No abstract

A comprehensive taxonomic assessment of the most agriculturally important and highly diverse spider mite genus, Oligonychus Berlese (Acari: Tetranychidae) was performed. The sub-generic division, species groups, doubtful species, species complexes and the interpretation of a key generic character are discussed. Based on the orientation of the male aedeagus, only two subgenera, namely Oligonychus Berlese (aedeagus downturned) and Reckiella Tuttle & Baker (aedeagus upturned), are valid in the genus Oligonychus. The subgenera Homonychus Wainstein, Metatetranychoides Wainstein, and Wainsteiniella Tuttle & Baker are considered to be synonyms of the subgenus Oligonychus, whereas the subgenus Pritchardinychus Wainstein is proposed as a synonym of the subgenus Reckiella. Moreover, based on female morphological characters, four species groups (coffeae, exsiccator, iseilemae, and peruvianus) and 11 species subgroups (aceris, biharensis, coffeae, comptus, exsiccator, gossypii, iseilemae, peruvianus, pritchardi, smithi, and subnudus) are suggested in the subgenera Oligonychus and Reckiella. Fourteen Oligonychus species are proposed as species inquirendae, and potential cryptic species complexes in the genus Oligonychus are briefly highlighted. It is agreed that the clunal seta h1 is always absent, while the para-anal setae h2 and h3 are always present in the genus Oligonychus. A key to subgenera, species groups, and species subgroups of the genus Oligonychus is provided.

To elucidate the taxonomic problems in species delineation within the Oligonychus punicae complex (O. punicae, O. mangiferus, and O. vitis) (Acari: Prostigmata: Tetranychidae), we performed morphological and molecular investigations on mite samples, collected from different hosts/countries. Thirty-nine samples of punicae complex, collected from Egypt, Pakistan, and Saudi Arabia (SA), did not show any considerable morphological differences in females and males. All 39 samples of the punicae complex resembled the original description of O. punicae, while the claimed Mexican O. punicae was distinctively different based on male aedeagus. Molecularly, the low nucleotide diversity ranged from 0% to 2.1% (ITS2-rDNA) and 0% to 1% (COI-mtDNA), and was observed among various DNA sequences of the punicae complex from Egypt, India, Israel, Pakistan, and SA, confirming their identity as one species. The high genetic divergence ranged from 17.2% to 18.8% (ITS2) and 9.2% to 10.2% (COI), observed between the claimed Mexican O. punicae and all other sequences of the punicae complex, indicating that the Mexican sample do not belong to O. punicae. Basing our findings on both morphological and molecular data, we can conclude that O. mangiferus and O. vitis are synonymized with O. punicae. Additionally, this study reveals that the claimed Mexican O. punicae needs to be re-identified.

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We present the first comprehensive inventory of the mites of Pakistan, based on data from published books and papers. The fauna as presently understood includes 126 families, 316 genera, and 1105 species. The best-documented genera are those that include pests of stored food (for example Acotyledon, 28 species), plant pests (Brevipalpus, 49 species; Tenuipalpus, 35 species), and beneficial predators (Euseius, 44 species; Neoseiulus, 37 species; Phytoseius, 36 species; Typhlodromus, 47 species). Some economically important families such as the Eriophyidae are almost completely unknown. Some of the Cryptostigmata have been studied, but other groups of soil mites are very poorly known. Other large groups such as the feather mites, water mites, Uropodina, and parasitic Astigmata and Prostigmata, have not been studied in a systematic way. An increase in knowledge of these groups would help an assessment of their economic importance, and would make a valuable contribution to the biogeography of the western section of the Oriental Region and the southern section of the Palaearctic Region.

Two new species of the genus Eutetranychus Banks are described and illustrated based on adult females and males, E.spinosussp. n. from Indigoferaspinosa Forssk (Leguminosae), E.neotransversussp. n. from Juniperusprocera Hochst. ex Endl. (Cupressaceae), and E.palmatus Attiah, 1967 is redescribed from Washingtoniarobusta H. Wendl. (Arecaceae). Additionally, the intraspecific morphological variations within E.orientalis populations, collected from 28 various host plants and 80 different localities from six regions of Saudi Arabia from 2009 to 2017, are discussed and presented. The genus Eutetranychus is divided into two species groups based on the presence of one seta (orientalis group) or two setae (banksi group) on coxa II. In addition, seven Eutetranychus species are suggested as synonyms of E.orientalis (Klein, 1936) and E.papayensis Iqbal & Ali, 2008 is considered as species inquirenda. A key to all known species of the genus Eutetranychus is provided.

The oriental red spider mite, Eutetranychus orientalis (Klein) is a major pest of citrus in many countries including Saudi Arabia (SA). The morphological variations among the different populations of E. orientalis were reported. In the present study, phenotypic variations based on 40 different morphological characteristics were evaluated in 10 E. orientalis populations collected from different hosts and regions of SA. Further, ITS2-rDNA sequences were used to confirm the identity of these phenotypically varying populations. Phenotypic variations in all populations were found in the shape and length of dorsal setae, striation pattern between setae d1 and e1, and leg chaetotaxy. The rDNA sequence analysis of these morphologically varying populations resulted in 10 different ITS2 Saudi haplotypes. The phenotypic and genetic variations were more related to the host plants rather than their geographic distribution. The E. orientalis population collected from Phoenix dactylifera was phenotypically distinct and genetically divergent. The populations collected from citrus species were also more phenotypically and genetically related to each other than to populations collected from non-citrus host plants. The haplotypes recovered from Ziziphus sp., Morus sp., and Azadirecta indica from different regions were grouped in the same sub-clade. Further, the ITS2 haplotypes of Saudi E. orientalis recovered from Citrus reticulata from Riyadh and Al Ula were 100% identical to the ITS2 haplotypes recovered from Citrus sp. from Israel. It is concluded that phenotypic variations exist among different populations of E. orientalis inhabiting different host plants. This species should be identified carefully by considering phenotypic intraspecific variations.

In the present study, a co-culture technique was adopted with an aim to investigate a hyper production of exoglucanase, and β-glucosidase using cheap and easily available agro-industrial residue corn stover as growth supporting substrate. Various physio-chemical and nutritional variables were optimized using classical and completely randomized designs for induced production of exoglucanase, and β-glucosidase from the co-culture of Trichoderma viride and Ganoderma lucidum in solid state fermentation (SSF). Analysis profile showed that when the conditions of the SSF medium containing 15 g corn stover substrate (50% w/w moisture) inoculated with 6 mL of inoculum were optimal, the maximum productions of exoglucanase (485 ± 6.5 U/mL) and β-glucosidase (255 ± 3.3 U/mL) were recorded after 5 days of incubation at pH 6 and 35˚C.