Finlandicus Oudemans Research Articles

Study on predatory mites of Aceria tristriatus (Nalepa, 1890) from Hamedan and Lorestan provinces, Western Iran

The walnut leaf gall mite ( Aceria tristriatus ) is one of the major pests of walnut in western Iran. Therefore, a study to determine the predatory mites associated with this pest in Hamedan and Lorestan provinces was carried out during 2014–2017. In this survey, totally 10 species belong to six genera and three different families including Phytoseiidae: Kuzinellus kuzini Wainstein, Typhlodromus bagdasarjani Wainstein & Arutunjan, Typhlodromus khosrovensis Arutunjan, Euseius finlandicus Oudemans; Iolinidae: Neopronematus iranensis Ahmad-Hosseini et al. , Neopronematus solani Ripka et al. , Pronematus rykei Meyer & Rodrigues; Tydeidae: Tydeus caryae Khanjani & Ueckermann, Tydeus goetzi Schruft, and Tydeus electus Kuznetzov were collected and identified. Kuzinellus kuzini Wainstein had the highest frequency and distribution in this survey. Among the collected species, Typhlodromus khosrovensis , Typhlodromus bagdasarjani , E. finlandicus , N. solani , Tydeus caryae , Tydeus goetzi and Tydeus electus are re-described in the present paper. Tydeus goetzi and Neopronematus solani are reported for the first time for Hamedan and Lorestan provinces.

Egg hatching response to a range of ultraviolet-B (UV-B) radiation doses for four predatory mites and the herbivorous spider mite Tetranychus urticae.

Egg hatchability of four predatory mites-Phytoseiulus persimilis Athias-Henriot, Iphiseius [Amblyseius] degenerans Berlese, Amblyseius swirskii Athias-Henriot, and Euseius finlandicus Oudemans (Acari: Phytoseiidae)-and the spider mite Tetranychus urticae Koch (Acari: Tetranychidae) was determined under various UV-B doses either in constant darkness (DD) or with simultaneous irradiation using white light. Under UV-B irradiation and DD or simultaneous irradiation with white light, the predator's eggs hatched in significantly lower percentages than in the control non-exposed eggs, which indicates deleterious effects of UV-B on embryonic development. In addition, higher hatchability percentages were observed under UV-B irradiation and DD in eggs of the predatory mites than in eggs of T. urticae. This might be caused by a higher involvement of an antioxidant system, shield effects by pigments or a mere shorter duration of embryonic development in predatory mites than in T. urticae, thus avoiding accumulative effects of UV-B. Although no eggs of T. urticae hatched under UV-B irradiation and DD, variable hatchability percentages were observed under simultaneous irradiation with white light, which suggests the involvement of a photoreactivation system that reduces UV-B damages. Under the same doses with simultaneous irradiation with white light, eggs of T. urticae displayed higher photoreactivation and were more tolerant to UV-B than eggs of the predatory mites. Among predators variation regarding the tolerance to UV-B effects was observed, with eggs of P. persimilis and I. degenerans being more tolerant to UV-B radiation than eggs of A. swirskii and E. finlandicus.

Екологія та поширення Euseius finlandicus (Parasitiformes, Phytoseiidae) у садах Закарпатської області

Описано екологію та поширення Euseius finlandicus Oudemans, 1915 (Parasitiformes, Phytoseiidae) у садових фітоценозах Закарпатської області. В Україні подібні дослідження проведено для зони Лісостепу. Кліщів збирали протягом 2012–2014 рр. Досліджено 9 населених пунктів Закарпатської області. На території досліджень Eu. finlandicus заселяє щонайменше 26 видів рослин. Уперше визначено статус виду в акарокомплексах родини Phytoseiidae у садових фітоценозах Закарпатської області. Для виду розраховано індекси трапляння та домінування. Описано види рослин, на яких трапляється Eu. finlandicus у вказаних фітоценозах. Результати дозволяють вважати Eu. finlandicus фоновим видом у садових фітоценозах Закарпатської області. Отримані результати можуть стати теоретичною основою для розроблення схем підвищення захисної функції корисних кліщів у фітоценозах Ужгородського району.

Overwintering sites and winter mortality of Euseius finlandicus (Acari: Phytoseiidae) in a peach orchard in northern Greece.

In peach orchards of northern Greece Euseius finlandicus Oudemans overwinters in various sites on the trees, usually in groups of 5-15 females. Overwintering females were mostly found in bark crevices near the hibernation cocoons of the peach moth Adoxophyes orana (Fischer von Rosslerstamm), and also in small crevices of the bark and in pedicels left after fruit harvesting. Empty scales of dead diaspidids and dead coccids, cocoons of lacewings and mummies of parasitized aphids sporadically found on trees, were less common overwintering sites for females of the mite. In two successive years, mortality of overwintering females was very low, approximately 4 and 4.5% which could be due to the mild climate of northern Greece and the high cold tolerance of the mite.

Diapause induction and termination in the predatory mite Euseius finlandicus in peach orchards in northern Greece.

The course of diapause induction as well as of diapause termination in females of the predatory mite Euseius (Amblyseius) finlandicus Oudemans (Acari: Phytoseiidae) in Northern Greece was determined by transferring females during winter and early spring from peach trees to a short day (LD 8:16) or a long day (LD 16:8) photoperiod both at 20 degrees C. The first diapause females were found in mid September and by the first week of October all the females were in diapause. The mean number of days required for diapause termination under the short day photoperiod LD 8:16 was gradually reduced from 93.7 days in the beginning of October to less than 20 days in mid February and early March. Under the long day photoperiod of LD 16:8 diapause was terminated in less than 20 days irrespective of the date of collection. These results indicate that by mid February photoperiodic sensitivity of females was lost and diapause was terminated. However, females were found in their overwintering sites until the second half of March, probably because of the prevailing relatively low temperatures and lack of adequate food.

Development, survival and reproduction of Euseius finlandicus (Acari: Phytoseiidae) at different constant temperatures.

Development, survival and reproduction of Euseius finlandicus Oudemans were studied at seven constant temperatures (15, 20, 25, 27, 30, 32 and 34 degrees C) in the laboratory. Within the temperature range tested, developmental period from egg to adult varied from 148 to 360.5 h and 133.7 to 336.5 h for females and males, respectively. The lower thermal threshold for immature development for females and males was 8.9 and 6.4 degrees C, respectively. Survival during immature development exceeded 90% at all the temperatures from 15 to 32 degrees C, but at 34 degrees C an abrupt decline was recorded. Female longevity decreased gradually from 82.7 d at 15 degrees C to 12.2 d at 34 degrees C. The mean generation time ranged from 44.3 d at 15 degrees C to 15.9 d at 32 degrees C. The highest rm value (0.2817) was obtained at 30 degrees C and the lowest at 15 degrees C (0.0976). Temperatures above 30 degrees C had an adverse effect on population increase.

Effect of Different Pollens on Development, Survivorship and Reproduction ofEuseius finlandicus(Acari: Phytoseiidae)

Development, imaginal survivorship, adult longevity and fecundity of the predatory phytoseiid mite Euseius (Amblyseius) finlandicus Oudemans reared on seven different plant pollens were determined in the laboratory. The rationale behind these experiments was to assess the nutritional value and the possible effect on development and population dynamics of the mite. Mites were kept individually on bean (Phaseolus vulgaris L.) leaf disks at 20 6 18C and a photoperiod of 16:8 (L:D) h, with a sufficient quantity of pollen of apple (Malus silvestris M.), pear (Pyrus communis L.), cherry (Prunus avium L.), peach (Prunus persica L.), apricot (Prunus armeniaca L.), walnut (Juglans regia L.), or poppy (Papaver rhoeas L.). Developmental time from neonate larva to adult emergence varied between the different pollens from 6.03 to 6.62 d for females and from 5.46 to 6.14 d for males. Survivorship during immature development varied from 67.2 to 95.9% with the lowest value recorded on peach pollen. The average life span of adult females reared on the different pollens varied from 18.2 to 56.2 d, whereas the respective total fecundity ranged from 2.5 to 46.5 eggs per female. The estimated values of the intrinsic rate of increase (rm) varied from 0.012 to 0.150. The analysis of these results show that cherry, peach, apricot, walnut, and poppy pollens are of higher nutritional value for E. finlandicus than apple and pear pollens and thus may play an important role in the field for sustaining and increasing the predator's population.

Survival, development and fecundity in Euseius finlandicus, Typhlodromus pyri and Kampimodromus aberrans (Acari, Phytoseiidae) feeding on the San José scale Quadraspidiotus perniciosus (Coccina, Diaspididae)

Abstract: Studies on juvenile survival, development and reproduction of Euseius finlandicus Oudemans, Typhlodromus pyri Scheuten and Kampimodromus aberrans Oudemans feeding on crawlers of the diaspidid San José scale Quadraspidiotus perniciosus Comstock were conducted in the laboratory at 25 ± 1°C, 65 ± 5% RH and 16 h photoperiod. Immature life stages as well as adult females readily accepted crawlers as prey. All predatory species preying upon scale crawlers were able to complete development and to sustain reproduction during a 10‐day‐period. Immatures of E. finlandicus and K. aberrans had a low juvenile mortality, whereas nearly 50% of T. pyri protonymphs died. Mean development from larva to adult took 5.6 days in E. finlandicus, 13.2 days in K. aberrans and 17.4 days in T. pyri. E. finlandicus had a higher fecundity (0.7 eggs/day/female) than T. pyri (0.5 eggs/female/day) and K. aberrans (0.4 eggs/female/day). However, San José scale crawlers must be considered a suboptimal prey. Its nutritional value is discussed in relation to that of more adequate food sources. Data on development and fecundity are also discussed in relation to other phytoseiid species feeding on armoured scale insects.

The influence of relative humidity on egg hatch in Euseius filandicus, Typhlodromus pyri and Kampimodromus aberrans (Acari, Phytoseiidae)

Abstract: The effects of different relative humidities (50%, 55%, 65%, 75%, 85% and 100% RH) on egg hatch were tested at 25 ± 1°C for three strains of Euseius finlandicus Oudemans, two strains of Typhlodromus pyri Scheuten and two strains of Kampimodromus aberrans Oudemans. At decreasing humidity, egg mortality increased earlier in K. aberrans than in E. finlandicus and T. pyri. E. finlandicus and T. pyri had similar humidity responses. Differences between strains within each species were small. RH50 values (relative humidity at which 50% of eggs hatch) were 50.4%, 52.4% and 53.1% for strains of E. finlandicus, 51.8% and 53.3% for strains of T. pyri, and 55.3% and 57.5% for strains of K. aberrans, respectively. Eggs of the Finnish E. finlandicus strain were most drought resistant (50.4% RH50), eggs of the French K. aberrans strain were most sensitive (57.5% RH50). The results are discussed in relation to the abundance of these species on certain plants and to the humidity responses of other phytoseiids.

Predatory phytoseiid mites (Acari: Mesostigmata) in vineyards and fruit orchards in Southern Tyrol

Results of monitoring communities of the predatory phytoseiid mites in 70 commercial vineyards and 29 apple orchards in the Eisack-and Etsch-river valleys, Southern Tyrol, are reported and discussed.Typhlodromus pyri Scheuten,Amblyseius andersoni (Chant) and, locally,A. finlandicus Oudemans were the most abundant species.