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Common ragweed is not an autochthonous European species. It originates from Nothern America and was introduced into the old world with clover and alfalfa seeds in 1863. It is an annual herbaceous species of the Asteraceae family (Compositae) that has separate male and females inflorescences on each individual. Common ragweed has a pronounced allometric sex proportion, i.e. a relative disproportion in terms of numbers and sizes of male and female inflorescences on any individual plant. Optimal temperature for its germination and emergence is 20-22oC and it flowers and bears fruit from July until September, depending on weather conditions over the season. It causes enormous damages in maize, sunflower, soybean and sugar beet crops, as well as in small grain crops of smaller density. More than 10% human population has been estimated as being susceptible to polen, while more than 50% of all pollinoses are caused by common ragweed polen. Ambrozija (Ambrosia artemisiifolia L.) nije autohtona evropska vrsta. Ona je poreklom iz Severne Amerike, a na stari kontinent je uneta 1863. godine sa semenom deteline i lucerke. To je jednogodišnja zeljasta vrsta iz familije Asteraceae (Compositae, glavočike) kod koje se na istoj individui nalaze razdvojene muške i ženske cvasti (glavice). Kod ambrozije je izražena alometrijska raspodela polova, tj. relativna disproporcija u pogledu broja i veličine muških i ženskih cvasti na jednoj individui. Optimalne temperature za klijanje i nicanje ove vrste su 20-22oC, cveta i plodonosi od jula do septembra shodno meteorološkim prilikama u datoj godini. Velike štete pravi u usevu kukuruza, suncokreta, soje, šećerne repe, kao i u usevima strnih žita ređeg sklopa. Procenjuje se da je više od 10% humane populacije osetljivo na polen biljaka, a od tog broja čak više od 50% od svih polinoza izaziva polen ambrozije. |
