Laporan baru tungau Tarsonemus bilobatus Suski dan karakter utama tungau lain pada daun tanaman jeruk di Pulau Jawa, Indonesia

Citrus is one of the most important fruit crops in Indonesia. One of the main problems in citrus production is mite infestation. Many mite species were reported attacking citrus around the world. This study was aimed to identify mites and describe the main characters of various species of mites on citrus in Java, Indonesia. Sampling was carried out at the location of citrus plantations and citrus plants in the yard of the house which was carried out purposively. In a large planting area, sampling was carried out on 10 citrus trees that showed symptoms of mite attack. The identification process is carried out by a mounting process to obtain specimens that can be observed under a compound microscope using PVA. Eight species of mites were collected from 8 various of citrus from 15 location. Six mites species were identified as phytophagous, i.e., Panonychus citri McGregor, Eotetranychus sp., Eutetranychus sp. (Family Tetranychidae), Brevipalpus phoenicis (Geijskes) (Family Tenuipalpidae), Tarsonemus bilobatus Suski (Family Tarsonemidae), and Phyllocoptruta oleivora (Ashmead) (Family Eriophyidae). Meanwhile, the other two species, Amblyseius sp. (Family Phytoseiidae) and Cheletogenes ornatus (Canestrini & Fanzago) (Family Cheyletidae) were predators. Unidentified mites were Family Tydeidae and Winterschmidtiidae. According to Regulation No. 31 of 2018, P. citri and Ph. oleivora are quarantine pest. T. bilobatus is firstly reported in Indonesia.

Effect of biofertilizers and Verticillium lecanii (Zimm.) Viégas applied to Canavalia ensiformis L. (Fabaceae) on the bioecology of Brevipalpus phoenicis (Acari: Tenuipalpidae)

Two assays were conducted to evaluate the effect of biofertilizer suspensions applied to Canavalia ensiformis (L.) DC. plants on Brevipalpus phoenicis (Geijskes) bioecology. In the first assay (residual effect), the following treatments were tested: a) Distilled water (Control); b) Biofert - biofertilizer produced in a single bioreactor; c) Biomix – a mix of biofertilizers produced in four bioreactors; and d) Bio+VL - Biofert + Verticillium lecaniiI (Zimm.) Viégas. In the second assay (systemic effect) only two suspensions were tested: a) Biofert and b) Distilled water (control). In the first assay, the biofertilizer was applied once on the whole plant and mites were confined in arenas on both leaflets. In the second assay, the plants were sprayed weekly only in one leaflet and the mites were confined in arenas on the non-sprayed leaflet. In both bioassays, bioecological parameters related to survival and oviposition were evaluated. The biofertilizer effects on potential population growth during the first generation were measured by fertility life table parameters (net reproductive rate (Ro), mean generation time (T), doubling time (DT), intrinsic rate of increase (Rm) and finite rate of increase (). The biofertilizer had adverse effects on both survival and oviposition parameters. The net reproduction rates (Ro) were of 18.1; 12.9; 12.5 and 10.5 females/female (assay I) and 19.4 and 13.0 females/female (assay II), respectively for the treatments in the above-mentioned orders. These results show that the biofertilizer reduced the potential population growth of B. phoenicis in either residual or systemic effect assays.

Interactions between Host Plants and Biofertilizers: Contact Effect on Biological Parameters of the Mite Brevipalpus phoenicis

This study was conducted aiming to evaluate interactions between deleterious action of biofertilizers on Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) and host plants. In the first bioassay the following concentrations were tested: 0% (control), 5%, 15%, 30% and 50%. The experimental unit was a leaf of Ligustrum lucidum plant (six leaves per treatment). Twelve mites were liberated in arenas on each leaf. The second bioassay was run on 20 days old Canavalia ensiformis plants, using ten plants per treatment. Ten mites were transferred for arenas on each host plant cotyledonal leaf. Five concentrations were also tested: 0%, 5%; 10%; 20% and 30%. The adult female mortality and the number of eggs laid in each arena were quantified daily during 72 h in the first assay and 120 h in the second one. The mite survivorship and oviposition were significantly reduced with the increase of biofertilizer concentration in both experiments. The LC25 estimates for the 24, 48 and 72 h periods were respectively 50,04; 15,70 and 4,95% in L. lucidum. The LC25 andLC50 estimates for the 24, 48, 72,96 and 120 h periods in C. ensiformis were 8,15; 7,78; 0,63; 0,68 and 0,63 and of 19,64; 19,03; 2,38; 2,60 and 2,67, respectively. No LC50estimates were obtained in L. lucidum, due the low mortality rates. The biofertilizer had deleterious action on fertility and survival of B. phoenicison both host plants, being more severe on C. ensiformis. The mites dead by the biofertilizer action showed evidences of microbial colonization. A colloidal compound of the biofertilizer induced mite immobilization and obstruction in its digestive tract.

Parámetros de transmisión del virus de la leprosis de los cítricos por Brevipalpus yothersi (Acari: Tenuipalpidae)

La leprosis de los cítricos, causada por virus (Citrus Leprosis Virus, CiLV), es un problema fitosanitario de importancia económica y cuarentenaria para la citricultura de países productores. En Colombia su presencia fue confirmada en 2004 en los departamentos del Meta y Casanare; el ácaro Brevipalpus yothersi Baker (antes identificado como Brevipalpus phoenicis Geijskes) (Acari: Tenuipalpidae), se reconoce como el principal vector del virus en el país. Se determinaron los parámetros: período de acceso para adquisición, período de acceso para inoculación y porcentaje de ácaros infectados con CiLV, por medio de pruebas de transmisión y análisis moleculares en el Centro de Investigación “La Libertad” de CORPOICA, Meta, Colombia. Al probar períodos de adquisición entre 10 minutos y 72 horas, se encontró que B. yothersi adquiere el virus después de 30 minutos de alimentación sobre hojas de naranja Valencia (Citrus sinensis L.) Osbeck con lesiones de leprosis. El período mínimo requerido por los ácaros para transmitir el virus hacia plantas de C. sinensis fue de 10 minutos. Para períodos de transmisión desde 10 minutos hasta 24 horas, los porcentajes de infección variaron entre 25 y 68,75 % en las hojas receptoras. De acuerdo a pruebas de transmisión y análisis RT-PCR, después de tres días de alimentación sobre lesiones de leprosis, el 40 % de las poblaciones del ácaro evaluadas adquirió el virus CiLV-C2. Los resultados obtenidos amplían el conocimiento de las interacciones planta - virus - vector, lo cual es fundamental para el establecimiento de programas de prevención y manejo de la enfermedad.

Vertical volumetric distribution of an axial fan sprayer on the Brevipalpus phoenicis control

ABSTRACT Spray distribution generated by axial fan sprayer, among other factors, should be critically analyzed, in order to prevent unnecessary costs and environmental contamination. This study aimed at evaluating the effect of the vertical volumetric distribution of an axial fan sprayer on the Brevipalpus phoenicis control efficiency. First, an assay was performed to evaluate the vertical volume distribution uniformity of the sprayer, assessing different spray nozzles configurations on the spray arcs, sides of the sprayer and spray heights. Afterwards, another experiment was carried out to analyze the relationship between the distribution of the Fenpyroximate acaricide on Coffea arabica L. and the B. phoenicis control efficiency. The treatments were arranged in a 4 x 2 factorial + 1 additional control, consisting of four spray volumes (200 L ha-1, 400 L ha-1, 600 L ha-1 and 800 L ha-1) and two spray nozzles configurations (1: 100 % of MAG1.5 nozzles; 2: upper extension with 5 MAG3.0 nozzles, middle extension with 9 MAG1.5 nozzles and lower extension with 4 MAG3.0 nozzles). Configuration 2 provided the smallest coefficient of variation (28 %). Nozzle configurations had no effect on the incidence of B. phoenicis. The use of nozzles with different flow rates on the spraying arc improves the vertical volumetric distribution uniformity of axial fan sprayers, but does not affect the B. phoenicis control efficiency.