Tetranychid Mites Research Articles

Prevalence of Tetranychus urticae Koch and T. turkestani (Ugarov & Nikolskii) (Acari: Tetranychidae) and their endosymbiotic bacteria in cotton fields of Aydin, Türkiye

Spider mites are important pests of cotton, a vital fiber crop cultivated in sun-drenched regions. This study investigated the prevalence and distribution of spider mite species infesting cotton fields in Aydin province, Türkiye. Spider mites were found in a significant portion (89%) of the surveyed fields. The two most abundant mite species, were the red form (RF) of Tetranychus urticae (57.1%) and T. turkestani (39.3%). A minor presence of T. urticae green form (GF) (3.6%) was observed. Tetranychus urticae RF was more prevalent in coastal areas, while T. turkestani was more common inland. Field surveys demonstrated that areas with higher T. urticae RF prevalence exhibited more frequent spraying, potentially due to this species’ greater capacity to develop resistance compared to T. turkestani. This study also investigated the prevalence of Wolbachia, Rickettsia, Cardinium and Spiroplasma endosymbionts, which are linked with pesticide resistance due to their ability to degrade pesticides, in these mite populations. The study confirmed the presence of Wolbachia and Rickettsia endosymbionts in spider mite populations in Türkiye. However, no Cardinium or Spiroplasma were detected in any of the populations. Infection rates of the detected endosymbionts differed between T. urticae and T. turkestani. Future studies should investigate the resistance levels of these tetranychid mite species as well as the role of their endosymbiotic bacteria in resistance in cotton-growing areas.

First report on life history and population parameters of Typhlodromus (Typhlodromus) setubali (Dosse) feeding on two tetranychid mites or pollen (Acari: Phytoseiidae, Tetranychidae)

ABSTRACT The predatory mite, Typhlodromus (Typhlodromus) setubali Dosse (Acari: Phytoseiidae), is a potential natural enemy for controlling mite and insect pests in the Mediterranean basin. The objective of this study is to investigate the life history and population parameters of T. (T.) setubali feeding on Panonychus ulmi Koch and Tetranychus urticae Koch or the cattail pollen Typha latifolia L. at 15, 20, 25, 30, and 35°C with 65% (RH) and photoperiod of 16:8 (L:D). The results revealed that both tetranychid mites were satisfactory diets for T. (T.) setubali, which completed its entire life cycle on the pollen regardless of the temperature tested. When the target prey was P. ulmi, the highest fecundity was 19.32 eggs per female at 30°C (15.90 eggs on T. urticae and 11.06 eggs on T. latifolia) and the maximum of R 0 , r m , and λ was 14.16 offspring/individual, 0.177, and 1.194 days−1, respectively. Typha latifolia pollen can be an alternative diet for effectively mass-rearing the generalist polyphagous phytoseiid mite, T. (T.) setubali. This species can be released as a biological control agent against P. ulmi and T. urticae populations, in perfect compliance with the principles of integrated mite management.

Ecologo-faunistic review of tetranychid (Acariformes: Tetranychoidea) and phytoseiid mites (Parasitiformes: Phytoseiidae) in the Transcarpathian Region, Ukraine</p >

The results of long-term research on tetranychid and phytoseiid mites in the Transcarpathian region of Ukraine are summarized. Transcarpathian Tetranychoidea are represented by 28 species from 10 genera, and the same list for Phytoseiidae included 49 species from 11 genera. For 77 species of mites from 21 genera, species composition, abundance, trophic specialization, and biotopic distribution in different altitudinal zones of Transcarpathia, Ukraine was analysed. Ten species of tetranychid mites (Bryobia rubrioculus, Tetranyhus horridus, Amphytetranyhus viennensis, Eotetranycuus carpini, E. quercicola, Neotetranychus rubi, Oligonychus ununguis, Panonychus ulmi, T. turkestani and T. urticae), and 11 species of phytoseiid mites (Neoseiulus umbraticus, Kampimodromus aberrans, Amblyseius andersoni, A. rademacheri, Euseius ucrainicus, Dubininellus echinus, D. juvenis, Typhloctonus aceri, T. tuberculatus, Anthoseius (A.) rhenana and A. (A.) clavata) were common to all three studied altitudinal zones. The species diversity of tetranychids was highest in the lowlands (23 species), slightly lower in the foothills (19 species), and the lowest in the mountain zone (11 species). For phytoseiid mites, it was the highest in the foothills (38 species), 25 in the lowlands and 21 in mountains. Among the tetranychids, the transzonal species A. viennensis retained its dominant status in all altitudinal zones. In the lowland, the highest rates of occurrence and dominance indices were observed for the species B. rubrioculus and T. turkestani, and in the foothills—for P. ulmi and T. horridus. The species composition of mites in the lowlands and mountains varied the most for both predators and phytophagous mites. Among the tetranychids, the most striking marker species in the mountains were P. ulmi and N. rubi. Only in the mountains were found such phytoseiid species as N. alidis, N. montanus, T. runiacus, T. mutatus, and A. salviae, which could thus be considered strictly mountainous. All of them have fragmented habitats and are tied to mountainous regions. In that altitudinal zone, an exceptionally high occurrence rate and dominance index were established for N. montanus among the phytoseiids. This is most probably due to significantly greater differences in the temperature and humidity regimes and range of host plants and, for predatory mites, prey species. The results of this study provide additional information about the structure of the communities of phytophagous and predatory mites in the natural zones of the mountain landscape and changes in the composition of the communities under the influence of environmental factors and the forage base, which is a consequence of the altitudinal distribution of the investigated biocenoses.

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.

Comparison of chemosensilla in three phytoseiid mites with different feeding habits

Phytoseiidae comprised over 2000 described species with different feeding habits. However, the mechanisms of food selection were virtually unknown in most phytoseiid mites. To explore the potential mechanism of odor perception, we compared the type and number of chemosensilla on the tarsi of legs and pedipalps by scanning and transmission electron microscopy in three representative predatory mites, i.e., Phytoseiulus persimilis (specialized predator of Tetranychus), Neoseiulus californicus (selective predator of tetranychid mites), and Amblyseius swirskii (generalist predator). All three species had two types of putatively olfactory sensilla, with a porous vs. grooved surface on the tip of the first pair of legs. Of these, five porous setae were found in each of the three species of predatory mites studied. However, only one grooved seta was found at the tip of the first pair of legs in P. persimilis, and two in A. swirskii and N. californicus. In addition, the pedipalp has nine grooved setae, which were hypothesized to be contact chemosensilla in each of the three species. No porous setae were found on either pedipalp or the other three pairs of legs, i.e., leg II, III and IV. Additionally, we provided a new chaetotactic notation for the tarsus of leg I by considering the type and number of setae based on our observation of the three species of Phytoseiidae studied.

The effects of a novel botanical pesticide on demographic and some biochemical parameters of Panonychus citri (McGregor)

ABSTRACT Panonychus citri (McGregor) is one of the most destructive pests of citrus trees. Its control is difficult because it has developed resistance to some synthetic pesticides. GC-mite is a novel botanical pesticide based on cottonseed, clove, and garlic oils that has shown the potential to control tetranychid mites. This study aimed to evaluate the effects of sublethal concentrations of GC-mite on the life history and biochemical parameters of P. citri. Age-stage life table procedure was used to evaluate the effects of two sublethal concentrations (LC20 = 59.40 μg ml−1 and LC30 = 78.66 μg ml−1) of GC-mite on the development, longevity, and reproduction of P. citri. The biochemical analysis included the content of lipids, carbohydrates and glycogen, esterase, and glutathione S-transferase (GST) activities. The developmental time of treated mites with LC30 was significantly longer than the control but the adult longevity and oviposition days of P. citri treated with both sublethal concentrations decreased. The total fecundity of treated mites decreased with increasing GC-mite concentration applied. The life table analysis showed that sublethal concentrations of GC-mite significantly affected gross reproductive rate (GRR), net reproductive rate (R 0), intrinsic rate of increase (r), and mean generation time (T). The estimated values of r were significantly lower than the control in LC20 (0.130 day−1) and LC30 (0.117 day−1). The lipids, carbohydrates and glycogen contents as well as esterase and GST activities were significantly lower in mites treated with LC30 concentration, but no significant effect was found in mites treated with LC20 and control. These results suggest that sublethal concentrations of GC-mite had significant effects on both demographic and biochemical parameters of P. citri.

Life Table Parameters of Tetranychus merganser Boudreaux (Acari: Tetranychidae) on Five Host Plants.

The quality of the host plant affects the life history parameters of tetranychid mites. The biology and fertility life tables of Tetranychus merganser on five host plants (Carica papaya, Phaseolus vulgaris, Capsicum annuum var. glabriusculum, Helietta parvifolia, and Rosa hybrida) were assessed under laboratory conditions at 28 ± 1 °C and 70-80% relative humidity (RH) with a photoperiod of 12:12 h (L:D). The development period of immature females differed among the tested host plants and ranged from 9.32 days on P. vulgaris to 11.34 days on H. parvifolia. For immature males, it ranged from 9.25 days on P. vulgaris to 11.50 days on H. parvifolia. The female survival rate varied from 53.97% on H. parvifolia to 94.74% on P. vulgaris. The highest total fecundity rate was recorded on P. vulgaris (125.40 eggs/female) and the lowest on H. parvifolia (43.92 eggs/female). The intrinsic rate of increase (rm) varied from 0.271 (H. parvifolia) to 0.391 (P. vulgaris). The net reproductive rate (RO) was higher on P. vulgaris than on the other host plants. The longest mean generation time (GT) was calculated on C. annuum var. glabriusculum and the shortest on Rosa hybrida. The demographic parameters suggest the unsuitability of H. parvifolia as the host for the development of red spider mites, and the best performance of T. merganser was on P. vulgaris.

Predator-Unfriendly Pesticides Harm the Beneficial Mite Neoseiulus idaeus Denmark & Muma (Acari: Phytoseiidae)

Pesticides are commonly used to control weeds, diseases, and pests in soybean crops, although natural enemies are also key components of integrated pest management programs protecting soybean from pests. The predatory mite Neoseiulus idaeus Denmark & Muma is commonly found in soybeans associated with tetranychid mites. We determined the compatibility of some pesticides used in Brazilian soybean fields with N. idaeus on the basis of their lethal and sub-lethal effects. We assessed the acute toxicity of pesticides that are considered harmless to females of N. idaeus and evaluated the effects on the mite offspring. Acephate as well as imidacloprid and bifenthrin were most toxic to adult females and were classified as harmful. Chlorfenapyr, indoxacarb, and the neonicotinoid and pyrethroid mixtures were classified as slightly to moderately harmful. Immatures of N. idaeus were able to develop and reach the adult stage when treated with chlorantraniliprole, flubendiamide, glyphosate, and teflubenzuron, but immature survival was reduced to 42 and 64% for offspring of females treated with chlorantraniliprole or teflubenzuron, respectively. Reproduction was most affected in females exposed to chlorantraniliprole and teflubenzuron; these females had daily oviposition rates of 0.5 and 0.4 egg/female/day, respectively, and mean fecundities of 2.7 and 5.8 eggs/female, respectively. On the basis of sublethal effects and life table parameters, chlorantraniliprole was classified as moderately harmful, while the other pesticides tested were classified as harmless. In considering the use of pesticides while targeting the conservation of N. idaeus as a predator of important pests in soybean crops, one must prioritize pesticides that will most likely have less harmful effects on this predator in the field.

GENETIC DIVERSITY OF MAJOR POLYPHAGOUS SPIDER MITE SPECIES ACROSS HOST PLANTS AND SPATIAL DISTRIBUTION

Different agroecosystems of southern Karnataka sampled for plant associated mites recorded six genera of tetranychid mites viz., Aponychus, Eutetranychus, Oligonychus, Petrobia, Schizotetranychus and Tetranychus. Neutrality test revealed a lowest haplotype diversity (0.993) of T. neocaledonicus population and Tajima’s D and Fu’s Fs test values were negatively significant for T. fijiensis, E. orientalis and S. baltazari populations, indicating the greater expansion of populations. Genetic analysis with ITS2 (rDNA) sequences revealed highest similarity between mite genera Petrobia and Aponychus showing lowest genetic distance of 0.51. Schizotetranychus has sister relationship with Eutetranychus which in turn clustered with Petrobia and Aponychus. Tetranychus and Oligonychus genera with lower genetic distance of 0.60 are clustered together. The study confirmed the clustering of morphologically related genera and lower genetic distances observed between related genera, expressed sister relationship. Molecular phylogenetic analysis of species under genus Oligonychus showed clustering in line with the morphology-based species taxonomic keys, while polyphagous species under the genus Tetranychus did not express form this grouping. Genetic diversity study of ten polyphagous mite species across their host plants and geographical occurrence revealed grouping according to locations in the phylogenetic tree. However, populations of Oligonychus tylus with a narrow host range showed close relationship for host plants than geographical locations which was evident in phylogenetic tree branching.

Spider mites (Acariformes, Tetranychidae) of the Massane Nature Reserve (France)

We present results of the inventory of the spider mites of the Massane Forest Nature Reserve made during several field samplings from 2013 to 2017. Nineteen species have been recorded, which represents more than one third of the known spider mite fauna in France. Among them, three new species were disclosed and are described: Bryobia (Bryobia) alberensis sp. nov. collected on Phyteuma spicatum and Helichrysum stoechas, B. (Periplanobia) polymorpha sp. nov. on Genista pilosa and Tetranychus visigothus sp. nov., on Eryngium campestre, respectively. In addition, three spider mite species, Bryobia (Periplanobia) serifiotica, Eotetranychus aurantii and Eotetranychus fagi are recorded from France for the first time and three plant species are recorded as new host plants for tetranychid mites. The species delineation of B. (P.) polymorpha sp. nov., that presented large variation in dorsal setae length and shape, was investigated using a combination of morphological and molecular data. This approach allowed us to conclude that, despite such variations in a morphological key character, all the specimens observed belong to the same species.

Rapid cold hardening response of the phytoseiid mite Neoseiulus striatus: increased cold tolerance but not reduced predation

The predatory mite Neoseiulus striatus (Wu) (Acari: Phytoseiidae), which has been found on maize plants in Inner Mongolia, is regarded as a promising biological control agent of small sucking pests, especially Tetranychid mites. Temperature is an important abiotic factor, and a sudden drop in temperature may affect its performance when released in areas with big circadian temperature differences. Rapid cold hardening is a type of phenotypic plasticity that allows ectotherms to quickly enhance their cold tolerance in response to a brief chilling exposure. However, it is not clear whether N. striatus possesses such plasticity. To understand how this species of phytoseiid mite copes with short-term low-temperature stress, its rapid cold hardening response was studied in the laboratory by first exploring its critical temperature. Then, the effects of exposure to a series of temperatures (0, 5, 10, 15, and 20°C) for different durations on the survival of N. striatus were investigated to determine the optimal temperature and duration for cold hardening. Moreover, the effect of cold hardening on the consumption of Tetranychus urticae by N. striatus was also investigated, as was the response of immature stages. The critical temperature for N. striatus was - 15°C, at which its survival dropped below 10%. An exposure to 5°C for 2h was optimal for rapid cold hardening, efficiently increasing survival in N. striatus. Rapid cold hardening was found in all developmental stages of N. striatus, and there was no significant effect of exposure on the consumption of spider mites. Our study shows that exposure to low temperatures during a limited period can enhance the cold hardiness but not reduce predation by N. striatus, which will be advantageous to its field applications during a period of large diurnal temperature fluctuations.

An annotated checklist of Tetranychidae (Acari: Trombidiformes) of the Transcarpathian region (Ukraine)

The first checklist of spider mites (Tetranychidae) of Transcarpathia, Ukraine is compiled based on the revision of collection materials stored in I. I. Schmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine. The mite collections of I. Akimov, A. Putrashik, and of the authors were studied, thus covering a 45 year-long period of research of spider mites in the study region. The checklist includes 28 species of 10 genera of tetranychid mites, which is about 40% of the species diversity of spider mites in Ukraine. For each species, information is provided on the number of individuals (males, females, nymphs, and larvae), host plants, record localities (for own collections—with geographic coordinates), as well as data on distribution in other regions of Ukraine. The largest part of the collection includes the findings of common species, such as Amphitetranychus viennennsis, Bryobia rubrioculus, and Panonychus ulmi. The genus Eotetranychus is represented by the largest number of species (8). Two species (Eotetranychus quercicola Auger & Migeon, 2014 and Schizotetranychus beckeri Wainstein, 1958) are recorded for the first time for the fauna of Ukraine. In addition, 21 species of spider mites are noted for the first time for the territory of Transcarpathia. Three of the 11 species previously indicated for Transcarpathia, namely Oligonychus brevipilosus Zacher, 1932, Oligonychus lagodechii Liv. et Mitr., 1969, and Schizotetranychus jachontovi Reck, 1953 are not represented among the collection materials. In addition to the two taxa noted here for the first time in Ukraine, five species of tetranychids (Bryobia praetiosa, Bryobia lagodechiana, Eurytetranychus furcisetus, Schizotetranychus spireafolia, and Tetranychus frater), which were previously discovered in other regions of Ukraine, should be included in the electronic database of Spider Mites Web as those recorded in Ukraine. Eight host plant species are indicated for the first time for six spider mite species (Eupatorium cannabinum for B. praetiosa, Armoracia rusticana, Betonica officinalis, and Melilotus officinalis for B. lagodechiana, Picea abies for E. furcisetus, Ribes nigrum for A. viennensis, Quercus robur for E. quercicola, and Salix glauca for S. shizopus).

Temperature-dependent Functional Response of the Arboreal Rove Beetle, Oligota flavicornis (Coleoptera: Staphylinidae), a Voracious Predator of Tetranychus urticae (Acarina: Tetranychidae).

The functional responses of Oligota flavicornis (Boisduval & Lacordaire) (Coleoptera: Staphylinidae) preying on the eggs of Tetranychus urticae Koch (Acarina: Tetranychidae) were examined at seven constant temperature settings (12, 15, 18, 22, 25, 30, and 32°C) to elucidate the predator-prey interactions between them. Logistic regression showed that O. flavicornis exhibited type II functional responses to T. urticae eggs at different temperatures. The reciprocal of handling time declined exponentially with warming, and the search rate presented a single hump-shaped relationship with temperature. For the search rate, the lower temperature thresholds were 9.1°C (linear) and 8.7°C (Briere). The optimal temperature and upper temperature threshold were 29.1 and 37.8°C for Logan and 29.7 and 35.8°C for Briere, respectively. The predation threshold window of O. flavicornis reached 27.1°C with a range of 8.7-35.8°C. The predator could consume 244.7-388.4 T. urticae eggs in a day in the optimal temperature range (18-32°C). The voracious predatory behavior of O. flavicornis against T. urticae eggs over a broad temperature range indicates that the predator shows promise as a potential biological control agent and that temperature-dependent predation could be a basis for formulating strategies to control tetranychid mites.

Spider mite predator Feltiella acarisuga (Vallot, 1827) (Diptera: Cecidomyiidae) in greenhouse strawberry cultivation in Antalya Province: recognition, population dynamics and parasitization by Aphanogmus sp.

Feltiella acarisuga (Vallot, 1827) (Diptera: Cecidomyiidae) is an effective and common beneficial species that feeds on many species of Tetranychid mites. Although it has been detected in Turkey, there are few studies on this predatory species. In this study, weekly leaf samples were taken to represent the growing area in the soilless strawberry greenhouse of Akdeniz University in 2020 and 2021. In leaf examinations, it was determined that F. acarisuga had an average egg size of 0.21 mm, young and mature larva of 0.26-1.51 mm, and a cocoon size of 2.01 mm. The average body length of male and female individuals was measured as 0.89 mm and 1.11 mm, respectively. It was determined that F. acarisuga can feed on all biological stages of Tetranychus urticae Koch, 1836 (Acari: Tetranychidae), as eggs, larvae, nymphs and adults were seen in the greenhouse in all seasons. Feltiella acarisuga is the most common natural enemy of T. urticae , with a maximum average of 0.38 larvae + cocoons/leaf in the greenhouse in the first year and 0.62 larvae + cocoons/leaf in the second year. In this study, a new species was detected, Aphanogmus sp., which was determined to be the parasitoid of F. acarisuga and different from its known congeners. The parasitization rate of F. acarisuga was found to be between 0 and 51.5%.

Toxicological Effects of Compounds from the Leaves of Schinus terebinthifolius Against Two Tetranychid Mites (Acari: Tetranychidae)

The use of synthetic acaricides is becoming increasingly hazardous to non-target organisms. Plant-derived natural products are alternative candidates with general low toxicity to human and environment. Two extracts and nine phenolic compounds (1-9) from the leaves of the Brazilian pepper tree (Schinus terebinthifolius Raddi) were investigated for their acaricidal effects against two tetranychid mites, Tetranychus cinnabarinus (carmine spider mite) and Tetranychus urticae (two-spotted spider mite). After 7-days of treatment, the ethyl acetate fraction demonstrated remarkable mortality against T. cinnabarinus (86.67%) while, the n-hexane fraction showed the highest mortality against T. urticae (96.67%) at 200 μg/mL. Among the tested compounds, afzelin (2) and protocatechuic acid (7) exhibited remarkable activity. Regarding T. cinnabarinus, afzelin showed the highest mortality (86.67%), toxic activity (LC50 22.32 μg/mL and toxicity index, Ti 0.972), and the fastest lethality by time. Whereas, protocatechuic acid achieved the highest mortality (96.67%), the lowest LC50 (0.232 μg/mL, Ti 73.71), and fastest lethality by time against T. urticae. This study reported a promising in vitro acaricidal activity of the phytoconstituents of the Brazilian pepper tree and suggested its isolated compounds, such as afzelin and chatechuic acid, as alternative leads for the development of echo-friendly acaricides.

A drought-tolerant Neoseiulus idaeus (Acari: Phytoseiidae) strain as a potential control agent of two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae)

The two-spotted spider mite Tetranychus urticae Koch is a key pest of many crops worldwide and is mainly controlled using acaricides. To mitigate the undesired impacts of acaricides (e.g., evolution of resistance and resurgence of secondary pests), phytoseiid mites are often used as a biological control alternative. Control of this pest is a more serious issue in arid regions which favor the development of spider mite populations and limit the efficacy of phytoseiids. The phytoseiid mite Neoseiulus idaeus Denmark & Muma is commonly found in semiarid regions of South America in association with tetranychid mites. Thus, we used laboratory assays to compare the predation and oviposition performance of a drought-tolerant strain of N. idaeus with those of a commercial species, Neoseiulus californicus (McGregor), which is used to control tetranychids. Furthermore, we compared the effectiveness of the drought-tolerant strain of N. idaeus with a common acaricide for control of T. urticae on cowpea plants under semiarid conditions. Drought-tolerant N. idaeus had a higher predation rate than N. californicus (17.50 ± 0.28 T. urticae eggs/female/day vs. 15.90 ± 0.19) and similar oviposition performance (3.52 ± 0.07 vs. 3.30 ± 0.06 eggs/female/day). Additionally, N. idaeus was able to control the pest population at a relatively low density on cowpea, exhibiting efficacy similar to that of a phenylthiourea acaricide. The practical implications of our results for biological control of T. urticae in semiarid regions are discussed.

Seasonal population dynamics of Aceria oleae (Nalepa, 1900) (Acari: Eriophyidae) in generative organs of olives in Hatay Province, Turkey

Olive, Olea europaea L., is an evergreen tree native to areas with Mediterranean climates. Its fruit and oil are key ingredients in the Mediterranean cuisine. Olive gall mite, Aceria oleae (Nalepa, 1900) (Acari: Eriophyidae) is a mite species that feeds on olive leaves, buds or flowers. This study was conducted to determine the population dynamics of A. oleae in generative organs of olive in Altınözü, Antakya and Samandağ Districts of Hatay between in April and October 2017 and 2018. The highest mite density was detected in Altınözü during the flowering period in 2017 and the budding period in 2018; and a second peak was seen during fruiting period for both years. A peak occurred in samples collected from Antakya for both years (in fruit stage, June 2017, and in budding stage, April 2018) but no prominent peak was noted Samandağ samples. A high rate of flower and fruit dropping was observed and this concurred with noticeable decreases in A. oleae population in Altınözü and Antakya Districts in both years. Three phytoseiid species, Typhlodromus ( Anthoseius ) athenas Swirski & Ragusa, 1976 (44%), Typhlodromus ( Anthoseius ) rapidus Wainstein & Arutunjan, 1968 (29%) and Typhlodromus ( Typhlodromus ) athiasae Porath & Swirski, 1965 (26%) (Acari: Phytoseiidae) were detected in these orchards. It is thought they probably fed on A. oleae since their primary prey, tetranychid mites were unavailable. Correlation results showed that population sizes of A. oleae did not decrease significantly with temperature and humidity in 2017. In 2018, the population was negatively correlated with temperature, but no significant increase occurred as humidity rose.

Effects of Three Artificial Diets on Life History Parameters of the Ladybird Beetle Stethorus gilvifrons, a Predator of Tetranychid Mites.

Simple SummaryThe ladybird beetle Stethorus gilvifrons is an important natural enemy of spider mites, which are pests of numerous agricultural crops. Mass production of S. gilvifrons would be necessary to generate large numbers of individuals for augmentative biological control. Using alternative prey/foods or artificial diets as a substitute to natural prey (spider mites) would be important in the cost-effective production of S. gilvifrons. The objectives of the current study were to determine the developmental and reproductive characteristics of S. gilvifrons fed on different artificial diets. Artificial diets consisted of sucrose, honey, royal jelly, agar, yeast, date palm pollen supplemented with hen’s egg yolk (AD1, as basic diet), Ephestia kuehniella eggs (AD2), or E. kuehniella eggs and 2,4-dihydroxybenzoic acid (AD3). Adults and larvae of S. gilvifrons performed best on AD3, indicating the potential of this artificial diet for mass rearing of this important predatory ladybird beetle.Background: The ladybird beetle Stethorus gilvifrons (Mulsant) is an important natural enemy of tetranychid mites and functions as a biological control of these plant pests. The development, survival and reproduction of S. gilvifrons were studied when fed on three artificial diets. The components of the artificial diet that S. gilvifrons could be reared successfully on for one generation with no use of tetranychid mites were examined. Methods: Artificial diets consisted of sucrose, honey, royal jelly, agar, yeast, date palm pollen supplemented in different diets with hen’s egg yolk (AD1, as basic diet), Ephestia kuehniella Zeller eggs (AD2), or E. kuehniella eggs and 2,4-dihydroxybenzoic acid (AD3). Results: Adults and larvae of Stethorus gilvifrons fed on AD1 had a shorter immature development and preoviposition periods than those fed on AD2 and AD3. The total number of deposited eggs was significantly higher for the females fed on AD3 than on the other diets. The intrinsic rate of increase (r) of S. gilvifrons was highest on AD3, followed by AD2, and AD1. Conclusion: Stethorus gilvifrons performed best on AD3, indicating the potential of this artificial diet for the mass rearing of this important predatory ladybird beetle.

Effect of factitious diets on development and reproduction of the ladybird beetle Stethorus gilvifrons, a predator of tetranychid mites

The ladybird beetle Stethorus gilvifrons is a predator of tetranychid mites. The hypothesis that factitious diets had no negative effect on S. gilvifrons development and reproduction was tested. Experimental diets included natural prey Tetranychus turkestani eggs, Ephestia kuehniella eggs plus date palm pollen, E. kuehniella eggs plus maize pollen, and E. kuehniella eggs plus bee pollen. The results indicated that S. gilvifrons development time was longer and fecundity was lower on all factitious diets tested compared to natural prey, T. turkestani eggs. S. gilvifrons fed E. kuehniella eggs plus date palm pollen had a higher net reproductive rate (R0), intrinsic rate of increase (r), and lower generation time (T) than those fed other factitious diets. Although T. turkestani eggs are more nutritious than the factitious diets, the combination of E. kuehniella eggs plus date palm pollen holds promise as an alternative food for the mass production of S. gilvifrons.

Some Physiological Observations on Date Palm Fruits during its infestation by the date palm dust mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae)

The current study aimed to survey the phytophagous tetranychid mite, Oligonychus afrasiaticus (McGregor) Tetranychidae in different regions of Egypt. Also, the effect of O. afrasiaticus infestation on the different components of date palm fruits was determined after one month of filed infestation. The results showed that the O. afrasiaticus appeared infested the date palm fruits in New -Valley, Giza, and Marsa Matruh Governorates only and disappeared from the other tested locations of Egypt. It was observed from the study that O. afrasiaticus infested Barhi Variety (Fresh) with a rare number in Sharq El-Ewinate region (New –Valley) only. On the other hand, Siwi variety (Semi-dry) infested with O. afrasiaticus on date palm fruits in Baharia Oasis (Giza Governorate), Siwa Oasis region (Marsa Matruh), El-Kharga Oasis and Dakhla Oasis region (New -Valley ). However, it was noticed that Samani and Zaghloul (Fresh varieties) did not infest with O. afrasiaticus during this study. The current study indicated that the protein contents were decreased when the fruits exposed to the infestation by O. afrasiaticus where it was recorded 18.6 mg/gm of fruits in infested fruits compared to 26.37 mg/gm in non-infested fruits. The highest level of carbohydrate content was (445.0 mg/gm) in non-infested date palm fruits. While the lowest carbohydrates level (308.0 mg/gm) was found when the date fruits exposed to mite's infestation. The obtained data showed that the nitrogen content of infested date palm fruits was 3.33 ug/gm of fruits but the recorded level of nitrogen in non-infested fruits was 4.37 ug/gm of fruits.The lowest content of phosphorus (3.1 µg/gm) was observed with infested fruits compared with 7.43µg/gm in the case of non-infested fruits. There were slight differences in potassium contents(7.16 and 7.83 µg/gm ) between infested and non-infested date fruits respectively,.The biochemical data revealed that the level of calcium contents was slightly differed (16.4 and 16.67 µg/gm) in date palm fruits infested and non-infested with mite individuals of O. afrasiaticus, respectively.