PRŠICE PRELKE (Tetranychidae) – ŠKODLJIVCI KORUZE

  
Tatjana DOBNIKAR, Stanislav GOMBOC, Lea MILEVOJ, Nevenka VALIČ

Biotehniška fakulteta, Oddelek za agronomijo, SI-1111 Ljubljana, Slovenija

Pršice prelke (Tetranychidae) so v slovenskem strokovnem slovstvu le redko omenjene kot škodljivke koruze, čeprav jih v nekaterih državah uvrščajo med povzročitelje zmanjšanja pridelkov koruze. V poskusih smo ugotavljali pojav pršic in njihovo število na posameznih koruznih listih na štirih hibridih (BC 175, BC 678, carla in helga). Poskuse smo postavili na Laboratorijskem polju Biotehniške fakultete v Ljubljani ter na njivah v Kamniku in Biljah. Že pri prvem ocenjevanju v mesecu juliju smo ugotovili pršice na vseh lokacijah. V Ljubljani sta bila pri prvem ocenjevanju najmočneje napadena hibrida BC 175 in BC 678, pri tretjem ocenjevanju v mesecu septembru pa hibrida carla in helga. Na lokaciji v Kamniku je bil začeten napad zelo majhen. Kasnejši rezultati so si zelo podobni. Preference pršic za posamezen hibrid koruze nismo mogli opredeliti, saj je bila stopnja napada odvisna od vremenskih razmer na posamezni lokaciji. Na splošno lahko trdimo, da pršice najprej napadejo ranejše hibride in se nato selijo na poznejše, ki jim dalj časa zagotavljajo ugodne življenjske razmere. Pršice prelke (Tetranychidae) pri nas še ne povzročajo gospodarsko pomembne škode na koruzi.

ABSTRACT

SPIDER MITES (Tetranychidae) – PESTS OF MAIZE

Spider mites (Tetranychidae) are being very rearly mentioned as maize pests in slovenian professional literature although in some countries they are considered to be a causer of reduced yield of maize. In field experiments on three locations (Ljubljana, Kamnik, Bilje) the presence of spider mites was observed. The number of spider mites on maize leaves of four hybrids (BC 175, BC¸678, Carla, Helga) was counted, too. The first evaluation in July showed up the presence of spider mites on all locations. In Ljubljana there was the strongest attack  on BC 175 and BC 678 in July and on Carla and Helga in September. In Kamnik location initial attack was very low. Later observations are very similar among each other. Preference of spider mites for tested hybrids was not able to be distinguished because the rate of attack depends on weather conditions on each location. Generally speaking, spider mites attack early hybrids first and than move onto the later ones which provide them better life conditions through a longer period of time. Field data show that spider mites do not cause serious economic damage on maize in Slovenia.