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

Phytoparasitica (Impact Factor: 0.68). 01/2003; 31(2):144-153. DOI: 10.1007/BF02980784

ABSTRACT 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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    ABSTRACT: The old world date mite Oligonychus afrasiaticus (McGregor) is an important spider mite pest of the date palms Phoenix dactylifera in most of North Africa and the Middle East. To identify potential predators of this key pest we monitored the phytoseiids in the date palm canopy and on the orchard floor for three consecutive years in the Southern Arava Valley of Israel. In this study we report on the phytoseiid species found. We describe two new species, Neoseiulus cozae and Typhlodromus shoshae, and redescribe seven species, Proprioseiopsis beatus, Neoseiulus marginatus, N. conterminus, N. rambami, N. bicaudus, Cydnoseius negevi and Typhlodromus athiasae, found on date palms or on the understorey Bermuda grass, Cynodon dactylon, gramineae in these orchards. A key to all species collected from date palm orchards worldwide is given. Proprioseiopsis beatus, N. marginatus and N. conterminus are recorded for the first time in Israel.
    Journal of Natural History 06/2009; 43:1715-1747. · 0.93 Impact Factor
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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. · 3.53 Impact Factor
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    ABSTRACT: Oligonychus afrasiaticus is the dominant spider mite pest of date fruit in the Southern Arava Valley of Israel. Growers have dusted fruit bunches prophylactically with sulfur (since 1990), applying as many as five treatments per year, but recently its efficacy has declined. Alternative mite control techniques evaluated in this study to decrease pest damage included: (1) Reducing the overwintering populations; (2) Employing physical barriers to prevent ambulatory and airborne mites from reaching fruit bunches; (3) Exploring the option of using indigenous phytoseiids to control the pest; (4) Applying a single properly timed seasonal acaricide, and (5) Post harvest treatments to mitigate any evident mite damage. Control methods 1–3 did not yield satisfactory results. Mite damage was higher on palms (trees) that had their stems (trunks) scorched in the winter and fruit bunch infestation was not prevented by glue barriers or dense netting. Indigenous phytoseiids were not found on fruit between mid-July till the end of August, when pest populations peaked. In contrast, a single treatment with the acaricides fenbutatin oxide, hexythiazox or abamectin, applied when the first mites were found on the fruit, provided seasonal pest control. The post-harvest re-hydration treatment was also effective, increasing the amount of marketable fresh fruit by approximately 20% on the economically important ‘Medjool’ cultivar.
    Crop Protection 05/2004; 23(5):387-392. · 1.54 Impact Factor


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Jun 2, 2014