Liana Johann

Mites fluctuation population on peach tree (Prunus persica (L.) Batsch) and in associated plants

, NOELI JUAREZ FERLAABSTRACT - Despite the importance of peach (Prunus persica (L.) Batsch) in Rio Grande do Sul, little is known about mites fluctuation population considered important to this crop. The objective of this study was to know the population diversity and fluctuation of mite species associated with Premier and Eldorado varieties in Roca Sales and Venâncio Aires counties, Rio Grande do Sul. The study was conducted from July 2008 to June 2009 when 15 plants were randomly chosen in each area. The plants were divided in quadrants and from each one a branch was chosen from which three leaves were removed: one collected in the apical region, another in the medium and the other in the basal region, totalizing 180 leaves/area. Five of the most abundant associated plants were collected monthly in enough amounts for the screening under the stereoscopic microscope during an hour. A total of 1,124 mites were found belonging to 14 families and 28 species. Tetranychus ludeni Zacher, 1913, Panonychus ulmi (Koch, 1836) and Mononychellus planki (McGregor, 1950) were the most abundant phytophagous mites, whereas Typhlodromalus aripo Deleon, 1967 and Phytoseiulus macropilis (Banks, 1904) the most common predatory mites. The period of one hour under stereoscopic microscope was enough to get a representative sample. In both places evaluated the ecologic indices were low, but little higherin Premier (H’ 0.56; EqJ: 0.43) when compared to Eldorado (H’ 0.53; EqJ 0.40). In Premier constant species were not observed and accessory only Brevipalpus phoenicis (Geijskes, 1939), T. ludeni and T. aripo. Higher abundance was observed in December and January and bigger amount in April. Already in Eldorado, T. ludeni and P. ulmi were constants. Greater abundance was observed in November and December, whereas grater richness in December and January. In both orchards were not found mites in buds. Tetranychus ludeni is the most abundant phytophagous mites with outbreak population in November, December and January and high predator diversity was observed on associated plants and on peach plants, indicating the existence of species mobility in peach orchard.Index terms: Acari, biological control, Panonychus ulmi, Tetranychus ludeni, Typhlodromalus aripo.

Functional response of Phytoseiulus macropilis under different Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae) population density in laboratory

We tested the functional response of the phytoseiid predator Phytoseiulus macropilis (Banks, 1904) to different population densities of Tetranychus urticae Koch, 1836 (the two-spotted spider mite - TSSM) in the laboratory. We evaluated the curve that best fits the data obtained, based on the reduced X2. The predators were obtained from leaves of Oso Grande strawberries at the municipality of Bom Principio, state of Rio Grande do Sul, Brazil. Fifteen seemingly healthy females of P. macropilis were randomly chosen and individualized in each of the arenas with different TSSM densities. The following prey densities were tested: 1, 2, 3, 5, 10, 20, 30, 35, 45, 55, 70 and 125 females. The tests were performed in a germination chamber with photoperiod of 12 hours at 28 ± 1oC per day and 22 ± 1oC at night and 80 ± 5% relative humidity. In all tests with up to three prey items, P. macropilis showed low functional response, whereas higher rates were observed when more prey items were offered. There was a strong positive correlation between increased prey numbers and daily prey consumption (r = 0.84 and p = 0.0006). A significant correlation was found between prey consumption and total oviposition (r = 0.70, p = 0.01). The daily oviposition rate was lower when few prey items were offered, increasing significantly with increased prey availability. The results showed a positive correlation between the number of prey items offered to the predator and its oviposition rate (r = 0.66, p = 0.01). Nevertheless, a strong correlation was observed between the daily consumption of prey and eggs/female/day (r = 0.92, p < 0.0001). A shorter oviposition period was reported when up to three prey items were offered. The oviposition period and the increase in prey numbers were positively correlated (r = 0.30, p = 0.34), but the difference was not statistically significant. Nevertheless, the longer the egg-laying period, the greater the oviposition rate (r = 0.90, p < 0.0001). The curve that best fits the data obtained in each case was also calculated, based on the least square method.

Ecological interactions between phytophagous and predaceous mites in citrus agroecosystems in Taquari Valley, Rio Grande do Sul, Brazil

Abstract We examined the interaction between phytophagous and predaceous mites in Valencia orange (Citrus sinensis) orchards at different altitudes in the Taquari Valley, Rio Grande do Sul, Brazil. Mites were sampled monthly from February 2005 to January 2006 in three citrus agroecosystems: Arvorezinha, Encantado and Taquari. For each agroecosystem, twelve leaves were taken from each of ten citrus plants, plus ten fruits and leaves from five associated plants found in citrus orchards. Predaceous species considered important were Agistemus floridanus Gonzalez (Stigmaeidae), Euseius ho (De Leon) (Phytoseiidae) and Pronematus anconai Baker (Iolinidae). Other predators found were Iphiseiodes zuluagai Denmark & Muma (Phytoseiidae), in Taquari and Homeopronematus sp. (Iolinidae), Parapronematus sp. (Iolinidae), Neoseiulus tunus (DeLeon) (Phytoseiidae) and Typhlodromips cananeiensis Gondim Jr. & Moraes (Phytoseiidae), in Encantado. The most frequent phytophagous mites were Brevipalpus phoenicis (Geijskes) (Tenuipalpidae), Lorryia formosa Cooreman (Tydeidae), Lorryia sp. (Tydeidae), Tegolophus brunneus Flechtmann (Eriophyidae) and Tetranychus mexicanus (McGregor) (Tetranychidae). Other phytophages were Eutetranychus banksi (McGregor) (Tetranychidae) in Taquari and Phyllocoptruta oleivora (Ashmead) (Eriophyidae) in Arvorezinha. The predator A. floridanus had the strongest correlation to the presence of common phytophagous mites, followed by P. anconai that seemed to be associated with eriophyid and tetranychid mites. The least number of predators occurred in Arvorezinha, where mowing and phytosanitary treatments were frequent. The associated plants Thelypteris dentata (Forssk.) E.P. St. John and Solidago chilensis Meyen had the largest abundance of predatory mites. However, Ageratum conyzoides L. had the highest diversity of predatory mites.

Occurrence of the quarantine mite pest Aculus schlechtendali (Acari: Eriophyidae) in apple orchards of Serra Gaúcha, Rio Grande do Sul state, Brazil

Abstract The aim of this work is to report the presence of Aculus schlechtendali (Nalepa, 1890) (Prostigmata: Eriophyidae) (Apple rust mite—ARM), in apple orchards of Serra Gaúcha, state of Rio Grande do Sul, Brazil. Surveys were conducted from apple leaves of Gala cultivar in a commercial orchard of Vacaria County (S 28′ 34.540 W 050′ 52.153) in the Northeast region of the state of Rio Grande do Sul, between November 2016 and January of 2017. The morphological traits and the relative measurements matched with those of A. schlechtendali. This is the first report of this mite pest in Brazil, so far regulated as a quarantine pest, and the third country report in South America. Consideration on the potential pest status of ARM is discussed.

A new species of Stigmaeus Koch (Acari: Stigmaeidae) from southern Brazil

Abstract A new species of Stigmaeidae (Acari: Trombidiformes), namely Stigmaeus pampaensis Da-Costa & Johann n. sp., is described and illustrated based on the specimens collected from litter in the municipality of São Francisco de Assis, Rio Grande do Sul state, Brazil. A key to the Brazilian species is provided.

Molothrognathus brasiliensis sp. nov. (Acari: Caligonellidae) and the first report of Paraneognathus wangae for Brazil

Abstract A new species of Molothrognathus Summers and Schlinger (1955) (Caligonellidae), Molothrognathus brasiliensis Silva, Brentano & Ferla sp. nov., is described and illustrated, and Paraneognathus wangae (Fan & Li, 1995) is reported for the first time from south of Brazil.

Patogenicidade de Isaria fumosorosea sobre o ácaro vermelho europeu em laboratório

Pathogenicity of Isaria fumosorosea to European red mite in the laboratory. Vineyard in Rio Grande do Sul State, Brazil have suffered signiicant infestations of mites, especially Panonychus ulmi (Koch) recently. There are reports on the ability to control mites with Isaria fumosorosea. The objective of this study was to evaluate in the laboratory the pathogenicity of I. fumosorosea to P. ulmi mites. Panonychus ulmi was reared from harvests from vineyards in Serra Gaucha. Fungal spore suspensions at different concentrations were applied to P. ulmi eggs. Triplicates of females, 12 to 15 days old, were treated with a spore suspension of 10 mL. Controls were treated with distilled water. Seven days after application, 55.6% of eggs treated with a spore suspension of 106 mL did not hatch, and treated females showed a total mortality of 85-90% and conirmed mortality of 50-55%. The maximum mortality of water-treated control

Influence of various preys in soybean and the biological performance of the predatory mite Neoseiulus californicus (Phytoseiidae)

Abstract Mites and insects cause damage to soybean crops (Glycine max (L.): Fabaceae). Mononychellus planki McGregor, Tetranychus ludeni Zacher (Acari: Tetranychidae) and Caliothrips phaseoli Hood (Insecta: Thripidae) have been mentioned as pests of soybean crops in Brazil, while Neoseiulus californicus McGregor (Acari: Phytoseiidae) is considered a generalist predatory mite. This work aimed to determine the biological parameters of N. californicus feeding on T. ludeni, M. planki and C. phaseoli on transgenic soybean leaves. Thirty N. californicus eggs were individually placed in arenas with T. ludeni, M. planki and C. phaseoli. Egg-to-adult duration (in days) was longest when fed T. ludeni (5.52±0.06) and shortest when fed C. phaseoli (4.89±0.06). Mean fertility was approximately 32 eggs/female and did not differ significantly when N. californicus fed on T. ludeni or M. planki. During the adult stage, N. californicus did not lay eggs when feeding on C. phaseoli and survived for only a few days. The net reproductive rate (R0) of N. californicus was larger when fed T. ludeni (20.30±0.68) than M. planki (14.66±0.29). Both M. planki and T. ludeni were suitable prey for N. californicus, while C. phaseoli was not.

A new species of Zetzellia Oudemans (Acari, Trombidiformes, Raphignathoidea, Stigmaeidae) and a key to Stigmaeidae of Japan

Abstract A new mite species, Zetzellia camphorae sp. n. (Acari, Stigmaeidae), is described and illustrated based on adult females. Mites were collected from leaf domatia of camphor trees, Cinnamomum camphora (L.) J. Presl. (Lauraceae) infested with the eriophyid mite, Aceria sp. (Eriophyidae) in Kyoto, Japan. An identification key to the adult females of the Japanese Stigmaeidae is provided.