1 and S2) recorded the lowest mortality rates of 21.25% and 23.75% respectively. According to the IOBC classification, Spirodiclofen (S1 and S2) was classified as harmless (N,) against all three natural enemies. Abamectin (A) was classified as slightly harmful (M) for all three species, while Buprofezin was rated as slightly harmful (M) for C. bipustulatus but harmless (N,) for A. pseudococci and A. swirskii. This research highlights the differential effects of pesticides on different natural enemies and underlines the importance of considering such impacts in pest management strategies.

Are predatory mites effective as biological control agents to suppress Oligonychus ilicis (Acari: Tetranychidae) in blueberry plantings?

Southern red mite, Oligonychus ilicis McGregor (Acari: Tetranychidae), is an important polyphagous spider mite pest that causes economic damage to many ornamentals, coffee, and fruit crops. Blueberry growers in the Southeastern United States, including Florida and Georgia, have experienced severe losses due to outbreaks of O. ilicis. Predatory mites are an important management tool used for controlling spider mites; however, predators have not been studied and successfully evaluated in blueberry systems. Amblyseius swirskii Athias-Henriot, Phytoseiulus persimilis Athias-Henriot, and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) are among the most economically important arthropod agents used in augmentative biological control worldwide. To evaluate the potential of these 3 commercially available predatory mites for use in blueberry plantings, we conducted experiments under controlled laboratory conditions and in the greenhouse. In preliminary laboratory experiments, P. persimilis and N. californicus significantly reduced the number of O. ilicis motile stages below those found in the untreated control, indicating the potential for these 2 predatory mite species to suppress O. ilicis populations. Amblyseius swirskii did not perform well controlling O. ilicis motiles in the laboratory. Under greenhouse conditions, N. californicus and P. persimilis significantly reduced the number of eggs after 7 days of release and the number of motile stages after 14 days of release. This is the first report of using phytoseiid mites to suppress O. ilicis in blueberry systems in the United States. Further studies on predator behavior, feeding preferences, and acaricide compatibility with predators are required to investigate the possibility of using P. persimilis, and N. californicus as biological control agents of O. ilicis in blueberry systems.

Rearing Neoseiulus cucumeris and Amblyseius swirskii (Mesostigmata: Phytoseiidae) on non-target species reduces their predation efficacy on target species

Abstract In Florida, strawberries are prone to infestation by Tetranychus urticae Koch (twospotted spider mite; Trombidiformes: Tetranychidae) and Scirtothrips dorsalis Hood (chilli thrips; Thysanoptera: Thripidae). Management of these pests using conventional insecticides is becoming difficult, thereby forcing many growers to adopt the use of commercially available biological control agents including Neoseiulus cucumeris Oudemans and Amblyseius swirskii Athias-Henriot (both Mesostigmata: Phytoseiidae). These predators are mass reared on prey different from T. urticae, and their prey switching capacity is unknown. Therefore, the objective of this study was to compare the predation capacity of A. swirskii and N. cucumeris feeding on familiar and unfamiliar prey. Thus, using T. urticae as a non-familiar prey model organism, a no choice test was conducted where A. swirskii and N. cucumeris were each provided with Acarus spp. (commonly used as prey for commercial rearing of predatory mites) as familiar prey and eggs, deutonymphs, and adult females of T. urticae as unfamiliar prey. Prey consumption was recorded at 12, 24, 36 and 48 h. Our results show that both A. swirskii and N. cucumeris exhibited higher prey consumption when prey was familiar (Acarus spp.) compared to unfamiliar prey. Additionally, both predators showed higher consumption of eggs compared to T. urticae nymphs and adults. In 12 h, both predators had consumed 50 % of eggs, however, 36–48 h were required for 50 % of the T. urticae adults and nymphs to be consumed. Therefore, strawberry growers utilizing these predatory mites ought to refrain from the use of insecticides known to be detrimental to predatory mites for a period of at least 48 h to allow the predators to adjust to the new prey and environment.

Integration of the Generalist Predator Nabis americoferus (Hemiptera: Nabidae) in a Greenhouse Strawberry Biocontrol Program with Phytoseiid Predatory Mites and the Entomopathogenic Fungus Beauveria bassiana.

In strawberry production, western flower thrips (WFT) and two-spotted spider mites (TSSM) inflict feeding damage and reduce the yield. Biological control for these pests often includes phytoseiid predatory mites and entomopathogenic fungi. The hemipteran family Nabidae have been reported as prominent predators in open-field strawberry. Nabis americoferus Carayon is a new biocontrol agent developed in Canada. This study examined if this species was a good candidate for integration with biological control for greenhouse strawberry production. The laboratory trials showed that Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot were compatible with N. americoferus, especially when alternative food was available. In contrast, the nabid was not compatible with the Beauveria bassiana (Balsamo) GHA strain. A greenhouse cage study was conducted to determine if it was beneficial to add N. americoferus to the phytoseiid-mites-based biological control program for WFT and TSSM in greenhouse strawberry. The release of N. americoferus on a banker plant together with the placement of sachets of Neoseiulus cucumeris (Oudemans) and Neoseiulus californicus (McGregor) was beneficial, not only potentially reducing the number of sachet applications, but also providing better pest control than phytoseiid mites alone. Neither the phytoseiids nor the N. americoferus numbers were significantly affected by the presence of each other.

Effect of nine pesticides against the date palm mite, Oligonychus afrasiaticus (Acari: Tetranychidae) and the predatory mite, Amblyseius swirskii (Acari: Phytoseiidae) under laboratory and field conditions.

Date palm trees, their cultivation and harvesting have become challenging due to infestations caused by some specific mites including Oligonychus afrasiaticus (McGregor) (Tetranychidae). Current research has been carried out to investigate the efficiency of nine pesticides against eggs and date palm mite, Oligonychus afrasiaticus against nine pesticides. Side effects of the nine pesticides were also examined on predatory mite, Amblyseius swirskii Athias-Henriot (Phytoseiidae). Mites and their eggs were treated with the recommended dosage of nine pesticides namely, Bifenazate 24%, Bifenthrin 10%, Matrine 0.6%, Imidacloprid 37% + Abamectin 3%, Sulphur 99.5%, Micronized Sulphur 80%, Mineral oil 95%, Pyrethrin 1.5% and Hexythiazox 10%, while they were present in their natural environment on the date palm trees in the experimental fields. Highest mortality of 91.16% was observed when O. afrasiaticus was treated with Bifenazate (24%) followed by 87.31%, 85.20%, 72.06%, 71.34%, 65.35%, 64.14%, 61.06% and 24.25% in case of Bifenthrin 10%, Matrine 0.6%, Imidacloprid 37% + Abamectin 3%, Sulphur 99.5%, Micronized Sulphur 80%, Mineral oil 95%, Pyrethrin 1.5%, and Hexythiazox 10%, respectively. A minimum hatching of 25.74% was observed when eggs of O. afrasiaticus were treated with Hexythiazox 10% and the highest success of hatching (99.07%) was seen when treatment was given with Imidacloprid 37% + Abamectin 3%. When same trials with same nine pesticides were performed on predatory mite; Amblyseius swirskii, the highest mortality in terms of percentage reduction (75.63%) was observed with Bifenthrin and the lowest (14.69%) with Matrine. Nine pesticides used in this study have distinct toxicity against targeted mite, their eggs and the predatory mite. A two steps control strategy is recommended for this treatment. First spray Hexythiazox at the egg laying stage and then at the moving stage of mites by using Matrine which is toxic to mites but negligibly toxic to predatory mites. Further studies are recommended to evaluate varied actions of the pesticide against eggs, phytophagous mites, and predatory mites.

Field evaluation of the efficacy of copper nanoparticles against mites associated with orange trees.

Phytophagous mites are dangerous pests, causing economic losses to the world's crops. Nanotechnology is a promising field for pests and disease management, and enhancement of agricultural productivity. The aim of the study was to evaluation of the effectiveness of copper nanoparticles (CuNP) against all stages of eriophyid mite, the citrus rust mite, Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) and tetranychid mite, the citrus brown mite Eutetranychus orientalis (Klein) (Acari: Tetranychidae), and Tenuipalpid mite, the false spider mite, Brevipalpus obovatus Donnadieu (Acari: Tenuipalpidae). This includes its impacts on predacious mites, Amblyseius swirskii Athias-Henriot and Euseius scutalis (Athias-Henriot) (Acari: Phytoseiidae), on orange trees under field conditions. Five different concentrations of copper nanoparticles (40, 80, 160, 240, and 320 ppm), as well as the control (well water) were examined. The obtained results indicated that the mortality rate of both phytophagous and predacious mites was associated with an increase in the concentrations of copper nanoparticles. Copper nanoparticles were significantly effective in killing P. oleivora, E. orientalis and B. obovatus with minimal effects on A. swirskii and E. scutalis. The mortality percentage was 15.24, 20.32, 46.32, 78.97 and 86.37% for P. oleivora, 6.87, 9.86, 28.91, 56.30 and 77.52% for E. orientalis and 8.38, 23.50, 48.83, 68.80 and 84.08% for B. obovatus while the mortality percentage was 0.00, 0.56, 5.83, 9.91 and 15.19% for A. swirskii and 0.44, 3.96, 6.93, 8.63 and 21.39% for E. scutalis one week after exposure to 40, 80, 160, 240 and 320 ppm of copper nanoparticles, respectively. Moreover, the results showed that copper nanoparticles caused a reduction in the percentage of eggs hatching. The percentages of larvae hatching from eggs were 96.29, 80.00, 64.13, 45.66 and 32.17% for P. oleivora, 97.38, 83.28, 69.41, 48.01 and 35.29 for E. orientalis and 96.60, 76.92, 56.38, 40.55 and 33.28% for B. obovatus one week after exposure to copper nanoparticles at 40, 80, 160, 240 and 320 ppm respectively, compared with the control (well water). According to the results, the use of copper nanoparticles significant effect on reducing the population of phytophagous mites associated with orange trees, with low detrimental effects on predatory mites.

Biological aspects and life-tables of the predatory mites, Amblyseius swirskii Athias-Henriot and Neoseiulus californicus (McGregor), reared on four types of food

Biological aspects and life-tables of the predatory mites, Amblyseius swirskii Athias-Henriot and Neoseiulus californicus (McGregor), reared on four types of food

Bird-of-paradise, thorn apple and maize pollens are promising alternative diets for the long-term rearing of predatory mite Amblyseius swirskii (Acari: Phytoseiidae)

Pollen grains can provide important nutrients for reproduction of different predators such as phytoseiid mites. Since mass rearing of phytoseiid predatory mites may be facilitated by feeding on alternative diets, the current study evaluated the utility of plant pollen as diet for mass rearing of the predatory mite Amblyseius swirskii Athias-Henriot, which is a commercially available biocontrol agent of phytophagous mites and insects. Demographic parameters of A. swirskii fed on pollens of bird-of-paradise (Caesalpinia gilliesii), thorn apple (Datura stramonium), and maize (Zea mays) were determined over 10 continuous generations. In addition, the pollens of common hibiscus (Hibiscus syriacus), and velvetleaf (Abutilon theophrasti) were assessed, but the predatory mite was unable to reach adulthood when fed on these pollens, and most of them died in nymphal stages. This study also evaluated the preying ability of A. swirskii on the natural prey Tetranychus urticae Koch before and after 10 generations. All experiments were conducted in the laboratory under controlled conditions of 25±1°C, 60±5% RH, and a photoperiod of 16:8 (L: D) h. According to the life table parameters, the pollen grains of bird-of-paradise, followed by maize and thorn apple, were shown to be promising diets for the long-term rearing of A. swirskii. Furthermore, the study found that A. swirskii reared on bird-of-paradise pollen had a high predation capability, with a mean of 677 prey per generation after 10 generations. Overall, it is concluded that while bird-of-paradise pollen was the most suitable alternative diet for the predatory mite, both maize and thorn apple pollen grains were also found to be promising diets for A. swirskii. These diets can be used for mass rearing of this predatory mite.

Effects of botanical acaricides on Tetranychus urticae and compatibility with the predatory mite Amblyseius swirskii

The evaluation of biorrational products to control the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is of primary importance in the agriculture sector. In this study, we evaluated the effects of commercial botanical acaricides (BAs) on T. urticae and its predatory mite Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). In the laboratory, T. urticae was exposed to acaricide-immersed leaves and A. swirskii to acaricide-coated glass vials. In the greenhouse, potted eggplants infested with mites were sprayed with different BAs. In the laboratory, Zea mays oil-based and Glycine max oil-based BAs caused more than 95% and 80% mortality of adults after 48 h of application and caused also 100% mortality of eggs. Residual exposure of A. swirskii adults to the BAs caused 45–60% mortality. In the greenhouse, these BAs caused more than 50% decrease in the population of T. urticae for 21 d.

Influence of sub-lethal exposure to Rosmarinus officinalis L. (Lamiaceae) essential oil on demographic parameters of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiideae)

ABSTRACT In this study, the side effects of LC30 and LC50 concentrations of Rosmarinus officinalis L. (Lamiaceae) essential oil on the life table parameters of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) fed on first instar Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) larvae were determined under lab conditions. The age-stage, two-sex life table method was used to evaluate the life table parameters. The net reproductive rate (R0) (8.76, 8.68 and 6.83 eggs per individual), intrinsic rate of increase (r) (0.116, 0.116 and 0.098 day −1), finite rate of increase (λ) (1.123, 1.123 and 1.103 day −1), mean generation time (T) (18.7, 18.6 and 19.6 days) and total fecundity (19.77, 19.00, and 17.70 offspring per female) acquired for control, LC30 and LC50 applications, respectively. The findings of this study indicate that using the tested essential oil, particularly the LC30, in combination with A. swirskii can be an alternative to synthetic pesticides. However, semi-field and field studies are still needed to assess the effects of the essential oil tested on F. occidentalis and A. swirskii before incorporating into integrated pest management (IPM) strategies.

Modeling linear and nonlinear relationship between temperature and development rate of Amblyseuis swirskii (Acari: Phytoseiidae)

In recent years, the utilization of biocontrol agents to administer agriculture pests has received more attention, which has conduce to an growth in companies generating biocontrol agents, including predators and parasitoids. Amblyseius swirskii Athias-Henriot as a part of predatory communities in greenhouses is currently used worldwide as a biocontrol agent against small insects and various mites, especially to suppress the population of the two-spotted spider mite (TSSM), Tetranychus urticae Koch. To improve mass rearing of A. swirskii and optimize its application in integrated pest management programs, its development rate was determined at seven constant temperatures ranging from 15 to 34 (±1)°C, 50±10% RH and a photoperiod of 16:8 (L:D) h under laboratory conditions. None of the eggs hatched at 34°C and no development was observed. To determine the lower temperature threshold (T0) and thermal constant (K) of different stages of the predator, two linear models (ordinary and Ikemoto) were used. In addition, 26 nonlinear models were fitted to evaluate the development rate at different temperatures. The lower temperature threshold (T0) and thermal constant (K) of total immature stages were estimated by the ordinary (3.72°C and 133.22 DD) and Ikemoto (10.64°C and 86.51DD) linear models. Based on the Akaike information criterion (AIC), the best model for the description of the temperature-dependent development rate of the egg, larval, protonymphal, and dutonymphal stages was the Ratkowsky model and for the whole pre-adult stage, it was the Logan-6 model. Our results provided a detailed evaluation of the thermal requirements of A. swirskii, which can be important in improving the role of this mite in biological control programs.

Is UV-C light compatible with biological control of twospotted spider mite?

Biological control agents such as predatory mites, Neoseiulus cucumeris Oudemans, Amblyseius swirskii Athias-Henriot, and Phytoseiulus persimilis Athias-Henriot are effective in the management of a cosmopolitan crop pest, Tetranychus urticae Koch. Studies have shown that physical control by ultraviolet B (UV-B, 280–315 nm) light applications can control T. urticae by reducing egg hatch. However, to have a successful biological control program, the compatibility with other crop management strategies such as use of UV light needs to be determined. Therefore, the objectives of this study were to, 1) assess the impact of UV-C (200–280 nm) application on egg hatchability of biological control agents, A. swirskii, N. cucumeris, P. persimilis, and the pest T. urticae; 2) assess the impact of UV-C application on feeding efficiency of P. persimilis on T. urticae eggs; and 3) determine the LD50 and LD90 of adult female T. urticae to UV-C exposure. Results indicate that more eggs of A. swirskii survived when 200 J/m2 UV-C was used to control T. urticae, which suffered higher egg loss from the same UV-C dose. Also, UV-C treatments of 200 and 350 J/m2 did not have a significant impact on predation by P. persimilis adult females on T. urticae eggs. Therefore, UV-C can be compatibly utilized along with biological control of T. urticae by timing the application before release of predators. After 24 h of application, the UV-C LD50 for T. urticae adults was 8,839.35 J/m2 and the LD90 was 12,352.91 J/m2. After 48 h of application, the LD50 was 7,449.81 J/m2 and the LD90 was 9,621.83 J/m2. These UV-C doses are not feasible for T. urticae adult suppression, but biological control agents can play a crucial role with effective predation on T. urticae adults.

The toxic effects of some acaricides on the tomato russet mite and its predator Amblyseius swirskii Athias-Henriot, 1962 (Acari: Phytoseiidae)

The tomato russet mite, Aculops lycopersici (Massee, 1937) (Acari: Eriophyidae) is a common pest of tomatoes. The predatory mite, Amblyseius swirskii Athias-Henriot, 1962 (Acari: Phytoseiidae), can control A. lycopersici populations. To integrate biological and chemical control of A. lycopersici, side effects of the lethal concentrations of acaricides, as a predator, on A. swirskii should be considered. The lethal concentrations of 14 acaricides for A. lycopersici were determined under laboratory conditions at Bursa Uludağ University during 2017-2018. To understand the toxic impacts of the acaricides on juveniles and females of A. swirskii, the LC99 values for A. lycopersici of each acaricide were applied to A. swirskii. The reproduction reduction effects of the LC99 values were also assessed. Quite low concentrations of abamectin, milbemectin, pyridaben, azadirachtin and sulphur were found to be toxic for A. lycopersici. Based on the side effect scale, the LC99 values of abamectin, acequinocyl, bifenazate, fenproximate, fenbutatin oxide, hexythiazox, milbemectin and sulphur that killed A. lycopersici were found to be slightly toxic to both females and juveniles of A. swirskii. The results of this comparative toxicological study have showed that more field studies should be conducted to evaluate the effectiveness of using low concentrations of acaricides with A. swirskii in combination for controlling A. lycopersici.