Raoiella indica (Acari: Tenuipalpidae): an exploding mite pest in the neotropics

Major infestations of the flat mite species Raoiella indica Hirst affecting bananas, palms and other ornamental plants have been reported from the Caribbean islands, Mexico, FL (USA), Venezuela, Colombia and Brazil. Specimens from these localities were examined using traditional light microscopy and low-temperature scanning electron microscopy techniques. While little is known about the biology of this mite, its recent appearance in the Americas in both commercial coconut and banana plantations has raised concerns about its economic impact as an invasive pest.     

Prey-stage preferences and functional and numerical responses of Amblyseius largoensis (Acari: Phytoseiidae) to Raoiella indica (Acari: Tenuipalpidae)

Raoiella indica Hirst (Acari: Tenuipalpidae) is a phytophagous mite that recently invaded the Western Hemisphere. This mite is a multivoltine and gregarious species that can reach very high population densities and cause significant damage to various palm species (Arecaceae). The predatory mite Amblyseius largoensis (Muma) (Acari: Phytoseiidae) has been found associated with R. indica in Florida. This study evaluated A. largoensis for potential to control R. indica by (1) determining predator preferences among developmental stages of R. indica, and (2) estimating predator functional and numerical responses to varying densities of its most preferred prey-stage. Under no-choice conditions A. largoensis consumed significantly more eggs than other stages of R. indica. In choice tests A. largoensis showed a significant preference for R. indica eggs over all other prey stages. Amblyseius largoensis displayed a type II functional response showing an increase in number of prey killed with an increase in prey population density. Consumption of prey stabilized at approximately 45 eggs/day, the level at which oviposition by the predator was maximized (2.36?±?0.11 eggs/day; mean?±?SEM). Results of this study suggest that A. largoensis can play a role in controlling R. indica populations, particularly when prey densities are low.     

Effect of coconut palm proximities and Musa spp. germplasm resistance to colonization by Raoiella indica (Acari: Tenuipalpidae)

Although coconut (Cocos nucifera L.) is the predominant host for Raoiella indica Hirst (Acari: Tenuipalpidae), false spider mite infestations do occur on bananas and plantains (Musa spp. Colla). Since its introduction, the banana and plantain industries have been negatively impacted to different degrees by R. indica infestation throughout the Caribbean. Genetic resistance in the host and the proximity of natural sources of mite infestation has been suggested as two of the main factors affecting R. indica densities in Musa spp. plantations. Greenhouse experiments were established to try to determine what effect coconut palm proximities and planting densities had on R. indica populations infesting Musa spp. plants. Trials were carried out using potted Musa spp. and coconut palms plants at two different ratios. In addition, fourteen Musa spp. hybrid accessions were evaluated for their susceptibility/resistance to colonization by R. indica populations. Differences were observed for mite population buildup for both the density and germplasm accession evaluations. These results have potential implications on how this important pest can be managed on essential agricultural commodities such as bananas and plantains.     

First record of the olive bud mite Oxycenus maxwelli (Keifer) (Acari: Eriophyidae) from Brazil

The mite Oxycenus maxwelli (Keifer) (Eriophyidae) is reported for the first time in Brazil infesting olive trees, Olea europaea. Specimens were found on seedlings at Maria da Fé, state of Minas Gerais, in 2007. Although minor symptoms were not noticed, significant damage to plants were observed. There is no reliable evidence of when the mite could have been introduced. It is believed that the mite occurs since the first introductions of olive trees, around 1820, through vegetative propagating material, but the mite remained unnoticed due to the lack of studies with olive trees in Brazil.     

House dust mites in Brazil--an annotated bibliography.

House dust mites have been reported to be the most important allergen in human dwellings. Several articles had already shown the presence of different mite species at homes in Brazil, being Pyroglyphidae, Glycyphagidae and Cheyletidae the most important families found. This paper is an annotated bibliography that will lead to a better knowledge of house dust mite fauna in Brazil.     

Host plant range of Raoiella indica (Acari: Tenuipalpidae) in areas of invasion of the New World

Raoiella indica has spread rapidly through the Neotropical region where the mite damages economically and ecologically important plants. Three studies were conducted to determine the host plant range of R. indica, using the presence of colonies containing all life stages as an indicator of reproductive suitability. Periodic surveys at the Fairchild Tropical Botanic Garden (Miami Dade County, FL, USA) and the Royal Botanical Gardens (Port of Spain, Trinidad and Tobago) identified 27 new reproductive host plants. The reproductive suitability of two dicotyledonous species and three native Florida palm species was examined. An updated list of reproductive host plants of R. indica is presented. All reported reproductive hosts (91 plant species) of R. indica are monocots from the orders Arecales (Arecaceae), Zingiberales (Heliconiaceae, Musaceae, Strelitziaceae, Zingiberaceae) and Pandanales (Pandanaceae). Most are palms of the family Arecaceae that originated in areas of the Eastern Hemisphere; about one fourth of the reported hosts are native to the New World and could be considered new host associations of R. indica. Six years after the initial detection in the Caribbean, R. indica has expanded its host plant range. Here we report 27 new reproductive host of R. indica that represent 30% of increase on previous host plant records. As this mite continues spreading in the Neotropical region a great diversity of plants is potentially affected.     

Chemical control of the red palm mite, Raoiella indica (Acari: Tenuipalpidae) in banana and coconut

The red palm mite (RPM), Raoiella indica Hirst, is a predominant pest of coconuts, date palms and other palm species, as well as a major pest of bananas (Musa spp.) in different parts of the world. Recently, RPM dispersed throughout the Caribbean islands and has reached both the North and South American continents. The RPM introductions have caused severe damage to palm species, and bananas and plantains in the Caribbean region. The work presented herein is the result of several acaricide trials conducted in Puerto Rico and Florida on palms and bananas in order to provide chemical control alternatives to minimize the impact of this pest. Spiromesifen, dicofol and acequinocyl were effective in reducing the population of R. indica in coconut in Puerto Rico. Spray treatments with etoxanole, abamectin, pyridaben, milbemectin and sulfur showed mite control in Florida. In addition, the acaricides acequinocyl and spiromesifen were able to reduce the population of R. indica in banana trials.     

Phylogenetic investigation of the genus Raoiella (Prostigmata: Tenuipalpidae): diversity, distribution, and world invasions

The genus Raoiella is best known because of the red palm mite, R. indica, a major pest of palms spreading aggressively throughout the Americas. Not much was known about the biology, geographic origins, or evolutionary history of the genus when R. indica emerged as a major invasive pest. This paper attempts to address some of the basic historical questions regarding the palm mite as well as the genus. Molecular characters from COI and 28S regions were used to produce a phylogenetic hypothesis for the genus in an effort to understand its geographic origin. It also uses COI barcode data to delimit several potentially new species discovered by the authors in Australia. Results show a basal split between R. indica and all other Raoiella species, which indicates Africa or the Middle East as the most probable origin of the genus. Additionally, COI data suggests that at least eight new species are represented among the 20 Australian populations included in this study.     

Changes in the reproductive ability of the mite Varroa destructor (Anderson e Trueman) in africanized honey bees (Apis mellifera L.) (Hymenoptera: Apidae) colonies in southern Brazil

Varroa destructor has been in Brazil for more than 30 years, but no mortality of honeybee colonies due to this mite has been recorded. Africanized bee infestation rates attained by varroa have been low, without causing measurable damage to Brazilian apiculture. The low reproductive ability of this parasite in Africanized bee worker brood cells has been considered an important factor for maintaining the host-parasite equilibrium. Nevertheless, the possible substitution of the haplotype of the mite Varroa destructor that has occurred recently in Brazil could affected the reproductive ability of the population of this parasite in Brazil. The reproductive ability of worker of the mite females was evaluated in over one thousand 17-18 day-old Africanized worker brood cells each of the two periods. The percentage of fertile mites increased from 56% in the 1980s to 86% in 2005-2006. The difference in the percentage of females that produced deutonymphs, female progeny that can reach the adult stage at bee emergence, was even greater. In 2005-2006, 72% of the females that invaded worker brood had left at the least one viable descendant, compared to 35% in 1986-1987.     

The invasive coconut mite Aceria guerreronis (Acari: Eriophyidae): origin and invasion sources inferred from mitochondrial (16S) and nuclear (ITS) sequences

Over the past 30 years the coconut mite Aceria guerreronis Keifer has emerged as one of the most important pests of coconut and has recently spread to most coconut production areas worldwide. The mite has not been recorded in the Indo-Pacific region, the area of origin of coconut, suggesting that it has infested coconut only recently. To investigate the geographical origin, ancestral host associations, and colonization history of the mite, DNA sequence data from two mitochondrial and one nuclear region were obtained from samples of 29 populations from the Americas, Africa and the Indo-ocean region. Mitochondrial DNA 16S ribosomal sequences were most diverse in Brazil, which contained six of a total of seven haplotypes. A single haplotype was shared by non-American mites. Patterns of nuclear ribosomal internal transcribed spacer (ITS) variation were similar, again with the highest nucleotide diversity found in Brazil. These results suggest an American origin of the mite and lend evidence to a previous hypothesis that the original host of the mite is a non-coconut palm. In contrast to the diversity in the Americas, all samples from Africa and Asia were identical or very similar, consistent with the hypothesis that the mite invaded these regions recently from a common source. Although the invasion routes of this mite are still only partially reconstructed, the study rules out coconut as the ancestral host of A. guerreronis, thus prompting a reassessment of efforts using quarantine and biological control to check the spread of the pest.     

Reproductive biology of <Emphasis Type="Italic">Varroa destructor</Emphasis> in Africanized honey bees (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

Since its first contact with Apis mellifera, the population dynamics of the parasitic mite Varroa destructor varies from one region to another. In many regions of the world, apiculture has come to depend on the use of acaricides, because of the extensive damage caused by varroa to bee colonies. At present, the mite is considered to contribute to the recent decline of honey bee colonies in North America and Europe. Because in tropical climates worker brood rearing and varroa reproduction occurs all year round, it could be expected that here the impact of the parasite will be even more devastating. Yet, this has not been the case in tropical areas of South America. In Brazil, varroa was introduced more than 30 years ago and got established at low levels of infestation, without causing apparent damage to apiculture with Africanized honey bees (AHB). The tolerance of AHB to varroa is apparently attributable, at least in part, to resistance in the bees. The low fertility of this parasite in Africanized worker brood and the grooming and hygienic behavior of the bees are referred as important factors in keeping mite infestation low in the colonies. It has also been suggested that the type of mite influences the level of tolerance in a honey bee population. The Korea haplotype is predominant in unbalanced host-parasite systems, as exist in Europe, whereas in stable systems, as in Brazil, the Japan haplotype used to predominate. However, the patterns of varroa genetic variation have changed in Brazil. All recently sampled mites were of the Korea haplotype, regardless whether the mites had reproduced or not. The fertile mites on AHB in Brazil significantly increased from 56% in the 1980s to 86% in recent years. Nevertheless, despite the increased fertility, no increase in mite infestation rates in the colonies has been detected so far. A comprehensive literature review of varroa reproduction data, focusing on fertility and production of viable female mites, was conducted to provide insight into the Africanized bee host-parasite relationship.     

A review of the natural enemies of the red palm mite, Raoiella indica (Acari: Tenuipalpidae)

A review of all the available information about the natural enemies reported in association with the red palm mite, Raoiella indica is presented. Twenty-eight species of predatory arthropods, including mites and insects, have been reported in association with R. indica in Asia, Africa and the Neotropics. In addition, pathogenic fungi associated with R. indica in the Caribbean have been reported. The available literature indicates that each site has a different natural enemy complex with only one predator species, Amblyseius largoensis (Acari: Phytoseiidae), present in all the geographical areas. The phytoseiids, Amblyseius caudatus Berlese, Amblyseius channabasavanni Gupta and A. largoensis, were regarded as important natural enemies of R. indica, and their predatory efficiency was studied in some detail. Among the predatory insects the coccinellids Stethorus keralicus Kapur and Telsimia ephippiger Chapin were reported as major predators of R. indica. The known distribution, abundance and relative importance of each species reported in association with R. indica are discussed.     

Status of Aceria guerreronis Keifer (Acari: Eriophyidae) as a Pest of Coconut in the State of Sao Paulo, Southeastern Brazil

The coconut mite, Aceria guerreronis Keifer, is one of the main pests of coconut palms (Cocos nucifera) in northeastern Brazil. The objective of this study was to evaluate the levels of the coconut mite and other mites on coconut palms in the state of S?o Paulo and to estimate the possible role of predatory mites in the control of this pest. The effect of cultivated genotypes and sampling dates on the mite populations was also estimated. We sampled attached fruits, leaflets, inflorescences, and fallen fruits. The coconut mite was the main phytophagous mite found on attached and fallen fruits, with average densities of 110.0 and 20.5 mites per fruit, respectively. The prevalent predatory mites on attached and fallen fruits were Proctolaelaps bulbosus Moraes, Reis & Gondim Jr. and Proctolaelaps bickleyi (Bram), both Melicharidae. On leaflets, the tenuipalpids Brevipalpus phoenicis (Geijsks) and Tenuipalpus coyacus De Leon and the tetranychid Oligonychus modestus (Banks) were the predominant phytophagous mites. On both leaflets and inflorescences, the predominant predatory mites belonged to the Phytoseiidae. Neoseiulus baraki (Athias-Henriot) and Neoseiulus paspalivorus (De Leon), predators widely associated with the coconut mite in northeastern Brazil and several other countries, were not found. The low densities of the coconut mite in S?o Paulo could be related to prevailing climatic conditions, scarcity of coconut plantations (hampering the dispersion of the coconut mite between fields), and to the fact that some of the genotypes cultivated in the region are unfavorable for its development.     

Testing prey DNA fingerprinting on Amblyseius largoensis (Acari: Phytoseiidae) predation of Raoiella indica (Acari: Tenuipalpidae)

Molecular detection of predation by identifying prey markers in the digestive tract of predators has developed into a powerful tool to assess predator-prey systems in which diet identification is too time consuming or impossible. Here we explore its utility for detecting predation of the pest mite Raoiella indica Hirst by the predatory mite Amblyseius largoensis Muma, taking advantage of the color the predator acquires after eating this mite to cross-reference our results. For this, a ~410?bp segment of the cytochrome c oxidase subunit I (COI) mitochondrial gene marker specific for the subfamily Tetranychoidea was used. Amblyseius largoensis that had recently eaten were collected from greenhouse colonies containing both mites, and isolated from any other food source. Predator mites were taken for fingerprinting at 24, 48, 72 and 96?h of starving after collection, and the same process was repeated a second time, offering pollen as an alternative food source to see whether detection changed. Lastly, a sampling trial was conducted in the greenhouse, in which mites were collected regardless of their color and frozen immediately for fingerprinting. Raoiella indica DNA was detected for 48 h on starving predators, and for 96 h on those who had eaten pollen. The segment was detected in 26?% of the samples collected on the trial. This technique needs refinement specific for this system, but the results obtained here confirm that it could turn into a very useful tool for assessing aspects of this predator-prey system.     

Profile: Professor Oleg Nikolayevich Bauer (1915–2003)

A lectotype series is designated for Gigantolaelaps gilmorei Fonseca, 1939 in the Acari Collection of the Instituto Butantan in Sao Paulo, Brazil. This laelapid mite species has a widespread geographical distribution. We report a close association with Oryzomys russatus (Wagner) in southeastern Brazil and Argentina, the most southerly part of its range. In Paraguay, the primary host is O. nitidus (Thomas).     

Spatial distributions of the red palm mite, Raoiella indica (Acari: Tenuipalpidae) on coconut and their implications for development of efficient sampling plans

The red palm mite (Raoiella indica), an invasive pest of coconut, entered the Western hemisphere in 2004, then rapidly spread through the Caribbean and into Florida, USA. Developing effective sampling methods may aid in the timely detection of the pest in a new area. Studies were conducted to provide and compare intra tree spatial distribution of red palm mite populations on coconut in two different geographical areas, Trinidad and Puerto Rico, recently invaded by the mite. The middle stratum of a palm hosted significantly more mites than fronds from the upper or lower canopy and fronds from the lower stratum, on average, had significantly fewer mites than the two other strata. The mite populations did not vary within a frond. Mite densities on the top section of the pinna had significantly lower mite densities than the two other sections, which were not significantly different from each other. In order to improve future sampling plans for the red palm mite, the data was used to estimate the variance components associated with the various levels of the hierarchical sampling design. Additionally, presence-absence data were used to investigate the probability of no mites being present in a pinna section randomly chosen from a frond inhabited by mites at a certain density. Our results show that the most precise density estimate at the plantation level is to sample one pinna section per tree from as many trees as possible.     

Mesostigmatid mite infestations of rodents in diverse biotopes of central and southern India

Examination of 165 rodents trapped in domestic, peridomestic, and feral biotopes of central and southern India revealed the presence of 1,359 mesostigmatid mites. Rodents in central India were infested with 1 species of mite, Laelaps nuttalli; 98% of these mites were recovered from the peridomestic rodent Bandicota bengalensis. Material from the burrow nest of a peridomestic rodent examined in central India revealed the mite, Hypoaspis miles. Rodents from the diverse biotopes of southern India were infested by 8 species of mites: L. nuttalli, Laelaps buxtoni, Laelaps myonyssognathus, Androlaelaps aduncus, Androlaelaps marshalli, Androlaelaps sp. A, Hypoaspis sp. 1, and Hypoaspis sp. 2. Sheep from nearby villages regularly graze in feral biotopes. From the hair of these sheep, 2 species of mesostigmatid mites were recovered, A. aduncus and A. marshalli. The sheep appeared to aid the dispersal of rodent-infesting mites passively. Laelaps nuttalli was the predominant mite species found on the peridomestic rodent B. bengalensis. In both central and southern India, the prevalence, mean intensity, and relative density of this mite were much higher on peridomestic rodents than on domestic and feral rodents. A significant negative correlation was found between the numbers of mites and fleas infesting rodents in central India. A highly significant positive association between A. marshalli and A. aduncus on the feral rodent Tatera indica was recorded. In southern India, the overall prevalence of the 8 species of mites was highest on Mus platythrix. However, the combined prevalence of these mites on 2 feral rodents T. indica and M. platythrix was lower than their prevalence on B. bengalensis. Similarly, the combined values for mean intensity and relative density of these mites on the 2 feral rodents were lower than on the peridomestic rodent B. bengalensis.     

Pathogenicity and specificity of Neozygites tanajoae and Neozygites floridana (Zygomycetes: Entomophthorales) isolates pathogenic to the cassava green mite

The cassava green mite (CGM), Mononychellus tanajoa, a native of South America was accidentally introduced into Africa where it causes serious crop losses. The possibility of introducing classical biological agents from the native home of CGM into Africa was investigated. Thus, we conducted a series of laboratory assays of the native fungal pathogens, Neozygites tanajoae from Brazil and Neozygites floridana from Colombia and Brazil, and compared them with N. tanajoae isolates from Benin. Infectivity of both fungal species, was assayed against the twospotted spider mite, Tetranychus urticae, and against the red mite, Oligonychus gossypii. Pathogenicity against CGM and host range studies were conducted by transferring adult females of each mite species to leaf discs containing sporulated cadavers with a halo of conidia of each fungal isolate. All isolates caused some degree of infectivity to CGM. None of the isolates of N. floridana and N. tanajoae tested were pathogenic to O. gossypii, and only two isolates infected T. urticae. Most isolates from Brazil were highly virulent and infected only CGM. Sixteen N. tanajoae isolates caused more than 89% mortality and more than 62% of the CGM became mummified. A mummified CGM is characteristically a swollen, brown fungus-killed mite that has great potential to produce conidia. However, high mortality was not always associated with high mummification. The median mummification time ranged from 4.4 to 6.7 days. Five Brazilian isolates caused >75% mummification with a median mummification time <5 days. Isolates that cause high mummification in a short period of time would be more likely to cause epizootics and to establish in the new environment. Therefore, these isolates would be the best candidates for introduction to Africa.     

A new species of laelapine mite (Acari: Parasitiformes: Laelapidae) associated with Proechimys dimidiatus in the Atlantic forests of Brazil

Tur megistoproctus, a new species of Laelapinae, is described from the pelage of the echimyid rodent Proechimys dimidiatus from the Atlantic forests of Ilha Grande, south of Rio de Janeiro. Measurements and illustrations are included for females and males. Another laelapine mite species, Tur turki Fonseca, co-occurred with T. megistoproctus in our studies and was recorded from the same host individuals and localities. These 2 laelapine mite species appear to be exclusively associated with a complex of echimyid rodent species (subgenus Trinomys) in the Atlantic forests of southeastern Brazil.