Red spider mite population on different apple cultivars in Zadar

Crveni voćni pauk (Panonychus ulmi, Koch) je prisutan štetnik na gotovo svim poljoprivrednim kulturama u Hrvatskoj, a jedan je od najopasnijih štetnika jabuke. Napad pauka na jabuci prepoznajemo po nekim specifičnim simptomima: napadnuto lišće se suši i otpada, zbog čega voćka slabi, razvoj pupova je slab, plodovi ostaju sitni te prijevremeno sazrijevaju. Panonychus ulmi, Koch također ima preferencije prema određenim sortama jabuke isto kao i prema sadržaju dušikovih spojeva. Procjena populacije pauka se provodi prije same vegetacije, na način da se uzorkuju grane jabuke tijekom zime i broje jaja pauka, iako štete nastaju u samoj vegetaciji. Istraživanje je provedeno tijekom dvije godine (2017. i 2018. godine) u voćnjaku jabuka Sveučilišnog poljoprivrednog dobra ''Baštica'' gdje je ujednačena tehnika proizvodnje. Cilj rada je temeljem brojnosti zimskih jaja utvrditi preferenciju grinje prema određenim sortama jabuke. Tijekom dvije godine istraživanja nisu postojale statistički značajne razlike u broju jaja na pregledanim sortama jabuke. Rezultati istraživanja dobiveni procjenom jaja crvenog pauka statistički su obrađeni analizom varijance ( F- test).The European red mite (Panonychus ulmi, Koch) is a major agricultural pest of almost all crops in Croatia, and is one of the most dangerous apple pests. The attact of the spit in the apple is recognized by some specific symptoms: the attacked leaves are dried and waste, the tree deteriorates, fruits remain small and can drop prematurely. Panonychus ulmi, Koch also has preferences to a specific apples cultivars, as well as to the content of nitrogen compounds. Estimation of the population of spiders is carried out before the growing season, so that the sampled branches apples during the winter and counted the eggs of spiders, although the damage occurring in the vegetation. The experiment was carried out during the two years (2017. and 2018.) in the apple orchard ''Baštica'', Agricultural University, where there is a uniform production technique. Purpose of this study is to determine, on the basis of the number of winter eggs, the preference of mites, according to certain apple cultivars. During two years of research, there were no statistically significant differences in the number of eggs on the examined apple cultivars. Research results obtained by estimating the number of eggs of red spiders mite, statistically processed using the analysis of variance (F-test)