Predators Of Spider Mites Research Articles

Evaluation of selected crops for rearing predatory mite (Phytoseiulus persimilis), a predator of two-spotted red spider mites

The damage caused by two-spotted spider mites, and the risks associated with chemical pesticides, including health and environmental risks necessitate the exploration of sustainable pest management methods. Predatory mites, such as Phytoseiulus persimilis, are effective biocontrol agents against pests like the two-spotted spider mite (Tetranychus urticae). Thus, this study aimed to evaluate the suitability of different crops for rearing predatory mites (Phytoseiulus persimilis) and assess their effectiveness in controlling two-spotted spider mites (Tetranychus urticae). Linear regression analysis showed significant effects of selected crops on mite populations across all collection times (Collection 1: F (3, 8) = 22.46, p = 0.0003; Collection 2: F (3, 8) = 11.45, p = 0.0029; and Collection 3: F (3, 8) = 9.17, p = 0.0057). ANOVA showed significant differences in mite counts among the crops (F (3, 32) = 18.06, p < 0.001), corroborated by bootstrapping analysis. Beans demonstrated the highest potential for supporting predatory mite populations, followed by eggplant and black nightshade, illustrating that crop diversification can enhance predatory mite production while suggesting adoption of Integrated pest management (IPM) strategies to reduce pesticide costs and environmental impacts. There is the need for collaborative research and policy support to drive innovation and promote sustainable pest management practices in agriculture, thus addressing pesticide-use related environmental issues.

Prey stage preference of Amblyseius paraaerialis (Acari: Phytoseiidae) on varied life stages of the spider mites Tetranychus urticae, Tetranychus macfarlanei and Oligonychus biharensis (Acari: Tetranychidae) and exploring the mass rearing possibilities of this predatory mite on alternative diets.

Spider mites Tetranychus urticae, Tetranychus macfarlanei and Oligonychus biharensis are considered to be highly polyphagous in nature and causes severe damage to a wide range of plants around the world. Amblyseius paraaerialis is an efficient phytoseiid predator of spider mites with a potential to survive on both natural and alternative diets. Evaluation of predatory potential and prey stage preference provides valuable information on the efficacy of the predatory species in controlling mite population. Feeding experiments were conducted on mulberry leaf discs under the laboratory conditions of 30 ± 2 °C and 70 ± 5% relative humidity (RH). After 24h of feeding experiment, the adult female predator exhibited a significant preference in feeding towards the eggs of T. macfarlanei (42.6%) and the larval stages of T. urticae (46%) and O. biharensis (25.3%). The mass rearing possibilities of A. paraaerialis was tested by tracking and comparing the developmental duration of individual life stages on varied food sources like, honey, castor (Ricinus communis) pollen, honey-pollen mixture and mixed life stages of T. urticae. The predator was failed to complete its development on honey and pollen when supplied separately. However it was successfully developed on honey-pollen mixture and mixed life stages of T. urticae. The developmental studies unravelled a shortest developmental duration and an extended adult longevity and lifespan of A. paraaerialis when reared on the alternative diet, thus opened up the mass rearing possibility of the predatory species under laboratory conditions.

Prospects for use of the predatory mite Transeius herbarius 1960) (Mesostigmata: sam. Phytoseiidae, subfamily. Amblyseiinae)

The predatory mite Transeius herbarius (Wainstein, 1960) isused as a specialized acariphage mainly on berry crops. In the openground, T. herbarius is one of the effective predators of strawberry(Tarsonemidae) and spider mites (Tetranychidae). The predator canpenetrate into the primordial, reproduces better in humid places, migrating2–3 meters per season. On strawberries effectively regulates the strawberrymites population and even uses proportionate female spider mites in thefood chain. The predator is amenable to breeding on loose substrate usingbarn mites of various species. High survival rate is found on industrialuterine plantings of garden strawberries in the open ground, with use ofcomplex of protective measures including insecticides. Due to the naturalsmall population of this predator in the fields, research and saturatingreleases in a normalized amount are required for optimal protection frompests.

Aspects of use and features of the predatorymite Neoseiulus longispinosus (Evans, 1952) (Mesostigmata: family Phytoseiidae, subfamily. Amblyseiinae) in comparison to N. californicus

The predatory mite Neoseiulus longispinosus (Evans, 1952) isused as a specialized acariphage on vegetable, flower and berry crops inAsia. In protected ground of European agriculture, N. californicus is one ofthe effective predators of spider mites (Tetranychidae). The periodicity ofattacks on the victim depends on the temperature. The predator prefers tohunt immature individuals of T. urticae, often ignoring adult female spidermites if there is a choice. N. longispinosus does not show preferencebetween eggs and T. urticae nymphs. However, as the density of the spidermite population increases, the predatory mite switches its diet from theeggs to its larvae and nymphs. Adult females of N. californicus exhibit atype 2 functional response to both eggs and T. urticae nymphs. Pyrethroidand avermectin substances are highly toxic to predator populations, despitelow acute toxicity of many other insecticides (Actara, Envidor, etc.).

Expression and function analyses of sex-lethal gene in Phytoseiulus persimilis

Phytoseiulus persimilis is a specialist predator of spider mites, with promising control effects. Its population generally has a stable sex ratio. Under appropriate conditions, the proportion of female offspring can reach 80%. But the mechanisms of sex determination in P. persimilis is still unclear. Sex-lethal (sxl) is an important gene in studying sex regulation mechanisms in insects. In the model organism Drosophila melanogaster, it has been proved to be a switch controlling sex determination. Herein, we screened one sex-lethal gene ortholog in the genome of P. persimilis (Ppsxl). We separated male and female offspring successfully based on the order of the egg laid, and found Ppsxl is expressed in both sexes at different stages. The expression peak was found in females 10 h after mating, and it was also highly expressed in eggs that developed into males. RNA interference was used to study the function of Ppsxl. When Ppsxl was interfered, all female individuals remained fertile. However, their cumulative fecundity decreased by 18.0%, daily fecundity decreased by 13.4%, and the proportion of female offspring decreased by 22.7%. This study showed that Ppsxl gene has a certain influence on the reproduction of P. persimilis, but its influence on sex determination may not be as critical as that in D. melanogaster. The regulation of sxl on P. persimilis was different from that in D. melanogaster.

Thermal Oviposition Performance of the Ladybird Stethorus gilvifrons Preying on Two-Spotted Spider Mites

The ladybird, Stethorus gilvifrons (Mulsant) (Coleoptera: Coccinellidae), is an important predator of two-spotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae), in southeastern Europe and western and southwestern Asia, such as Iran, India, and Turkey. To enhance forecasting the occurrence and performance of this predator in natural control and improve its usage in biological control, we evaluated and compared four non-linear oviposition models, i.e., Enkegaard, Analytis, Bieri-1, and Bieri-2. The models were validated by using data of age-specific fecundity of female S. gilvifrons at six constant temperatures (15, 20, 25, 27, 30, and 34 °C). All four models provided good fit quality to age-dependent oviposition at 15 to 30 °C (R2 0.67 to 0.94; R2adj 0.63 to 0.94) but had a poor fit at 34 °C (R2 0.33 to 0.40; R2adj 0.17 to 0.34). Within temperatures, the best performing models were Bieri-1 (R2), Bieri-2 (R2adj), and Analytis (RSS) at 15 °C, Bieri-1 at 27 °C, and Analytis at 20, 25, and 30 °C. Analytis was the best suited model across the wide temperature range tested (from 15 to 30 °C). The models presented here allow for prediction of the population dynamics of S. gilvifrons in field and greenhouse crops in temperate and subtropical climates.

Expression and function analyses of sex-lethal gene in Phytoseiulus persimilis

Phytoseiulus persimilis is a specialist predator of spider mites, with promising control effects. Its population generally has stable sex ratio. Under appropriate conditions, the proportion of female offspring can reach 80%. But the mechanism of sex determination in P. persimilis is still unclear. Sex-lethal (sxl) is an important gene in studying sex regulation mechanisms in insects. In the model organism Drosophila melanogaster, it has been proved to control sex determination and dose compensation. Herein, we screened one sex-lethal gene ortholog in the transcriptome of each stage of P. persimilis that fed with spider mites (Ppsxl). It contains three highly conservative RRM domains. The expression pattern and function of Ppsxl were analyzed using real-time quantitative PCR and RNA interference. Ppsxl expressed in P. persimilis males and females at different developmental stages: the expression peaked 10 h after mating in females, and it was also highly expressed in eggs that developed into males (the first egg). The adult females, 5 hours after mating, were interfered through soaking in a mixed system of dsRNA and nanomaterials Star Polycation (dsRNA and SPc were 1:1 mixed, the concentration was 500 ng/μl). When Ppsxl was interfered, the expression of Ppsxl decreased by 47%. All female individuals after interference were fertile, and the first eggs still always developed into males. However, the daily fecundity per female decreased by 13.4%, and the proportion of female offspring decreased by 22.7%. This study showed that Ppsxl gene had a certain influence on reproduction of P. persimilis, but its influence on sex determination may not be as critical as that of D. melanogaster.

Pest mites and their interaction with Phytoseiidae and other arthropod predators in an almond orchard in South-West Spain

The almond crop in Spain has increased in importance in recent years and consequently there is a need to improve knowledge about pests, diseases, and weeds. The present study was conducted from 2017 to 2020, with the objective of determining the fauna of spider mites and their natural enemies, with a special emphasis on phytoseiids. The main spider mite species was Tetranychus urticae Koch, and secondary species were Bryobia rubrioculus (Scheuten) and Eutetranychus banksii (McGregor). Phytoseiidae were the most abundant group of natural enemies, with 59% of the individuals observed; Euseius stipulatus (Athias-Henriot) was the predominant species, accounting for 96% of adult females identified, Typhlodromus (Anthoseius) athenas Swirski & Ragusa accounted for the remaining 4%. Other (potential) natural enemies were Chrysopidae, Scolothrips longicornis Priesner, and Stethorus sp. with 36, 2, and 3%, respectively, of the natural enemy individuals. The seasonal pattern of T. urticae indicated population peaks from July to September, and its control was based on miticides in most seasons. Euseius stipulatus and T. athenas appeared mainly in May–June and did not show interaction with the spider mite population. Chrysopidae were present throughout the season, from May to October in the 4 years, but no direct relationship with the spider mite population was observed. In contrast, the seasonal pattern of both S. longicornis and Stethorus sp. coincided with the most important peaks of spider mites and these predators were seen in the spider mite colonies, although in very low numbers. The importance of these latter specialized spider mite predators and ways to strengthen them are discussed.

Novel sustainable strategies to control Plasmopara viticola in grapevine unveil new insights on priming responses and arthropods ecology.

Reduction of fungicide consumption in agriculture is globally recognized as a priority. Government authorities are fostering research to achieve a reduction of risks associated with conventional pesticides and promoting the development of sustainable alternatives. To address these issues, in the present study, alternative protocols for the control of downy mildew infection in grapevine were compared to the standard protocol. In the first protocol, only resistance inducers were used, comprising a single formulation with Acibenzolar S-methyl, laminarin and disodium-phosphonate. The second and third protocols followed the standard protocol but substituted phosphonates with phosphorus pentoxide and Ecklonia maxima extract. The results showed that at veraison downy mildew incidence and severity in all tested protocols were significantly reduced compared to nontreated controls on both canopy and bunches. Expression analysis of key genes involved in plant stress response, indicated that the two protocols for phosphites substitution induced a remodulation of salicylic acid (SA) and jasmonic acid (JA), with positive impact on yields. Analysis of the first protocol revealed that the primed state induced a short delay in bunch ripening, with a shift of carbohydrate metabolism to boost the plant defences, involving an upregulation of defence related-gene, SAR response and a decreased ROS detoxification. Additionally, analysis on the arthropods populations, in parallel with the positive results achieved using alternatives to conventional fungicides, were enriched by those showing the potential of naturally occurring predators of spider mites. This study provides practical solutions to reduce the environmental impact of treatments for the control downy mildew in viticulture. © 2022 Society of Chemical Industry.

ECOLOGY Susceptibility of Apple Varieties to Tetranychus urticae Koch and Panonychus ulmi Koch and its Relation to the Nutrient Contents and Spider Mite Predators in Apple Trees

El-Abdallah, J., M. Muflih and L.H. Aslan. 2022. Susceptibility of Apple Varieties to Tetranychus urticae Koch and Panonychus ulmi Koch and its Relation to the Nutrient Contents and Spider Mite Predators in Apple Trees. Arab Journal of Plant Protection, 40(2): 119-126. https://doi.org/10.22268/AJPP-40.2.119126 The susceptibility to T. urticae and P. ulmi of eight apple varaietis were studied in southern Syria (Sweida) from 2018 to 2020. Significant differences of susceptibility to the two species between apple varieties, in addition to significant differences of apple-leaf nutrients content (NPK) were found. Results obtained showed that apple-leaf nutrients content affect the susceptibility to the two spider mite species differently. Principal component analysis (PCA) showed positive correlation to P. ulmi with apple-leaf contents of potassium and negative correlation with apple-leaf contents of nitrogen and showed positive correlation between T. urticae numbers and nitrogen and phosphorous content. T. urticae had a weak correlation with potassium apple-leaf content in 2019. Cluster analysis showed that apple varieties were distributed in three clusters based on the studied factors in 2020. The first cluster included the varieties Top Red, Starking Delicious and Starking Red Delicious which were the most sensitive to P. ulmi. The second cluster included Golden Delicious, Golden 972 and Granny Smith, and those were less sensitive to P. ulmi and the third cluster included Ozark Gold and Royal Red and these varieties were moderately sensitive to P. ulmi. The effects of studied factors were clearer on P. ulmi than on T. urticae. Keywords: Apple, T. urticae, P. ulmi, Phytoseiidae, Principal component analysis, PCA.

RETRACTED ARTICLE: Artificial heat waves induce species-specific plastic responses on reproduction of two spider mite predators

AbstractClimate change models predict that the frequency, intensity and duration of heat waves will increase in the next decades. Heat waves can have profound impact on the reproduction of biocontrol agents ranging from postponing oviposition to manipulating offspring quantity via egg number and quality via egg size. Such species-specific responses of biocontrol agents to heat stress may also affect their success in controlling the target pest. Here, we evaluated the predation and reproductive performance of the two spider mite predators Phytoseiulus persimilis and Neoseiulus womersleyi exposed to simulated mild, moderate and extreme heat wave conditions over three days. Irrespective of heat wave conditions, all N. womersleyi females survived, whereas 12% of the P. persimilis females died. Both species responded to heat stress via plastic modifications resulting in increased predation rates and smaller egg sizes. Significantly more P. persimilis females postponed oviposition during the experimental phase than N. womersleyi. The deposited egg number of Phytoseiulus persimilis was not affected by heat wave conditions. On the contrary, the reproductive output of N. womersleyi was a function of temperature, i.e., the higher the temperature, the higher the number of deposited eggs. These findings indicate that P. persimilis is more heat sensitive in relation to reproduction than N. womersleyi. However, further investigations of heat wave effects on other fitness-related traits and their consequences at population level are needed to find out whether N. womersleyi is an alternative or supplement to P. persimilis as spider mite control agent under heat waves.

Pests of Florida Hops: Preliminary Observations

Surveys of arthropods associated with hops at the University of Florida's Gulf Coast Research and Education Center, Wimauma, Florida, USA, from 2016 to 2020 reveal that spider mites are the primary pest of the crop. Lepidoptera and lace bugs also were observed causing occasional damage to the crop. Whiteflies and thrips have been observed on the crop in low numbers. The tall (5.5 m) canopy of the hops trellis creates a challenge to applying insecticides with adequate coverage. Sampling data indicate that spider mite densities tend to be higher in the upper canopy than at ground level. Efforts to control spider mites with releases of the commercially available predator Phytoseiulus persimilis showed promise. Naturally occurring spider mite predators observed on hops at Gulf Coast Research and Education Center include Stethorus sp., Neoseiulus sp., Orius sp., and trash bugs.

Impact of a tarsonemid prey mite and its fungal diet on the reproductive performance of a predatory mite.

Phytoseiid predatory mites are the most important group of biocontrol agents currently used in protected cultivations worldwide. The possibility to produce these predators at high densities on factitious prey mites is a crucial factor for their success. Commonly used factitious prey mites comprise mainly species belonging to the cohort of Astigmatina. In the present study, we investigated the potential of tarsonemid prey mites as a food source for the spider mite predator Neoseiulus californicus (McGregor) (Acari: Phytoseiidae). The oviposition of N. californicus on mixed stages of Tarsonemus fusarii Cooreman (Acari: Tarsonemidae) was similar to that on its natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). As most tarsonemids are specialized fungus-feeders, we tested the effect of different fungal species on the growth of T. fusarii. Subsequently, we analysed the impact on the fungal growing medium on the oviposition of N. californicus. The fungal growing medium of T. fusarii had a significant negative effect on the reproductive output of the predatory mite. When T. fusarii was separated from the rearing medium, these detrimental effects were not observed. The present study shows the potential of using tarsonemid prey mites in the production of phytoseiid predatory mites.

Evaluation of Sticky Traps for Monitoring Scolothrips sexmaculatus (Thysanoptera: Thripidae) and Stethorus punctum (Coleoptera: Coccinellidae) as Predators of Spider Mites in California Almonds.

Changes in almond production practices have caused sixspotted thrips, Scolothrips sexmaculatus Pergande, and the coccinellid beetle, Stethorus punctum LeConte, to replace phytoseiid mites as the dominant predators of spider mites in California almonds. We conducted a series of field studies to evaluate nine commercially available adhesive traps for S. sexmaculatus and S. punctum and found that the yellow strip trap was the most effective, least expensive, and easy to use. At peak population levels, individual cards routinely caught >1,000 S. sexmaculatus and >100 S. punctum trap-1 week-1. We documented that larger traps collected more S. sexmaculatus, and more S. sexmaculatus per square area, suggesting that the trap surface was attractive. We determined the number of traps needed to have 50, 70, and 90% confidence that the averages of trap captures were within 10, 30, and 50% of the population mean. Two yellow strip traps per orchard provided 90% confidence that trap captures were within 50% of the population mean if there were an average of 16.0 S. sexmaculatus trap-1 week-1 or 7.9 S. punctum trap-1 week-1. Populations required to attain the same levels of confidence using four traps per orchard were 3.9 S. sexmaculatus and 2.9 S. punctum trap-1 week-1. We conclude that use of the yellow strip trap to monitor for natural enemies, in combination with leaf samples for spider mites, has the potential to improve integrated pest management programs for spider mites, and assist future research to understand the biology and phenology of both predator species.

THE FEATURES OF BIOLOGY OF HARMONIA AXYRIDIS PALL. AND THE MOST COMMON SPECIES OF COCCINELLIDS IN UKRAINE AGROCOENOSIS

The research was conducted in 2017–2019 years in the Institute of Plant Protection of The National Academy of Agrarian Sciences of Ukraine in the Laboratory of entomology and resistance of agricultural crops against pests (Kyiv, Ukraine). The objective of the research is investigation of particular biology features of Harmonia axyridis Pall. in comparison with the main species of coccinellids in typical agrocoenosis. The research methods are the following: laboratory method that means laboratory maintenance of coccinellids; mathematical-statistical method that means statistical processing of the obtained results. The Coccinellidae family (Latreille, 1807) has an important economic value in the human business activities. Most species are predators of aphids, scale insects, thrips, spider mites, leafhoppers, whiteflies, eggs and larvae of other small arthropods. Coccinellids are marked by their high gluttony, polyphagous, fertility. Beetles and larvae of ladybirds play a significant role in the quantity control of pests of agricultural, forest and ornamental plants. Since 2009 researchers in Ukraine have devoted great attention to identification and distribution of invasive species of Asian lady beetle, or Multicolored Asian lady beetle, Harlequin ladybird, Halloween ladybeetle (Harmonia axyridis Pallas, 1773). H. axyridis Pall. is characterized by its wide ecological plasticity, trophic specialization, greater gluttony, fertility and number of generations leading to the gradual displacement of local species of coccinellids. The comparative results of researches of some biology features of H. axyridis Pall. and the most common species of ladybirds are presented. The survival of coccinellids imago during the wintering, in the active period in the absence of feed, their gluttony for different species of aphids is examined. Features of oviposition and duration of various stages of coccinellids development are presented. In the laboratory the Asian lady beetle was marked among other species by the number of its laid eggs, oviposition period, duration of various stages of its development, survival and gluttony

&lt;p class="Body"&gt;&lt;strong&gt;&lt;em&gt;Typha angustifolia &lt;/em&gt;&lt;/strong&gt;&lt;strong&gt;L. pollen as an alternative food for the predatory mite&lt;em&gt; Neoseiulus californicus &lt;/em&gt;(McGregor) (Acari: Phytoseiidae)&lt;/strong&gt;&lt;/p&gt;

Neoseiulus californicus (McGregor) (Mesostigmata: Phytoseiidae) is considered a specialized predator of spider mites and has mainly been used to control Tetranychus urticae Koch (Acari: Tetranychidae). However, this phytoseiid is also able to feed and reproduce on certain pollens. In the present laboratory study, survival, development time, and reproduction of N. californicus were determined when reared on T. urticae, Typha angustifolia pollen, or on a combined diet of both foods. The immature stages of N. californicus developed faster when T. urticae was present in the diet. The total developmental time of females was longer when offered T. angustifolia pollen only (6.6 days), than when fed on T. urticae (4.5 days) or T. urticae + pollen (4.5 days). The oviposition rate of N. californicus was higher on the two diets containing T. urticae (3.1-3.3 eggs/female/day) than on T. angustifolia pollen alone (0.9 eggs/female/day). The intrinsic rates of natural increase (rm) were estimated to be 0.273, 0.268 and 0.149 females/female/day on T. urticae, T. urticae + T. angustifolia and T. angustifolia, respectively. Our results indicate that supplementing a T. urticae diet with T. angustifolia pollen would not improve population parameters. However, in the absence of spider mites, providing commercial pollen might help sustain populations of the phytoseiid in the field.

The stealthiness of predatory mites as spider mite biological control agents

Adult spider mite females that are aware of predatory mites can reduce predation by dispersing from patches invaded by predators or by shifting their oviposition site onto webs where eggs are predated less than on leaf surfaces. Therefore, the stealthiness of predatory mites stalking spider mite females should largely determine the success of spider mite control. This study examined the stealthiness of three predatory mites: Phytoseiulus persimilis Athias-Henriot, Neoseiulus californicus McGregor, and Neoseiulus womersleyi Schicha. The first two species have been commercialized as spider mite biological control agents, whereas the last species is a native predator of spider mites in Japan. We measured two indices of predator stealthiness in bioassays using Tetranychus kanzawai Kishida as prey: the proportion of prey mites that dispersed from their patches in response to predator intrusion and the proportions of prey eggs laid on webs in response to predator eggs. Both indices resulted in the same ranking, with P. persimilis ranking highest and N. womersleyi lowest. The greater stealthiness of P. persimilis eggs compared with N. womersleyi eggs seemed to be due to the lower amount of detectable substances on the egg surface. We also measured this index of stealthiness for European and Japanese Tetranychus urticae Koch populations and found that they had the same stealthiness ranking as measured using T. kanzawai. Therefore, we predict that the stealthiness of predatory mites is consistent across prey species and could be an effective index, along with conventional indices, for evaluating predatory mites as spider mite biological control agents.

Effects of spirodiclofen on life history traits and population growth of a spider mite predator Oligota flavicornis (Coleoptera: Staphyllinidae) based on the age-stage two-sex life table theory.

Knowledge of the compatibility between spirodiclofen and the predator Oligota flavicornis is an important aspect for the management of spider mites. We used the age-stage, two-sex life table to assess the effects of spirodiclofen on the life history traits and population growth of O. flavicornis. At the maximum recommended concentration (60 mg a.i. L-1 ) and also at twice the maximum recommended dosage (120 mg a.i. L-1 ), the preadult stages of O. flavicornis were significantly lengthened, while the adult longevity and fecundity decreased significantly. The finite rate (λ), intrinsic rate of increase (r), and net reproduction rate (R0 ) decreased, while the mean generation time (T) was longer after both the 60 and 120 mg a.i. L-1 treatments than it was in the control and 30 mg a.i. L-1 treatments. Life expectancy and reproductive value were higher in the control and 30 mg a.i. L-1 treatment than in the 60 and 120 mg a.i. L-1 treatments; the two higher concentrations were detrimental to the development of O. flavicornis. A proper combination of the O. flavicornis and spirodiclofen to control the spider mite, while avoiding the side effect of spirodiclofen, could be achieved based on the knowledge of life tables. © 2018 Society of Chemical Industry.

Linking pollen quality and performance of Neoseiulus californicus (Acari: Phytoseiidae) in two-spotted spider mite management programmes.

It has been shown that pollen as a dietary supplement may increase the establishment of generalist predatory mites, and therefore pest control by these mites can be provided. Life table studies were performed to evaluate the nutritional value of seven different pollens (almond, castor-bean, date-palm, maize, bitter-orange, sunflower and mixed bee pollen) as a supplementary food source for the spider mite predator Neoseiulus californicus McGregor. In addition, the nutritional quality of each pollen species was assessed through morphological and chemical analysis. Preadult duration was longer when the predator fed on castor-bean pollen (10.01 days) and bee pollen (9.94 days) compared with the others (5.58-7.27 days). The cohort reared on almond pollen had the highest intrinsic rate of increase (r) (0.231 day-1 ), and those on mixed bee pollen had the lowest r (0.005 day-1 ). The levels of nutritional content (sugar, lipid and protein) were significantly different among tested pollens. Comparison of N. californicus life table parameters on different diets revealed that the almond pollen (and after that the maize pollen) was a more suitable diet than the others. These findings will be useful in developing appropriate strategies for conservation of N. californicus to control spider mites. © 2016 Society of Chemical Industry.

Intraguild interactions among three spider mite predators: predation preference and effects on juvenile development and oviposition.

A first step to evaluate potential negative effects of intraguild predation (IGP) when using multiple predators against a pest species is the determination of the predation behavior of the predators and the nutritional value of intraguild (IG) prey in terms of development and oviposition. Here, we investigated the predation preference of the female predatory mites Neoseiulus californicus, Typhlodromus bagdasarjani and Phytoseius plumifer, when having choice between larvae of the two other predatory mite species (IG prey) with and without extraguild prey, the spider mite Tetranychus urticae (EG prey). Additionally, we evaluated the juvenile development and oviposition of the three predator species when provided with larvae from each other species. Irrespective of EG prey, IG prey species affected neither the first attack nor attack times of the three female IG predator species. The IG predation rates of the predator females, however, were influenced by prey species in the absence of EG prey. Neoseiulus californicus females killed more P. plumifer than T. bagdasarjani larvae, whereas T. bagdasarjani and P. plumifer females killed more N. californicus than P. plumifer and T. bagdasarjani larvae, respectively. All IG predator species consumed significantly more EG than IG prey. IG prey species did not influence juvenile and adult survival probabilities of the IG predators. We conclude that IGP is a weak force among the three predators and the potential consequences of IGP should not result in the elimination of one by another tested predatory mite species at least in the presence of spider mites.