Freeze mortality characteristics of the mold mite Tyrophagus putrescentiae, a significant pest of stored products

The mold mite Tyrophagus putrescentiae (Shrank) is a common pest of stored food products. Until recently, commodity and facility treatments have relied on acaricides and fumigants to control this mite. However, T. putrescentiae will cause infestations in areas where acaricide or fumigant use may be restricted, prohibited, or highly impractical. Because temperature is an essential factor that limits the survival of arthropod species, extreme temperatures can be exploited as an effective method of control. Making low-temperature treatments reliable requires better temperature-time mortality estimates for different stages of this mite. This was accomplished by exposing a representative culture (eggs, nymphs, and adults) of noncold-acclimated T. putrescentiae to subfreezing temperatures to determine their supercooling points (SCPs), lower lethal temperatures (LLTs) and lethal times (LTimes) at set temperatures. The results indicate that the adult and nymphal stages of T. putrescentiae are freeze intolerant; based on 95% CIs, the adult LLT90 of -22.5 degrees C is not significantly different from the SCP of -24.2 degrees C and the nymphal LLT90 of -28.7 degrees C is not significantly different from the SCP of -26.5 degrees C. The egg stage seems to be freeze tolerant, with an LLT90 of -48.1 degrees C, significantly colder by approximately 13.5 degrees C than its SCP of -35.6 degrees C. The LTime demonstrates that 90% of all mite stages of T. putrescentiae can be controlled within commodity or packaged product by freezing to -18 degrees C for 5 h. By achieving the recommended time and temperature exposures, freezing conditions can be an effective way of controlling mites and reducing chronic infestations.     

Temperature preference and respiration of acaridid mites

The thermal preferences in a grain mass and respiration at various temperatures in mites (Acari: Acarididae) of medical and economical importance [Acarus siro (L. 1758), Dermatophagoides farinae Hughes 1961, Lepidoglyphus destructor (Schrank 1871), and Tyrophagus putrescentiae (Schrank 1781)] were studied under laboratory conditions. Based on the distribution of mites in wheat, Triticum aestivum L., grain along a thermal gradient from 10 to 40 degrees C, L. destructor, D. farinae, and A. siro were classified as eurythermic and T. putrescentiae as stenothermic. The lowest preferred temperature was found for D. farinae (28 degrees C), followed by A. siro (28.5 degrees C), L. destructor (29.5 degrees C), and T. putrescentiae (31.5 degrees C). The relationship between the respiration rate and the temperature was similar for all four mite species. The highest respiration was found in the range from 31 to 33 degrees C. This is approximately 2 degrees C higher than the preferred temperature of these species. The lower temperature threshold of respiration ranged from 1 to 5 degrees C and the upper threshold ranged from 45 to 48 degrees C. Acclimatization of A. siro to temperature regimes of 5, 15, and 35 degrees C resulted in thermal preferences between 9 and 12 degrees C, 9 and 20 degrees C, and 28 and 35 degrees C, respectively. The respiration rate of acclimatized specimens increased with the temperature, reaching a maximum at 29.0 degrees C for mites acclimatized at 5 and 15 degrees C and a maximum at 33.7 degrees C for those acclimatized at 30 degrees C.     

Acaricidal effect of a diatomaceous earth formulation against Tyrophagus putrescentiae (Astigmata: Acaridae) and its predator Cheyletus malaccensis (Prostigmata: Cheyletidae) in four grain commodities

Laboratory bioassays were conducted to evaluate the effect of the diatomaceous earth (DE) formulation SilicoSec (Biofa GmbH, Münsingen, Germany), against two stored-product mite species, Tyrophagus putrescentiae (Shrank) and the predator Cheyletus malaccensis Oudemans. For this purpose, DE was applied in wheat, oat, rye, and maize, at the dose rates 0, 0.5, 1, and 2 g/kg grain. The mortality of the exposed mites was assessed after 24 h, 48 h, 7 d, and 14 d of exposure in the treated substrate. After this interval, the treated grains were checked for oviposition or progeny. The tests were conducted at 80% RH and at two temperatures, 20 and 25 degrees C. Generally, for both species, mortality was higher at 25 degrees C than at 20 degrees C. For T. putrescentiae, at both temperatures, the mortality in grains treated with the highest DE rate was 100% after only 24 h of exposure, with the exception of maize at 20 degrees C, where mortality was 91.7%. The mortality of C. malaccensis after 24 h of exposure to the treated grains, in the absence of prey, did not exceed 29% at any of the temperature- grain-dose combinations, whereas no mites were dead in rye and maize treated with 0.5 and 1 g of DE. Even after 14 d of exposure at the highest DE rate, mite mortality did not reach 100%. The presence of T. putrescentiae individuals as prey in the treated substrate enhanced C. malaccensis survival. Hence, after 14 d of exposure, the mortality of C. malaccensis, in wheat, oat, rye, and maize treated with the highest DE rate was 51.7, 59.7, 70, and 36.9, respectively. No progeny production was recorded in the treated substrate for T. putrescentiae; in contrast, oviposition and F1 progeny were recorded for C. malaccensis. Our results suggest that the use of C. malaccensis with low doses of DE may be an appealing integrated pest management (IPM) approach against T. putrescentiae, and probably against other stored-grain mite species.     

Tyrophagus putrescentiae (Sarcoptiformes: Acaridae) in the in vitro cultures of slime molds (Mycetozoa): accident,contamination, or interaction?

Experimental and Applied Acarology - Tyrophagus putrescentiae (Schrank), commonly known as the cereal mite, cheese mite, or ham mite, is a cosmopolitan species reported from various environments in...     

腐食酪螨螨体正己烷提取物的生物活性及成分分析

【目的】确定腐食酪螨Tyrophagus putrescentiae报警信息素的存在及其成分。【方法】采取正己烷溶剂浸提法提取获得腐食酪螨螨体提取物, 通过观察腐食酪螨对提取物的行为反应确定其生物活性, 最后用气相色谱-质谱联用仪(gas chromatograph-mass spectrum, GC-MS)对提取物的成分进行分析。【结果】腐食酪螨正己烷提取物对该螨有明显的报警作用。GC-MS分析显示, 提取物中含有橙花醇甲酸酯、Z-柠檬醛、E-柠檬醛等成分。【结论】该实验证明了腐食酪螨报警信息素的存在, 为进一步明确各成分及其作用奠定了基础。     

Differential levels of mite infestation of wheat and barley in Czech grain stores

Abstract  While mites are able to utilize numerous food sources, the suitability of the food strongly influences population growth. The different suitabilities of various stored agricultural products will thus affect the level of infestation. In this study, we compared field mite infestation rates in two stored cereals: wheat and barley. We analyzed mite abundance, frequency and species composition in samples of grain obtained from 79 selected Czech grain stores. Stored barley seemed to be more vulnerable to mite attack than wheat, as we consistently found more infested samples, more species and higher mean and median mite abundance per sample in barley as compared to wheat. The mean mite abundance per sample were 55 and 506 individuals for wheat and barley, respectively. In barley, 10% of samples exceeded allergen risk threshold (i.e., 1 000 individuals per kg of grain). Altogether, 25 species were identified from approximately 35 000 individuals. The most frequently identified species were the same in wheat and barley, that is, Tydeus interruptus Sig Thor, Acarus siro L., Tarsonemus granarius Lindquist, Lepidoglyphus destructor (Schrank) and Tyrophagus putrescentiae (Schrank). Based on principal components analysis, we found a closer association of T. interruptus , T. putrescentiae , L. destructor and Cheyletus eruditus (Schrank) with barley samples, corresponding to the high frequency and abundance values of these mites. The probable reasons for the higher infestation, especially mite abundance in barley, are discussed in relation to the higher proportion of crushed parts, which may release favorable nutrient sources and amplify the abundance values.     

Suppressive potential of bean (Phaseolus vulgaris) flour against five species of stored-product mites (Acari: Acarididae)

Previous research has demonstrated that legume proteins have insecticidal activity against stored-product pests, but activity against stored-product mites has not been tested. A study was therefore conducted to explore the potential of bean, Phaseolus vulgaris L., flour as novel botanical acaricide against five species of storage and dust mites: Acarus siro L., Aleuroglyphus ovatus (Troupeau), Caloglyphus redickorzevi (Zachvatkin), Lepidoglyphus destructor (Schrank), and Tyrophagus putrescentiae (Schrank). The effect of wheat, Triticum aestivum L., grain enriched with bean flour to eight concentrations (0, 0.01, 0.1, 0.5, 1, 2.5, 5, and 10%) on population growth initiating from the density of 50 mites per 100 g of wheat was recorded for 21 d under laboratory conditions (grain moisture 14.6% moisture content and 25 degree C in darkness). The enrichment of grain with bean flour suppressed the population growth of all tested species: 0.01% concentration reduced population growth of all tested species to >50% in comparison with the control population. The most sensitive species were A. siro and L. destructor, followed by T. putrescentiae and C. redickorzevi. The least sensitive species was A. ovatus. The terminal (i.e., after 21 d) density of mites positively correlated with bean flour concentration. The suppressive effect of bean flour was not linear but rather asymptotic. The results of this study are discussed in the context of the application of bean flour in integrated control of stored-product mites and the elimination of stored-product mite allergens.     

纳氏皱皮螨生活史的研究

纳氏皱皮螨Suidasia nesbitti Hughes是我国重要储藏物螨类之一.在我国大陆和台湾省,腐食酪螨Tyrophagus putrescentiae (Schrank)是最重要的储藏物螨类,其次是皱皮螨属Suidasia的二个种,即大陆的纳氏皱皮螨和台湾省的棉兰皱皮螨S. medanensis Oudemans.本文研究了纳氏皱皮螨的生活史,并对生活史各发育阶段的形态进行描述.本文还对纳氏皱皮螨和棉兰皱皮螨的形态,分布和为害情况列表进行比较.     

腐食酪螨、粉尘螨传播霉菌的实验研究

探讨粉满能否携带、传播霉菌,对腐食酪螨(Tyrophagus putrescentiae)和粉尘螨(Dermatophagoides farinae)传播5种霉菌进行实验观察,并对自然环境中分离出的腐食酪螨和粉尘螨进行霉菌培养。结果表明,无论是实验条件下,还是自然情况下,腐食酪螨和粉尘螨均可携带、传播霉菌,两者无明显差异(p>0.05),且腐食酪螨和粉尘螨携带、传播霉菌不受其种类的影响。因此认为粉螨是携带、传播霉菌的重要媒介之一,应积极控制粉螨孳生,减少粉螨和霉菌对人类的危害。     

Vectoring of Hypocrea Nigricans (Hypocreales: Hypocreaceae) by Three Fungivorous Mite Species (Acari: Acaridae)

A bioassay was developed to quantify germination rates of Hypocrea nigricans spores passing through the alimentary canals of the three acarid mite species Tyrophagus putrescentiae, Histiogaster sp. and Schwiebea sp. These mites are suspected of causing damage to mushroom production in Japan. All three species feed on the fungus and excrete fungal spores and fungal particles. Fecal material of the mites was plated on malt agar plates supplemented with 1% CuSO₄ to assess spore germination. Germination rates, and hence the possibility for the mites to disseminate spores of H. nigricans, was so high that these mites may indeed be important vectors of weed fungal spores in indoor mushroom production units.     

Molecular cloning and the allergenic characterization of tropomyosin from Tyrophagus putrescentiae

Storage mites have been recognized as a cause of asthma and rhinitis. Studies from several countries have shown that the IgE-mediated allergy to storage mites is of considerable importance, especially in rural populations. This study aimed to identify and characterize new allergens from Tyrophagus putrescentiae. A partial cDNA sequence encoding tropomyosin was isolated from the cDNA library by immunoscreening using anti-mouse IgG1 sera raised against T. putrescentiae whole body extract. The deduced amino acid sequence shares 64-94% identity with previously known allergenic tropomyosins. Its recombinant protein was produced by using a pET 28b expression system and purified by affinity chromatography using Ni-NTA agarose. The IgE reactivities of tropomyosins from T. putrescentiae and Dermatophagoides farinae were compared by enzyme linked immunosorbent assay (ELISA). Recombinant Tyr p 10 showed 12.5% (5/40) IgE-binding reactivity, whereas recombinant Der f 10 showed 25% (10/40) IgE-binding reactivity against the same sera from storage mite-sensitized and house dust mite-sensitized subjects. Both recombinant Tyr p 10 and Der f 10 showed little inhibition of IgE binding to T. putrescentiae crude extract by ELISA. Tropomyosin seems to contribute only a small portion of the cross-reactivity with house dust mites.     

Detection and identification of species-specific bacteria associated with synanthropic mites

Internal bacterial communities of synanthropic mites Acarus siro, Dermatophagoides farinae, Lepidoglyphus destructor, and Tyrophagus putrescentiae (Acari: Astigmata) were analyzed by culturing and culture-independent approaches from specimens obtained from laboratory colonies. Homogenates of surface-sterilized mites were used for cultivation on non-selective agar and DNA extraction. Isolated bacteria were identified by sequencing of the 16S rRNA gene. PCR amplified 16S rRNA genes were analyzed by terminal restriction fragment length polymorphism analysis (T-RFLP) and cloning sequencing. Fluorescence in situ hybridization using universal bacterial probes was used for direct bacterial localization. T-RFLP analysis of 16S rRNA gene revealed distinct species-specific bacterial communities. The results were further confirmed by cloning and sequencing (284 clones). L. destructor and D. farinae showed more diverse communities then A. siro and T. putrescentiae. In the cultivated part of the community, the mean CFUs from four mite species ranged from 5.2?×?10(2) to 1.4?×?10(3) per mite. D. farinae had significantly higher CFUs than the other species. Bacteria were located in the digestive and reproductive tract, parenchymatical tissue, and in bacteriocytes. Among the clones, Bartonella-like bacteria occurring in A. siro and T. putresecentiae represented a distinct group related to Bartonellaceae and to Bartonella-like symbionts of ants. The clones of high similarity to Xenorhabdus cabanillasii were found in L. destructor and D. farinae, and one clone related to Photorhabdus temperata in A. siro. Members of Sphingobacteriales cloned from D. farinae and A. siro clustered with the sequences of "Candidatus Cardinium hertigii" and as a separate novel cluster.     

Effectiveness of education for control of house dust mites and cockroaches in Seoul, Korea

We evaluated the efficacy of health education in reducing indoor arthropod allergens in Seoul. The mite control measures comprised the use of mite-proof mattress and pillow coverings, regular washing of potentially infested materials, maintenance of a low humidity, removal of carpets, and frequent vacuum cleaning. Cockroach control measures included trapping, application of insecticides, and protecting food. Of 201 homes enrolled in October 1999, 63 volunteers were included in a 2-year follow-up survey between April 2000 and January 2002. Before intervention, the density of mites/g of dust varied greatly; 27.1/g in childrenos bedding, 20/g in adult bedding, 7.2/g on the floors of childrenos bedrooms, 6.8/g in sofas, 5.9/g on the floors of adultos bedrooms, 3.9/g on living room floors, 3.7/g in carpets, and 1.9 mites/g on kitchen floors. The predominant mite species and house percentages infested were; Dermatophagoides farinae 93%, D. pteronyssinus 9%, and Tyrophagus putrescentiae 8%. Comparing 1999 and 2001 infestations, before and after 25 mo of education, mite abundance was reduced by 98%, from 23.7 to 0.57 mites/g of dust. In 1999, cockroaches were detected in 62% homes: 36% Blattella germanica and 35% Periplaneta spp., including 9% double infestations of B. germanica and P. americana. Following intervention, cockroach infestation rates decreased to 22% of houses in 2000 and 23% in 2001. We conclude that continuous and repetitive health education resulted in the effective control of domestic arthropods.     

Molecular and biochemical properties of storage mites (except Blomia species)

In recent years, the allergological importance of different mite species not belonging to the family Pyroglyphidae has been demonstrated. These mites, commonly named storage mites, include Lepidoglyphus destructor, Glycyphagus domesticus, Tyrophagus putrescentiae, Acarus siro, Aleuroglyphus ovatus, Suidasia medanensis and Thyreophagus entomophagus. Several allergens from these species have been purified, sequenced and cloned. Many of these allergens have shown sequence homology and a biological function similar to those previously described in Blomia tropicalis and the Dermatophagoides spp. The main allergens described in storage mites include fatty acid binding proteins, tropomysin and paramyosin homologues, apoliphorine like proteins, alfa-tubulines and other, such as group 2, 5 and 7 allergens, which definitive biological function has not been described yet. Besides the purification and characterization of allergens, the allergenicity of other species such as Acarus farris, Austroglycyphagus malaysiensis, Blomia kulagini and B. tjibodas, Cheyletus eruditus, Chortoglyphus arcuatus, Gohieria fusca, Thyreophagus entomophagus and Tyrophagus longior has been investigated. Research has also been conducted to identify allergens in parasitic mites, such as Psoroptes ovis, Sarcoptes scabiei, Varroa jacobsoni, Diplaegidia columbae and Hemisarcoptes cooremani. The allergenicity of mites present in agricultural environments has been investigated. Crossreactivity studies have also been performed to elucidate to what extent all these mites share common, or species specific epitopes. Herein we present a comprehensive review of the allergenicity of mite species which have been implicated in human respiratory and/or dermatological diseases.     

叶螨及两种替代食物对尼氏真绥螨发育和繁殖的影响

在温度25 ℃、相对湿度80％条件下,以油茶花粉、二斑叶螨和腐食酪螨3种食物饲喂尼氏真绥螨,研究不同食物对尼氏真绥螨生长发育和繁殖的影响.结果表明：尼氏真绥螨虽能取食腐食酪螨的卵,但因摄食量不足导致不能完成正常发育;而取食油茶花粉和二斑叶螨能正常完成发育,并进行繁殖.取食油茶花粉的尼氏真绥螨全世代发育历期、雌螨寿命、产卵历期、平均每雌总产卵量分别为6.18 d、24.97 d、16.72 d和23.03粒,取食二斑叶螨的尼氏真绥螨分别为5.67 d、25.72 d、18.17 d和25.38粒;以二斑叶螨为食的尼氏真绥螨发育快,寿命和产卵历期长,平均每雌产卵量高.以油茶花粉和二斑叶螨为食的尼氏真绥螨实验种群数量动态均呈上升趋势,其中以油茶花粉饲养的种群趋势指数最高（I=14.28）,以二斑叶螨饲养的种群加倍时间最短（t=3.5201 d）.     

Delayed hypersensitivity to house dust-storage mites Thyrophagus putrescentiae in experimental allergic dermatoses]

House dust mites and storage mites proved to be one of the main allergens causing hypersensitivity in atopic dermatitis in allergic patients. The authors reproduced experimental allergic dermatosis on the model of delayed type hypersensitivity in guinea pigs, caused by sensitization to the allergen from the mite's bodies Tyrophagus putrescentiae--species having wide distribution in the country. The results characteristic for T-cell type hypersensitivity have been obtained: delayed positive skin tests after 24 hours, typical histomorphological picture (strong allergic alteration, epidermis desquamation, vasculitis, dermis T-cell infiltration and spongiosis--Waksman's syndrome). It is concluded that side by side with humoral IgE-mediated reaction there is strong delayed T-cell hypersensitivity to the storage mites Tyrophagus putrescentiae.     

Perspectives for mass rearing of Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae)

Iphiseiodes zuluagai Denmark & Muma is an important predator of Brevipalpus phoenicis (Geijskes) on citrus in Brazil. The suitability of Tyrophagus putrescentiae (Schrank) as a food source of I. zuluagai in laboratory rearing was investigated at 25.5 +/- 0.5 masculineC, 88 +/- 7% RU and photophase of 12h. Initially, levels of oviposition of the predator fed on eggs were evaluated, as well as the dead or live post-embryonic stages of T. putrescentiae, in a period of 10 days. The daily oviposition rate was 1.3 egg per female when they were fed on eggs on T. putrescentiae, 0.7 egg per female when they were fed on dead post embryonic stages and about 0.3 egg per female when they were fed on live post-embryonic stages. Later, the life table of I. zuluagai was constructed, when eggs of T. putrescentiae were offered to the predators as prey. The immature stages were observed every 8h, to determine the corresponding durations. In the adult phase, the mites were observed every 24h, to determine the reproductive parameters. The intrinsic rate of natural increase (r m) was 0.11 female/ female/day; resulting in a finite rate of increase of 1.11 (l). The net reproductive rate (R0) was 7.1 females/generation, with a mean generation time (T) 18.6 days. The results show that T. putrescentiae is a favorable food source for the development of I. zuluagai.     

Housedust mites in Punta Arenas city, Chile

In medicine, the importance of mites in house dust gains importance from day to day. The close relation between these arthropods and man is the cause of a series of health problems such as allergic asthma, rhinitis and/or dermatitis. House dust samples were collected between January and December 1991 in Punta Arenas, city, Chile. Samples were processed by the Artigas and Casanueva (1983) technique, modified by Mu?oz et al. (1983). The isolated specimens were subsequently identified using the Artigas and Casnueva (1983) pictorial key. Of the 134 samples study, 29.1% presented one or more mite species. A total of 13 species were classified. Eight of them were registered for the city of Punta Arenas for the first time. Average weight of the dust analysed was 8.4 g. Mites were found from 0.2 g. onwards. A total of 1768 specimens was collected. The species more representative were: Blomia tjibodas (30.1%), Glycyphagus destructor (22.5%) and Tyrophagus putrescentiae (10.8%). The seasons that presented the higher proportions of mites were autumn (39.4%) and spring (37.1%).     

粉螨危害储藏中药材的实验研究

随机选取１０种中药材分别进行直接孵育（自然组）、高压灭菌后直接孵育（对照组）、高压灭菌并接种腐良酪螨后孵育（试验组）、高压灭菌并接种粉尘螨后孵育（试验组）,探讨粉螨对储藏中药材的危害。结果从自然缓和 药材中分离出螨的种数、虫口密度及真菌污染程度均较高于试验组和对照组,药材质量及重量显著下降,与其它各组相比,差异均有显著性（Ｐ〈０．０１）。人为接种腐食酪螨、粉尘螨的２实验组,粉螨孳生密度高,药材重量     

Rapid method for the detection of storage mites in cereals: feasibility of an ELISA based approach

This paper describes the development of rapid immunodiagnostic tests for the detection of storage mite infestations in cereals and cereal products. The study's first phase (proof of concept) involved the production of a species-specific enzyme-linked immunoassay (ELISA) for the flour mite, Acarus siro (L.), a major pest of stored commodities. The specificity of this new assay was assessed against key stored product contaminants (13 species of mites of which three were predatory, five species of insects and five species of fungi) in the presence and absence of grain. The assay was species-specific (no cross-reactivity to other storage contaminants) and was unaffected by the presence of cereal antigens in the extract. In the study's second phase, species- and genera-specific ELISAs were developed for a range of key storage mite pests: the cosmopolitan food mite (Lepidoglyphus destructor), the grocers' itch mite (Glycyphagus domesticus), the grainstack mite (Tyrophagus longior), mites of the Tyrophagus and Glycyphagus generas, and all storage mites. All tests were demonstrably specific to target species or genera, with no cross-reactions observed to other storage pest contaminants or cereals. The final, validation phase, involved a comparative assessment of the species-specific A. siro and the genus-specific Tyrophagus ELISAs with the flotation technique using laboratory and field samples. Both ELISAs were quantitative (0-30 mites per 10 g wheat) and produced good comparative data with the flotation technique (A. siro r(2)=0.91, Tyrophagus spp. r(2)=0.99).