Morphological and anatomical alterations of common walnut leaves caused by eriophyids aceria erinea and a. Tristriata

Abstract

Eriophyoid mites (Acari: Eriophyoidea) are considered to be one of the most important cecidogenic groups of animals. Aceria erinea Nal. and Aceria tristriata Nal. appeared to be the most important and detrimental eriophyoids among 16 species registered on Common walnut in the world of fauna. Until recently, in the literature, the alterations of leaves and /or fruits, induced by these mites, i.e. erinea and galls have been described only superficially. Morphology of galls and the drawings, based on cross sections (of leaves), were presented mostly in earlier papers (Canestrini,1892; Küster, 1911; Ross, 1932; Mani, 1964; Jeppson et al. 1975). The aim of these investigations was to emphasize the level of reorganization of plant tissues, complexity of galls and the mechanism of its formation. Morphological and anatomical analyses of healthy leaves and the leaves with visible alterations were made on cross-sections comparatively. The cross-section slides were prepared by standard methods of light microscope, whereas the leaf surface and peripheral structures were studied by scanning electron microscope (SEM). In addition, various leaf parameters, such as thickness of upper and lower epidermal cells, as well as thickness of mesophyl of normal and infested leaves were measured. The results of the current investigations have determined two eriophoyid walnut leaf mites: complex erineum and blister gall. They have caused two types of damages induced by the mite's feeding. Anatomical analysis have established that blister galls were of intermediate type - between pouch and typical blister gall in their histological structure and by their origin. The morphologies of erineum and gall, peripheral structures and their anatomy have been compared with the normal leaves of walnut.

Eriofidne grinje su jedna od značajnih grupa cecidogenih životinja. Aceria erinea i A. tristriata su dve najčešće i najštetnije vrste eriofida na orahu među 16 do sada registrovanih. Promené na listovima i plodovima, koje ove vrste izazivaju, poznate su do sada samo na osnovu kratkih opisa spoljašnjeg izgleda gala i crteža njihovih preseka. Morfološkim i anatomskim istraživanjima promena na listu infestiranog oraha definisan je stepen reorganizacije tkiva biljke, kompleksnost gala i mehanizam njihovog nastajanja. Ustanovljena su dva tipa strukturnih promena na listu emergencne erinoze i plikaste gale posebnog tipa. Na osnovu anatomske analize i geneze, plikaste gale na listovima oraha se mogu uvrstiti u prelazni tip između kesastih i plikastih gala. Uporedo su prikazane karakteristične odlike neinfestiranih listova i promene na infestiranim listovima, odnosno diferencijacije površinskih struktura i gala.