Seasonal variation in the populations of Polyphagotarsonemus latus and Tetranychus bastosi in physic nut (Jatropha curcas) plantations

Abstract

Studies on the seasonal variation of agricultural pest species are important for the establishment of integrated pest control programs. The seasonality of pest attacks on crops is affected by biotic and abiotic factors, for example, climate and natural enemies. Besides that, characteristics of the host plant, crop management, location and the pests' bioecology also affect this seasonality. The mites Polyphagotarsonemus latus (Prostigmata: Tarsonemidae) and Tetranychus bastosi (Prostigmata: Tetranychidae) are the most important pests in the cultivation of physic nut, Jatropha curcas (Euphorbiaceae). All parts of J. curcas can be used for a wide range of purposes. In addition many researchers have studied its potential for use as neat oil, as transesterified oil (biodiesel), or as a blend with diesel. However studies about physic nut pests have been little known. The objective of this study was to assess the seasonal variation of P. latus and T. bastosi in physic nut. This study was conducted at three sites in the state of Tocantins, Brazil. We monitored climatic elements and the densities of the two mite species and of their natural enemies for a period of 2 years. Attack by P. latus occurred during rainy seasons, when the photoperiod was short and the physic nut had new leaves. In contrast, attack by T. bastosi occurred during warmer seasons with longer photoperiods and stronger winds. Populations of both mites and their natural enemies were greater in sites with greater plant diversity adjacent to the plantations. The predators found in association with P. latus and T. bastosi were Euseius concordis (Acari: Phytoseiidae), spiders, Stethorus sp. (Coleoptera: Coccinellidae) and Chrysoperla sp. (Neuroptera: Chrysopidae).

Spatial-temporal distribution of phytophagous and predatory mites in the canopy of Jatropha curcas L.

“…In the present study, phytophagous and predatory mite occurrences on J. curcas plantations were influenced by seasonality and followed the same distribution trend, with higher populations being observed during the rainy season. Our results are consistent with previous studies that evaluated phytophagous and predatory mite occurrence in the state of Tocantins (CRUZ et al, 2012;2013b;ROSADO et al, 2015b). In addition, our results can provide a basis for the development of new sampling procedures for phytophagous and predatory mites in J. curcas plantations.…”

“…Considering the potential use of Jatropha curcas L. for biofuel production (ALONSO; LEZCANO, 2014), integrated management studies of pest arthropods associated with this crop are necessary for optimizing its production. For example, phytophagous mites are usually reported to be potential pests of J. curcas (SARMENTO et al, 2011;CRUZ et al, 2013a;LOFEGO et al, 2013;PEDRO-NETO et al, 2013;ROSADO et al, 2015a;2015b;SARAIVA et al, 2015). Predatory mites, especially those in the family Phytoseiidae, also colonize J. curcas plants and play a key role in limiting phytophage population (SARMENTO et al, 2011).…”

Factors Affecting Thrips (Thysanoptera: Thripidae) Population Densities in Watermelon Crops

“…The identification of factors that regulate the intensity of pest attacks on crops is important for pest sampling and control (Picanço et al 2000(Picanço et al , 2002Rosado et al 2015). Such studies also permit the establishment of predictive models of pest attacks on crops, so that the farmers can determine the correct time to start pest control (Herms 2004;Rosado et al 2015;Silva et al 2016).…”

“…Among the principal factors that regulate pest populations on crops are the characteristics of the host plant, weather and climate, and populations of natural enemies (Price et al 1980). Among the characteristics of the host plant that affect populations of herbivorous insects are phenological stage (Herms 2004), and the age of the plant tissue on which these organisms feed (Joost & Riley 2008;Rosado et al 2015). The age and phenological stage of the plant on which the insects feed also may affect the nutritional content, as well as the chemical and morphological defenses against arthropod herbivores (Moreira et al 2016).…”

“…The principal elements of weather and climate that affect populations of pests on crops are air temperature, rainfall, wind, and photoperiod (Wellington 1957;Morsello et al 2008;Rosado et al 2015). Weather and climate affect the survival, development, reproduction, and dispersal of insects (Wellington 1957;Morsello et al 2008;Rosado et al 2015). In tropical regions, the weather and climate features that vary most over the year consist of rainfall intensity and wind speed, whereas air temperature and photoperiod display less variation (Alvares et al 2013).…”