The citrus leprosis mite, Brevipalpus yothersi Baker, is not considered to cause major damage to orange trees in the Brazilian Amazonas state. However, little is known about the diversity of plant mites and about mite damage to plants in this state of northern Brazil. The objective of the present study was to evaluate the level of occurrence of the leprosis mite in this region and the diversity and prevailing population levels of associated mites in unsprayed orange groves of the surroundings of Manaus, Amazonas state. In total, 1,614 mites were collected on citrus trees (616 of eminently predatory groups, 541 of eminently phytophagous groups and 457 of other groups). On plants growing spontaneously in orange groves, 514 mites were collected (270 of eminently predatory groups, 26 of eminently phytophagous groups and 218 of other groups). Most predators collected (638 specimens) belonged to Phytoseiidae, representing 14 species. The most abundant phytoseiids were Amblyseius aerialis Muma and Iphiseiodes zuluagai Denmark & Muma. Only 197 B. yothersi were collected, on leaves of orange, Lantana camara L. and Solanum paniculatum L.. Leprosis symptoms were not observed, and this may be related to the relatively low densities of the leprosis mite. The plant species Borreria verticillata (L.), Clidenia hirta (L.), L. camara, Paspalum virgatum L. and S. paniculatum are reservoirs of two abundant predatory mites of orange trees, A. aerialis and I. zuluagai.

The coconut mite, Aceria guerreronis Keifer, is one of the main pests of the coconut tree (Cocos nucifera L.) worldwide. Its control is mainly based on the use of acaricides. However, due to the habitat of this pest mite, which is protected by fruit bracts that act as a physical barrier, chemical control is often inefficient. Thus, natural enemies have been studied as an alternative to acaricides. We evaluated the functional and numerical responses of Amblyseius aerialis (Muma) to increasing densities of A. guerreronis (40, 80, 160, 240 and 360) and additionally the oviposition rates of the phytoseiid A. aerialis over 11 days on different food sources: coconut pollen, A. guerreronis and a mix of pollen and A. guerreronis. Our results showed that Amblyseius aerialis showed a type III functional response, where prey consumption increasing as the density of A. guerreronis increased, with a maximum consumption of up to 175 prey per predator. All the prey densities allowed female oviposition. The number of eggs laid by A. aerialis increased with increasing prey density and stabilized between 240 and 360 A. guerreronis individuals, with an average oviposition of 1.7 eggs/female. Furthermore, our results showed that all the food sources (coconut pollen, A. guerreronis and a mix of pollen and A. guerreronis) supported oviposition. The mean oviposition was approximately 1.5 eggs/female on all the food sources. Our study suggests that A. aerialis can be effective in the biological control of A. guerreronis. However, further studies are needed to investigate whether A. aerialis can explore the habitat of A. guerreronis and if that prey can support the development of immature stages and the reproduction of A. aerialis.

The coconut mite Aceria guerreronis Keifer is considered one of the most important pests of the coconut tree (Cocos nucifera L.), causing fruit malformation due to the appearance of cracks on the surface of the perianth below the bracts. This damage compromises fruit growth, reducing the production of solid and liquid albumen. The continuous use of chemical pesticides increases pest control costs, as in addition to being a practice highly harmful to the environment, it can also cause selection of resistant populations, as well as eliminate beneficial species. Therefore, the objective was to evaluate the population dynamics of A. guerreronis and its natural enemies, through the quantification of the most frequent and abundant predator species in two commercial areas of coconut plantation of the cultivar PB-121 (cross between Malaysian Yellow Dwarf x West African Giant). The study was conducted in Area 1 (with pesticide application), and Area 2 (without pesticide application - control) monthly from August 2018 to July 2019. Leaflets were collected (basal, median and apical part) from leaf 14 and fruits (bunches 4, 5, 6 and 7–4 to 6 months after inflorescence fertilization). In both areas, 933.580 mites were collected, 426,245 in Area 1 and 507.335 in Area 2, with emphasis on A. guerreronis (931.706 specimens – estimated value). Eriophid mites represented almost 100% of the specimens sampled, with high population density in periods with less precipitation. Among the predators, specimens belonging to the Phytoseiidae family were predominant, highlighting the species Amblydromalus zannouii Famah Sourassou, Amblyseius aerialis (Muma) and Amblyseius tamatavensis Blommers, present both in leaflets and in fruits, with the exception of A. zannouii, which was found only in leaflets.

Some species of spider mites belonging to the Tetranychidae family are known to associate with oil palm (Elaeis guineensis Jacq. - Arecaceae). The occurrence of Tetranychus palmarum Flechtmann & Noronha (Acari, Tetranychidae) was verified on oil palm seedlings under greenhouse conditions in the State of Pará in Northern Brazil. Plants with colonies of T. palmarum presented yellowish spots on leaflets and leaves with chlorosis. The objective of this study was to access the biology and fertility life table of T. palmarum in E. guineensis leaves. The experiment was conducted under four constant temperatures, 22, 25, 28, and 31°C, at 70 ± 10% RH under a 12:12 LD photoperiod. The duration of the egg-to-adult period was 18.4 and 9.8 days, at 22 and 31°C, respectively. The parameters of the fertility life table showed that 28°C is most suitable for the development and reproduction of T. palmarum, with higher values for reproductive parameters (R , r , and λ) and lower values for duplicating the population (TD). Therefore, it is apparent that the best temperature conditions for the development of T. palmarum are found in the warmer regions of Brazil, such as those observed in northern Brazil.

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