Species of Oligonychus infesting date palm cultivars in the Southern Arava Valley of Israel

Phytoparasitica (Impact Factor: 0.9). 01/2003; 31(2):144-153. DOI: 10.1007/BF02980784


In a study of date fruit damage caused byOligonychus spp., we investigated whether the cultivar affects phenology, and on what hosts the mites over-winter. Samples were taken
from ‘Deglet Noor’, ‘Barhi’ and ‘Medjool’ trees from mid-April through mid-September during the years 1999–2002. In the ground-cover
mites were monitored by collecting Bermuda grass (Cynodon dactylon) under each sampling tree. Over 99% of the mites collected on Deglet Noor and Barhi fruit were identified asO. afrasiaticus. Mean population levels ofO. afrasiaticus reached ten mites or more (initiation of infestation) on Medjool in the second half of May, whereas on Deglet Noor this did
not occur before the first week of July. On Barhi the initiation of infestation varied between plots and years, ranging from
the second half of May to the beginning of July, but always occurred earlier than Deglet Noor. Mite populations on the pinnae
remained low from June through October, not exceeding seven mites per pinna, whereas on fruit strands they reached peak populations
of approximately 4000 mites per strand. The sex ratio (proportion of females) ofO. afrasiaticus on fruit of all three cultivars was highly female-biased, usually above 0.85. During winter,O. afrasiaticus was found on Bermuda grass in the orchard ground-cover as well as on fronds of all three cultivars.

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Available from: Eric Palevsky, Feb 27, 2014
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    • "[31]), causing a slow response to its outbreaks in newly invaded areas, an issue often reported for spider mites (e.g. [32]). Detailed recent genetic studies of different populations of T. evansi around the world suggest that the species is native to South America, and show that two main distinct clades, both coming from Brazil, and genetically characterized as clade 1 and 2, explain current patterns of species genetic diversity [33], [34]. "
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    ABSTRACT: Many species are shifting their distributions due to climate change and to increasing international trade that allows dispersal of individuals across the globe. In the case of agricultural pests, such range shifts may heavily impact agriculture. Species distribution modelling may help to predict potential changes in pest distributions. However, these modelling strategies are subject to large uncertainties coming from different sources. Here we used the case of the tomato red spider mite (Tetranychus evansi), an invasive pest that affects some of the most important agricultural crops worldwide, to show how uncertainty may affect forecasts of the potential range of the species. We explored three aspects of uncertainty: (1) species prevalence; (2) modelling method; and (3) variability in environmental responses between mites belonging to two invasive clades of T. evansi. Consensus techniques were used to forecast the potential range of the species under current and two different climate change scenarios for 2080, and variance between model projections were mapped to identify regions of high uncertainty. We revealed large predictive variations linked to all factors, although prevalence had a greater influence than the statistical model once the best modelling strategies were selected. The major areas threatened under current conditions include tropical countries in South America and Africa, and temperate regions in North America, the Mediterranean basin and Australia. Under future scenarios, the threat shifts towards northern Europe and some other temperate regions in the Americas, whereas tropical regions in Africa present a reduced risk. Analysis of niche overlap suggests that the current differential distribution of mites of the two clades of T. evansi can be partially attributed to environmental niche differentiation. Overall this study shows how consensus strategies and analysis of niche overlap can be used jointly to draw conclusions on invasive threat considering different sources of uncertainty in species distribution modelling.
    PLoS ONE 06/2013; 8(6):e66445. DOI:10.1371/journal.pone.0066445 · 3.23 Impact Factor
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    • "(Cynodon dactylon) in the Arava region. In the early 1980's, it caused damage to date palms in that area (Gerson et al., 1983), but has since declined to be a very minor component of the spider mite guild that infests date palms (Palevsky et al., 2003). Panonychus citri (McGregor, 1916) (Figures 94-97) Panonychus citri (known as the citrus red mite) has been collected from about 110 different host plants, but is mainly a pest of all varieties and species of citrus wherever it is grown. "
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    ABSTRACT: An annotated list and key to twenty four species of spider mites (Prostig-mata: Tetranychidae) known from Israel is provided. About half of the spe-cies are considered to be exotics, having invaded Israel within the last fifty years. Nine species, all of which belong to the subfamily Tetranychinae: Eutetranychus orientalis, Eutetranychus palmatus, Oligonychus afrasiat-icus, Oligonychus perseae, Panonychus ulmi, Panonychus citri, Schizo-tetranychus asparagi, Tetranychus turkestani and Tetranychus urticae, are agricultural pests, whereas the others have little economic impact, or else are controlled by their natural enemies.
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    • "Some spider mite species have been present for years in agricultural areas without causing noticeable damage before reaching pest status. Oligonychus afrasiaticus (McGregor), a serious pest of dates in North Africa and the Middle East, was first reported in Israel in 1980 on weeds growing in palm orchards but commercial damage to palms was only observed in 1996 (Palevsky et al. 2003). In addition, changes in the mite's susceptibility to acaricides or resistance development could enhance the economic impact of these mites. "
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    ABSTRACT: Several mite species commonly attack cultivated citrus around the world. Up to 104 phytophagous species have been reported causing damage to leaves, buds and fruits, but only a dozen can be considered major pests requiring control measures. In recent years, several species have expanded their geographical range primarily due to the great increase in trade and travel worldwide, representing a threat to agriculture in many countries. Three spider mite species (Acari: Tetranychidae) have recently invaded the citrus-growing areas in the Mediterranean region and Latin America. The Oriental red mite, Eutetranychus orientalis (Klein), presumably from the Near East, was detected in southern Spain in 2001. The Texas citrus mite, Eutetranychus banksi (McGregor), is widely distributed in North, Central and South America. It was first reported in Europe in 1999 on citrus in Portugal; afterwards the mite invaded the citrus orchards in southern Spain. In Latin America, the Hindustan citrus mite, Schizotetranychus hindustanicus (Hirst), previously known only from citrus and other host plants in India, was reported causing significant damage to citrus leaves and fruits in Zulia, northwest Venezuela, in the late 1990s. Later, this mite species spread to the southeast being detected on lemon trees in the state of Roraima in northern Brazil in 2008. Whereas damage levels, population dynamics and control measures are relatively well know in the case of Oriental red mite and Texas citrus mite, our knowledge of S. hindustanicus is noticeably scant. In the present paper, information on pest status, seasonal trends and natural enemies in invaded areas is provided for these species, together with morphological data useful for identification. Because invasive species may evolve during the invasion process, comparison of behavior, damage and management options between native and invaded areas for these species will be useful for understanding the invader's success and their ability to colonize new regions.
    Experimental and Applied Acarology 11/2012; 59(1-2). DOI:10.1007/s10493-012-9635-9 · 1.62 Impact Factor
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