Phytophagous and predaceous mites associated with vegetable crops from Riyadh,Saudi Arabia

This study was conducted to investigate phytophagous and predatory mites associated with vegetable plants in Riyadh, Saudi Arabia. Eight phytophagous and 10 predacious mites were collected from 14 species of vegetable crops covering five major production localities. Out of these 18 mite species, 13 species are new to the mite fauna of Saudi Arabia. In addition, the two species, Tenuipalpus punicae and Agistemus exsertus, are reported for the first time on vegetable crops in Saudi Arabia. For each mite species found, notes on host plant association and occurrence period are given. An illustrated key for the identification of the 18 mite species reported in this study is provided and this can be used to improve the IPM programs by applying the local natural predatory mites in controlling mite pests in Saudi Arabia.     

Mite pests and their predators on seven vegetable crops (Arachnida: Acari)

During this study the frequency of occurrence and dominance of phytophagous and predatory mites harboring seven vegetable crops in Egypt, namely common bean, cowpea, eggplant, okra, squash, sweet pepper and sweet potato during 2017–2018 were investigated to identify predatory mites that might be useful for the biological control of the phytophagous mites. Three phytophagous and nine predatory mite species were surveyed. The two spotted spider mite Tetranychus urticae Koch of the family Tetranychidae was the dominant pest on these vegetables, while phytoseiids Phytoseiulus persimilis (Athias- Henriot), Typhlodromips swirskii (Athias- Henriot) and Euseius scutalis Chant were the dominant predators. The population of the native or indigenous phytoseiid mite fauna in Egypt such as Phytoseiulus persimilis could be considered as a good biocontrol agent and a part of the Integrated Pest Management (IPM) program in the future. Mite fauna of Egypt especially local populations of Phytoseiulus persimilis can be considered for implementation in future Integrated Pest Management (IPM).     

Mites associated with stored grain commodities in Benin, West Africa

After insects, mites are the major arthropod pests that inhabit stored agricultural products worldwide. To determine the acarofauna that infests cowpea, maize, paddy rice and sorghum in Benin (West Africa), surveys were conducted in some principal markets (Dantokpa, Glazoue and Parakou) of this country. A total of 555 samples of grains and debris were collected in May and September 2011. More than 56 species belonging to 24 mite families were recorded in the four products. These mite species included predators, parasites, fungivorous, phytophagous and other groups whose feeding habits are not well known. The family Cheyletidae was the most prevalent and the most diverse predatory mite family encountered, in which Cheyletus malaccensis Oudemans was the most abundant species. Several families of mite pests and mites responsible for allergies (Acaridae, Glycyphagidae, Pyroglyphidae, Pyemotidae and Saproglyphidae) were also detected. The three most dominant and frequent species were C. malaccensis, Suidasia nesbitti (Hughes) and Suidasia sp. Statistical analysis showed that densities of these three mite species were higher in Parakou than in Glazoue and Dantokpa, on one hand, and higher in debris than in grains, on the other hand. The densities of S. nesbitti and Suidasia sp. decreased significantly during the dry season, whereas C. malaccensis remained stable throughout the two samplings. Of all grains, sorghum was the least infested with mites. This study shows that in Benin mites are present in stored agricultural products to which they cause serious damage, and may cause various allergies to people.     

Acarofauna present in organic strawberry fields and associated weed species in southern Brazil

The presence of weeds in the margins of strawberry crops can enhance populations of predatory mites as a measure to support conservation biological control. The aims of this study were (i) to assess the composition of the acarofauna associated with strawberries and the accompanying herbaceous plants in an organic farming system, and (ii) to evaluate the possible relationships between phytophagous and predatory mites occurring in this system. Strawberry leaves and whole plants of weeds were sampled biweekly from August 2014 to February 2015 in Lapa (Paraná, Brazil). In total, 23 weed species belonging to 10 families were identified; 3768 mite individuals (from 15 families and 4 suborders) were recovered, 77% on strawberries and 23% on weeds. Abundance of predatory mites on weeds was greater than on strawberry cultivars. On strawberries, the most abundant family was Tetranychidae (84%) followed by Phytoseiidae (11.6%). In total, 16 predatory mite species from the Phytoseiidae family were identified, 13 of them occurring on strawberry leaflets. Typholodromalus aripo, Neoseiulus californicus and Typhlodromips mangleae were the most abundant mite species on strawberry leaves. On weeds, most individuals were predatory mites (59%), whereas phytophagous mites represented 17.2%. The most abundant family was Phytoseiidae (36.4%). On weeds, the phytoseiid mite T. aripo was the most abundant species, representing 34.7%. Besides being found on strawberry leaflets, T. aripo was associated with 15 weed species. Among the weeds, Bidens pilosa showed the highest values of the Shannon index (1.97), Margalef index (3.04), and Pielou’s evenness index (0.95). This study emphasizes the importance of surrounding weeds as a shelter for beneficial mitefauna in strawberry fields, likely contributing to enhance conservation biological control.

     

Abundance of phytoseiid mites on Vitis species: effects of leaf hairs,domatia, prey abundance and plant phylogeny

We observed the number of predatory mites (Phytoseiidae:Typhlodromus caudiglans) on the foliage of 20 North American species of grapes (Vitis spp) plus the domesticated EuropeanVitis vinifera, all grown in a common garden. We found relatively few phytophagous mites. The numbers of phytophagous mites were not correlated with the plant characteristics that we measured. We found approximately five times as many predatory mites as phytophagous mites and the numbers of these phytoseiid predators were not affected by the availability of prey. Similarly, numbers of phytoseiids were unaffected by plant gender and, hence, the availability of pollen, another source of food. The numbers of phytoseiids were not clustered according to the taxonomic grouping of the tested plant species. Leaf surface characteristics explained over 25% of the variance in the numbers of phytoseiids. Numbers of phytoseiids were positively associated with the density of vein hairs, the density of bristles in leaf axils, and the presence of leaf domatia. These results suggest that sheltered habitats rather than food availability may limit the numbers of phytoseiid mites on grapevines.     

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.     

Emission of volatile organic compounds by apple trees under spider mite attack and attraction of predatory mites

Emission rates of volatile organic compounds (VOCs) from Pirus malus L. subsp. mitis (Wallr.) var. Golden Delicious and var. Starking attacked by the phytophagous mite Panonychus ulmi Koch, and their attractiveness to the predatory mites Amblyseius andersoni Chant and Amblyseius californicus McGregor, were studied during three years. A large variability was found in the emission of individual VOCs depending on the infestation, the apple tree variety and the date. There were larger total VOC emission rates and larger total VOC leaf concentrations in apple trees attacked by phytophagous mites, especially in the var. Starking. In infested trees of this variety, there were also more predatory mites. An olfactometer assay showed that predatory mites preferentially chose branches infested by Panonychus ulmi (85% went to infested branches vs 15% to uninfested control branches) indicating that volatiles may be used as cues to find their prey.     

Assessment of mite fauna in different coffee cropping systems in Brazil

Agro-ecological diversification may increase natural biodiversity and decrease environmental impacts caused by the intensification of management practices, especially with respect to pest control. This study aimed to evaluate mite populations from surveys in commercial coffee (Coffea arabica) orchards managed in different ways. Four different cropping systems were compared: a conventional system (CS), non-pesticide system (NPS), organic system (OS) and organic agroforestry system (OAS). Mite samples were taken from 24 coffee plantations (n?=?6 for each management strategy). Six leaves per plant were collected from five sampling sites totalling 30 leaves from each plantation. Mites were removed from individual leaves, counted and identified to family level. Amongst the predatory mites, two families were detected; the Phytoseiidae was the most abundant family while the Stigmaeidae, generalist predatory mites, were only found in two management systems (NPS and AOS). Of the two families of phytophagous mites, the family Tenuipalpidae was the most abundant, but rarely found in AOS. The other phytophagous family, Tetranychidae, was less abundant in coffee crops than Tenuipalpidae, but the most abundant phytophagous family in CS. Understanding the relationship between mite populations and management practices can aid in choice of spraying strategies for different coffee management systems.     

Assessment of Amblyseius fallacis (Acari: Phytoseiidae) for biological control of tetranychid mites in an Ontario peach orchard

We introduced a mass-reared pyrethroid-resistant strain of the predatory phytoseiid mite Amblyseius fallacis (Garman) into an Ontario peach orchard in an attempt to control populations of the phytophagous mites Panonychus ulmi Koch and Tetranychus urticae Koch (Acari: Tetranychidae). Releases of 1,000 and 2,000 mites per tree were made, at three different times. The release of 2,000 mites per tree in June and in July resulted in significantly higher phytoseiid densities than was observed on control trees. However, densities of P. ulmi or T. urticae were not significantly affected by any release rate or by timing. The release of 1,000 A. fallacis per tree, or of any density in August, did not significantly increase phytoseiid abundance. In the following year, population dynamics of both phytoseiid and phytophagous mites were not significantly affected by the previous year's release. Amblyseius fallacis can be a useful predator in some fruit orchards. However, further research is necessary into the timing and rate of release, modified spray programmes, and with different crops, in order to clarify the role of this species for biological control in Ontario peach orchards.     

Phytophagous and predatory mites (Acari: Tetranychidae,Eriophyidae, Phytoseiidae,Stigmaeidae) in South Moravian vineyards,Czechoslovakia, treated with various types of chemicals

Communities of phytophagous and predatory mites on vine can be influenced by the type of chemical treatment. Ten species of phytoseiid mites inhabit vines in the region of South Moravia. Populations ofTyphlodromus pyri Scheuten play leading roles in effective suppression of tetranychid and eriophyid mites in commercial vineyards sprayed with pesticides, except synthetic pyrethroids and mancozed, which are considered to be detrimental to the predatory phytoseiid mites.     

Mites associated with soybean crop in Rio Grande do Sul State, Brazil

During the last growing seasons, high infestations of phytophagous mites were observed in the State of Rio Grande do Sul, Brazil, becoming necessary to apply pesticides for their control. The objective of this study was to identify phytophagous and predatory mite species associated with soybean in ten counties of that state, during the 2002/03 and 2003/04 growing seasons, in five soybean cultivars (A 6001 RG, A 7001 RG, A 8000 RG, A 8100 RG, Anta 82), all genetically modified. In samples of soybean leaves four phytophagous mite species (Mononychellus planki (McGregor), Polyphagotarsonemus latus (Banks), Tetranychus desertorum Banks and Tetranychus gigas Pritchard & Baker) and two predatory mite species (Phytoseiulus fragariae Denmark & Schicha and Typhlodromalus aripo De Leon) were found. T. desertorum was found for the first time associated with soybean in the country. Phytoseiulus fragariae and T. aripo are reported for the first time on soybean. The potential of phytoseid mites as biological control agents in soybean crop was discussed. Among the hypotheses to explain the increasing infestation of soybean fields with phytophagous mites area are the progressively larger cultivated area, the dry spells observed in the last few years in the growing season, changes in soybean cropping system that led to increased use of pesticides and utilization of new soybean cultivars with morphological or biochemicals characteristics that favour the development of these mite populations.     

Contrasting structures of plant–mite networks compounded by phytophagous and predatory mite species

Differences in the feeding habits between phytophagous and predatory species can determine distinct ecological interactions between mites and their host plants. Herein, plant–mite networks were constructed using available literature on plant-dwelling mites from Brazilian natural vegetation in order to contrast phytophagous and predatory mite networks. The structural patterns of plant–mite networks were described through network specialization (connectance) and modularity. A total of 187 mite species, 65 host plant species and 646 interactions were recorded in 14 plant–mite networks. Phytophagous networks included 96 mite species, 61 host plants and 277 interactions, whereas predatory networks contained 91 mite species, 54 host plants and 369 interactions. No differences in the species richness of mites and host plants were observed between phytophagous and predatory networks. However, plant–mite networks composed of phytophagous mites showed lower connectance and higher modularity when compared to the predatory mite networks. The present results corroborate the hypothesis that trophic networks are more specialized than commensalistic networks, given that the phytophagous species must deal with plant defenses, in contrast to predatory mites which only inhabit and forage for resources on plants.     

Is Neoseiulus wearnei the Neoseiulus californicus of Australia?

Species of the family Phytoseiidae are known as predatory mites, some of them being used in crops to control mite pests, all around the world. Neoseiulus (=Cydnodromus) californicus is among the most commonly used Phytoseiidae species in biological control programs, especially in vineyards, orchards and vegetable fields. This species is distributed world-wide but has never been reported from Australia. On the other hand, specimens morphologically close to N. californicus have been assigned to a species called Neoseiulus wearnei, only reported from Australia. Investigations based on morphological and molecular comparisons were carried out to investigate whether these two taxa are conspecific. Morphological analyses showed no significant difference between specimens identified as N. wearnei and N. californicus. Similarly, genetic distances between these taxa were null, showing that all these specimens belong to the same species. Although it is not yet possible to conclude that all the specimens identified as N. wearnei are N. californicus, we can conclude that N. californicus is present in Australia. The information about the biology of N. californicus can thus now be applied to the Australian population of this species for biological control purposes.     

Mite diversity on plants of different families found in the Brazilian Atlantic Forest

This work reports the occurrence of mites predominantly predatory, phytophagous and with varied feeding habits on plants of the Atlantic Forest vegetation type of the State of S?o Paulo. The objective was to estimate the possible role of the Atlantic Forest vegetation as reservoir of these groups of mites which are also found on plants of agricultural importance. Samples were taken from 187 plant species belonging to 73 families in three vegetation types of the Atlantic Forest from February of 2001 to October of 2002. A total of 2,887 mites belonging to 163 morpho-species of 16 families were collected. Mite diversity was high, especially of predatory mites; these corresponded to 1,562 specimens of 92 morpho-species. Within this group, Phytoseiidae comprised 71% of the specimens and 62% of the morpho-species. Phytophagous mites comprised 836 specimens of 36 morpho-species. Within this group, Tenuipalpidae comprised the larger proportion of specimens (61%) whereas Tetranychidae corresponded to the larger proportion of morpho-species (64%). Mites with varied feeding habits corresponded to 491 specimens of 36 morpho-species. In this group, the larger proportion of specimens (52%) consisted of Ascidae and the larger proportion of morpho-species (42%) consisted of Tydeinae (family Tydeidae). High abundance and high morpho-species richness of mites of predominantly predatory, phytophagous and variable feeding habits were observed on 17, five and nine plant species, respectively. The results obtained suggest the importance of plants of the studied vegetation as reservoirs of predatory mites.     

Mites (Acari) from rubber trees (Hevea brasiliensis Muell. Arg., Euphorbiaceae) and spontaneous euphorbiaceous in rubber trees cultivation

Quarterly samples were done in 2001 on three rubber tree plantation in the northwest of the state of S?o Paulo. Three rubber trees of each locality were sampled. Between the rows of rubber tree four species of spontaneous euphorbiaceous were collected: Chamaesyce hirta, C. hyssopifolia, Euphorbia heterophylla and Phyllanthus tenellus. A total of 8.954 mites of 38 species, belonging to 31 genera of 11 families were collected. Tydeidae and Phytoseiidae had the highest diversity of species, 9 and 7, respectively. The most abundant families were Eriophyidae (3.594), Tydeidae (2.825) and Tenuipalpidae (1.027). The most abundant species on the rubber trees were: phytophagous - Calacarus heveae Feres, Tenuipalpus heveae Baker, Lorryia sp.2, Lorryia formosa Cooreman and Lorryia sp.1; predators - Zetzellia quasagistemas Hernandes & Feres, Pronematus sp., Iphiseiodes zuluagai Denmark & Muma and Euseius citrifolius Denmark & Muma. Among the spontaneous euphorbiaceous, predatory mites were abundantly found on C. hirta and E. heterophylla, mainly Pronematus sp. and E. citrifolius, suggesting that these plants could be important in the maintenance of these predators in the rubber tree cultivation areas. However, plants that can shelter predators and at the same time exert strong competition (nutrients, water etc) to rubber trees, can not be recommended for pest management programs. Studies about competition between rubber trees and spontaneous plants need to be conducted for feasible efficient programs of environmental management, aiming at the control of pest mites of rubber tree.     

Diversity of phytoseiid mites (Acari: Mesostigmata: Phytoseiidae) in the Atlantic Forest of São Paulo

The objective of this study was to evaluate the diversity of Phytoseiidae in the Atlantic Forest of São Paulo State, Brazil, and to estimate the possible role of this ecosystem as a reservoir for mites of this family. Samples were taken from 187 plant species belonging to 73 plant families in three vegetation types of the Atlantic Forest, from February 2001 to October 2002. In total, 1102 specimens of 54 species belonging to 20 genera of the three phytoseiid subfamilies were found. Most specimens (93%) and species (91%) belonged to the Amblyseiinae. The majority of species found belong to taxonomic groups largely composed of generalist predators (especially Amblyseius and Euseius). In general, the more abundant mites were found on a diversity of plant species, but a few of the abundant species were found on only a small number of plant species. Only nine of the mites encountered during this study are of known agricultural importance. The results obtained suggest the importance of the wide plant diversity in the region to sustain a wide diversity of phytoseiids. The extensive clearance of the Brazilian Atlantic Forest is a threat to the diversity of these mites, important predators of mite pests.     

Prey preference,intraguild predation and population dynamics of an arthropod food web on plants

The theory of intraguild predation (IGP) largely studies effects on equilibrium densities of predators and prey, while experiments mostly concern transient dynamics. We studied the effects of an intraguild (IG) predator, the bug Orius laevigatus, on the population dynamics of IG-prey, the predatory mite Phytoseiulus persimilis, and a shared prey, the phytophagous two-spotted spider mite Tetranychus urticae, as well as on the performance of cucumber plants in a greenhouse. The interaction of the predatory mite and the spider mite is highly unstable, and ends either by herbivores overexploiting the plant or predators exterminating the herbivores. We studied the effect of IGP on the transient dynamics of this system, and compared the dynamics with that predicted by a simple population-dynamical model with IGP added. Behavioural studies showed that the predatory bug and the predatory mite were both attracted to plants infested by spider mites and that the two predators did not avoid plants occupied by the other predator. Observations on foraging behaviour of the predatory bug showed that it attacks and kills large numbers of predatory mites and spider mites. The model predicts strong effects of predation and prey preference by the predatory bugs on the dynamics of predatory mites and spider mites. However, experiments in which the predatory bug was added to populations of predatory mites and spider mites had little or no effect on numbers of both mite species, and cucumber plant and fruit weight.     

The impact of insecticides applied in apple orchards on the predatory mite Kampimodromus aberrans (Acari: Phytoseiidae)

Kampimodromus aberrans is an effective predatory mite in fruit orchards. The side-effects of insecticides on this species have been little studied. Field and laboratory experiments were conducted to evaluate the effects of insecticides on K. aberrans. Field experiments showed the detrimental effects of etofenprox, tau-fluvalinate and spinosad on predatory mites. Spider mite (Panonychus ulmi) populations reached higher densities on plots treated with etofenprox and tau-fluvalinate than in the other treatments. Single or multiple applications of neonicotinoids caused no detrimental effects on predatory mites. In the laboratory, spinosad and tau-fluvalinate caused 100 % mortality. Etofenprox caused a significant mortality and reduced fecundity. The remaining insecticides did not affect female survival except for imidacloprid. Thiamethoxam, clothianidin, thiacloprid, chlorpyrifos, lufenuron and methoxyfenozide were associated with a significant reduction in fecundity. No effect on fecundity was found for indoxacarb or acetamiprid. Escape rate of K. aberrans in laboratory was relatively high for etofenprox and spinosad, and to a lesser extent thiacloprid. The use of etofenprox, tau-fluvalinate and spinosad was detrimental for K. aberrans and the first two insecticides induced spider mite population increases. The remaining insecticides caused no negative effects on predatory mites in field trials. Some of them (reduced fecundity and repellence) should be considered with caution in integrated pest management programs.