Influence of host plant species on the development and reproduction of hawthorn spider mites

A leaf disc bioassay was employed to investigate the influence of host species of deciduous fruit trees, like apple, peach, plum, cherry and apricot, on the development and reproduction of the hawthorn spider mite Tetranychus viennensis Zacher in the laboratory under conditions of 25±1°C, 60±10% RH and a photoperiod of 16 h: 8 h light: dark. This was done by determining the duration of each life stage of the mites, the intrinsic rate of population increase (r _m ), mean generation time (T) and net reproductive rate (R ₀) of the spider mites on each of the host plant species. Differences in life table parameters of the spider mite among host plants were analyzed with the jack-knife method. The results indicated that plum might be the best suitable plant for the spider mite among the plants tested due to shorter developmental period and higher intrinsic rate of increase, whereas cherry and apricot were least suitable due to their long developmental duration and low intrinsic rates of increase. When the spider mites were transferred from apple to other fruit trees, negative effects on developmental duration, fecundity and life table parameters were found in the first generation, but the effects faded out in succeeding generations. When transferred onto plum and peach, the spider mite adapted to the new hosts in the second generation; however, on cherry and apricot, it adapted in the third generation. __________ Translated from Acta Ecologica Sinica, 2005, 27(7) [译自: 生态学报, 2005, 27(7)]     

The colonization preference and population trends of larval fig psylla, <Emphasis Type="Italic">Homotoma ficus</Emphasis> L. (Hemiptera: Homotomidae)

The colonization preference and population trends of larval fig psylla Homotoma ficus L. were studied in Bursa, northwestern Turkey, from March 2000 to July 2001. Homotoma ficus overwintered at the egg stage on terminal buds and lenticels of shoots. Larval emergence occurred on 30th and 11th March in 2000 and 2001, respectively. Degree-day (DD) accumulations since 1st January indicate that the emergence of first larvae averaged 47 DD based on the larval developmental threshold of 10.9°C. Although the population trends of Homotoma ficus larvae were affected by temperature and rainfall, there was only significant relationship between larval abundance and temperature. The first instar larvae significantly preferred the bottom and the inside stipule of leaves. The second instar larvae distributed not only on expanding green tissues but also on both the upper and lower surface of leaves corresponding to the fig bud development period. Third to fifth instars colonized significantly greater on the bottom of leaves compared with the stipule and upper surface. In addition, significant linear relationship was found between fig phenology and cumulative larval counts. The importance of the colonization preference of larval instars and the use of fig phenology as well as DD for timing of insecticide treatments are discussed.     

Side effect of some fungicides on the mite population in an apple orchard in Croatia

The research into the side effect of fungicides used in the control of the most serious disease in apples (Venturia inaequalis) i. e. the research into the influence of fungicides on the population of phytophagous mites, was carried out at Nedeli??e (North-West Croatia) during 1997 and 1998. The study is related to the population of the mites most present in apple orchards, such as red spider mite (Pananychus ulmi) and other mites (Aculus schlechtendali andTetranychus urticae). Fungicides which are known to be effective against scab, i. e.Venturia inaequalis, and used in fruit production in Croatia, were tested in order to investigate their secondary properties which have not yet been studied. The following fungicides were used: cyprodinil, dodine, dichlofluanid + bitertanol (as tank mix), and kresoxim-methyl. The tests were repeated three times; the application time was determined by monitoring the conditions for infection. The treatments were done curatively, i. e. up to 96 h after the onset of infection conditions. The mite population was estimated by the pressing method, which yielded the average number of mites per leaf. All the results were statistically processed by variance analysis and by Duncan’s Multiple Range Test, and are presented graphically and in tables. The paper also presents graphically the climatic conditions, scab infections and application time. The research over two years have shown a pronounced suppressive effect of dichlofluanid + bitertanol on populations of phytophagous mites, while the other fungicides used in the research had a neutral effect on the mite papulation.     

Resistance to amitraz in the parasitic honey bee mite Varroa destructor is associated with mutations in the β-adrenergic-like octopamine receptor

Varroa destructor is considered a major reason for high loss rate of Western honey bee (Apis mellifera) colonies. To prevent colony losses caused by V. destructor, it is necessary to actively manage the mite population. Beekeepers, particularly commercial beekeepers, have few alternative treatments other than synthetic acaricides to control the parasite, resulting in intensive treatment regimens that led to the evolution of resistance in mite populations. To investigate the mechanism of the resistance to amitraz detected in V. destructor mites from French and U.S. apiaries, we identified and characterized octopamine and tyramine receptors (the known targets of amitraz) in this species. The comparison of sequences obtained from mites collected from different apiaries with different treatment regimens, showed that the amino acid substitutions N87S or Y215H in the OctβR were associated with treatment failures reported in French or U.S. apiaries, respectively. Based on our findings, we have developed and tested two high throughput diagnostic assays based on TaqMan technology able to accurately detect mites carrying the mutations in this receptor. This valuable information may be of help for beekeepers when selecting the most suitable acaricide to manage V. destructor.

     

Phoretic mites of three bark beetles (<Emphasis Type="Italic">Pityokteines</Emphasis> spp.) on Silver fir

The species composition and abundance of phoretic mites of the bark beetles Pityokteines curvidens, P. spinidens, and P. vorontzowi on Silver fir (Abies alba) were investigated in 2003 at two locations (Trakoscan and Litoric) in Croatia. Stem sections and branches from A. alba trees infested by Pityokteines ssp. were collected and incubated in rearing cages. Bark beetles emerging from the stem sections and branches were examined for photetic mites. A total of ten mite species were documented for the first time as associates of Pityokteines spp. on A. alba. These included Dendrolaelaps quadrisetus, Ereynetes scutulis, Histiostoma piceae, Paraleius leontonychus, Pleuronectocelaeno japonica, Proctolaelaps hystricoides, Schizostethus simulatrix, Tarsonemus minimax, Trichouropoda lamellose, and Uroobovella ipidis. T. minimax was the most frequent phoretic mite of all the three scolytines and U. ipidis was also common, whereas, the other mite species occurred less frequently. The species spectrum and relative abundance of mite associates were similar for all three Pityokteines species. Another species, Pleuronectocelaeno barbara was commonly found phoretic on P. curvidens, captured in pheromone traps in 2005 at the location Litoric. Furthermore, two previously collected mite specimens from Switzerland, phoretic on P. curvidens, were identified as Nanacarus sp. and Bonomia sp. The records from Croatia and Switzerland in the present study increase the number of known mite associates of Pityokteines spp. from one previously documented species to 14 species. None of the phoretic mites found in the survey in Croatia appear to have the potential to be used for biological control of Pityokteines spp., although the feeding habits are unknown for many species recorded.     

Harmfulness of eriophyid mites (Eriophyoidea,Acari) causing galls on trees and shrubs in the Czech Republic

Fifteen eriophyid mite species are the most abundant species in the Czech Republic from which four, viz.Eriophyes fraxinivorus onFraxinus excelsior, E. platanoideus onAcer platanoides, Phytoptus pyri onPyrus communis andStenacis triradiatus on various species ofSalix injure their host plants and are evaluated as pests. The weight of the leaves attacked by eriophyid mites increase with increasing number of galls pro leaf but the surface of attacked leaves decrease with increasing attack. Harmfulness of eriophyid mites manifests by reducing of assimilation processes, retardation of growth, precocious drying and fall-off of attacked leaves. Heavily attacked young shrubs and trees may dry and decease.With one figure and 2 tables     

Varroa mites,viruses and bacteria incidences in Kenyan domesticated honeybee colonies

Varroa mite (Varroa destructor Anderson and Trueman) is a major global threat to the western honey bee (Apis mellifera L.). The ectoparasite has been implicated in the spread of honeybee viruses. Beekeeping plays a major role in transmission of the mite. The study aimed at assessing levels of Varroa infestation, bee viruses and bacteria incidences in domesticated honeybee colonies. Samples of adult honey bees, bee brood and Varroa mites were collected from Baringo, Narok, Kwale, Magarini, Voi, Ijara, Busia and Siaya in Kenya. Ten hives in each site were inspected for the presence of Varroa mites on adult bees using the icing sugar technique and forceps in sealed brood cells. The number of mites observed were recorded per site. Ribonucleic acid was extracted from the mites, brood and adult bees and a polymerase chain reaction was performed to detect the black queen cell virus. Pooled RNA samples of brood and adult bees were used in next generation sequencing on a 454 GS FLX platform to detect bee viruses and bacteria. Varroa mites were reported in all the study sites at varying levels. The black queen cell virus and three iflaviruses, European foul brood and its secondary causative agent Enterococcus faecalis were reported. The Kenyan honeybee population is threatened by bee pests and pathogens. There is a need for constant monitoring of bee pests and diseases in honeybee colonies in the country for early detection and to provide data on the status of bee health. All stakeholders in the beekeeping value chain should be enlightened on their role in pest and disease transmission.     

Über Nahrungskreis und wirtschaftliche Bedeutung der Raubmilbe Agistemus exsertus Gonz. (Acari,Prostigmata)

Food range and economic importance of the predator mite, Agistemus exsertus Gonz. (Acari, Prostigmata) The predator miteAgistemus excertus fed on eggs ofTetranychus arabicus, crawlers of the scale insectChrysomphalus ficus, eggs of bothLipidosaphes baledi, andL. beckii, while it did not feed on eggs ofC. ficus and crawlers ofL. beckii. The predator developed and reproduced on all the four former prey types but at different rates. Eggs ofT. arabicus were the best food for quiker development, longer longevity and higher rate of reproductivity. These were followed by eggs ofL. baledi, crawlers ofC. ficus, and eggs ofL.beckii.     

Acaricidal,repellent and oviposition deterrent activities of <Emphasis Type="Italic">Datura stramonium</Emphasis> L. against adult <Emphasis Type="Italic">Tetranychus urticae</Emphasis> (Koch)

The ethanol extracts obtained from both leaf and seed in the Thorn apple (Datura stramonium L.) (Solanaceae) were investigated for acaricidal, repellent and oviposition deterrent properties against adult two-spotted spider mites (Tetranychus urticae Koch) (Acari: Tetranychidae) under laboratory conditions. Leaf and seed extracts, which were applied in 167,250 and 145,750 mg/l concentrations, respectively (using a Petri leaf disc-spray tower method), caused 98 and 25% mortality among spider mite adults after 48 h. The simple logistic regression analysis showed that the independent variable, an increase in the dose of leaf extract was associated with a significant increase in the death rate of T. urticae females, but an increase in the dosage of seed extracts did not have a significant effect. Using probit analysis and estimating the parameters with a confidence limit of 95%, we determined the LC₅₀ values of leaf extract to be 70,593 mg/l. According to Pearson’s χ² test, mites showed the strongest run off to bean leaf surfaces sprayed with both leaf and seed extracts (in sub-lethal doses: <7,500 mg/l and <25,000 mg/l, respectively) and moved towards surfaces that had not been sprayed with extracts. Furthermore, repeated measures ANOVA indicated a significant difference between the number of eggs laid on unsprayed bean leaves compared to bean leaves that were sprayed with leaf and seed extracts at sub-lethal doses, 2,500 and 25,000 mg/l concentrations, respectively. These results suggest that D. stramonium extracts could be used to manage the two-spotted spider mite.     

House dust mites and their sensitivity to wood oils and volatiles

Allergic diseases such as bronchial asthma, perennial rhinitis, and atopic dermatitis caused by the house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae, which are dominant species in homes, have recently become serious health problems. Reducing the number of and exposure to mites and mite allergens are the most important factors in preventing allergic diseases. Recently, the effects of essential oils of plants on house dust mites have received much attention with a view to producing natural mite-killing agents. Essential oils and their components of wood and their leaves have also received much attention. In this article, we summarize the biology of house dust mites, mite allergens, and their concentration in homes, and discuss the control of house dust mites by using plant and wood extractives, especially in relation to the influence of essential oils and volatiles from wood on house dust mites.     

The toxicity of selected acaricides against five stored product mites under laboratory assay

In laboratory tests, the toxicity of acaricides targeted against house dust mites was tested on five species of stored product mites (Acarus siro, Aleuroglyphus ovatus, Carpoglyphus lactis, Lepidoglyphus destructor, and Tyroborus lini). The formulations of benzyl-benzoate, benzyl-benzoate/permethrin/pyriproxyfen, and neem were diluted in water and applied to filter paper in an unventilated chamber. The mortality of mites was observed after 24 h of exposure to acaricide-impregnated filter paper. All of the tested acaricides were toxic to all of the mite species. There were significant differences in mortality among the species and the acaricides. Benzyl-benzoate/permethrin/pyriproxyfen was the most effective, followed by benzyl-benzoate and neem. L. destructor (LD₅₀ 0.01–0.11 μg) was the most sensitive mite species, followed by A. siro (LD₅₀ 0.04–0.12 μg), T. lini (LD₅₀ 2–21 μg), A. ovatus (LD₅₀ 3–18 μg), and C. lactis (LD₅₀ 4–64 μg). Based on the highly toxic effects of the tested acaricides against the stored product mites, the acaricides should be considered as a potential tool in the control of stored product mites, although next screening is necessary.     

Effect of soybean cultivar on life history parameters of <Emphasis Type="Italic">Tetranychus urticae</Emphasis> Koch (Acari: Tetranychidae)

The two-spotted spider mite, Tetranychus urticae Koch, is a very polyphagous pest with a worldwide distribution. In order to appraise population growth parameters of this pest, samples of two-spotted spider mites were taken from soybean (Glycine max) fields of Moghan region, Iran in June 2007 and are reared on bean plants var. Derakhshan (Phaseolus vulgaris) in a growth chamber. The life table parameters of this pest were calculated on three commercial soybean cultivars (Zane, Hach, and L17) and one hybrid (Hob × Will) at 25 ± 1°C, 60 ± 10%RH, and 16 h photophase. The developmental times of immature stages varied from 9.69 on Hach to 9.82 days on L17, whereas the immature survival was 57–79% on Hach and Hob × Will, respectively. On average, there were 65.5, 40.8, 38.8 and 34 eggs produced per female on L17, Hach, Hob × Will and Zane, respectively. The intrinsic rate of natural increase (r _m ) for T. urticae on Hob × Will was the highest, whereas the values for r _m ranged from 0.211 (females/female/day) on Zane to 0.292 on Hob × Will. Also, jackknife values of other life table parameters such as net reproductive rate (R ₀), generation times (T), doubling time (DT), and finite rate of increase (λ) on these cultivars were estimated. Overall, the two-spotted spider mite indicated a better performance on Hob × Will than on the other soybean cultivars.     

Effect of hinoki (Chamaecyparis obtusa) wood-wool in tatami mat on the activity of house dust mite Dermatophagoides pteronyssinus

To suppress the activity of house dust mites in tatami mats, where they tend to breed, a tatami mat consisting of hinoki (Chamaecyparis obtuse) wood-wool was prepared. The suppressive effect of hinoki wood-wool on house dust mites (Dermatophagoides pteronyssinus) was then measured. To investigate the effective period of the wood-wool on the mites, 5-day exposure tests were conducted every few weeks for a total of 52 weeks. In the tests of the first and sixth weeks, the activity of the mites was strongly suppressed, and no walking or moving mite was found after 5 days of exposure. The suppressive effect on mites was maintained for 52 weeks. It was concluded that using hinoki wood-wool to produce tatami mats is an effective method of suppressing the activity of mites for about 1 year.     

Zum Massenwechsel der SpinnmilbeTetranychus cinnabarinus (Boisd.) und der RaubmilbeAmblyseius gossypii (Elbadry) auf Baumwolle

Population dynamics of Tetranychus cinnabarinus (Boisd.) and Amblyseius gossypii (Elbadry) (Acari) on cotton plants Population dynamics of spider mites and predators on cotton plants were influenced by the date of cotton plantation. The plantation of cotton in October–November led to earlier and higher infestation of cotton leaves with spider mites than that of cotton planted in March. Similar magnitude of predatory mite infestation was observed in the cotton planted either October–November or in March. However, another lower peak of predatory mite population was recorded during May in the cotton planted in October–November. Spider mite populationl decreased gradually when predatory mite population increased rapidly on cotton leaves during August regardless to the date of cotton plantation. Chemical control of tetranychid mites on cotton plants should be applied by the first week of July to encounter population outbreaks which arise by the end of July and during August.     

Effect of volatile matter from wood chips on the activity of house dust mites and on the sensory evaluation of humans

The effect of volatile matter from various wood chips on house dust mites and their influence on human comfort were measured. To investigate the effect of volatile matter on the mite speciesDermatophagoides pteronyssinus, the activity of the mites was observed after exposure to volatile matter from six species of wood chips. The degree of activity of the mites was classified into two categories: (1) walking or moving and (2) immobilized. To measure their influence on human comfort, the smells of those wood chips were evaluated by the subjects. Among softwoods, volatile matter fromChamaecyparis obtusa andThujopsis dolabrata var.hondai chips suppressed the activity of the mites highly and made the subjects feel refreshed and unexcited.Cryptomeria japonica showed slight suppression of the mites and was considered to be refreshing, natural, and unexciting by the subjects. Among hardwoods,Cinnamomum camphora highly suppressed mites activity and was considered to be non-refreshing and exciting by the subjects. Part of this paper was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999     

Cannibalism and interspecific predation of the phytoseiid mite,<Emphasis Type="Italic"> Amblyseius swirskii</Emphasis>

A laboratory study revealed that females of the phytoseiid mite, Amblyseius swirskii Athias-Henriot, fed on protonymphs of their own species or of other predatory mites i.e. Agistemus exsertus Gonzales and Euseius scutalis Athias-Henriot exhibited a marked decline in their fecundity and a shortening in their longevity. Moreover, the rate of predation was also reduced. When A. swirskii females were fed on nymphs of the two-spotted spider mite Tetranychus urticae Koch after having been fed previously on protonymphs of either A. swirskii or A. exsertus increases in the rates of oviposition and consumption were observed, although these rates were lower than those of conspecific females reared continuously on the two-spotted spider mite only.     

Effective period of volatiles from softwood veneers embedded in tatami mats on the activity of house dust mites

To suppress the activity of house dust mites in tatami mats, where they tend to breed, tatami mats were prepared with embedded softwood veneers. The effective period of the volatiles from the veneers on the mites was then measured. To investigate the effective period of volatiles from hiba (Thujopsis dolabrata var. hondai) and hinoki (Chamaecyparis obtusa) veneers on house dust mites (Dermatophagoides pteronyssinus), 5-day exposure tests were conducted every few weeks for 54 weeks. In the exposure tests, the activity of the mites was observed after 5 days of exposure to the volatiles. Volatiles from hiba veneers strongly suppressed the activity of the mites for 15 weeks. The suppressive effect decreased gradually after that, but it was maintained for 54 weeks. Volatiles from hinoki veneers showed moderate to high suppression of mite activity for 11 weeks, but no suppressive effect was observed after that. In conclusion, embedding hiba or hinoki veneers in tatami mats is an effective method of suppressing the activity of mites for about a year or for slightly less than 3 months, respectively.Part of this paper was presented at the 51st Annual Meeting of the Japan Wood Research Society in Tokyo, April 2001     

Leaf dynamics and protein content of six important fodder trees of the western Himalaya

Leaf production, leaf fall, leaf protein and net primary productivity have been reported for 4-year-old fodder trees in the mid-western Himalaya (altitude 1350 m; rainfall 1100 mm). The species include; Grewia optiva, Robinia pseudoacacia and Celtis australis growing in the open and Quercus glauca, Q. leucotrichophora and Ilex odorata growing in the forest. G. optiva, R. pseudoacacia and C. australis showed two distinct periods of leaf flush, and their leaves were short-lived (180 to 360 days) compared with the remaining three species which retained their leaves for more than two years, and had only one flush period during March–April. The open site species showed much higher leaf production, and the leaves contained a significantly (P < 0.05) higher protein content, compared with the forest group. Net primary productivity of G. optiva, C. australis and R. pseudoacacia was significantly (P < 0.05) higher than the forest species, which may be related to their high leaf production and rapid turnover rate of the leaves. The results are useful for management of these species in agroforestry systems.     

Neue und wenig bekannte Milben im Iran

Summary New and little known mite-species found in Iran Report is made about the most important mites of the family Tenuipalpidae, Tetranychidae and Eriophyidae (Acari), which, until now, have been found to be pests in Iran. The new speciesCenopalpus irani Dosse was identified on apple and quince, as well asCenopalpus crataegi Dosse onCrataegus oxyacantha andCr. monogyne. The spider miteEotetranychus weldoni (Ewing) was found onSalix pentandra. Gall-forming and vagrant kinds of Eriophyidae have been observed onAlnus glutinosa, Amygdalus communis, Ficus carica, Juglans regia, Pyrus communis, P. malus, Punica granatum andRubus idaeus recently. The discovery ofPhyllocoptes granati K. (deutogyne) onAmygdalus communis andEriophyes brevipunctatus Nal. onUlmus campestris is completely new in Iran. For the first timeRhyncaphytoptus ficifoliae K. in deutogyne form has been identified on leaves ofFicus carica. BesidesZetzellia mali, especially predatory mites of the Phytoseiidae family seem to play an important role in Iran, as we discoveredPhytoseius finitimus on figs, grapes andRubus idaeus, andPhytoseius corniger on figs, too.The importance of mites of the Tydeidae family and a number of other rare mites is still widely unknown.     

Begünstigung von Erdnuß-Spinnmilben durch Anbau von Erdnüssen in Obst-Plantagen sowie Ergebnisse von Bekämpfungsversuchen

Favouring Tetranychid mites by intercropping peanut plants on citrus plants and results of chemical control measures The mite populations ofT. cucurbitacearum (Sayed) andT. arabicus (Attiah) reached noxious levels on the peanut plants intercropped on orange trees, during July and August, when the increasing in temperature was accompanied with increasing in humidity. It seems that intercropping the peanut plants on fruit trees and cultural practices may affect as well peanut plant condition as the mortality of mites and consequently increase mite infestation.Regarding, the control experiments, it had been found that 5 acaricides used were very effective in decreasing Tetranychid populations on peanut plants.