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This publication is a brief description of the life cycle and damage of citrus rust mite and pink citrus rust mite. It is one publication in a series of quick guides to citrus pests. Each fact sheet is designed to be a quick reference of citrus pests for both residential and commercial industry audiences.

This document discusses the identification of common citrus mites. Written by L. M. Diepenbrock, J. D. Burrow, and D. Carrillo and published by the UF/IFAS Entomology and Nematology Department; 2 pp. https://edis.ifas.ufl.edu/in1374

Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) is a significant pest. The use of pesticides is the main strategy for its control and it has increased year by year. However, citrus growers stated that the effects of the acaricides have decreased in recent years. In order to determine whether this is due to resistance, P. oleivora populations were collected from Erdemli (Mersin), Karataş, Kozan, Yüreğir (Adana), and Balcalı (as a susceptible) in Turkey. Adults were bioassayed with abamectin, sulfur, spirodiclofen, and pyridaben, which are widely used and have different modes of action. Based on the bioassay experiments, the most resistant population to abamectin was found to be that from Kozan with 25.31-fold, and the population with the lowest resistance was determined to be that from Yüreğir with 8.13-fold both compared to susceptible population. All populations showed low resistance against sulfur, the highest resistance ratio to sulfur was found in Yüreğir with 2.53-fold. The highest resistance population against spirodiclofen was detected in Erdemli with 24.00-fold, followed by Karataş, Yüreğir, and Kozan populations with 15.39, 14.05, and 9.21-fold, respectively. The resistance ratios of P. oleivora populations against pyridaben were found to be 30.30, 15.85, 10.10, and 7.55-fold in Erdemli, Kozan, Yüreğir, and Karataş, respectively. The detected status of acaricide resistance indicates that this phenomenon takes place and should be a concern in the Eastern Mediterranean Region of Turkish populations of P. oleivora requiring monitoring and planning of resistance management strategies. The use of acaricides with different modes of action in sequential spraying is essential to prevent the development of resistance. • P. oleivora is a crucial and small pest that also is very difficult to work on. • Status of resistance against acaricides registered for the control of Phyllocoptruta oleivora in Turkey. • All populations of P. oleivora remained susceptible to sulfur. • This is the first report on abamectin, pyridaben, and spirodiclofen resistance in P. oleivora in Turkey. • Resistance in P. oleivora to registered acaricides appears to be due to selection pressure at the farm level. [ABSTRACT FROM AUTHOR]

Most citrus farmers in Indonesia believed that rust on citrus fruits resulted from insect attacks. This research aims to determine the cause of rust on citrus fruit and its damage intensity. The study was carried out in commercial citrus plantations in three provinces, on Citrus sinensis and C. reticulata plantations in East Java, C. reticulata and C. suhuensis in West Kalimantan and C. suhuensis in North Sumatra. An additional observation was also conducted to collect mite specimens on citrus plantations in Malang, East Java. Scanning Electron Microscope (SEM) and light microscope were used to observe and identify each collected sample. Results showed that the cause of rust-colored citrus fruit in three provinces is the citrus rust mite, Phyllocoptruta oleivora (Ashmead). It belongs to the family Eriophyidae with two pairs of legs with regular segmentation, five-rayed featherclaws, and a net pattern on prodorsum. The specific damage produced by this mite is rust-colored symptoms. Damage intensity of citrus rust mite in tree provinces averaging 32.6%, ranging from 30 to 40%, and ca. the mite attacks 90% of citrus fruits. Predaceous mites, predaceous insects, and entomo-acaropathogenic fungi are found on plantations.

Phyllocoptruta oleivora (Ashmead) (Acari:Phyllocoptidae) is a serious pest of citrus in most humid regions of the world. This pest can cause losses in the yield and quality of fruit. In this study, the effect of the fruit quality traits of P. oleivora was inspected under the Adana ecological condition. For this reason, infested and non-infested fruit with P. oleivora was collected from Valencia orange trees. The collected fruits were classified according to presence and absence of damage of P. oleivora. The fruits were separated into four categories: 1. Normal, 2: Soft bronze, 3. Bronze and 4. Wide bronze. The classified fruits were detected in terms of fruit quality traits. As a result of this study, the fruit with localized and extensive surface bronzing had a lower juice volume, lower TSS/TA, lower rind thickness, higher total soluble solids (TSS), higher titratable acid (TA) than normal fruit. It was found that correlation coefficients of the number of carpel and fruit index were significantly lower than those of other fruit quality characteristics. Moreover, fourth category fruits as a result of intense population damage were 16% smaller than normal fruits and number of seed was detected as zero on the fruits.

Most citrus farmers in Indonesia believed that rust on citrus fruits resulted from insect attacks. This research aims to determine the cause of rust on citrus fruit and its damage intensity. The study was carried out in commercial citrus plantations in three provinces, on Citrus sinensis and C. reticulata plantations in East Java, C. reticulata and C. suhuensis in West Kalimantan and C. suhuensis in North Sumatra. An additional observation was also conducted to collect mite specimens on citrus plantations in Malang, East Java. Scanning Electron Microscope (SEM) and light microscope were used to observe and identify each collected sample. Results showed that the cause of rust-colored citrus fruit in three provinces is the citrus rust mite, Phyllocoptruta oleivora (Ashmead). It belongs to the family Eriophyidae with two pairs of legs with regular segmentation, five-rayed featherclaws, and a net pattern on prodorsum. The specific damage produced by this mite is rust-colored symptoms. Damage intensity of citrus rust mite in tree provinces averaging 32.6%, ranging from 30 to 40%, and ca. the mite attacks 90% of citrus fruits. Predaceous mites, predaceous insects, and entomo-acaropathogenic fungi are found on plantations. [ABSTRACT FROM AUTHOR]

Citrus rust mite, Phyllocoptruta oleivora (Ashmead) (Acari: Phyllocoptidae), is one of the most important pests of citrus fruit trees. In this study, the population density of P. oleivora was carried out on an orange orchard at Çukurova University (Balcalı-Adana) between 2013 and 2015. Ten leaves, one fruit and one twig were collected from 10 randomly chosen orange trees. The samples were taken every week between April and January while biweekly between January and April. As a result of these studies, the first individuals were observed in June. The highest population of P. oleivora on leaves was counted as average 57.25 in August. The last individuals on leaves were detected in January both year. The highest population of this mite on fruits was observed in August. The last individuals on fruits were counted between October and November both years. The highest population on twigs was observed as average 72.13 in the first week of January. The population of P. oleivora on twigs was reduced after May. Also, the population of P. oleivora was increased after light rainy days while was decreased after very rainy and cold days. The overwintering sites P. oleivora was observed as a twig. Also, Amblyseius swirskii, Euseius scutalis and E. stipulatus Athias-Henriot (Acari: Phytoseiidae) was detected as predator mite during the study. The low population of predator mite was observed when the high population of P. oleivora was present. [ABSTRACT FROM AUTHOR]

Copyright of Derim is the property of Bati Akdeniz Agricultural Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The citrus rust mite, Phyllocoptruta oleivora Ashmead (Acari: Eriophyidae), is a major pest of citrus, affecting both quality and yield. Although entomopathogenic fungi such as Beauveria bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae), Metarhizium anisopliae (Metschn.) Sorokīn (Clavicipitaceae), and Isaria fumosorosea Wize (Cordycipitaceae) have been used for insect and mite control, the last 2 have never been applied to control citrus rust mite. The aim of this study was to evaluate the effect of 3 concentrations of B. bassiana, M. anisopliae, and I. fumosorosea on mortality and growth rate (r) of P. oleivora populations under greenhouse conditions. The fungi were isolated from agricultural soil samples. Mobile stages of P. oleivora were collected from leaves of commercial Valencia orange groves. At a concentration of 1 × 108 conidia mL-1, B. bassiana and M. anisopliae caused > 60% mortality in P. oleivora populations, whereas mortality due to I. fumosorosea never exceeded 50%. There was a significant inverse relationship between the percent mortality and the LT50. Application of B. bassiana resulted in the slowest growth rate of P. oleivora populations, which was 10.5 × slower than the control population receiving no fungus application. Our results demonstrate that B. bassiana and M. anisopliae are efficient in control of P. oleivora populations under greenhouse conditions, whereas I. fumosorosea produces moderate control. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Taiwan Agricultural Research is the property of Taiwan Agricultural Research Institute, Council of Agriculture, Executive Yuan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Panonychus citri McGregor (“Citrus red mite”) and Phyllocoptruta oleivora Ashmead (“Citrus rust mite”) are key pests of citrus crops in the Chancay valley, Peru, causing dramatical losses in yield and fruit quality. These pest‐mites affect food security in the area, where the small farming prevails, as the citrus crop is the main generating income source for most of households. Small farmers fight against these pest‐mites by spraying nutritional elements on leaves, as it is cheaper and less harmful than using a chemical miticide. Thus, the aim of this work was determining the influence of the foliar application of elements currently used by farmers (Calcium, Magnesium, Zinc, Copper, Iron, Manganese, and Boron) and a mix of all of them at two dosage levels on the population dynamic of these two key citrus pests on tangerine cv. Clemenules, along a whole crop season in the Chancay Valley. Panonychus citri was detected on leaves during the whole crop cycle, while Phyllocoptruta oleivora was visible during the third leaf and bloom shooting period. There were not statistical differences between dosages, but statistical differences were observed between treatments and the control, the latter registering the highest population level of both mites during the whole crop cycle. Application of Cu, Mn, Mg, and Zn did show the lowest P. citri population rates, while Fe, Mix, Cu, Mg, and Zn did show the lowest population levels of P. oleivora. The foliage analysis revealed that the nutritional content of leaves of tangerine trees under study during the crop cycle was mostly at optimal levels, according to the standards for the crop. These results support the current practice of farmers and confirm that the foliar application of microelements represents a potential pesticide alternative method for management/control of citrus mites, lowering production costs, avoiding excessive pesticide applications, and increasing yield and fruit quality. [ABSTRACT FROM AUTHOR]

We sampled 526 dooryard, 18 varietal block, and 784 commercial citrus trees in Florida between May 2009 and Apr 2014 for eriophyoid mites including Diptilomiopus floridanus Craemer & Amrine, Aceria sheldoni (Ewing), Aculops pelekassi (Keifer), and Phyllocoptruta oleivora (Ashmead). In total, 1,423 D. floridanus individuals were collected from dooryard citrus trees and 1 each from the lemon cultivar 'Bearss' and sweet lime trees from the Florida Citrus Arboretum in Winter Haven. Diptilomiopus floridanus was collected from dooryard citrus in the following counties in Florida: Broward, Collier, Dade, Indian River, Lee, Martin, Palm Beach, Pinellas, Polk, Sarasota, and St. Lucie. The mite was not observed in Charlotte, Hardee, Hendry, Highlands, Manatee, or Okeechobee counties (Florida). Percentages of the eriophyoid mite species collected from dooryard citrus trees and varietal blocks were: A. pelekassi 3.2%, A. sheldoni 9.1% , D. floridanus 17.3%, and P. oleivora 84.2%. The 6 counties with the highest percentages of D. floridanus on dooryard trees were: Collier 36%, Broward 25%, Indian River 25%, Palm Beach 25%, Martin 23%, and St. Lucie 22%. In commercial citrus, A. sheldoni was collected less than 1.0%, A. pelekassi 4.0%, and P. oleivora 75.5%, of the time. Diptilomiopus floridanus was not collected in commercial citrus orchards during this survey. Diptilomiopus floridanus had significantly greater infestation rates on lime and lemon trees compared with grapefruit, tangerine, tangelo, sweet orange, and pummelo trees. However, infestation rates on lime and lemon trees were not significantly different from those on sour orange trees. [ABSTRACT FROM AUTHOR]

Citrus are attacked by pest mites such as the citrus rust mite Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) and the spider mite Tetranychus mexicanus (McGregor) (Acari: Tetranychidae). However, little is known on citrus rootstocks influencing pest mites. We aimed to evaluate the influence of rootstocks on population densities of pest mites on the sweet oranges 'Pera CNPMF D-6' and 'Valencia Tuxpan' throughout time. Adults of both mite species were monthly counted during 19 months from June 2011 to February 2013. Rootstocks influenced the populations of pest mites, since lower densities of P. oleivora were found on 'Pera CNPMF D-6' sweet orange grafted on the hybrid TSKC × CTTR - 002 and on 'Swingle' citrumelo in comparison with the hybrid LVK × LCR - 010, 'Red' rough lime and 'Santa Cruz' rangpur lime as rootstocks. Similarly, lower densities of T. mexicanus were found on 'Valencia Tuxpan' sweet orange grafted on the hybrid HTR-051 in comparison to 'Indio' citrandarin, 'Sunki Tropical' mandarin and LVK × LCR - 010 as rootstocks. We concluded that densities of the mites P. oleivora and T. mexicanus on the sweet oranges 'Pera CNPMF D-6' and 'Valencia Tuxpan' were affected in some periods of the year by some rootstocks, suggesting influence of some genotypes on these pests. [ABSTRACT FROM AUTHOR]

The article focuses on geographic distribution of Phyllocoptruta oleivora, known as Citrus Rust Mite (CRM), which is negative economic importance of this vagrant species is mostly due to the damage on fruit. It mentions global trade poses the highest risk of introducing pests to new geographical areas and prevention requires the monitoring of pests on fruits, seeds, plants, and their identification at the entry points. It also mentions eriophyoids are very tiny mites.

The citrus rust mite (CRM), Phyllocoptruta oleivora (Acari: Eriophyidae) is a cosmopolitan key pest of citrus, inflicting severe economic damage if not controlled. In Israel, CRM damages all citrus cultivars. International regulation and increasing control failures of CRM led growers to seek sustainable biological control solutions such as acarine biological control agents. Laboratory studies conducted in Israel have indicated that the indigenous predator species Amblyseius swirskii, Iphiseius degenerans, Typhlodromus athiasae and Euseius scutalis (all Acari: Phytoseiidae) can potentially control CRM. Our general objective in the present study was to bridge the gap of knowledge between laboratory studies and the lack of control efficacy of these species in commercial orchards. Predator augmentation in the field showed that although predator populations increased immediately following releases they later decreased and did not affect CRM populations. When A. swirskii augmentation was combined with a series of maize pollen applications, A. swirskii populations were enhanced substantially and continuously but again CRM populations were not affected. Growth chamber studies with CRM-infested seedlings, with or without a maize pollen supplement, indicated that pollen provisioning led to population increase of E. scutalis and A. swirskii but only E. scutalis significantly lowered CRM populations. Control with E. scutalis was confirmed in the field on CRM infested seedlings with pollen provisioned by adjacent flowering Rhodes grass. While experiments in mature citrus orchard showed that pollen supplement usually increased predator populations they also indicated that other factors such as intraguild interactions and pesticide treatments should be taken into account when devising CRM biological control programs. [ABSTRACT FROM AUTHOR]

Vários defensivos agrícolas, incluindo um juvenóide, foram aplicados contra o acaro da falsa ferrugem em pomar localizado em Limeira,SP, uma das principais áreas citrícolas do Brasil. Os tratamentos constaram de uma única aplicação, feita em 01/10/89. Tratamentos: A) testemunha; B) flucicloxurom (juvenóide) 40 cm³; C) bromopropilato 65 cm³; D) quinometionato + enxofre 200 cm³; E) quinometionato + enxofre 250 cm³; F) formetanato22,5 g; G) formetanato 31,5 g. As quantidades referem-se aos produtos comerciais para 100 litros de água. Cada laranjeira recebeu 10 litros de calda. Espalhante-adesivo: "Extravon" (25 cm³/100 litros). O delineamento estatístico feito foi de blocos ao acaso, com 4 repetições. Foram feitas 6 avaliações: 1 prévia e 5 após 06, 20, 36, 50 e 68 dias da aplicação. F, G e C foram os melhores tratamentos. D e E foram eficientes somente aos 06 e 20 dias e o juvenóide, aos 20, 36 e 50 dias.In order to control the citrus rust mite on orange-trees a field experiment was carried out in Limeira, State of São Paulo, Brazil, an important citrus producing area. Treatments correspondend to a single application on 01/10/89 of: A) check; B) juvenoid flucycloxuron, 40 cm³; C) bromopropilate 65 cm³; D) quinomethionate + sulphur 200 cm³; E) quinomethionate + sulphur 250 cm³; F) fonnetanate 22,5 g; G) formetanate 31,5 g. The quantities are of commercial formulations in 100 liters of water. Each tree received 10 liters of the mixtures. Avaliations were made before spraying and 6, 20, 36, 50 and 68 days after the application. The most effective results in the last three avaliations were obtained with treatments F, G and C. Treatments D and E were effective only for 6 and 20 days and the juvenoid for 20, 36 and 50 days after spraying.

A metabolite of the fungus Meira argovae Boekhout, Scorzetti, Gerson & Sztejnberg (Exobasidiomycetidae) was assayed as an antagonist of mites. Separation of extracted fungal metabolites by reversed phase liquid chromatography (RPLC), with subsequent testing of the obtained fractions, allowed us to isolate a single mite-antagonistic fraction (also active against a bacterium) that primarily includes one major component. This active compound (herein termed 'argovin') was identified by analyzing its spectral characteristics as 4,5-dihydroxyindan-1-one, which has previously only been described as a product of chemical reactions. The growth rate of the fungus was higher at a neutral pH than at an acidic one. Meira argovae adjusts the pH of its media to values optimal for its colony growth and toxic secretions. RPLC-cleaned argovin at 0.2 mg ml−1 killed 100% of a population of the citrus rust mite, Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae). This trait may be used to control citrus rust mites in the field, as well as for toxin production for industrial and pharmaceutical uses. [ABSTRACT FROM AUTHOR]

Abstract: Arrowhead scale (AHS), Unaspis yanonensis (Kuwana) (Hemiptera: Diaspididae), and pink citrus rust mite (PCRM), Aculops pelekassi (Keifer) (Acari: Eriophyoidae), are important arthropod pests of organic citrus orchards in Jeju. This study was conducted to evaluate the stage-specific mortality effects of petroleum spray oil (PSO) (AI 95%) and lime sulfur (LSF) (AI 22%) against AHS and PCRM in the laboratory. The developmental stages of AHS were divided into the 1st nymph, the three sub-stages of the 2nd nymph (N2a=early soft body, N2b=hardened body, and N2c=late apolysis), and the two sub-stages of adult females (A3a=early age, and A3b=middle age). The developmental stages of PCRM were divided into eggs, the 2nd nymphs, and adults. PSO 100× and LSF 80× resulted in high mortality against the 1st nymphs of AHS. The effects of PSO and LSF were significantly different among the application rates on 2nd nymphs of AHS and were higher on N2a. The PSO and LSF treatments significantly affected egg hatch rate of PCRM: LSF 50× (2.4%), LSF 100× and PSO of 50× and 200× (17.8% to 20.4%), and LSF 200× (39.0%). PSO and LSF also significantly affected the mortality of the 2nd nymphs and adults of PCRM. PSO and LSF resulted in low direct mortality on A3a and A3b of AHS, but induced an abnormal morphology. PSO treatment resulted in a loose attachment of AHS scale cover on the leaf surface and LSF treatment resulted in an abnormal or lacking scale cover. [ABSTRACT FROM AUTHOR]

We review published and unpublished studies conducted in Israel with six acaropathogenic fungi, assayed in order to control the citrus rust mite, Phyllocoptruta oleivora (Ashmead) (CRM). Hirsutella thompsonii Fisher was introduced twice, killed 80-90% of the exposed mites, but due to its requirements for near-saturation humidities was deemed unsuitable for local outdoors conditions. Hirsutella kirchneri (Rostrup) Minter et al. and Hirsutella necatrix Minter et al. were also introduced and assayed against CRM and spider mites, but their eYcacy was unsatisfactory. Three indigenous fungi found to be associated with mites, Meira geulakonigii, Meira argovae and Acaromyces ingoldii-all three recently described by Boekhout, Gerson, Scorzetti & Sztejnberg-were assayed against several mites. Meira geulakonigii killed 80-90% of several spider mites and of the CRM, and caused some mortality of Iphiseius degenerans (Berlese), one out of three phytoseiid predators assayed. Mortality was not due to parasitization; extracts from the media in which the fungi had developed caused considerable mite death, suggesting that it was a result of fungal toxins. Data from a Weld study indicated that spraying blastoconidia of M. geulakonigii on grapefruits infested by CRM significantly reduced pest-incurred damage from 23 to 13%. Applying qRT-PCR methodology indicated that M. geulakonigii was endophytic within sealed grapefruit flowers and in the flavedo of the fruits' peel. Neither in the laboratory nor in the Weld was any evidence ever obtained that this fungus damaged the plants, leading us to hypothesize that M. geulakonigii serves as a "body guard" of grapefruits (and perhaps other plants as well). All three fungi suffered very little mortality after being exposed to various insecticides and acaricides that are in current local use (with the exception of sulfur). The ability of M. geulakonigii to reduce mite numbers without affecting the host plant, the minimal fungal eVect on some predatory mites, its endophytic nature along with the apparent tolerance of M. geulakonigii to many insecticides and acaricides, suggest that this fungus could be suitable for integrated pest management (IPM) program. [ABSTRACT FROM AUTHOR]

Aims: The fungus Meira geulakonigii has been shown to reduce populations of citrus rust mite (CRM; Phyllocoptruta oleivora) on citrus leaves and fruits, in both the field and laboratory. However, attempts to isolate the fungus from leaves and fruits have been unsuccessful. The aims of this study were therefore to determine whether M. geulakonigii is a citrus endophyte, and to assess possible mechanisms involved in its mite-antagonist activity. Methods and Results: A quantitative real-time PCR and regular PCR approaches were developed to detect M. geulakonigii in both the field and laboratory. The fungus was detected throughout. Different methods revealed that M. geulakonigii is an endophyte, which colonizes both the peel of grapefruits. Applications of conidia protected the grapefruits against CRM, and fungal secretions extracted from growth media caused 100% CRM mortality. Conclusions: Meira geulakonigii is a beneficial endophyte of grapefruits that colonizes the fruit’s peel, and protects it from CRM. Significance and Impact of the Study: Findings from this study demonstrate the endophytic nature of M. geulakonigii in its interaction with grapefruits. In addition, a molecular approach was developed to specifically detect the fungus inside the grapefruit peel. This approach can be used to assess the natural occurrence of M. geulakonigii in grapefruit. [ABSTRACT FROM AUTHOR]

Binomial sampling based on the proportion of samples infested was investigated for estimating mean densities of citrus rust mite, Phyllocoptruta oleivora (Ashmead), and Aculops pelekassi (Keifer) (Acari: Eriophyidae), on oranges, Citrus sinensis (L.) Osbeck. Data for the investigation were obtained by counting the number of motile mites within 600 sample units (each unit a 1-cm² surface area per fruit) across a 4-ha block of trees (32 blocks total): five areas per 4 ha, five trees per area, 12 fruit per tree, and two samples per fruit. A significant (r² = 0.89), linear relationship was found between ln(-ln(1 - P0)) and ln(mean), where P0 is the proportion of samples with more than zero mites, The fitted binomial parameters adequately described a validation data set from a sampling plan consisting of 192 samples. Projections indicated the fitted parameters would apply to sampling plans with as few as 48 samples, but reducing sample size resulted in an increase of bootstrap estimates falling outside expected confidence limits. Although mite count data fit the binomial model, confidence limits for mean arithmetic predictions increased dramatically as proportion of samples infested increased. Binomial sampling using a tally threshold of 0 therefore has less value when proportions of samples infested are large. Increasing the tally threshold to two mites marginally improved estimates at larger densities. Overall, binomial sampling for a general estimate of mite densities seemed to be a viable alternative to absolute counts of mites per sample for a grower using a low management threshold such as two or three mites per sample. [ABSTRACT FROM AUTHOR]

Development and reproduction of Iphiselodes quadripilis (Banks) were evaluated on single food diets of pollen (Malephora crocea Jacquin [ice plant] or Quercus sp. [oak]), spider mites, [Eutetranychus banksi (McGregor) or Panonychus citri (McGregor) (Acari: Tetranychidae)], or the citrus rust mite Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae). Experiments were conducted in an environmental chamber at 28° ± 1°C, 14:10 (L:D) daylength, and 45% RH. I. quadripilis completed development and laid viable eggs that subsequently hatched on diets of either ice plant or oak pollen or eggs and motile stages of E. banksi. P. citri was acceptable as prey, but survival of larvae to adults was only 36%, whereas survival on E. banksi, ice plant pollen, and oak pollen was 48, 60, and 68%, respectively. The webbing produced by P. citri seemed to inhibit foraging behavior of I. quadripilis larvae and nymphs. Larvae of!. quadripilis developed only to the second nymphal instar on a diet of P. oleivora alone or water alone. Starved I. quadripilis females and deutonymphs were observed preying on the pink citrus rust mite, Aculops pelekassi (Keifer) (Eriophyidae). During 4-min observation trials, two series of I. quadripilis fed on 1.8 ± 0.47 and 3.5 ± 0.45 A. pelekassi motile stages after being starved for 6 and 24 h, respectively. I. quadripilis females did not prey on P. oleivora in arenas containing both rust mite species. [ABSTRACT FROM AUTHOR]

The pathogenicity of Beauveria bassiana to one of the major pests of citrus crops, Phyllocoptruta oleivora, was assessed by inoculating mites with different concentrations of conidia (1×106, 5×106, 1×107, 5×107 and 1×108). Treated mites were kept at controlled conditions (25±0.5 °C, 12 h photoperiod and 98% relative humidity) and mite survivorship was evaluated daily. Mortality was found to increase in time and was dependent on the conidia concentration, with values ranging from 24 to 91% for the lowest and highest conidia concentration, respectively. The calculated LC50 on the fifth day was 4.23×106 conidia/ml. Mean lethal time was 3.98, 9.79, 3.09 and 2.74 days for 5×106, 1×107, 5×107 and 1×108 conidia/ml, respectively. Conidia were found to adhere all over the mite body surface, especially at the anal region, where vegetative mycelium was found entering the mite body. We noticed the formation of small crystals inside the mite's body that were produced during colonization of the body cavity by the fungus. This is the first report of B. bassiana pathogenicity for this species. [ABSTRACT FROM AUTHOR]

The consequence of reducing sample size on the accuracy and precision of estimates of citrus rust mite, Phyllocoptruta oleivora (Ashmead), densities on oranges was investigated. The sample unit was a 1-cm² surface area on fruit. Sampling plans consisting of 360, 300, 200, 160, 80, 48, 36, or 20 samples per 4 ha were evaluated through computer simulations by using real count data from 32 data sets of 600 sample units per 4 ha. The original and reduced sampling plans were hierarchical with different numbers of sample areas per 4 ha, trees per area, fruit per tree, and samples per fruit. Individual estimates (n = 100 simulations per data set) using each plan were sometimes considerably below or above target densities. In an original set of count data with a mean of six mites per cm², simulations of 36 samples per 4 ha produced individual estimates ranging from one to 16 mites per cm², whereas 80 samples per 4 ha produced estimates ranging from two to 10 mites per cm². The plans consisting of 36 or more samples were projected to provide precision levels of 0.25 (SEM/mean) or better at densities of five or more mites per cm² based on log-data, a projection that needs to be verified under real-grove situations. Each plan consistently provided mite detection in these sampling simulations except those consisting of 20 or 36 samples, which sometimes failed to detect mites when the target density was less than five mites per cm². The study provided insight into the probable precision, accuracy and detection thresholds for eight candidate sampling plans varying from relatively low to high resource input. [ABSTRACT FROM AUTHOR]

The present investigation was accomplished in the county of Güemez, Tamaulipas, Mexico during the period june of 1998 to October of 1999. The objectives were to evaluate the spatial distribution and the population fluctuation of the citrus rust mite Phyllocoptruta oleivora (Ashmead). This investigation was conducted on 10 orange trees of the variety Valencia selected at random in an area of a hectarea. Each tree was divided into 7 sampling areas. Samples were taken every 14 days, using the leaf as the sample unit and counting the number of mites present on both sides of the leaves. A total of 10 leaves were observed in each of 7 sections, making a total of 70 leaves for each tree and 700 for each sampling date. Using the mean densities and the variance obtained in each sampling, a statistical analysis was conducted to determine the spatial distribution of the mite in the area study. Eight indexes were used to determine the spatial distribution. The index values of Lexis, Charlier, David & Moore, Green and the dispersion parameter (K) of negative binomial indicated a clumped distribution for this mite over all 16 sampling dates. However the values of Morisita, Iwao, and Taylor's power law showed random distribution in two, two, and three sampling dates, respectively. In all samples, the highest mite densities were found in the middle tree stratum (with higher aggregation toward last section of tree) followed by bottom and top strata, respectively. Population peaks were found during march 27 th and september 25 th. The dependent variable used to estimate the populate on fluctuation was the mean density of the mites in each sampling date. The independent variables were: temperature, relative humidity and precipitation. A detected positive correlation between the mean density of the mites and temperatures was observed. [ABSTRACT FROM AUTHOR]

A total of 162 strains of Hirsutella thompsonii, isolated from infected mites collected worldwide, were examined for the production of Hirsutellin A (HtA). More than half of the broth filtrates exhibited mortality rates superior to 50% when assayed against Galleria mellonella. The presence of the gene coding for HtA, a previously characterized H. thompsonii protein exotoxin, was determined by PCR amplification using gene-specific primers. Most isolates (100 out of 162) were shown to possess the HtA gene. However, the presence of the gene could not be associated with enhanced insecticidal activity. Both isolate groups (with or without an amplifiable HtA gene) produced filtrates that caused the same average mortality rate (65%) when assayed against G. mellonella. The production and secretion of the HtA toxin were estimated by probing broth filtrates with an anti-HtA monoclonal antibody. Again, the detection of the HtA protein was poorly correlated with subsequent mortality rates induced by the broth filtrates of the various H. thompsonii strains. This study suggests that HtA is requisite for neither survival nor pathogenicity, and that H. thompsonii strains are likely to secrete other toxins that have yet to be characterized. Sequencing of a limited number of HtA genes showed that, when present, the gene is highly conserved, and it displays an interesting intronic polymorphism. [Copyright &y& Elsevier]

Aerial dispersal of citrus rust mite, Phyllocoptruta oleivora (Ashmead), in central Florida showed a diel periodicity peaking between late morning and early afternoon. The abiotic factors that best described the dispersal pattern were solar radiation, time, and leaf wetness; whereas wind speed, humidity, temperature, and rainfall had minimal effect. The longevity of adult mites removed from fruit was inversely related to constant temperatures between 25 and 35°C. The longevity of mites removed from fruit at 2-h intervals between 0700 and 1300 hours and exposed to ambient temperature and humidity outdoors was inversely related to the time of removal from the host. There was a linear relationship between the number of mites captured in traps and population density on fruit. Mites left fruit harboring extremely low populations and some fruit supporting dense populations yielded hundreds of dispersing mites per day. Mites were readily carried on air currents between adjacent citrus groves. Nearly all of the mites captured in dispersal traps were adult females, and were found in greater proportions in traps than would be expected from the sex ratio of mites on fruit. Studies using isolated fruit in the laboratory showed that a single virgin or inseminated female could initiate a local population through oedipal mating and sibmating. The data are discussed in relation to the selective forces that may shape the dispersal behavior of citrus rust mite and to the potential impact of aerial dispersal on mite management and the development of acaricide resistance. [ABSTRACT FROM AUTHOR]

A citrus leaf disk bioassay was developed to monitor the susceptibility of citrus rust mite, Phyllocoptnita oleivora (Ashmead), populations to abamectin. Disks from leaves of several citrus cultivars were equally suitable bioassay substrates, and there was no difference in mortality when mites were sprayed directly or exposed to dry abamectinresidue. The concentration-response relationship was determined at intervals over 2 yr for a reference population of citrus rust mites that had been maintained in culture and never exposed to acaricides. Three diagnostic concentrations of abamectin were selected based on theresponse of the reference population and were used to test the susceptibility of 15 populations of mites from commercial citrus groves. Comparisons with the reference population showed reduced levels of susceptibility in some populations. Populations of citrus rust mites from 6 commercial groves were sprayed twice in 1997 with combinations ofacaricides designed to exert different intensities of selection pressure from abamectin. None of these populations showed a change in their response to abamectin in pre- and postspray bioassays, although their susceptibility was usually less than that of mites from the susceptible reference population. Biweekly counts of rust mites on fruit in these 6 groves suggested that, relative to groves which received noabamectin or 1 abamectin spray, mite control was not adversely affected in the groves sprayed twice with abamectin. The bioassay method is discussed in relation to factors that affect the interpretation of results from its use, and factors that may affect the development of resistance to abamectin in citrus rust mite populations are presented. This study has provided baseline data with which the results of ongoing tests of the response of citrus rust mite populations to abamectin can be compared. [ABSTRACT FROM AUTHOR]