Since the early 1990s, and almost simultaneously, unknown diseases started to be observed in many crops, especially in tropical and subtropical regions. These diseases were predominantly caused by begomoviruses, which were poorly known at that time. Their vector, the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae), often reached unprecedented huge populations in agricultural areas. This elicited a serious production crisis worldwide, that caused losses of millions of dollars for farmers in many countries, including the Mesoamerican region. Fortunately, in Costa Rica, some local research centers, with the collaboration of foreign specialists, have been able to study the causes of this phenomenon, in the search for solutions based on solid epidemiological information. In addition to the previously reported native Bemisia tabaci species, New World (NW), two exotic species, - Mediterranean (MED) and Middle East-Asia Minor 1 (MEAM1) - were found. Moreover, native and exotic bipartite begomoviruses have been detected, especially in common bean, cucurbits, tomato and sweet pepper, as well as the worldwide spread monopartite begomovirus Tomato yellow leaf curl virus (TYLCV). Based upon biological and ecological knowledge accumulated to date, this review offers a comprehensive overview of the very dynamic ways in which the interactions of the different whiteflies and begomovirus species have expressed in Costa Rica, with emphasis on vegetable pathosystems. Hopefully, the information provided in this paper may allow farmers, extension agents, and researchers involved in vegetable production to develop sound practical responses to current and unforeseen problems regarding whiteflies and their associated viruses.

Keywords: Bemisia tabaci, begomoviruses, tomato, agroecosystems, sweet peper