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The two-spotted spider mite, Tetranychus urticae Koch, is a phytophagous pest that can cause significant yield losses in cotton fields, and pathogenic organisms are very important to control them. A study was conducted in some cotton fields at Al-Hassakeh province through season 2019 to survey pathogenic organisms associated with two-spotted spider mite. Results showed the isolation and diagnosis of five types of pathogenic fungi with an infection rate of 13.33% Results showed that five fungal species of 4 genera and one bacteria were identified. The Aspergillus niger was the most frequently isolated fungus with 23.33 % frequency, followed by, Neozygites floridana, Aspergillus terreus, Beauveria bassiana, Penicillium sp. and bacteria Bacillus thuringiensis with a frequency of 18.66, 14.66, 13.33, 6.66 % and 23.33%, respectively. The Results showed that the pathogens played an important role to control the two-spotted spider mite (T. urticae).

The present study aimed to identify predatory mite species of the family Phytoseiidae on citrus trees and common wild plants species within or around citrus orchards. Surveys were carried out in fifty orchards in seven different sites in Lattakia governorate (the main citrus growing region of Syria). Fifteen phytoseiid species belonging to ten genera were found, among which fourteen are recorded for the first time from Syria. Euseius stipulatus was the most abundant on citrus trees, followed by Typhlodromus (Typhlodromus) athiasae and Amblyseius andersoni. In this study, one female of the species Typhlodromus (Anthoseius) thesbites is rediscovered and illustrated. Information concerning locations, host plants, number of specimens, and measurements of morphological characteristics of each species collected are provided.

Two species of Phytoseiidae predominated in and around vineyards in an experimental site in the south of France: Typhlodromus exhilaratus is the dominant species on grapes, whereas T. phialatus occurs in the uncultivated areas surrounding these crops. To help understand their distribution, this study aims to determine their susceptibility to a fungicide (dimethomorph + mancozeb) and an insecticide (chlorpyriphos-ethyl), which have been widely used at the experimental site for at least four years. The hypothesis tested is that the effects of these two pesticides differ between T. exhilaratus and T. phialatus. Two populations of T. exhilaratus, one collected on a vine crop where the two pesticides were applied and the other in an unsprayed orchard of Sorbus domestica, and one population of T. phialatus collected on Viburnum tinus from uncultivated areas adjacent to the vine crop, were tested under laboratory conditions. The fungicide seems to affect the females of T. phialatus more than those of T. exhilaratus from vine. However, at the recommended field concentration the female mortality rates of the three strains were low and female fecundities were not significantly different. Conversely, mortality rates were very high for the three strains at the recommended field concentration of chlorpyrifos-ethyl. The strain of T. exhilaratus from vine seems to be more tolerant and 20% of females survived the recommended field rate. This suggests better survival after insecticide application than females of T. phialatus (100% mortality at a lower concentration than the recommended rate). As extrapolation of laboratory results to the field is often irrelevant, these differences could be just one of several factors affecting the spatial segregation of the two species in the agrosystem considered. Possible explanations other than pesticides for the poor settlement of T. phialatus in vine plots are discussed.

Typhlodromus phialatus and T. exhilaratus are morphologically close species. Their differentiation is based on the shape of the insemination apparatus and on idiosomal setae length. However, the setae length values are often intermediate between these two species and do not allow accurate identification. Furthermore, the handful of differences in insemination apparatus shape are also questionable as a means of differentiation. Synonymy between these species has thus been questioned. Three experiments were carried out. Idiosomal seta length measurements, molecular tests and cross experiments were conducted for three populations, identified as T. exhilaratus and T. phialatus according to the shape of their insemination apparatus. The results show that the variation range of seta lengths is great and that these criteria do not allow accurate separation of these populations into two species. However, molecular tests show a species-level nucleotide differentiation between them. Cross experiments confirm this result, showing complete reproduction incompatibility between the mites bearing different insemination apparatus shapes. Therefore, T. exhilaratus and T. phialatus could be considered to be two valid species and the insemination apparatus could be considered as a pertinent diagnostic criterion at the specific level.

The mite fauna of Syrian agroecosystems is poorly known. Only 34 species belonging to five families have been reported to date. The study presented here was conducted in two abandoned citrus orchards in Latakia Governorate. The aim was to identify the mite species present and to clarify their ecological roles. A total of 46 identified species belonging to 19 families were found. Of these, 29 species are recorded for the first time from Syria. At least 27 species are considered predators of phytophagous mites and other microarthropods, while the others are phytophagous, frugivorous or storage mite species. Morphological remarks on some species and a checklist of all mite taxa reported from Syria are presented.

The abundance and diversity of phytoseiid mites were surveyed from April to September 2003-2005 in several grape crops in the South of France, with Grenache and Syrah cultivars, co-planted with rows of Sorbus domestica or Pinus pinea and in plots with monocultures of grapes. Densities of phytoseiid mites differed on the two tree species. Pinus pinea seemed to be a better host than S. domestica. Typhlodromus exhilaratus was the dominant species in the crops and on co-planted rows of S. domestica and P. pinea, whereas T. phialatus was the most abundant species in plots with monocultures of trees. Agroforestry management does not seem to affect mite diversity in vine plots. The densities of phytoseiid mites in vine crops may well be affected by the co-plantation of trees, especially in 2005. Although the densities observed during 2003 and 2004 were probably low due to very dry and hot climatic conditions, the agroforestry management seems to have had a significant impact on mite densities in 2005. Further experiments should be carried out to confirm this effect.

The abundance and diversity of phytoseiid mites were surveyed from April to September 2003 to 2005 in vineyards (Grenache and Syrah cultivars) co-planted with rows of Sorbus domestica or Pinus pinea and in monoculture plots of grapes in the South of France. Densities of phytoseiid mites were different on the two tree species, with P. pinea a more suitable host than S. domestica. Typhlodromus (Typhlodromus) exhilaratus was the dominant species occurring on grapes and on co-planted rows of S. domestica and P. pinea, whereas T. (T.) phialatus was the most abundant species in monoculture plots of both S. domestica and P. pinea. Factors determining the dominance of T. (T.) phialatus over T. (T.) exhilaratus in monoculture trees are discussed. In this study, agroforestry management did not affect phytoseiid diversity in vineyards, but did affect phytoseiid density, especially in 2005. The results obtained in 2003 and 2004 are not easy to discuss in this regard because of the low densities of mites observed during these 2 years (very dry climatic conditions and pesticide applications).

Correspondance: kreiter@ensam.inra.fr; International audience; Two species of Phytoseiidae are found in the same agroecosystem: Typhlodromus exhilaratus prevails in vine plots, while T. phialatus prevails in uncultivated surrounding areas. The objective of the present paper was to investigate whether the poor settlement of T. phialatus in vine plots can be explained by intraguild predation of these two species and/or cannibalism. Predatory abilities of the females on larvae and protonymphs were studied under laboratory conditions. A first experiment was conducted with only conspecific or heterospecific phytoseiid prey, in a second experiment Tetranychus urticae eggs were added to the phytoseiid prey. Oviposition, prey consumption, and escape rates of females were recorded. Oviposition and intraguild predation rates were higher for T. exhilaratus than for T. phialatus. Typhlodromus exhilaratus consumed fewer conspecifics than heterospecific phytoseiids, and oviposited when feeding on both diets. Typhlodromus phialatus consumed equal amounts of con- and heterospecifics. Although these two generalist predators belong to the type III defined by McMurtry and Croft (Annual Review of Entomology 42:291-321, 1997), our results suggest that they have different predation behaviour. However, because these results were obtained in experiments where no choice was given between the two phytoseiid species, they are difficult to link to previous studies conducted on the intraguild predation of the Phytoseiidae. The greater voracity and prolificacy of T. exhilaratus could partially explain the poor settlement of T. phialatus in vineyards and the predominance of T. exhilaratus. However, a full understanding of this phenomenon will require the study of other factors, such as susceptibility to pesticides and micro-climatic conditions, as well as the ability to cope with different food sources and host plants.