The olive psyllid Euphyllura straminea Loginova (Hemiptera: Aphalaridae) is one of the most important pests of olive trees in Iran. To determine this pest’s economic injury level (EIL) and to evaluate the relationship between density of nymphs (DON) and yield loss, different densities of olive psyllid nymphs were maintained on olive trees by different insecticide concentrations. Counting nymphs on olive terminal shoots was done to determine nymph abundance at the end of nymphal stage. Different densities of olive psyllid nymphs resulted in significantly different yield losses of olive trees. Regression analysis was used to determine the relationship between nymph density and yield loss. Considering pest management costs, the market value of olive, and insecticide efficiency, economic injury levels were evaluated from 4.08 to 7.14 nymphal days. The olive psyllid EIL values could be used to plan a pest control program in Zanjan and Guilan provinces.

Plant parasites of the genera Longidorus Micoletzky, 1922 and Paralongidorus Siddiqi, Hooper and Khan, 1963 comprise a group of plant root ectoparasites, some of which are known as pests of economic importance. Their importance is further augmented by the fact that several species are known to be vectors of nepoviruses. To date 16 species from the genus Longidorus and two from Paralongidorus have been recorded in Poland. Despite their economic importance in agriculture currently there is no regional key for species identification. This paper presents such a key. The key has many illustrations and is based mainly on traits which are easily observable even by less experienced users. Thus, it should provide a useful tool for both scientists and specialists working in the field of plant protection, soil ecology and zoology as well as for teaching purposes.