Persian Journal of Acarology

Abstract This study investigated the population structure and genetic diversity of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), across three different environments: farm, greenhouse and laboratory. Analysis of a 632-nucleotide fragment of the mitochondrial COI gene revealed four distinct haplotypes, with one haplotype shared among all populations, suggesting a common genetic origin. The farm population exhibited the highest haplotype diversity (Hd = 0.699), while the greenhouse population showed minimal diversity and the laboratory population exhibited complete uniformity. Genetic distance analysis confirmed these differences, showing significant divergence between the farm population and the more genetically uniform greenhouse and laboratory groups. ISSR marker analysis supported these findings, with the farm population having the highest number of alleles (4) and effective alleles, as well as elevated values for Shannon's information index and expected heterozygosity. Principal Coordinates Analysis (PCoA) revealed clear genetic clustering: laboratory samples formed a tight isolated cluster, greenhouse samples showed moderate clustering and farm samples were broadly dispersed. These patterns indicate that rearing environments significantly influence the genetic structure of T. urticae, with open field conditions promoting genetic diversity, while controlled environments lead to reduced variation. These findings are important for understanding pest adaptability and optimizing integrated pest management (IPM) strategies.

Abstract Here we describe a new species of mite, Acalitus kosahuatlus Acuña-Soto & Vanegas-Rico sp. nov., from the family Eriophyidae, collected in the state of Morelos, Mexico. This species causes galls on the leaves of Ipomoea wolcottiana Rose (Convolvulaceae), and is the first eriophyoid mite species recorded on this host plant worldwide and the second Acalitus species found on the plants of genus Ipomoea.

Abstract Many bacteria associated with arthropods play important roles in host functional traits, and the structure of these bacteria can be influenced by intracellular symbionts. In this study, a survey of bacterial endosymbionts present in natural populations of the two-spotted spider mite, Tetranychus urticae, was conducted in North, Razavi, and South Khorasan Provinces. A total of 1440 spider mites collected from three localities associated with eight host plants were screened for endosymbionts. Among the three detected facultative endosymbionts, Wolbachia, Cardinium, and Rikettsia, different infection frequencies (91.6%, 9.72%, and 9.72%, respect-ively) were observed. None of the individuals carried Arsenophonus or Spiroplasma. In the majority of the studied populations, multiple infections by endosymbiont were detected and the prevalence of individuals with the Wolbachia-Rikettsia coinfection (9.72%) was higher than the frequency of the individual coinfection rates with other symbionts. The findings of the current study suggest that the frequencies of endosymbiont infections may be affected by collection site characteristics, including geographic location (latitude, longitude), altitude, and collection date, as well as host plant species. Wolbachia infection rates were higher in mites collected from Razavi Khorasan Province compared to those from other localities. The highest frequencies of Cardinium and Rickettsia were observed in North and South Khorasan Provinces. Host plants also significantly influenced the prevalence of endosymbionts in the present study. The results of vertical transmission experiments indicated that temperature influences vertical transmission in symbiotic bacteria.

Abstract During the survey on eriophyoid mite fauna of Lorestan province (Iran), samplings were done on Euphorbia helioscopia L. (Euphorbiaceae) plants in Malavi Rural District of Pol-e Dokhtar County. In result, one new species, Aculops helioscopiae sp. nov. was discovered, described and illustrated. This is the first record of eriophyoid mites on E. helioscopia. A list of eriophyoid mite species collected on the plants of family Euphorbiaceae in Iran and their type host, type locality and relation to the host plant, a gross comparison of some important traits among Aculops species associated to Euphorbiaceae plants of the world, and a key for identification of them are provided.

Abstract Pirnodus (Oribatida, Oripodidae) currently comprises seven species, collectively distributed in the tropical and southern Palaearctic areas. A new arboreal species – P. arboreus sp. nov. – is described, based on adults collected from branches of different trees in the Cat Tien National Park, southern Vietnam. The new species is characterized by distinct sexual dimorphism, e.g., interlamellar seta long, setiform in females versus medium-sized, phylliform in males, posterior part of notogaster not depressed in females versus depressed in males, notogastral seta h₁ well developed, setiform in females versus vestigial in males, notogastral seta lm located medial to la in females versus anteromedial in males, genital and anal apertures distanced from each other in females versus genital aperture shifted to anal aperture and connected to it in males, and dorsal side of tarsi I and II without tooth in females versus with tooth in males. Summary of distribution and habitats of the known species of Pirnodus are provided.

Abstract The present study is based on the oribatid mite (Oribatida) material collected from the Binh-Chau National Reserve, southern Vietnam. A list of 46 species, belonging to 38 genera and 23 families, is presented. The genus Zetorchestes (Zetorchestidae) currently comprises 19 species having a cosmopolitan distribution collectively. Here, one new species of Zetorchestes, Z. binhchauensis sp. nov., is described, based on the adult males collected from deciduous forest litter. The new species is characterized by the presence of one pair of anal setae, one pair of adanal setae, and transverse cerotegumental tuberculate row in the dorsosejugal region, the absence of the notogastral setae c₁, and the location of the notogastral setae lm in the dorsolateral position.

Abstract A new Rhyncaphytoptinae mite, Rhyncaphytoptus hanzanensis sp. nov., was discovered and described on Cotoneaster kotschyi (C.K. Schneid.) G. Klotz (Rosaceae) as a vagrant mite in the Bondare Hanza Village, Hanza area, Rabor County, Kerman Province, Iran. This new species was discovered concurrently with Eriophyes cotosarica Lotfollahi, Honarmand, Hashemi & Xue, 2023, which induced circular galls on the same host.

Abstract Saffron, Crocus sativus L. (Iridaceae), is known as the most expensive spice in the world and the saffron mite (R hizoglyphus robini Claparède, 1869) causes direct and indirect damage by feeding on healthy or damaged saffron corms and is known as the most important pest of this crop. In this study, the effect of certain environmental factors including temperature, some soil parameters and altitude, on the population of saffron mite (adults and nymphs) and its dominant predatory mite Gaeolaelaps aculeifer (Canestrini, 1884) (Acari: Laelapidae) was evaluated in 5-year-old saffron fields in Iran (Mashhad, Gonabad, Torbat Heydariyeh, Dargaz, and Quchan). The relationship between the population growth rate (PGR) of adult and nymphal stages of bulb mite and predatory mite throughout the year was fitted by non-linear regression. Based on this model, the PGR of adult bulb mite was lowest on June 24 and highest on December 3. For the nymphal bulb mite, the PGR was lowest on August 5 and highest on December 12. The PGR of the predator of bulb mite was maximally fitted with the model, with a coefficient of determination (R2) of 0.612. In this model, the PGR of predatory mite reached its lowest point on August 9 and its highest on January 3. The effect of temperature and soil moisture on the nymphs/adult population ratio (NAPR) of bulb mites was fitted to a multiple linear model, and according to the results, the NAPR increased with increasing temperature and decreasing soil moisture. The results of this study can play an important role in predicting and placing the development of saffron cultivation.

Abstract In a faunistic study on the family Stigmaeidae in East Azerbaijan Province of Iran, a total of 27 species of the genus Stigmaeus were collected and identified, of which two species —Stigmaeus creber Barilo, 1986 and S. pseudoangustus Stathakis, Kapaxidi & Papadoulis, 2019— were recorded for the first time from Iran. We also redescribed males and females of S. glypticus Summers, 1962 and S. sinai Swift, 1987, provided diagnosis for the rest of the species, and compiled an information table for all known species of Stigmaeus from Iran.

Abstract This study investigates the effects of temperature on the development, survival, and reproduction of Eutetranychus africanus (Tücker) (Acari: Tetranychidae) reared on White frangipani (Plumeria alba L.: Apocynaceae) under laboratory conditions. Development, survivorship, and reproduction of this mite were studied on units made of detached leaves of P. alba, at three constant temperatures (20, 25, and 30 ± 2 °C), relative humidity (70 ± 5% RH), and photoperiod (16L: 8D). Mites completed their development and reproduced at all three tested temperatures. Developmental time, oviposition period, adult longevity, and life span decreased as temperature increased, although daily oviposition rate and fecundity increased. The results indicated that while E. africanus develops across a wide temperature range, 30 °C has the highest intrinsic rate of increase (r), the net reproductive rate (R₀), and the shortest time for population doubling (DT). The gross reproductive rate (GRR) reached the highest value at 30 °C as well. This study might be a significant step toward funding the future establishment of effective mite control.

Abstract Pesticides are broadly used in the control of Tetranychus urticae Koch populations. In the present study, the toxicity and residual activities of abamectin, spirodiclofen, and pyridaben against T. urticae on cucumber plants were assessed under laboratory and greenhouse conditions. Furthermore, the influences of tested pesticides on some biological aspects of this pest were studied. In laboratory experiments, LC₅₀ values of abamectin, spirodiclofen, and pyridaben to females were 0.71, 41.04, and 28.56 ppm, respectively. Treated females presented low fecundities ranging from 0.18 to 3.81 eggs/female/day versus 8.4 eggs/female/day in control. Spirodiclofen and pyridaben were found to be have much stronger ovicidal activity as compared to abamectin. Abamectin and spirodiclofen had an elongation effect on the developmental durations of immatures with a mean pre-adult of 14.60 and 10.04 days, respectively, compared to 8.75 days in the control. The highest reduction effect of spirodiclofen and pyridaben on T. urticae populations were 100 and 87.14 %, respectively at 3 days post-treatment compared to 100% in abamectin at all tested durations. In the residual efficacy test, abamectin caused 100% mortality of T. urticae at 7 days after spraying compared to 63.27 and 47.96 % in the case of spirodiclofen and pyridaben, respectively. However, no phytotoxicity was observed on treated plants at recommended rates. The determined residues of spirodiclofen and abamectin in cucumber fruits were above the maximum residue limit (MRL) amounts after 10 days of treatment, so the preharvest intervals (PHI) for both compounds were 15 days, while PHI for pyridaben was 10 days. Therefore, the cucumber fruits could be consumed safely after these periods.

Abstract The successful rearing of predators and parasitoids is crucial for the effectiveness of biological control programs. A notable challenge in rearing phytoseiid mites, specifically Amblyseius swirskii and Transeius wainsteini, is preventing mold contamination in their diets. This study evaluated the efficacy of three herbal powders, thyme, green tea, and lemongrass, as well as the chemical agent, calcium propionate, in suppressing mold development. Experiments were conducted using a diet composed of cattail pollen and rice husks under controlled laboratory conditions (25 ± 1 °C, 65 ± 5% RH, and 16L: 8D h photoperiod). A diet without any additive agents served as the control. To quantify mold growth within each rearing unit, a numerical index, the Mold Contamination Index (MCI), ranging from 0 to 4 was employed. The results demonstrated that calcium propionate was significantly more effective than the other treatments, achieving complete inhibition of mold development (MCI = 0), compared to the control treatment (MCI = 1.45 and 1.40 for A. swirskii and T. wainsteini, respectively). The incorporation of calcium propionate into the diet significantly enhanced population growth rates, reaching 31.95% for A. swirskii and 23.57% for T. wainsteini, compared to the control treatments, which showed increases of only 2.3% and 1.74%, respectively, over one month. In contrast, the addition of botanical powders did not inhibit mold growth and was associated with a decrease in population growth rates relative to the controls. The mixture of cattail pollen, rice husks, and calcium propionate provided sufficient nutritional support, facilitating population growth of both mite species. Consequently, the populations expanded to a total of 494.3 and 368.6 individuals across all developmental stages, originating from an initial density of 15 adult mites, within one month for A. swirskii and T. wainsteini, respectively. This study presents a promising strategy for managing mold in phytoseiid mite diets, ultimately fostering healthier rearing conditions.