The influence of abiotic factors on the presence of European corn borer (Ostrinia nubilalis Hübner)

Istraživanja su provedena tijekom trogodišnjeg razdoblja (2012. – 2014.) u poljskim uvjetima s prirodnom zarazom kukuruznoga moljca, na Poljoprivrednom institutu u Osijeku. Cilj istraživanja bio je utvrditi utjecaj različitih varijanti navodnjavanja i gnojidbe i utjecaj genotipa na pojavu i oštećenost biljki od kukuruznoga moljca te povezanost ishrane gusjenica s koncentracijom dušika, silicija i C/N odnosa u listu kukuruza. Na kraju svake vegetacijske sezone zabilježena je masa klipa (g), dužina oštećenja stabljike (cm), oštećenje drške klipa (cm), broj gusjenica u stabljici kukuruza, broj gusjenica u dršci klipa, te ukupan broj gusjenica po biljci. U 2014. godini kada su bile niže temperature, a veća količina oborina utvrđen je značajno niži napad u odnosu na druge dvije ispitivane godine. Uz pomoć feromonskih mamaca utvrđena je dominantnost Z-tipa kukuruznoga moljca na području istočne Slavonije. Povišenom razinom sadržaja vode u tlu utvrdilo se manje oštećenje biljke, a povećanjem razine gnojidbe utvrđeno je veće oštećenje na biljkama kao posljedica ishrane gusjenica. Utvrđena je različita otpornost hibrida u odnosu na oštećenje od gusjenica te se hibrid C4 izdvojio kao najotporniji, dok je C1 bio najosjetljiviji. Koncentracija dušika i silicija u listu kukuruza u negativnoj su korelaciji kao i koncentracija dušika i C/N odnos. Otpornost kod hibrida nije isključivo ovisila o koncentracijama dušika i silicija iako se pokazalo kod većine hibrida pri povećanoj koncentraciji dušika veće oštećenje, a kod povećane koncentracije silicija utvrđeno je manje oštećenje.Field experiments with natural population of ECB were conducted in three vegetation seasons (2012-2014) at the Agricultural Institute in Osijek. The aim of this study was to determine the effect of different levels of irrigation and nitrogen fertilization and various genotypes on the occurrence and damage of maize plants from European corn borer larvae and relationship with nitrogen and silicon content as well as C/N ratio. At the end of each growing season were determined ear weight (g), tunnel length (stalk) (cm), ear shank damage (cm), the number of larvae in corn stalk, number of larvae in the ear shank, and total number of larvae in plant. In 2014, with lower temperatures and higher amount of precipitate compared to the previous years, a significantly lower ECB attack was determined. Dominance of Z-type European corn borer on pheromone traps in the area of eastern Slavonia was determined. Increasing the level of soil water content damage from larvae was reduced and increasing the level of nitrogen fertilization feeding activity was increased. We have confirmed different hybrid resistance in regards to damage from larvae, so C4 genotype was the most resistant while C1 was the most susceptible. Concentration of nitrogen and silicon in a maize leaf were in negative correlation as well as nitrogen concentration and C/N ratio. Hybrid resistance didn't entirely depend on nitrogen and silicon concentrations, even though there was greater damage at most hybrids with higher concentration of nitrogen, while damage was reduced with higher concentration of silicon