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Paulina Bermudez Ortiz - One of the best experts on this subject based on the ideXlab platform.

  • toxicity of thiamethoxam to tetranychus urticae koch and Phytoseiulus persimilis athias henriot acari tetranychidae phytoseiidae through different routes of exposure
    Pest Management Science, 2011
    Co-Authors: Alberto Pozzebon, Carlo Duso, Paola Tirello, Paulina Bermudez Ortiz
    Abstract:

    BACKGROUND: Knowledge of the impact of insecticides on Tetranychus urticae Koch and its predator Phytoseiulus persimilis Athias-Henriot is crucial for IPM. This study evaluates the effect of thiamethoxam on T. urticae and its predator by considering different routes of exposure (topical, residual and contaminated food exposures) and their combinations. RESULTS: Thiamethoxam effects on T. urticae were higher when residual and contaminated food exposures were considered. The total effect was higher than 90% where contaminated food exposure was involved. On P. persimilis, the total effect was higher in residual and contaminated prey exposures compared with topical exposure, and all combinations of routes of exposure attained a total effect higher than 90%. CONCLUSION: Thiamethoxam was found to be toxic to T. urticae and P. persimilis; however, the impact of the insecticide depended on the routes of exposure and their combinations. Lethal and sublethal effects occurred in residual and contaminated food exposures, while only sublethal effects occurred in topical exposure of predators and prey. The toxicity of thiamethoxam on prey and predator increased with the number of exposure routes involved. By limiting exposure to thiamethoxam to ingestion of contaminated food only, the impact of the pesticide was more favourable to P. persimilis than to its prey. Copyright © 2010 Society of Chemical Industry

Marcel Dicke - One of the best experts on this subject based on the ideXlab platform.

  • Maternal effect determines drought resistance of eggs in the predatory mite Phytoseiulus persimilis
    Oecologia, 2020
    Co-Authors: Sophie Le Hesran, Thomas Groot, Markus Knapp, Jovano Erris Nugroho, Giuditta Beretta, Tibor Bukovinszky, Marcel Dicke
    Abstract:

    The ability of an organism to adapt to short-term environmental changes within its lifetime is of fundamental importance. This adaptation may occur through phenotypic plasticity. Insects and mites, in particular, are sensitive to changes in temperature and humidity, especially during the juvenile stages. We studied the role of phenotypic plasticity in the adaptation of eggs to different relative humidity conditions, in the predatory mite Phytoseiulus persimilis , used worldwide as a biological control agent of the spider mite Tetranychus urticae . The biocontrol efficacy of P. persimilis decreases under dry conditions, partly because P. persimilis eggs are sensitive to drought. We exposed P. persimilis adult females from two different strains to constant and variable humidity regimes and evaluated the hatching rate of their eggs in dry conditions, as well as the survival and oviposition rates of these females. Whereas the eggs laid by P. persimilis females exposed to constant high humidity did not survive in dry conditions, females exposed to constant low humidity started laying drought-resistant eggs after 24 h of exposure. Survival and oviposition rates of the females were affected by humidity: females laid fewer eggs under constant low humidity and had a shorter lifespan under constant high and constant low humidity. The humidity regimes tested had similar effects across the two P. persimilis strains. Our results demonstrate that transgenerational phenotypic plasticity, called maternal effect, allows P. persimilis females to prepare their offspring for dry conditions.

  • Proximate mechanisms of drought resistance in Phytoseiulus persimilis eggs
    Experimental and Applied Acarology, 2019
    Co-Authors: Sophie Le Hesran, Thomas Groot, Markus Knapp, Jovano Erris Nugroho, Giuditta Beretta, Luis Francisco Salomé-abarca, Young Hae Choi, Marie Vancová, Antonio M. Moreno-rodenas, Marcel Dicke
    Abstract:

    Under drought stress, Phytoseiulus persimilis females are able to lay drought-resistant eggs through an adaptive maternal effect. The mechanisms making these eggs drought resistant still remain to be investigated. For this purpose, we studied the physiological differences between drought-resistant and drought-sensitive eggs. We compared the volume and the surface-area-to-volume ratio (SA:V) of the eggs, their sex ratio, their chemical composition (by gas chromatography-mass spectrometry), their internal and external structure [by scanning electron microscope (SEM) and transmission electron microscope (TEM) images], and their developmental time. Our results show that drought-resistant and drought-sensitive eggs have a different chemical composition: drought-resistant eggs contain more compatible solutes (free amino acids and sugar alcohols) and saturated hydrocarbons than drought-sensitive eggs. This difference may contribute to reducing water loss in drought-resistant eggs. Moreover, drought-resistant eggs are on average 8.4% larger in volume, and have a 2.4% smaller SA:V than drought-sensitive eggs. This larger volume and smaller SA:V, probably the result of a higher water content, may make drought-resistant eggs less vulnerable to water loss. We did not find any difference in sex ratio, internal or external structure nor developmental time between drought-resistant and drought-sensitive eggs. These results mark the first step in the understanding of the strategies and the energetic costs involved in the production of drought-resistant eggs in P. persimilis females.

  • information use by the predatory mite Phytoseiulus persimilis acari phytoseiidae a specialised natural enemy of herbivorous spider mites
    Applied Entomology and Zoology, 2005
    Co-Authors: Jetske G De Boer, Marcel Dicke
    Abstract:

    Plants can respond to infestation by herbivores with the emission of specific herbivore-induced plant volatiles. Many carnivorous arthropods that feed on herbivorous prey use these volatiles to locate their prey. Despite the growing amount of research papers on the interactions in tritrophic systems, it has remained unclear how carnivorous arthropods use herbivore-induced plant volatiles in prey-location. We investigated three important aspects of information use by the predatory mite Phytoseiulus persimilis, a specialised natural enemy of herbivorous spider mites. First, we showed that the foraging efficiency of predatory mites was not hampered by the presence of volatiles induced by nonprey caterpillars on brussels sprouts plants. Second, we revealed an important role for the volatile compound methyl salicylate. Predatory mites appear to use the presence of this compound, rather than its relative contribution to a volatile blend, to discriminate between two volatile blends. Third, we demonstrated that the role of methyl salicylate in the foraging behaviour of P. persimilis depends on previous experiences of the predators with this compound. Our research improves the understanding of the selection pressures that act on the foraging responses of carnivorous arthropods, and consequently on the selection pressures on volatile emission by plants in response to herbivory.

  • the role of methyl salicylate in prey searching behavior of the predatory mite Phytoseiulus persimilis
    Journal of Chemical Ecology, 2004
    Co-Authors: Jetske G De Boer, Marcel Dicke
    Abstract:

    Many carnivorous arthropods use herbivore-induced plant volatiles to locate their prey. These plant volatiles are blends of up to hundreds of compounds. It is often unknown which compounds in such a complex volatile blend represent the signal to the foraging carnivore. We studied the role of methyl salicylate (MeSA) as part of the volatile blend in the foraging behavior of the predatory mite Phytoseiulus persimilis by using a Y-tube olfactometer. MeSA is one of the compounds released by lima bean, infested with Tetranychus urticae—a prey species of the predatory mite. MeSA attracted satiated predatory mites in a dose-dependent way with optimum attraction at a dose of 0.2 μg. Predatory mites did not discriminate between a prey-induced lima bean volatile blend (that contains MeSA) and a prey-induced volatile blend to which an extra amount of synthetic MeSA had been added. However, they preferred a MeSA-containing volatile blend (induced by T. urticae) to an otherwise similar but MeSA-free blend (induced by jasmonic acid). Adding synthetic MeSA to the MeSA-free blend significantly increased the mites' choice for this odor, suggesting an important role for MeSA. This study is a new step toward unraveling the role of herbivore-induced plant volatiles in the foraging behavior of predatory arthropods.

  • attraction of Phytoseiulus persimilis acari phytoseiidae towards volatiles from various tetranychus urticae infested plant species
    Bulletin of Entomological Research, 2002
    Co-Authors: C E M Van Den Boom, T A Van Beek, Marcel Dicke
    Abstract:

    Plants infested with the spider mite Tetranychus urticae Koch, may indirectly defend themselves by releasing volatiles that attract the predatory mite Phytoseiulus persimilis Athias-Henriot. Several plants from different plant families that varied in the level of spider mite acceptance were tested in an olfactometer. The predatory mites were significantly attracted to the spider mite-infested leaves of all test plant species. No differences in attractiveness of the infested plant leaves were found for predatory mites reared on spider mites on the different test plants or on lima bean. Thus, experience with the spider mite-induced plant volatiles did not affect the predatory mites. Jasmonic acid was applied to ginkgo leaves to induce a mimic of a spider mite-induced volatile blend, because the spider mites did not survive when incubated on ginkgo. The volatile blend induced in ginkgo by jasmonic acid was slightly attractive to predatory mites. Plants with a high degree of direct defence were thought to invest less in indirect defence than plants with a low degree of direct defence. However, plants that had a strong direct defence such as ginkgo and sweet pepper, did emit induced volatiles that attracted the predatory mite. This indicates that a combination of direct and indirect defence is to some extent compatible in plant species.

Maurice W Sabelis - One of the best experts on this subject based on the ideXlab platform.

  • The Predatory Mite Phytoseiulus persimilis Does Not Perceive Odor Mixtures As Strictly Elemental Objects
    Journal of Chemical Ecology, 2010
    Co-Authors: Michiel Wijk, Paulien J. A. Bruijn, Maurice W Sabelis
    Abstract:

    Phytoseiulus persimilis is a predatory mite that in absence of vision relies on the detection of herbivore-induced plant odors to locate its prey, the two-spotted spider-mite Tetranychus urticae. This herbivorous prey is feeding on leaves of a wide variety of plant species in different families. The predatory mites respond to numerous structurally different compounds. However, typical spider-mite induced plant compounds do not attract more predatory mites than plant compounds not associated with prey. Because the mites are sensitive to many compounds, components of odor mixtures may affect each other’s perception. Although the response to pure compounds has been well documented, little is known how interactions among compounds affect the response to odor mixtures. We assessed the relation between the mites’ responses elicited by simple mixtures of two compounds and by the single components of these mixtures. The preference for the mixture was compared to predictions under three conceptual models, each based on one of the following assumptions: (1) the responses elicited by each of the individual components can be added to each other; (2) they can be averaged; or (3) one response overshadows the other. The observed response differed significantly from the response predicted under the additive response, average response, and overshadowing response model in 52, 36, and 32% of the experimental tests, respectively. Moreover, the behavioral responses elicited by individual compounds and their binary mixtures were determined as a function of the odor concentration. The relative contribution of each component to the behavioral response elicited by the mixture varied with the odor concentration, even though the ratio of both compounds in the mixture was kept constant. Our experiments revealed that compounds that elicited no response had an effect on the response elicited by binary mixtures that they were part of. The results are not consistent with the hypothesis that P. persimilis perceives odor mixtures as a collection of strictly elemental objects. They suggest that odor mixtures rather are perceived as one synthetic whole.

  • Morphology of the olfactory system in the predatory mite Phytoseiulus persimilis.
    Experimental & applied acarology, 2006
    Co-Authors: Michiel Van Wijk, Wytse J Wadman, Maurice W Sabelis
    Abstract:

    The predatory mite Phytoseiulus persimilis locates its prey, the two-spotted spider mite, by means of herbivore-induced plant volatiles. The olfactory response to this quantitatively and qualitatively variable source of information is particularly well documented. The mites perform this task with a peripheral olfactory system that consists of just five putative olfactory sensilla that reside in a dorsal field at the tip of their first pair of legs. The receptor cells innervate a glomerular olfactory lobe just ventral of the first pedal ganglion. We have made a 3D reconstruction of the caudal half of the olfactory lobe in adult females. The glomerular organization as well as the glomerular innervation appears conserved across different individuals. The adult females have, by approximation, a 1:1 ratio of olfactory receptor cells to olfactory glomeruli.

  • intraguild interactions between the predatory mites neoseiulus californicus and Phytoseiulus persimilis
    Experimental and Applied Acarology, 2006
    Co-Authors: Ibrahim Cakmak, Arne Janssen, Maurice W Sabelis
    Abstract:

    Species at the same trophic level may interact through competition for food, but can also interact through intraguild predation. Intraguild predation is widespread at the second and third trophic level and the effects may cascade down to the plant level. The effects of intraguild predation can be modified by antipredator behaviour in the intraguild prey. We studied intraguild predation and antipredator behaviour in two species of predatory mite, Neoseiulus californicus and Phytoseiulus persimilis, which are both used for control of the two-spotted spider mite in greenhouse and outdoor crops. Using a Y-tube olfactometer, we assessed in particular whether each of the two predators avoids odours emanating from prey patches occupied by the heterospecific predator. Furthermore, we measured the occurrence and rate of intraguild predation of different developmental stages of P. persimilis and N. californicus on bean leaves in absence or in presence of the shared prey. Neither of the two predator species avoided prey patches with the heterospecific competitor, both when inexperienced with the other predator and when experienced with prey patches occupied by the heterospecific predator. Intraguild experiments showed that N. californicus is a potential intraguild predator of P. persimilis. However, P. persimilis did not suffer much from intraguild predation as long as the shared prey was present. This is probably because N. californicus prefers to feed on two-spotted spider mites rather than on its intraguild prey.

  • absence of odour mediated avoidance of heterospecific competitors by the predatory mite Phytoseiulus persimilis
    Entomologia Experimentalis Et Applicata, 1999
    Co-Authors: Arne Janssen, Angelo Pallini, Madelaine Venzon, Maurice W Sabelis
    Abstract:

    Anthropods use odours associated with the presence of their food, enemies and competitors when searching for patches. Responses to these odours therefore determine the spatial distribution of animals, and are decisive for the occurrence and strength of interactions among species. Therefore, a logical first step in studying food web interactions is the analysis of behaviour of individuals that are searching for patches of food. We followed this approach when studying interactions in an artificial food web occurring on greenhouse cucumber in the Netherlands. In an earlier paper we found that one of the predators of the food web, the predatory mite Phytoseiulus persimilis Athias-Henriot, used to control spider mites, discriminates between odours from plants with spider mites. Tetranychus urticae Koch, and plants with spider mites plus conspecific predators. The odours used for discrimination are produced by adult prey in response to the presence of predators, and probably serve as an alarm pheromone to warn related spider mites. Other predator species may also trigger production of this alarm pheromone, which P. persimilis could use in turn to avoid plants with heterospecific predators. We therefore studied the response of the latter to odours from plants with spider mites and 3 other predator species, i.e. the generalist predatory bug Orius laevigatus (Fieber), the polyphagous thrips Frankliniella occidentalis and the spider-mite predator Neoseiulus californicus (McGregor). Both olfactometer and greenhouse release experiments yielded no evidence that P. persimilis avoids plants with any of the 3 heterospecific predators. This suggests that these predators do not elicit production of alarm pheromones in spider mites, and we argue that this is caused by a lack of coevolutionary history. The consequences of the lack of avoidance of heterospecific predators for interactions in food webs and biological control are discussed.

  • Improved control capacity of the mite predator Phytoseiulus persimilis (Acari: Phytoseiidae) on tomato
    Experimental and Applied Acarology, 1997
    Co-Authors: B. Drukker, Arne Janssen, Willem Ravensberg, Maurice W Sabelis
    Abstract:

    The predatory mite Phytoseiulus persimilis is frequently reported to perform poorly on greenhouse tomatoes. As the predators are mass-reared on another host plant (bean), we supposed that they are poorly adapted to tomato, a plant densely packed with poisonous and sticky glandular hairs. This hypothesis was tested by comparing the control capacity of a stain of P. persimilis directly obtained from a mass rearing with the same strain after four generations on tomato. Both strains were released in a tomato crop in two identical compartments of a greenhouse and the population dynamics of prey (a tomato strain of Tetranychus urticae) and predator were recorded at weekly time intervals. It was found that the strain previously exposed to a tomato environment performed better than the unexposed strain: (1) its population increased faster; (2) the prey population declined faster; and (3) the damage to new-grown tomato leaves was considerably lower. To investigate the causes of the difference in performance between the exposed and unexposed strains, oviposition and survival rates were assessed on a diet of two-spotted spider mites on tomato leaf sections. In addition, the unexposed strain was tested on a diet of two-spotted spider mites on bean leaf sections. The difference in oviposition rates of both predator strains was small compare to the overall mean. However, the oviposition rate of the first generation of predators since transfer from bean to tomato dropped to less than half of the original value. Moreover, mortality in the first generation increased from 14% to 89%, whereas it decreased to 0% after four generations. Future research should clarify whether these changes in life history are due to selection or to physiological adaptation.

Erris Nugroho Jovano - One of the best experts on this subject based on the ideXlab platform.

  • Efecto de bajas humedades relativas sobre hembras grávidas de Phytoseiulus persimilis y su puesta
    'Universitat Politecnica de Valencia', 2019
    Co-Authors: Erris Nugroho Jovano
    Abstract:

    [ES] El ácaro depredador Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) es uno de los agentes de control biológico más utilizado contra la araña Tetranychus urticae Koch (Acari: Tetranychidae). Sin embargo, su eficacia en el control de la plaga se reduce notablemente en condiciones de baja humedad ambiental, en las que la araña roja prospera. En este estudio, investigamos el efecto de bajas humedades relativas sobre el comportamiento de puesta de hembras grávidas y la tasa de supervivencia de sus huevos. En condiciones de elevada humedad (85% HR), la tasa de puesta fue 4,3 ± 0,3 huevos/día, mientras que en condiciones de baja humedad (65% HR) las hembras solo produjeron 2,5 ± 0,2 huevos/día. A pesar del escaso número de huevos puestos con humedad baja, la mayor proporción de ellos (0,89 ± 0,06) eclosionaron en condiciones de baja humedad (60% HR), al contrario de lo que ocurrió con los huevos puestos en condiciones de elevada humedad. Observamos que la mayor tasa de eclosión de estos huevos en condiciones secas era el resultado de un efecto maternal inducido por la sequedad, una alteración fenotípica. Las hembras grávidas que experimentaron stress hídrico redujeron la relación superficie:volumen (AS:V) de sus huevos y acumularon en el interior de los huevos sustancias osmoprotectoras (glicerol, mio-inositol y L-prolina), a fin de aumentar su tasa de supervivencia en condiciones de baja humedad. Esta adaptación a la sequedad está regulada por la duración del tiempo que las hembras de P. persimilis están expuestas a la baja humedad. Se discuten las implicaciones de estos resultados en el control biológico de T. urticae en condiciones de baja humedad.[EN] The predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) is one of the most widely used biocontrol agents to control two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). However, its performance in controlling this pest is severely reduced at low humidity conditions, in which T. urticae thrives. In this study we investigated the effect of low humidity conditions on the oviposition behaviour of adult gravid females and their eggs survival rate. Under high humidity conditions (85% RH), the oviposition rate was 4.3 ± 0.3 eggs/ day, while at low humidity conditions (65% RH) only 2.5 ± 0.2 eggs/ day were laid. Despite the lower number of eggs laid under low humidity, a substantial ratio (0.89 ± 0.06) of these eggs hatched at low humidity (60% RH), contrary to the eggs laid under high humidity conditions. We discovered that the higher hatching rate of these eggs under dry conditions was a result of a drought-induced maternal effect, a phenotypic alteration. Gravid females who experienced drought stress reduced their eggs surface area to volume ratio (SA:V) and accumulated osmoprotectants (glycerol, myo-inositol and L-proline) into their eggs to increase the survival rate of the eggs under low humidity conditions. This drought adaptation is tightly regulated by the length of time the P. persimilis females are exposed to low humidity. The implications of our findings on biological control of T. urticae under dry conditions are discussed.It is a great pleasure to thank PLANT HEALTH Erasmus Mundus Joint Master Degree Programme. This dissertation has been developed as a result of a mobility stay funded by the Erasmus+ - KA1 Erasmus Mundus Joint Master Degrees Programme of the European Commission under the PLANT HEALTH Project.Erris Nugroho, J. (2019). Efecto de bajas humedades relativas sobre hembras grávidas de Phytoseiulus persimilis y su puesta. http://hdl.handle.net/10251/124171TFG

  • Efecto de bajas humedades relativas sobre hembras grávidas de Phytoseiulus persimilis y su puesta
    'Universitat Politecnica de Valencia', 2019
    Co-Authors: Erris Nugroho Jovano
    Abstract:

    [ES] El ácaro depredador Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) es uno de los agentes de control biológico más utilizado contra la araña Tetranychus urticae Koch (Acari: Tetranychidae). Sin embargo, su eficacia en el control de la plaga se reduce notablemente en condiciones de baja humedad ambiental, en las que la araña roja prospera. En este estudio, investigamos el efecto de bajas humedades relativas sobre el comportamiento de puesta de hembras grávidas y la tasa de supervivencia de sus huevos. En condiciones de elevada humedad (85% HR), la tasa de puesta fue 4,3 ± 0,3 huevos/día, mientras que en condiciones de baja humedad (65% HR) las hembras solo produjeron 2,5 ± 0,2 huevos/día. A pesar del escaso número de huevos puestos con humedad baja, la mayor proporción de ellos (0,89 ± 0,06) eclosionaron en condiciones de baja humedad (60% HR), al contrario de lo que ocurrió con los huevos puestos en condiciones de elevada humedad. Observamos que la mayor tasa de eclosión de estos huevos en condiciones secas era el resultado de un efecto maternal inducido por la sequedad, una alteración fenotípica. Las hembras grávidas que experimentaron stress hídrico redujeron la relación superficie:volumen (AS:V) de sus huevos y acumularon en el interior de los huevos sustancias osmoprotectoras (glicerol, mio-inositol y L-prolina), a fin de aumentar su tasa de supervivencia en condiciones de baja humedad. Esta adaptación a la sequedad está regulada por la duración del tiempo que las hembras de P. persimilis están expuestas a la baja humedad. Se discuten las implicaciones de estos resultados en el control biológico de T. urticae en condiciones de baja humedad.[EN] The predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) is one of the most widely used biocontrol agents to control two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). However, its performance in controlling this pest is severely reduced at low humidity conditions, in which T. urticae thrives. In this study we investigated the effect of low humidity conditions on the oviposition behaviour of adult gravid females and their eggs survival rate. Under high humidity conditions (85% RH), the oviposition rate was 4.3 ± 0.3 eggs/ day, while at low humidity conditions (65% RH) only 2.5 ± 0.2 eggs/ day were laid. Despite the lower number of eggs laid under low humidity, a substantial ratio (0.89 ± 0.06) of these eggs hatched at low humidity (60% RH), contrary to the eggs laid under high humidity conditions. We discovered that the higher hatching rate of these eggs under dry conditions was a result of a drought-induced maternal effect, a phenotypic alteration. Gravid females who experienced drought stress reduced their eggs surface area to volume ratio (SA:V) and accumulated osmoprotectants (glycerol, myo-inositol and L-proline) into their eggs to increase the survival rate of the eggs under low humidity conditions. This drought adaptation is tightly regulated by the length of time the P. persimilis females are exposed to low humidity. The implications of our findings on biological control of T. urticae under dry conditions are discussed.It is a great pleasure to thank PLANT HEALTH Erasmus Mundus Joint Master Degree Programme. This dissertation has been developed as a result of a mobility stay funded by the Erasmus+ - KA1 Erasmus Mundus Joint Master Degrees Programme of the European Commission under the PLANT HEALTH Project.Erris Nugroho, J. (2019). Efecto de bajas humedades relativas sobre hembras grávidas de Phytoseiulus persimilis y su puesta. Universitat Politècnica de València. http://hdl.handle.net/10251/124171TFG

Mohammad Shaef Ullah - One of the best experts on this subject based on the ideXlab platform.

  • synergism of beauveria bassiana and Phytoseiulus persimilis in control of tetranychus urticae on bean plants
    Systematic & Applied Acarology, 2017
    Co-Authors: Mohammad Shaef Ullah, Un Taek Lim
    Abstract:

    Tetranychus urticae Koch (Acari: Tetranychidae) causes severe damage in both greenhouse and field crops. Previous studies have found that a phytoseiid predatory mite, Phytoseiulus persimilis Athias-Henriot, and an entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuillemin, are both potential candidates for the control of this pest and have shown varying degrees of success. We assessed the compatibility of these two biological control agents for control of T. urticae on potted bean plants, examining the following treatments: i) a low release rate of P. persimilis (10 prey:1 predator), ii) a high release rate of P. persimilis (5:1), iii) a single application of B. bassiana (1 × 108 spore/ml), iv) a single application of B. bassiana after application of the low release rate of P. persimilis, and v) a non-treatment control (no application of either B. bassiana or P. persimilis). A single application of B. bassiana reduced the egg and adult populations of T. urticae initially, but mite populations rebounded again after few days. Phytoseiulus persimilis at the high release rate eliminated the pest population completely, while the low release rate failed to control spider mites. The combined application of B. bassiana and low release rate of P. persimilis also successfully controlled T. urticae population (p < 0.001), with lowest corrected leaf damage (1.5%).

  • laboratory evaluation of the effect of beauveria bassiana on the predatory mite Phytoseiulus persimilis acari phytoseiidae
    Journal of Invertebrate Pathology, 2017
    Co-Authors: Mohammad Shaef Ullah, Un Taek Lim
    Abstract:

    Abstract Tetranychus urticae Koch (Acari: Tetranychidae), a major pest of many agricultural crops, is mainly controlled with chemical acaricides. However, predatory mites and entomopathogens have been proposed as alternative control agents. In this study, the effect of the BotaniGard ® GHA strain of Beauveria bassiana on the survival, longevity, fecundity, and egg hatch rate of the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) were studied under laboratory conditions. When B. bassiana was applied directly to P. persimilis eggs at a concentration of 1 × 10 8  conidia/ml, corrected hatchability was less than 5%, and the corrected mortality of nymphs and adults was not significantly different from control 10 days after treatment. Phytoseiulus persimilis nymphs that hatched from treated eggs showed no significant change in their development time, adult female longevity, hatch rate, survival rates over time, or offspring sex ratio. However, significant negative effects on fecundity and life table parameters (net reproductive rate, intrinsic rate of natural increase, mean generation time, finite rate of increase, and doubling time) were found when B. bassiana was applied to the adult stage. Spraying B. bassiana at 1 × 10 8  conidia/ml on newly emerged adults of P. persimilis caused 44% reduction in the oviposition period, 26% in adult longevity, and 63% in fecundity. Due to these negative effects, B. bassiana should be used with careful adjustment of application timing (first spray B. bassiana and then release P. persimilis ) to supplement biological mite control systems using P. persimilis .