Polyphagotarsonemus latus is one a major pest of Valencia orange in Colombia. To study its biology, it was established an experiment on young leaves of the Valencia orange at 25 ± 5°C, 70 ± 5% RH, and 12:12 L:D photoperiod. To characterize the nature of damage caused by this mite on leaves and young fruits, a trial in screenhouse conditions using young leaf and small fruits (0.1 -0.3 cm in diameter) and fruits between 1.0-3.0 cm in diameter, which were infested with 5, 15 and 30 adult females of P. latus, was established. The total duration of life cycle was 3.2 days; the female had an oviposition period of 7.4 days and longevity 9.6 days. Life table parameters were as follows: net reproductive rate (Ro) = 93.3, intrinsic rate of natural increase (rm) = 1.2, finite multiplication rate (λ) = 3.7, doubling time (TD) = 0.6 days and generation time (T) = 3.4. The first signs of damage and shoot drop in newly developed shoots occurred between 7.0 and 11.8 days after infestation. Small fruit infested with 5-30 mites showed damage 2.4 days after infestation. Shoot drop started 7.0 days after infestation. In the case of fruits between 1.0 and 3.0 cm in diameter, the damage and the collapse of the structure was between 3.0 and 13.5 days, respectively. These results explain how a mite with a very short life cycle and huge biotic potential causes such severe damage in shoots and newly formed fruits of Valencia orange.Keywords: Broad mite, biology, infestation levels, damage, Colombia. ResumenPolyphagotarsonemus latus es una de las principales plagas de la naranja Valencia en Colombia. Para estudiar su biología, se estableció un experimento sobre hojas jóvenes de naranja Valencia a 25 ± 5°C, 70 ± 5% de HR y fotoperiodo L: D 12:12. Para caracterizar la naturaleza del daño causado por este ácaro en hojas y frutos jóvenes, se realizó un ensayo en condiciones de invernadero utilizando hojas jóvenes y frutos pequeños (0.1 -0.3 cm de diámetro) y frutos entre 1.0-3.0 cm de diámetro, infestados con 5, 15 y 30 hembras adultas de P. latus. La duración total del ciclo de vida fue de 3.2 días; la hembra tenía un período de oviposición de 7.4 días y una longevidad de 9.6 días. Los parámetros de la tabla de vida fueron los siguientes: tasa reproductiva neta (Ro) = 93.3, tasa intrínseca de crecimiento natural (rm) = 1.2, tasa de multiplicación finita (λ) = 3.7, tiempo de duplicación (TD) = 0.6 días y tiempo de generación = 3.4. Los primeros signos de daño y caída de brotes en brotes tiernos ocurrieron entre 7.0 y 11.8 días después de la infestación. Los frutos pequeños infestados con 5-30 ácaros mostraron daño 2.4 días después de la infestación. La caída del brote comenzó 7.0 días después de la infestación. En el caso de frutos de entre 1.0 y 3.0 cm de diámetro, el daño y el colapso de la estructura se dio entre 3.0 y 13.5 días, respectivamente. Estos resultados explican cómo un ácaro con un ciclo de vida muy corto y un enorme potencial biótico, causa tal daño severo en brotes y frutos recién formados de naranja Valencia.
The citrus crop is rapidly expanding in the Province of Santa Cruz de la Sierra, Bolívia. Citrus, mostly planted by small growers, currently comprises approximately 15,000 ha. Sweet oranges (Citrus sinensis) and mandarins (C. reticulate) are the main citrus-types grown primarily for internal consumption. Recently, there has been an increase in incidence of leprosis-like symptoms (round to elliptic lesions on the leaves, chlorotic to necrotic lesions in young twigs, and depressed small lesions on the fruits). These symptoms were associated with infestations by the tenuipalpid mite Brevipalpus sp. To verify if Citrus leprosis virus was the causal agent of the observed symptoms, leaf and fruit samples (mostly from Valencia sweet orange) were collected from commercial groves in El Torno, 32 km south of Santa Cruz, and Yapacani and Colónia San Juan, 130 km northwest of Santa Cruz. Small fragments of these samples were placed immediately in a mixture of glutaraldehyde and paraformaldehyde in cacodylate buffer and later processed with transmission electron microscopy at ESALQ, Piracicaba, SP, Brazil. Some of the leaf samples were dried at 35°C and used for reverse transcription-polymerase chain reaction (RT-PCR) with primers that specifically amplify portions of the genome of Citrus leprosis virus, cytoplasmic type (CiLV-C) (1) at Centro APTA Citros, Cordeirópolis, SP, Brazil. Brevipalpus sp. mites were also collected and kept in 90% ethanol for further identification at the University of Florida, Gainesville and ESALQ. In the samples from the three surveyed areas, transmission electron microscopy confirmed the presence of short bacilliform particles within endoplasmic reticulum cisternae and electron dense viroplasms in the cytoplasm, typical of infection by CiLV-C (2). CiLV-C specific primers amplified DNA fragments of expected sizes in RT-PCR from dried leaf samples that came from these three localities. Direct sequencing of at least three amplicons of each sample confirmed the identity of the virus. The consensus sequence of the putative movement protein gene in samples from Yapacani and Colónia San Juan (GenBank Accessions Nos. AY960216 and AY960215, respectively) were identical and exhibited 99% nucleotide and 98% amino acid homology with the Brazilian isolate sequence available at GenBank (Accession No. AY289190). The consensus sequence of the putative replicase gene found in the sample from El Torno (GenBank Accession No. AY960214) exhibited 96 and 93% nucleotide and amino acid homology, respectively with the Brazilian isolate (GenBank Accession No. AY289191). Sampled mites were identified as B. phoenicis (Geijskes), the known vector of CiLV-C (2). The symptomatology, particle morphology and cytopathology, detection by molecular methods and the association with infestation by B. phoenicis, together indicate that the foliar, stem, and fruit lesions in sweet orange observed in the Santa Cruz region were caused by CiLV-C. To our knowledge, this is the first report of this virus in Bolivia. References: (1) E. C. Locali et al. Plant Dis. 87:1317, 2003. (2) J. C. V. Rodrigues et al. Exp. Appl. Acarol. 30:161, 2003.
The mite Tetranychus urticae is a key pest in papaya crop in Valle del Cauca (Colombia), and it has been generally controlled with chemical products; other management alternatives have not been used. Therefore, this study aimed to evaluate the effects of alternatives: plant extract (garlic-chili vegetable extract, Alisin®), mineral oil (vegetable fatty acid complex, Adimel®), entomopathogenic fungus (Successor®), chemical control (spiromesifen, abamectin, fenazaquin), untreated (control treatment) and farmer’s practices (14 applications of pesticides) in a randomized complete block design with three replications/treatment in a Hybrid Tainung-1 papaya crop in the municipality of Roldanillo. The sampling was done every 8 days by measuring the variables: number of leaves/plant, number of infested leaves/plant, number of floral structures/plant, number of fruits/plant, diameter of stem/plant (every 30 days), population of T. urticae/leaf and yield. It was found that the populations of T. urticae/leaf were low in entomopathogenic fungus (11.978) and chemical control (10.548), with no significant differences (P>0.05) from farmer’s practices (3.339). In contrast, the mite populations were very high in plant extract (22.086), mineral oil (20.411) and untreated (35.746), as compared to farmer’s practices. There was a significant difference in all treatments for the variable infestation from farmer’s practices, and the number of leaves/plant in mineral oil and untreated treatment was significantly different from farmer’s practices. No significant differences were found between the treatments in the rest of the evaluated variables. The entomopathogenic fungus turned out to be the best alternative for a management program of T. urticae in papaya in this region.
Gamasellodes unalpalmi Mesa, Abo-Shnaf & Rueda-Ramirez sp. nov. and Zerconopsis zumbambicae Mesa, Abo-Shnaf & Rueda-Ramirez sp. nov. are described based on the morphology of adults obtained from litter and soil samples collected at Valle del Cauca province, Colombia. A complement to a recently published key to the world species of Gamasellodes and a key for the separation of females of the 18 recognizable world species of Zerconopsis are provided.
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