Red Spider Mite Tetranychus Evansi Research Articles

Effect of Methyl Jasmonate on the Performance of Tetranychus evansi Baker & Pritchard, 1960 (Acari: Tetranychidae) and Phytoseiulus longipes Evans, 1968 (Acari: Phytoseiidae) on Tomato Plants

Inducible anti-herbivore defenses in plants are predominantly regulated by jasmonic acid (JA). The red spider mite Tetranychus evansi Baker & Pritchard, 1960 (Acari: Tetranychidae) is an invasive pest known for its detrimental impact on tomato plants and other Solanaceae crops. Here, we investigated the extent to which T. evansi and the predatory mite Phytoseiulus longipes Evans, 1968 (Acari: Phytoseiidae) are affected by induced JA-defenses. Initially, we artificially induced the JA-response in tomato plants using exogenous methyl jasmonate (MeJA) and subsequently assessed the effect of JA defenses on spider mite by evaluating mortality and oviposition rates. Our findings revealed a higher mortality and lower oviposition rates on plants treated with MeJA compared to non-treated control plants. Furthermore, we examined the predatory mite's predation rates on spider mite eggs produced on MeJA-treated and non-treated tomato plants. The results showed a reduced predation on T. evansi eggs derived from MeJA-treated plants, indicating a potential negative impact of JA-induced defenses on the predator's performance. Finally, we released five predatory females on T. evansi-infested tomato plants treated and non-treated with MeJA, monitoring the predator population density for three generations. Predator population was not affected, as the abundance of larvae and adults was not significantly different between treatments. These findings underscore the negative impact of JA defenses on herbivores and highlight the trade-off it may pose on natural enemies.

First record of the tomato red spider mite, Tetranychus evansi Baker and Pritchard (Acari: Tetranychidae) in Mexico, from cultivated and wild solanaceous plants

The tomato red spider mite Tetranychus evansi Baker and Pritchard is a pest of primary importance on cultivated Solanaceae in some countries. Based on morphological characters and sequencing of a fragment of the cytochrome oxidase subunit I (COI) of mitochondrial DNA (mtDNA), the presence of T. evansi is reported for the first time in Mexico, from four municipalities (counties) in three states: Baja California, Nuevo León and Tamaulipas, on solanaceous plants, both cultivated (tomato, Solanum lycopersicum L., and potato Solanum tuberosum L.) and wild (nigthshades, Solanum cf. americanum Mill. and Solanum nigrescens Mart. and Gal.). The molecular study confirms for the first time the presence of haplotype 4 (belonging to clade I) of T. evansi in North America (Nuevo Leon state). This clade includes most invasive T. evansi populations worldwide. Although no studies have been carried out on the economic impact of T. evansi in Mexico, it is of utmost importance to recognize the presence of this species to establish sound management strategies.

Comparative efficacy of three pesticides against the tomato red spider mite Tetranychus evansi Baker & Pritchard under laboratory conditions

Comparative efficacy of three pesticides against the tomato red spider mite Tetranychus evansi Baker & Pritchard under laboratory conditions

The role of salivary proteins from Tetranychus evansi in the mite-plant interaction

Herbivores and plants have been engaged in a tight co-evolutionary arms race, and saliva played important roles in this process. Some herbivore-derived small molecules or proteins called herbivore-associated molecular patterns (HAMPs) can be recognized by plants and thus trigger plant immune responses. Another type of salivary proteins, called effectors, utilize various strategies to suppress plant defense responses to establish successful feeding. The tomato red spider mite Tetranychus evansi is a worldwide pest of Solanaceous crops and causes enormous economic damage in many regions of the world. During the feeding process, T. evansi secretes saliva into plant cells through cheliceral stylets. Secreted saliva plays crucial roles in modulating plant-mite interaction, such as effectors Te28 and Te84 (Villarroel et al., 2016). We previously identified 136 salivary proteins from T. evansi by transcriptome and LC-MS/MS analyses (Huang et al., 2018). However, the role of these salivary proteins in mite-plant interaction was unknown. Here, we identified a salivary protein involved in the mite-plant interaction (Cui et al., 2022). This protein encodes a protein disulfide isomerase (TePDI) and acts as a HAMP that triggers plant defenses by inducing ROS burst, callose deposition and plant defense-related genes in Nicotiana benthamiana. TePDI can be recognized by multiple Solanaceae plants such as tomato, pepper, and eggplant. TePDI-mediated cell death in N. benthamiana is dependent on the plant signaling molecules SGT1 (suppressor of the G2 allele of skp1) and HSP90 (heat shock protein 90). To better feed on plants, T. evansi inhibited TePDI-triggered cell death and plant defense responses by secreting effectors Te28 and Te84. Further analysis revealed that PDI from phylogenetically distinct herbivorous and non-herbivorous arthropods all triggered cell death and immune response in N. benthamiana. Moreover, silencing PDI gene in spider mites and whiteflies resulted in the reduced survival rate of both pests. Altogether, our study revealed that PDI is a double-edged sword. On the one hand, it is functionally conserved in herbivores and required for their survival; on the other hand, it is recognized by Solanaceae plants and enhances plant resistance against herbivores. Our findings indicate that plants utilize evolutionarily conserved HAMPs to activate plant defense and resist pest damage, providing a potential strategy for pest management.
  

Comparative Effects of Some Botanical Extracts and Chemicals in Controlling the Red Spider Mite Tetranychus evansi Baker & Pritchard on Solanaceous Crops

The tomato red spider mite, Tetranychus evansi, is an invasive pest reported on solanaceous crops in Benin around 2008, causing heavy economic damage. The control of this mite by farmers is mainly done through intensive applications of chemical pesticides that are not always effective. In the present study, we evaluated in a laboratory, at IITA-Benin, the effects of two botanical insecticides: the Cashew Nut Shell Liquid (CNSL) and Neem oil. This is together with Acarius 18 EC, a chemical acaricide generally used by growers on eggs and adult females T. evansi. The half recommended dose (0.5 l/ha), the recommended dose (1 l/ha), and the double recommended dose (2 l/ha) of Acarius and Neem oil as well as solutions at 1%, 2 %, 3%, 4% and 5% of CNSL were tested. Mean egg hatching rates varied significantly among treatments, ranging from 0.00 ± 0.00% (Neem oil and CNSL) (respectively at half recommended dose and 4%) to 100% (Control). Mortality of adult female T. evansi also differed significantly among treatments (P < 0.0001), ranging from 22.00 ± 4.20% to 100%. The highest mortality rates were recorded with Neem oil at any doses and with CNSL at 4%, whereas the lowest rate was recorded with the control treatment. Fecundity of pesticide-treated females T. evansi and proportion of eggs that hatched revealed significant differences among all doses of products (P < 0.0001). It appears from this study that even the half recommended dose of Neem oil and the CNSL at 4% were very effective on suppressing T. evansi populations and should, therefore, be subject to further studies to test their compatibility with natural enemies, and to determine strategies for their efficient applications in greenhouse and under field conditions.
  
  

Diagnosis of a new to New Zealand spider mite, Tetranychus evansi Baker and Pritchard, 1960 (Acari: Tetranychidae)

ABSTRACT The tomato red spider mite Tetranychus evansi was detected for the first time in New Zealand in May 2020. There is an urgent need for rapid and accurate diagnostic tools on this species. In order to meet this demand, we developed methods for identification of T. evansi in the field and laboratory based on damage symptoms, morphological characters and DNA sequences. To distinguish T. evansi from the previously recorded species a key to all species of Tetranychus in New Zealand is provided. DNA barcoding employing the mitochondrial COI gene enabled us to differentiate T. evansi from closely related species.

Susceptibility of ten tomato cultivars to attack by Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) under laboratory conditions

We evaluated, in a laboratory experiment, the susceptibility of 10 tomato cultivars to the attack by the tomato red spider mite Tetranychus evansi, an invasive pest of this crop in Benin. Among the 10 cultivars tested, six were imported (i.e. Roma VF, Tima, Rio Grande, Buffalo, Petomech, and TLCV15) and four local (i.e. Akikon, Tounvi, TomL4, and Kekefo). Leaf disks (2.5 cm diameter) excised from leaves of tested cultivars, and placed upper side down on top of water-soaked cotton wool laying in 9.5 cm diameter Petri dishes (6 leaf disks per Petri dish), served both as experimental units and feeding source for the mites. Mites were individually placed on leaf disks of each cultivar and several biological parameters – development, reproductive parameters and longevity – were assessed. The experiments were performed at 27 ± 1 °C, 65–70% RH, and 12:12 h (L: D) photoperiod. Our results revealed significant effects of tomato cultivars on several biological parameters of T. evansi, especially the developmental time of the egg stage (P ˂ 0.0001), and the larval stage (P = 0.0113), as well as female oviposition period (P = 0.0002). Likewise, female longevity (P = 0.0095) and fecundity (i.e. egg/♀, P = 0.0055) were significantly affected. The sex-ratio of the progeny was generally similar for all the cultivars except for Buffalo and Tounvi on which most juveniles did not develop beyond the larval stage. These two cultivars appeared as potential tomato cultivars for implementation of IPM strategies for the control of T. evansi.

The role of preadaptation, propagule pressure and competition in the colonization of new habitats

To successfully colonize new habitats, organisms not only need to gain access to it, they also need to cope with the selective pressures imposed by the local biotic and abiotic conditions. The number of immigrants, the preadaptation to the local habitat and the presence of competitors are important factors determining the success of colonization. Here, using two experimental set‐ups, we studied the effect of interspecific competition in combination with propagule pressure and preadaptation on the colonization success of new habitats. Our model system consisted of tomato plants (the novel habitat), the two‐spotted spider mite Tetranychus urticae as our focal species and the red spider mite Tetranychus evansi as a competitor. Our results show that propagule pressure and preadaptation positively affect colonization success. More successful populations reach larger final population sizes either by having higher per capita growth rates (due to preadaptation effects) or by starting a population with a larger number of individuals. Although populations are more successful colonizing non‐competitive environments than competitive ones, propagule pressure and preadaptation counteract the negative effects of competition, promoting colonization success. Our study shows the importance of propagule pressure and preadaptation for successful colonization of new habitats by providing the ability to cope with both the exigencies of new environments and the community context.

Opposing Roles of Foliar and Glandular Trichome Volatile Components in Cultivated Nightshade Interaction with a Specialist Herbivore.

Plant chemistry is an important contributor to the interaction with herbivores. Here, we report on a previously unknown role for foliar and glandular trichome volatiles in their interaction with the specialist herbivore of solanaceous plants, the tomato red spider mite Tetranychus evansi. We used various bioassays and chemical analyses including coupled gas chromatography-mass spectrometry (GC/MS) and liquid chromatography coupled to quadrupole time of flight mass spectrometry (LC-QToF-MS) to investigate this interaction between cultivated African nightshades and T. evansi. We show that, whereas morphologically different cultivated African nightshade species released similar foliar volatile organic compounds (VOCs) that attracted T. evansi, VOCs released from exudates of ruptured glandular trichomes of one nightshade species influenced local defense on the leaf surface. VOCs from ruptured glandular trichomes comprising mainly saturated and unsaturated fatty acids deterred T. evansi oviposition. Of the fatty acids, the unsaturated fatty acids accounted for >40% of the oviposition deterrent activity. Our findings point to a defense strategy in a plant, based on opposing roles for volatiles released by foliar and glandular trichomes in response to attack by a specialist herbivore.

Visual, vibratory, and olfactory cues affect interactions between the red spider mite Tetranychus evansi and its predator Phytoseiulus longipes

Phytoseiulus longipes Evans (Mesostigmata: Phytoseiidae) is an exotic predator widely used in biological control programs for the red spider mite Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) in East Africa. However, little is known about the cues mediating this prey/predator interaction. Here, we performed behavioral assays to test the involvement of visual, vibratory, and olfactory cues using a combination of dead/living insects enclosed in either perforated or non-perforated transparent/opaque capsules. We monitored insect responses with a video tracking system and analyzed the data with Ethovision software. Our results showed avoidance behavior of T. evansi in the presence of live P. longipes through visual, vibratory, and olfactory cues. P. longipes was attracted by vibratory and olfactory cues emitted by T. evansi. The composition of volatiles from T. evansi was identified by GC/MS as methyl salicylate (MeSA), linalool, β-caryophyllene, octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid. Our behavioral assays with predatory mites in a Y-tube olfactometer revealed that among the identified volatiles, only MeSA, linalool, and MeSA + linalool attracted P. longipes. The implications of these findings for the control of T. evansi are discussed.

Farmers' control practices against the invasive red spider mite, Tetranychus evansi Baker & Pritchard in Benin

In 2008, the invasive tomato red spider mite Tetranychus evansi (Acari: Tetranychidae), a pest of solanaceous crops, was identified for the first time as the cause of serious damage on tomato (Solanum lycopersicum L.; Solanaceae) crops in Benin. Since then, frequent outbreaks have been observed on Solanaceae and other leafy vegetables such as purple amaranth (Amaranthus cruentus L.; Amaranthaceae) and bitter leaf (Vernonia amygdalina D.; Asteraceae) in all growing areas in southern Benin. The objective of this study was to evaluate the intensity of damage by this invasive pest and the impact of farmers' control practices on purple amaranth, African eggplant (Solanum macrocarpon L.; Solanaceae) and tomato crops. A survey was carried out in January 2013 among 150 farmers in the three major growing areas in southern Benin: Sèmè-Kpodji, Grand-Popo and Pahou. Tetranychus evansi was the only mite observed, causing production losses estimated at 65% for African eggplant, 56% for tomato and 25% for purple amaranth. Previously encountered species such as Tetranychus urticae Koch, Tetranychus ludeni Zacher (Acari: Tetranychidae) and Polyphagotarsonemus latus Banks (Acari: Tarsonemidae) were not observed in any of the 45 samples. To protect the infested crops, growers sprayed various synthetic pesticides at high frequencies according to crop phenology 3, 6 and 12 times per month, respectively, on purple amaranth, African eggplant and on tomato, on average. The most frequently used pesticides were pyrethroids and organophosphate compounds. Farmers reported that these compounds were largely ineffective against T. evansi. The risks posed to human and environmental health, as well as existing alternatives to chemical pesticide use, are discussed.

Resistance of tomato accessions from the horticulture germplasm bank to red spider mites: exploring mite preference patterns and antixenosis mechanism

The red spider mite Tetranychus evansi can cause up to 90% yield losses to tomato crops. Mechanisms and causes of plant resistance to this pest could contribute to improved planning of plant breeding programs that prevent damage by this pest. It is known that the morphology and chemical compounds present in tomato plants are important to Tetranychus spp. success. This study aims at evaluating the resistance of 84 arbitrarily chosen tomato accessions – obtained from the Horticulture Germplasm of the Universidade Federal de Viçosa (HGB-UFV), Minas Gerais State, Brazil – to T. evansi. We evaluated the number of spider mites per leaf disk, number of trichomes/mm2, and the concentration of hydrocarbons of leaf disk. A significant difference in the number of T. evansi adults/leaf disk was found among accessions. The resistance mechanism of the HGB-UFV accessions was determined to be antixenosis. Accessions 2004, 2098, 2121, and 2100 had higher trichome density and the lowest adult T. evansi per tomato leaf disk. For this reason, these accessions should be chosen as sources of resistance in plant breeding programs. The hydrocarbons C11, C13, and C22 had a negative correlation with T. evansi adults per leaf disk.

Differential effects of various African nightshade species on the fecundity and movement of Tetranychus evansi (Acari: Tetranychidae)

The tomato red spider mite Tetranychus evansi Baker & Pritchard is a serious pest of solanaceous plants worldwide. Management of this oligophagous pest in African nightshades has been a challenge to smallholder African farmers due to its high reproductive rate and rapid development of resistance to synthetic pesticides. The aim of the present study was to determine the influence of leaf trichomes on T. evansi by comparing its fecundity and movement on the leaf surfaces of five African nightshade species, namely Solanum sarrachoides Sendter, S. villosum Miller, S. tarderemotum Bitter, S. americanum Miller and S. scabrum Miller. Data were recorded in the laboratory at 23 ± 1°C, 50–70% relative humidity and a 12 h light:12 h dark photoperiod for the effect of trichome type and density of the abaxial leaf surface on mite fecundity. Distances travelled by mites on the leaf surface from the edge of a thumbtack pin inserted on the leaf were also recorded. Different trichomes, glandular and non-glandular types, were identified. There was a significant negative correlation of fecundity and distance walked by mites with the density of glandular trichomes. Significantly fewer eggs were laid on S. sarrachoides in comparison with the other Solanum species. The distance walked by mites was also significantly shorter in this species, indicating that higher densities of glandular trichomes interfere with mite movements. These results suggest that African nightshade genotypes differ in their levels of resistance to T. evansi, which is partially associated with differences in trichome types and their densities.

Biological control of Tetranychus evansi Baker & Pritchard and Tetranychus urticae Koch by Phytoseiulus longipes Evans in tomato greenhouses in Spain [Acari: Tetranychidae, Phytoseiidae]

The two-spotted spider mite Tetranychus urticae and the tomato red spider mite Tetranychus evansi are known to cause severe damage in tomato crops. Preliminary laboratory studies showed that a phytoseiid predatory mite from Argentina, Phytoseiulus longipes, could be a potential candidate for the control of those two pests. The present paper aims to assess the effectiveness of this predator for controlling both pests under tomato experimental greenhouse conditions. Six treatments were considered: T. urticae without predators, T. evansi without predators, a high and a low predator–prey ratios (1–5 and 1–25 predator–prey, respectively) used with both prey. Mites were counted twice a week during 35 days after the predators were released. Without predators, plant damage was quickly noticed. P. longipes was able to maintain T. urticae and T. evansi populations under a threshold of 25 mites/leaflet at a high predator–prey ratio. However, at the low predator–prey ratio, plants showed damages in presence of both pests. The predatory mite population considered could constitute a real improvement for the biological control of T. urticae and T. evansi in European tomato greenhouses. Perspectives for the use of P. longipes as a biocontrol agent and the additional work required to make this a reality are discussed.

Reproductive performance of seven strains of the tomato red spider mite Tetranychus evansi (Acari: Tetranychidae) at five temperatures

The tomato red spider mite Tetranychus evansi Baker et Pritchard occurs on solanaceous plants, and causes serious damage to a variety of crops in Africa and Europe. In 2001 this species was also found in Japan, on nightshade (Solanum nigrum L.), and its invasion to solanaceous of agricultural importance is feasible. To evaluate its potential severity as a pest, the present study assessed the life-history parameters, such as the rate of development and the intrinsic rate of natural increase (r(m)), on S. nigrum for T. evansi collected on seven sites worldwide. Increasing temperatures between 15 and 32.5°C significantly increased the developmental rate of the seven strains while immature developmental duration was about the same at 32.5-40°C. The rate of egg-to-adult development [(% hatch) × (% survival)] exceeded 88% at temperatures between 15 and 37.5°C. The lower thermal thresholds (LT) were 11.9-12.5°C for both egg-to-adult and egg-to-egg development. The optimum developmental temperatures ranged from 36.7 to 43.8°C and the upper developmental threshold (UT) ranged from 45.2 to 59.4°C. The r (m)-values became higher with temperature increasing from 15 to 35°C. The r (m)-values at 25°C ranged from 0.265 to 0.277 which are relatively high for species of the genus Tetranychus. These results indicate that T. evansi after invasion into Japan has the potential to become a serious pest on solanaceous crops, just the same as in Africa and Europe.

Effect of temperature on sporulation of Neozygites floridana isolates from different climates and their virulence against the tomato red spider mite, Tetranychus evansi

The fungal pathogen Neozygites floridana Weiser and Muma has been evaluated as a classical biological candidate for introduction into Africa against the invasive tomato red spider mite Tetranychus evansi Baker and Pritchard. In this study, the effect of temperature on sporulation, germination and virulence of three isolates of N. floridana collected from T. evansi in three climatically distinct regions of Brazil and Argentina was determined. Six constant temperatures of 13 °C, 17 °C, 21 °C, 25 °C, 29 °C and 33 °C were tested for their effect on the ability of the three fungal isolates to sporulate, germinate and kill the mites. Six alternating-temperature regimes of 17–13 °C, 21–13 °C, 29–13 °C, 33–13 °C, 33–23 °C, 33–28 °C under a 12 h photophase were also tested to estimate virulence of the three isolates against T. evansi. The Vipos isolate discharged more conidia than isolates from Recife or Piracicaba at all temperatures and sporulation was strongly temperature dependent. Optimal sporulation rates were observed at 25 °C while optimal germination rates were observed at 25 °C and 29 °C. At 29 °C, the shortest mean survival time of T. evansi (3.16 days, 95% CI of 3.05–3.27) was observed for the isolate from Vipos, while the longest LT 50 (3.47 days, 95% CI 3.34–3.59) was observed for the isolate from Piracicaba. Mortality of mites increased as the differences between alternating day and night temperatures increased from 8 °C (21–13 °C), to 10 °C (33–23 °C), to 16 °C (29–13 °C), with smallest and highest temperature differences of 4 °C (17–13 °C) and 20 °C (33–13 °C), both producing low mortalities. The overall results suggest that the Vipos isolate is better adapted to a wider range of temperatures than the other isolates tested.

First record of the invasive miteTetranychus evansi in Greece

The red spider miteTetranychus evansi (Acari: Tetranychidae) Baker and Pritchard was recorded for the first time in Greece, in the area of Tympaki (south-central Crete) onSolanum nigrum. T. evansi is a pest of crops of the family Solanaceae, which are grown extensively in Crete. The species identification was based on both morphological and molecular data. The second internal transcribed spacer was PCR amplified and sequenced in samples from Crete. Sequences were compared with the sequence ofT. evansi from Brazil and with the ITS2 sequences (retrieved from GenBank) of the two closely related tetranychid species most commonly found in Greece,Tetranychus turkestan andTetranychus urticae.

Surveys for natural enemies of the tomato red spider mite Tetranychus evansi (Acari: Tetranychidae) in northeastern and southeastern Brazil

Surveys for predators of the tomato red spider mite Tetranychus evansi Baker & Pritchard on solanaceous plants were carried out in north-eastern and south-eastern Brazil to determine prospective species for the control of the pest in Africa. Surveys were carried out in areas identified as climatically similar to regions in Africa where T. evansi has been reported as a pest and where prospective natural enemies may be introduced. A total of 56,445 mites and insects were found in 330 samples collected from 20 different species of solanaceous plants. Tetranychus evansi was found in only three samples, on Solanum americanum Mill. and Lycopersicon esculentum Mill.. A total of 5,023 specimens of predatory mites, of at least 44 species, and 494 specimens of acarophagous insects, of at least three species were collected. The predominant predatory mites were (in decreasing order): Phytoseius guianensis DeLeon, Pronematus ubiquitus (McGregor), Asca sp., Paraphytoseius orientalis (Narayanan, Kaur & Ghai), Phytoseius woodburyii DeLeon, Amblyseius compositus Denmark & Muma, Homeopronematus anconai (Baker), Neoparaphytoseius sooretamus (El-Banhawy), Cunaxoides sp., Typhlodromus paraevectus Moraes & McMurtry, Typhlodromalus peregrinus (Muma) and Phytoseius cismontanus DeLeon. However, no predatory mites were found in association with T. evansi. Among the insects, although not the most abundant, Stethorus tridens Gordon seemed to be most promising, as it was found associated with T. evansi in all samples in which the latter was found. Feltiella sp. was the most abundant acarophagous insect found, but it was never found associated with the pest.

Surveys for natural enemies of the tomato red spider mite Tetranychus evansi (Acari: Tetranychidae) in northeastern and southeastern Brazil

Surveys for predators of the tomato red spider mite Tetranychus evansi Baker & Pritchard on solanaceous plants were carried out in north-eastern and south-eastern Brazil to determine prospective species for the control of the pest in Africa. Surveys were carried out in areas identified as climatically similar to regions in Africa where T. evansi has been reported as a pest and where prospective natural enemies may be introduced. A total of 56,445 mites and insects were found in 330 samples collected from 20 different species of solanaceous plants. Tetranychus evansi was found in only three samples, on Solanum americanum Mill. and Lycopersicon esculentum Mill.. A total of 5,023 specimens of predatory mites, of at least 44 species, and 494 specimens of acarophagous insects, of at least three species were collected. The predominant predatory mites were (in decreasing order): Phytoseius guianensis DeLeon, Pronematus ubiquitus (McGregor), Asca sp., Paraphytoseius orientalis (Narayanan, Kaur & Ghai), Phytoseius woodburyii DeLeon, Amblyseius compositus Denmark & Muma, Homeopronematus anconai (Baker), Neoparaphytoseius sooretamus (El-Banhawy), Cunaxoides sp., Typhlodromus paraevectus Moraes & McMurtry, Typhlodromalus peregrinus (Muma) and Phytoseius cismontanus DeLeon. However, no predatory mites were found in association with T. evansi. Among the insects, although not the most abundant, Stethorus tridens Gordon seemed to be most promising, as it was found associated with T. evansi in all samples in which the latter was found. Feltiella sp. was the most abundant acarophagous insect found, but it was never found associated with the pest.

Identification of priority areas in South America for exploration of natural enemies for classical biological control of Tetranychus evansi (Acari: Tetranychidae) in Africa

Abstract The red spider mite Tetranychus evansi Baker and Pritchard is a pest of tomato in East and Southern Africa. It is probably native to South America. Three models were established to identify priority areas for the search of natural enemies in South America for classical biological control of this pest in Africa. The models were based on the concept of “fundamental ecological niche”, predicting regions in South America that have similar environmental conditions to areas where the mite is a problem in Africa, using Desktop-GARP (Genetic Algorithm for Rule-set Production). Based on the model established with data sets from Kenya and Zimbabwe, it was determined that priority areas include areas in Brazil, Argentina, Paraguay and Uruguay, as well as some restricted areas in other South American countries.