In Algeria, great undiscovered richness of entomofauna species still exist because of the different topographic conditions, the large diversity of vegetation and various kinds of climate. As part of doctoral research on insect pests associated with pear trees, insect samples were taken from February 2019 to August 2019, in an agro-ecosystem of pear orchards in Khemis Miliana City (Ain Defla). It is about 120 km away from Algiers. The plain of Khemis Miliana has an agricultural vocation, characterised by a semi-arid continental climate with dry summers and rainy winters. The surface area of the prospected parcel is 3 hectares containing 1200 trees planted in lines with a spacing of 1.50 m (Fig. 1). The prospected parcel has benefited from regular cultivation work. Weeds between the trees were removed and incorporated in soil between rows of pear plants in order to enrich the soil with organic matter. Its soil is of clay-silty type. For the phytosanitary monitoring of the orchard, the products used are precisely deficiency correctors, fungicides, acaricides and insecticides. The choice of the insecticides is based on the main insect pests (pear psyllid and codling moth) of the crop under study. The leafhoppers were trapped by setting up yellow pan-traps charged with salt solution (250 gm of sodium chloride (NaCl) dissolved in one litre of water with a few drops of odourless soap solution) and placed amongst the foliage of pear tree at a height of 1.50 m above ground level. The traps were placed from February to August 2019, but only in the period from June to August, we found the leafhoppers. The specimens collected were preserved in 70% ethanol in vials with airtight screw caps and labelled with date of collection, place and the number of yellow pan-traps. The specimens were examined under a stereoscopic microscope for detailed morphological characters. For studying the male genitalia characters, the abdomen was removed from the specimen which was dried and mounted on card with appropriate label data previously and macerated in hot 10% potassium hydroxide (KOH) till the soft tissues dissolved, the abdomen was then removed to distilled water, washed and then transferred to glycerol. We have followed the procedures advocated by Oman (1949) and Knight (1965) for the dissection of male and female genitalia which was done under a stereoscope microscope in glycerol and, after imaging male and female genitalia along with the remaining part of abdomen, these were stored in a microvial containing glycerol and stoppered with neoprene cork and pinned under the specimen from which the abdomen was removed. Habitus photos were taken using a Leica M205C stereo binocular microscope, equipped with a DFC 425 Camera. Images of male genitalia were taken using a Leica DM 2000 compound microscope, equipped with a camera Lucida and a DEC 425 camera. Partially focused images of each specimen or structure were stacked using the Zerene Stacker software.

Figure 1.  

Pear tree orchard, Khemis Miliana (Photos by Guerrouche N., 2019), A yellow pan-trap, B general aspect of the pear orchard, C flowering period of the pear trees, D the pear fruit in the harvest period (middle August).

The specimens used in this study are deposited in the laboratory of Dynamic and Biodiversity, University of Sciences and Technology Houari Boumediene, Algiers, Algeria and University of Agricultural Sciences, Bangalore, India, “UASB” collection.

There were 69 specimens of Platymetopius notatus Fieber amongst the leafhoppers trapped in the yellow pan-traps and formed the dominant group. Other leafhoppers collected were Aphrodinae (Aphrodini), Megophthalminae (Agalliini), Deltocephalinae (Athysanini, Deltocephalini, Eupelicini, Goniagnathini, Opsiini and Paralimnini) and Typhlocybinae (Empoascini) and these will be dealt with in other papers that will follow this. The leafhoppers from the genus Platymetopius were found only in the period from June to August. There was no apparent damage caused by Platymetopius on the foliage or on the plant growth of pear trees. The following works, Ribaut (1952) and Ossiannilsson (1983), were used to determine the genus Platymetopius. All the collected specimens were identified by Guerrouche N. and Prof. Marniche F. to the genus levels. A small sample of leafhoppers, collected during this study, were sent to Dr. C.A. Viraktamath for specific determination and confirmation. The species level identification of Platymetopius notatus was first made by Dr. C.A. Viraktamath using the original descriptions of species known from the northwest Africa as P. notatus which was later confirmed by Dr. I. Malenovsky. The species of Platymetopius involved is described and illustrated hereunder.

The genus Platymetopius is one of the large genera of the tribe Athysanini of the subfamily Deltocephalinae with more than 77 known species from the Palaearctic, Oriental and Afrotropical Regions. Most leafhopper species can only be recognised, based on the structure of the male genitalia and, for many species including P. notatus, this information is not available leading to difficulty in its accurate identification. Nast (1972) listed five species of the genus from northwest Africa, namely P. apicalis Puton, P. major Kirsc hbaum, P. notatus Fieber, P. perplexus Linnavuori and P. ziziphi Bergevin, amongst these, only two, P. apicalis and P. major, were reported from Algeria. P. major is widespread in the Palaearctic Region (Metcalf 1967, Nast 1972). Dlabola (1981) removed the species P. ziziphi as the type species of his new genus Masiripius Dlabola. P. major differs from P. notatus in the structure of the pygofer process which is long and curved with subapical leaf-like expansions (short, simple and straight process in P. notatus), laterobasal processes of aedeagal shaft are longer than shaft and are strongly curved dorsoanteriorly and the aedeagal shaft is with lateral apical short processes (in P. notatus, the lateral basal processes are not strongly curved and are about as long as the shaft and the aedeagal shaft apex lacks the lateral short processes). Linnavuori (1965), in describing P. perplexus, did not illustrate the male genitalia, but said the genitalia are similar to that in P. filigranus Scott, which was figured by Ribaut (1952) and has much shorter pygofer process and longer and subapically expanded laterobasal processes of the aedeagal shaft which are also longer than the aedeagal shaft. The male genitalia of P. apicalis and P. notatus were not previously illustrated. P. apicalis was described from Algeria by Puton. In the original description, Puton (1877) states that the vertex is a little prolonged and not very acute, hardly longer than broad behind and between the eyes; there is a milky white line on its anterior edge on each side of the median line and up to the eyes; its surface is of a beautiful black, except for a transverse white band on its posterior edge which, nevertheless, only touched on its median line and a small punctiform white spot at the same angle of the top and sometimes, perfectly isolated, sometimes united to the anterior white line. Hence it is quite different from the species that has been collected from pear trees in this study. The male and female genitalia of the specimens, collected in this study, exactly match those of specimens collected from Morocco and determined by Dr. J. Dlabola and Prof. H. Ribaut (Dr. Igor Malenovsky, personal communication to Dr. C.A. Viraktamath, see Acknowledgements for details). In fact, Fieber (1969) describes P. notatus as follows: crown is short, marbled rusty yellow, a little longer than half, broad at the nape, with yellowish-white central stripe and margin. Pronotum is brown with small white spots, forehead yellow, above with rusty yellow angular lines and a few side lines. Cheeks and clypeus are brown yellow. Clavus is brown yellow, in corium, short from the middle a large brown triangle, from the final seam to the edge, brown yellow inside down to the first end cell. Female pregenital segment transversely wide, a small blunt tooth in the middle of the posterior margin and the sides blunt-cornered in the middle and with a brownish-yellow central stripe. The male and female genitalia of P. notatus are described and illustrated for the first time.