Ioan ROSCA and Constantin POPOV
University of Agricultural Sciences and Veterinary Medicine-Bucharest, ROMANIA
The western corn rootworm (Diabrotica virgifera virgifera La Conte), [WCR], which was for the first time in Europe, in Yugoslavia in 1992, has spread rapidly into other east European countries. This most serious insect pest on maize in the USA and Canada has great economic importance for European maize growing countries, too. The EPPO has included this pest on its quarantine list as A2 pest, and it is assumed to become a quarantine pest for the EC in 2000
Romania has the largest maize-growing area in the Europe. The pest was recorded for the first time in Romania in 1996, and has established during 1997-98 in the southwestern part of the country. As for other countries, the establishing of D. virgifera virgifera in Romania would have an serious impact on maize yield and corn pests management. Therefore, the evaluation of its establishing potential as a part of pest risk assessment is absolutely necessary.
The emergence of the different developmental stages of D. virgifera virgifera was calculated for 6 main corn growing area in Romania by means of temperature sums basses on the lower development threshold of 110 C for larvae and of 90 C for the other stages.
In 1997-98, a countrywide system was worked out for records of presence of the pest in Romania. This system is based on the Integrated Forecasting System. The application of pheromone traps proved a large spreading of WCR. However, no any notable success in stopping the spreading of the pest in Romania was registered and no damage was registered in Romania, even at places with highest number of trapped beetles.
The WCR ability to adapt itself to the new conditions and absence of its natural enemies, makes especially a large effort for the new studies on the ecology and ethology of this pest in these new habitats. It was done a comparison between WCR and the most important corn pest, till now in Romania, Tanymecus dilaticollis Gyl..
The actual IPM strategies which should be adopted in Romania for attempt to control WCR pest is presented.