Dispersal, population fluctuations and natural enemies of cabbage whitefly Aleyrodes proletella L. on collard in Duzce province

This study was carried out on dispersal, hosts, emergence times in nature, population fluctuation and natural enemies affecting its population fluctuation of cabbage whitefly, Aleyrodes proletella (Linnaeus) which is harmful on collard plants during the years of 2016-2017 in Düzce province in Western Black Sea Region. Cabbage whitefly, Aleyrodes proletella was widespread in all district of Düzce province and infestation rate was 84,3%. According to the highest infestation rates of district were determined that Akçakoca (97,8%), Yığılca (93,3%), Gümüşova (88,9%), Kaynaşlı (84,4%), Cumayeri (82,2%), Gölyaka (80%), Çilimli (75,6%) and Merkez (75%) districts, respectively. Aleyrodes proletella's weed host was identified as Lapsana communis L. subsp. intermedia (Bieb.) Hayek plant known with names such as "tavşan salatası", "şebrek" and "meme otu" belonging to the Asteraceae family. Natural enemies of Aleyrodes proletella were determined that Encarsia tricolor (Hymenoptera: Aphelinidae) as parasitoid, and Clitostethus arcuatus (Coleoptera: Coccinellidae) and Chrysoperla carnea (Neuroptera: Chrysopidae) as predators. In addition, cabbage whitefly, A. proletella and parasitoids E. tricolor were identified using molecular methods in this study. When the examined the population levels of cabbage whitefly during the winter months, it was determined that hibernating adults started laying eggs from March depending on the weather temperature and it was revealed that whitefly adults were seen on the newly planted collard seedling in May. The populations of Aleyrodes proletella increased from mid June to early July and reached the highest levels in July-August. It has been determined that the populations of parasitoids Encarsia tricolor, which began to appear from the middle of July as parallel to the density of whiteflies which continued to increase. It was determined that the parasitization rate of whiteflies by E. tricolor reached its highest levels in July-August. A. proletella was found to causing decrease in whitefly populations as a result of natural parasite rates 56,8%, 82,7%, 63,5% and 35,5% in the gardens at Aziziye, Ağa, Mahirağa and Topçular locations, respectively.