Morphological, molecular and cross-breeding analysis of geographic populations of coconut-mite associated predatory mites identified as Neoseiulus baraki: evidence for cryptic species?

Surveys were conducted in Brazil, Benin and Tanzania to collect predatory mites as candidates for control of the coconut mite Aceria guerreronis Keifer, a serious pest of coconut fruits. At all locations surveyed, one of the most dominant predators on infested coconut fruits was identified as Neoseiulus baraki Athias-Henriot, based on morphological similarity with regard to taxonomically relevant characters. However, scrutiny of our own and published descriptions suggests that consistent morphological differences may exist between the Benin population and those from the other geographic origins. In this study, we combined three methods to assess whether these populations belong to one species or a few distinct, yet closely related species. First, multivariate analysis of 32 morphological characters showed that the Benin population differed from the other three populations. Second, DNA sequence analysis based on the mitochondrial cytochrome oxidase subunit I (COI) showed the same difference between these populations. Third, cross-breeding between populations was unsuccessful in all combinations. These data provide evidence for the existence of cryptic species. Subsequent morphological research showed that the Benin population can be distinguished from the others by a new character (not included in the multivariate analysis), viz. the number of teeth on the fixed digit of the female chelicera.

Fluctuación poblacional de dos eriófidos del olivo (Acari: Eriophyidae) en Coquimbito (Maipú, Mendoza, Argentina)

El cultivo del olivo actualmente es afectado por dos especies de eriófidos poco conocidas en Argentina. Estos organismos son fitófagos obligados de numerosas plantas, que infestan todos sus órganos, excepto las raíces; algunos causan daños económicamente significativos al provocar malformaciones en diferentes partes de la planta: falta de crecimiento, acortamiento de brotes, formación de escoba de brujas, torsión y decoloración de hojas. Las especies presentes en los olivares de Coquimbito, Maipú, son: Aceria oleae (Nalepa) y Oxycenus maxwelli (Keifer). Con el objetivo de establecer la fluctuación poblacional de ambas especies se realizó un monitoreo en un monte olivícola ubicado en Maipú, Mendoza. Se seleccionaron plantas con síntomas evidentes de la plaga. Se efectuó, quincenalmente, un muestreo dirigido, extrayendo 30 brotes y 30 inflorescencias o frutos con pedúnculo de los cuales se observaron, bajo estereomicroscopio, 100 hojas, 30 yemas vegetativas y 30 inflorescencias o frutos. Los resultados indican que estos ácaros pasan el invierno principalmente en las hojas y en las yemas vegetativas. A fines de septiembre se detecta una mayor proporción de individuos en yemas florales, flores y posteriormente en frutos recién cuajados, aumentando hasta llegar a su densidad máxima en diciembre.

Biology and phenology of the eriophyid mite, Floracarus perrepae, on its native host in Australia, Old World climbing fern, Lygodium microphyllum

The biology and phenology of the eriophyid mite, Floracarus perrepae Knihinicki and Boczek,a potential biological control agent of Lygodium microphyllum (Cav.) R. Br., was studied in its native range - Queensland, Australia. F. perrepae forms leaf roll galls oil tile subpinnae of L. microphyllum. It has a simple biology, with females and males produced throughout the year. Tile Population was female biased at 10.5 to 1. The immature development time was 8.9 ± 0.1 and 7.0 ± 0.1 days; adult longevity was 30.6 ± 1.6 and 19.4 ± 1.2 days and mean fecundity per female was 54.5 ± 3.2 and 38.5 ± 1.6 eggs at 21 and 26 ° C, all respectively. Field studies showed that tile mite was active year round, with populations peaking when temperatures were cool and soil moisture levels were highest. Two species of predatory mites, Tarsonemus sp. and a species of Tydeidae, along with the pathogen Hirsutella thompsonii, had significant effects oil all life stages of F. perrepae. Despite high levels of predators and the pathogen, F. perrepae caused consistent damage to L. microphyllum at all the field sites over the entire 2 years of the study.

A new species of eriophyoid mite (Acari : Eriophyidae) on sugarcane in Australia

Seven species of eriophyoid mites (Acari: Eriophyoidea) are known to attack sugarcane plants (Saccharum spp., Poaceae) and related grasses in various parts of the world, but except for unconfirmed reports of Aceria sacchari and Abacarus sacchari, Australia had been thought to be free of these pests. Herein, Abacarus queenslandiensis n. sp. (Eriophyidae), vagrant on leaf surfaces of sugarcane in Australia, is described. Also, Cathetacarus n. gen. is erected for the distinctive mite, Catarhinus spontaneae Mohanasundaram, 1984. In addition, a key to the eriophyoid mites known to occur on sugarcane plants in the world is given.

Estimated crop loss due to coconut mite and financial analysis of controlling the pest using the acaricide abamectin.

Reducing the losses caused by Aceria guerreronis Keifer has been an arduous task for farmers. However, there are no detailed studies on losses that simultaneously analyse correlated parameters, and very few studies that address the economic viability of chemical control, the main strategy for managing this pest. In this study the objectives were (1) to estimate the crop loss due to coconut mite and (2) to perform a financial analysis of acaricide application to control the pest. For this, the following parameters were evaluated: number and weight of fruits, liquid albumen volume, and market destination of plants with and without monthly abamectin spraying (three harvests). The costs involved in the chemical control of A. guerreronis were also quantified. Higher A. guerreronis incidence on plants resulted in a 60 % decrease in the mean number of fruits harvested per bunch and a 28 % decrease in liquid albumen volume. Mean fruit weight remained unaffected. The market destination of the harvested fruit was also affected by higher A. guerreronis incidence. Untreated plants, with higher A. guerreronis infestation intensity, produced a lower proportion of fruit intended for fresh market and higher proportions of non-marketable fruit and fruit intended for industrial processing. Despite the costs involved in controlling A. guerreronis, the difference between the profit from the treated site and the untreated site was 18,123.50 Brazilian Real; this value represents 69.1 % higher profit at the treated site. Keywords