Rad donosi fenološke i biološke podatke za kestenovog moljca minera u tri grada središnje Hrvatske – Zagrebu, Sisku i Čakovcu, prikupljene u razdoblju od 2001–2008. godine. Suprotno dosadašnjim spoznajama, kestenov moljac miner u središnjoj Hrvatskoj razvija četiri, a rijeđe tri generacije godišnje. Let prve generacije leptira utvrđen je od posljednje dekade travnja do kraja svibnja, dok je period leta druge generacije zabilježen tijekom lipnja i prve dvije dekade srpnja. Treća generacija bilježi se od kraja srpnja do kraja kolovoza, a četvrta generacija u drugoj polovici rujna. Tijekom osam godina istraživanja, četvrta generacija izostala je samo jedne godine u dva od tri promatrana grada. U provedenim istraživanjima zabilježeno je kako je druga generacija kes tenovog moljca minera brojnija u odnosu na prvu i treću generaciju, dok je četvrta generacija najmanje brojna. Uočeno je i da ženke prve generacijeodlažu jaja pretežito na listove donje trećine krošnje divljeg kestena. Ženke sljedećih generacija odlažu jaja češće na više dijelove krošnje.The paper deals with the biology of horse chestnut lefminer in central Croatia in three different towns within a circle of 150 km – Sisak, Zagreb and Čakovec. The data were collected by using pheromone traps and visual examinations of horse chestnut leves during the period of 2001–2008. Opposite to earlier assumptions, the horse chestnut leaf miner moth develops four and more seldom three generations annually in central Croatia. This is clearly presented in graphs 1–3, that show the horse chestnut male moth’s flight dynamics. The first generation moth’s flight starts in the last decade of April and lasts until the end of May; the second generation’s moths fly during June and the first two decades of July. Third generation of moths appear from the end of July until the end of August, and fourth generation from the middle to the end of September. During the eight years research, the fourth generation wasn’t recorded only in one year in two of three towns. Average duration of each developing period of horse chestnut leaf miner in Zagreb is presented in table 2. The second generation of horse chesnut monts is more numerous thent the first and the third one, while the fourth generation is even smaller. It was observed that the first generation’s females lay their eggs mainly on the upper sides of leaves of the lower third of the horse chestnut tree crown. Females of the second, third and fourth generation laid eggs on higher parts of the crowns, although their eggs can also be found on lower levels of the foliage
