The influence of the attack of the horse chestnut leaf miner's caterpillar on the assimilation potential of wild chestnut

Divlji kesten (Aesculus hippocastanum L.) je listopadna drvenasta biljka iz porodice Hippocastanaceae. Zbog svojih estetskih i gospodarskih karakteristika uzgaja se kao ukrasno drvo u urbanim sredinama, gradskim parkovima, ulicama i alejama kao soliter ili u skupinama, te u drvoredima. Divlji kesten nije samo ukrasno drvo, već je i važan bioindikator onečišćenog okoliša. Uloga zelenila u urbanim sredinama je višestruka: estetska, socijalna i ekološka. Stabla divljeg kestena doprinose pročišćivanju zraka, smanjenju buke, ravnoteži plinova u zraku, modificiranju temperaturnih ekstrema, te tako doprinose ublažavanju klimatskih promjena te povećavaju zelene površine gradova. Divlji kesten je domaćin nekoliko štetnih organizama. Njegov najvažniji štetnik je kestenov moljac miner (Cameraria ohridella Deschka et Dimić). Gusjenice kestenovog moljca minera se hrane parenhimskim stanicama mezofila lista. Ishranom se smanjuje količina fotosintetski aktivnog tkiva te tako dolazi do smanjenja asimilacijskog potencijala samog lista. Cilj ovog istraživanja bio je ispitati koliko napad gusjenice moljca minera utječe na smanjenje asimilacijskog potencijala lista divljeg kestena. U svrhu istraživanja praćene su tri generacije štetnika. Napadnuto lišće uzorkovano je u tri roka. Prvo uzorkovanje obavljeno je početkom svibnja, drugo početkom lipnja i posljednje krajem lipnja. Po svakom uzorkovanju prikupljeno je po 50 napadnutih listova. Listovi su isti dan fotografirani. Fotografije su zatim obrađene u računalnom programu „Adobe Photoshop“. Rezultati istraživanja pokazuju da ishrana gusjenica kestenovog moljca minera utječe na smanjenje asimilacijskog potencijala lišća divljeg kestena. Postotak oštećenog tkiva lišća kretalo se u rasponu od 0,76 % do 10,36 %, a povećavalo se pojavom svake nove generacije štetnika.Horse chestnut (Aesculus hippocastanum L.) is a deciduous woody plant form family Hippocastanaceae. Due to its aesthetic and economic characteristics, it is grown as an ornamental tree in urban areas, city parks, streets and alleys as a solitaire or in groups, and in tree rows. Chestnut is not only an ornamental tree, but also an important bioindicator of polluted environment. The role of greenery in urban areas is multiple: aesthetic, social and ecological. Chestnut trees contribute to air purification, noise reduction, balance of gases in the air, modification of temperature extremes, thus contributing to mitigating climate change and increasing the green areas of cities. Horse chestnut hosts several harmful organisms. Its most important pest is the horse chestnut leaf miner moth (Cameraria ohridella Deschka et Dimić). The caterpillars of the chestnut miner moth feed on the parenchymal cells of the leafs mesophyll. Nutrition reduces the amount of photosynthetically active tissue, thus reducing the assimilation potential of the leaf itself. The aim of this research was to examine the extent to which the attack of the miner moth caterpillar affects the reduction of the assimilation potential of the horse chestnut leaf. For the purpose of research, three generations of pests were monitored. Attacked leaves were sampled in three periods. The first sampling was done at the beginning of May, the second at the beginning of June and the last at the end of June. For each sampling, 50 attacked leaves were collected. The leaves were then photographed on the same day. The photos were processed in the computer program ˝Adobe Photoshop˝. The research results show that the feeding of the caterpillars of the horse chestnut leaf miner moth affects the reduction of the assimilation potential of wild chestnut leaves. The reduction in the assimilation capacity of the leaves ranged from 0.76 % to 10.36 %, and increased with the appearance of each new generation of pest