EPPO Global Database

The situation of Diabrotica virgifera virgifera (referred to here as D. virgifera for convenience) in Central Europe was reviewed during the 4th meeting of the EPPO ad hoc Panel on Diabrotica virgifera held jointly with the 6th International IWGO Workshop on Diabrotica virgifera in Paris, 1999-11-04/05. In summary, the spread of D. virgifera continues in Central Europe, and, in 1999, it has mainly spread northwards and southwards. An additional area of about 31000 km² was infested. D. virgifera has not spread to new countries but is approaching the borders of Slovakia, Slovenia, Austria and Ukraine. Economic damage has been seen on maize in Serbia, as in previous years. The numbers of insects caught in some parts of Romania, Bosnia ; Herzegovina and Croatia (close to the area in Serbia where economic damage is observed) suggest that economic damage may be expected in the near future. The map below shows the spread of D. virgifera in Europe from 1992 to 1999.

A monitoring programme was carried out for the first time in Albania, in the district of Shkodra (north of Albania, near the Former Yugoslav Rep. of Macedonia), in Tirana (near the international airport) and in the area of Durres, with pheromone traps and yellow sticky traps at 12 locations. D. virgifera has not been found in Albania.

In 1999, pheromone traps had been placed along the borders with Hungary (in Burgenland and Styria) and near Vienna international airport. D. virgifera has not been found in Austria. In 2000, monitoring will extend to counties with less maize-growing.

In Bosnia ; Herzegovina, maize is an important crop covering approximately 250.000 ha, mainly in the north and north-east parts of the country. D. virgifera was first found in 1997 in areas bordering Serbia and Croatia. In 1998, the monitoring was done in the cantons of Posavina and Tuzla-Podrinje (which are situated in the north near the borders of Croatia and Serbia) and Una (western part). It was found only in the first two, in the region around Tuzla (near Doboj, Gracanica and around Zvornik) and in the north along the river Sava (near Orasje). Populations had increased compared to the previous year, particularly in the region near the river Sava (border with Croatia). Minor damage caused by adults on maize silks had been observed in 1998 near Orasje (along river Sava).

In 1999, in the Federation of Bosnia ; Herzegovina, the survey was done using pheromone traps, yellow sticky traps, PALs traps (with flower volatile bait) and colour traps in the cantons of Posavina, Tuzla, Zenica-Doboj and Una. D. virgifera was not found in canton Una. It was found for the first time in the canton Zenica-Doboj (municipalities of Tešanj and Doboj Jug Zenica). Most captures concerned the cantons of Tuzla and Posavina. In canton Tuzla, it was found around Tuzla, Živinice and Lukavac. In canton Posavina (Oraske, Odsak), densities were especially high and it is expected that economic damage may occur in the near future, although no larval damage has been seen this year. The pest is spreading from eastern and northern parts towards the centre of the county, now passing from the plains to more mountainous areas. Future control will mainly be based on avoidance of monoculture.

In the Serbian areas of Bosnia ; Herzegovina, in 1998, the greatest numbers of D. virgifera were trapped in the eastern part (Bijeljina, Brčko). Only one adult was found in a single locality near Banjaluka. It was felt that the insect was spreading more rapidly along the river Sava towards the west than southwards. In 1999, pheromone and yellow sticky traps were placed in pairs at 51 locations of 24 communities. 3749 adults were caught at 31 locations. At some of them, populations had reached the level of economic damage and such damage might be observed in 2000, especially at Amajlija, Brodac, Bijeljinan Brezovo Polje and Karakaj, and to a lesser extent at Trnovi, Dragljevac, Tabus and Plazulja. The pest has now reached the central region of Banjaluka.

After the first IWGO Workshop in Graz (AT) in 1995, a trapping programme was initiated in Bulgaria. Cucurbitacin traps were used in 1995 and 1996, and pheromone traps were used in 1997. Field inspections were also carried out. During the period 1995-1997, results were all negative. In 1998, the insects were found in the north-west near the borders of with Serbia (YU) and Romania (along the Danube). The highest numbers of insects were caught near Bregovo. The estimated infested area was 200 km². In 1999, 300 pheromone traps and yellow sticky traps were used. The first three adults of D. virgifera were trapped on August 2nd (the last one was caught in October 4^th). In total, 303 adults were caught (against 156 in 1998). The insect has moved between 25 and 35 km inwards from the Serbian and Romanian borders.

D. virgifera was first found in the east of Croatia in 1995. One adult was caught in a cucurbitacin trap, but now it is considered that the pest was probably already present on an area extending about 30 km from the Yugoslav border and situated to the south of the river Bosut. In 1996, the pest spread westwards (80 km from the Yugoslav border) and adults were trapped in approximately 6000 km². In 1997, the area where adults were trapped reached 9000 km² and the front line of the outbreak was situated 100 km from the Yugoslav border. In 1998, D. virgifera spread towards the west (found in two new localities Nova Gradiška and Gornji Varoš) and over a distance of 37 km along the river Sava (up to the village Gornji Varoš; situated at 150 km from the Yugoslav border and 150 km from Slovenia). In the middle part of the front line (in the middle of Croatia), D. virgifera spread only 8 km to the west. In the northern part of Croatia, along the border with Hungary, no further spread was observed. In the north of Croatia, there is a marshland area (Kopački Rit) near Hungary where beetles were found for the first time in 1998. This marshland may have slowed down the spread of D. virgifera but it has not prevented it.

In 1999, pheromone and yellow sticky traps were placed in pairs on 117 sites and were replaced every 25 days. 30% of traps were situated in areas which were not infested in June 1999. About 12000 adults were caught (preliminary results). The Infested area is evaluated at 12750 km² in 1999 (against 10500 in 1998, 9000 in 1997, 6500 in 1996) on which 165000 ha of corn are grown. The population densities were much higher and high densities (25 adults) were trapped at locations where the pest was not present last year. Two more counties have been infested in 1999: Koprivnicko-Krizevacka next to Hungary and at its south, Bjelovarsko-Bilogorska. D. virgifera spread mainly in the North of the country next to Hungary, and in the middle part of the frontline. It spread to the west along the rivers Sava (120 km from Slovenia) and Drava (100 km from Austria). Despite a very strong traffic from east to west, no spread by vehicles was registered. Damage was assessed in a trial on insecticides carried out at the border with Yugoslavia. The highest damage was 5.5 (Iowa scale), with yield losses of 15-20% in this plot. However, it should be stressed that no economic damage has been reported on farmers' crops in 1999.

Maize is grown on approximately 3 million hectares in France (both for grain and silage), with about 25% in monoculture. In 1999, official monitoring was carried out at 16 locations at risk, near airports and in representative maize-growing areas. D. virgifera has not been found in France.

Monitoring for D. virgifera started in Germany in 1998 in Baden-Württemberg. In 1999, it extended to Bayern, Sachsen, Nordrhein-Westfalen, Baden-Württemberg, using 161 pheromone traps and 18 MCA (plant kairomone) traps at 53 locations. D. virgifera has not been found in Germany.

D. virgifera was first found in Hungary in 1995 in the south of the country. In 1997, D. virgifera spread towards the north (up to 100-120 km from the Yugoslav border). In 1996-1997, it was estimated that the pest has moved 40 km to the north and that approximately 10 000 km² were potentially infested by D. virgifera. The pest was present in the following counties: Baranya (Villány, Boly), Bács-Kiskun (Kecskemét), Csongrád (Szeged, Csanádpalota, Maroslele-Makó) and Békes (Mezökovacsháza, Mezöhegyes, Battonya, Csnádapáca). The highest population numbers were found in Békes and Czongrád counties. Larvae were seen for the first time, slightly damaging maize roots near Szeged (Czongrád county), but without any impact on maize yield. In 1998, the monitoring programme was carried out in infested areas, non-infested areas (according to 1997 results) and along the front line of the spread. It showed that the spread was very slow but that populations increased in the following areas: Baranya (Villány, Boly), Bács-Kiskun (Kunbaja, Bácsalmás), Csongrád (Szeged, Csanádpalota, Nagylak) and Békes (Mezöhegyes). In the area of Szeged, slight larval damage was observed but no impact on yield was recorded. D. virgifera did not spread towards the north in 1998 (the front line is still approximately at 120 km from the Yugoslav border), but it has slowly moved towards the west.

In 1999, the permanent monitoring network was set up at 19 sites of 9 infested counties with pairs of pheromone and yellow sticky traps. Scout trapping was also done in areas previously not infested using pheromone traps at 105 locations. The two trapping systems caught 9304 adults in total (against 1895 in 1998). D. virgifera was trapped in 12 counties: Bács-Kiskun, Baranya, Csongrád, Békes, Fejer, Somogy (up to the southern shore of lake Balaton), Pest, Jász-Nagykun-Szolnok, Hajdú-Bihar, Nógrád (close to the river Ipoly, near the Slovakian border), Budapest, Tolná, Komaróm-Esztergom (northern part of the country; not far from the Danube and the Slovakian border). D. virgifera spread northwards through the valleys and along the Danube. Larval damage was observed in Békés and Csongrád counties, and the economic damage level was reached near Szeged (Csongrád county) in an experimental field grown in monoculture. No damage was reported in farmers' fields in Hungary.

Following the establishment and spread of D. virgifera in Yugoslavia, an alert programme was set up in Italy in order to be able to take containment and eradication measures as soon as the pest is found. A monitoring programme was set up in the north-eastern part of Italy with 12 trapping sites in 1997 and 20 sites in 1998 (1 to 10 pheromone traps per site). Maize fields were selected in regions where maize is often grown continuously and also near potential points of entry (airports, firms trading with infested countries etc.). In 1997, no D. virgifera was found. In 1998, the first 7 specimens of D. virgifera were trapped between 21st July and 13th August in maize fields in Tessera, near the international airport of Venezia (Marco Polo). It was unexpected in the sense that, if the pest is spreading westward from the outbreak in the Danube basin, it would have been expected to occur first in Slovenia, Austria or western Croatia. In fact, the origin of this introduction is not known. Air-borne transport from USA or road-borne transport from the Danube basin are both possibilities.

After this finding an eradication programme was immediately set up. A focus area was delimited where D. virgifera had been found (1100 ha) and a safety area was defined in the surroundings (7-14 km around the focus, 35000 ha in all). In the focus area, a trapping grid (0.5 km ´ 0.5 km) was set up using pheromone traps. It was planned that, in this area, treatments would be applied to all the maize if D. virgifera was found early in the season, and treatments would nevertheless be applied at the beginning of July. Finally, continuous cropping of maize would be prohibited. In the safety area, a second trapping grid (1 km ´ 1 km) was established. It was planned that maize fields would be treated within 1 km of the trap if adults were caught and trapping would be intensified.

In 1999, official checks were made to verify that specific restrictions on maize cropping had been respected. Fenitrothion and chlorpyrifos were used for the above-mentioned treatments. In addition, it was prohibited to move fresh parts of maize and soil in which corn was grown in the previous year outside the focus area. It was also forbidden to thresh corn before the 1st of October to prevent possible spread of adults. These measures were funded through regional funds to cover farmer's costs caused by the prohibition and costs of treatment and monitoring.

In 1999, only 2 adults were caught, in one trap on July 6th and 26th near the airport. This trap was situated at the limit of the focus area and 11 ha of maize in the safety area was also treated. The eradication strategy therefore seems to have been effective. There was no increase in the number of males captured, and no spread outside the focus area. In the rest of the country, 26 traps were set up in the Veneto region, and 26 in Friuli Venezia Giulia, and no D. virgifera was caught. Monitoring in Lombardia, Emilia Romagna and Piemonte also gave negative results.

The first find of D. virgifera was made in 1996 at Nadlac (district of Arad – west of the country near Hungary) on yellow sticky traps. In 1997, D. virgifera was caught mostly in Arad, Timis, Caras-Severin and Mehedinti districts and it was estimated that an area of approximately 10000 km² was potentially infested. In 1998, approximately 12000 km² was potentially infested. Increase in population densities was recorded. In 1999, 241 sites were studied (each site having both pheromone and yellow sticky traps). The spread continued towards the east and the north-east within the districts of Bihor, Arad and Hunedoara. In the south, D. virgifera spread towards the south-east, along the Danube, near the Bulgarian border, and it reached the district of Dolj. The potentially infested area is approximately 14000 km². Although it was noted that in some areas the numbers of adults caught were approaching the economic thresholds, no economic damage has yet been observed in Romania.

In 1998, 37 traps were placed along the border with Hungary and no D. virgifera were caught. In 1999, 39 traps were used along the southern border of Slovakia and near Bratislava and Kosice airports. No Diabrotica virgifera were caught. D. virgifera has not been found in Slovakia.

A monitoring programme has been in place in Slovenia since 1995 in the north-east and south-east of the country, which are two intensive maize-growing areas near Hungary and Croatia. The monitoring programme was intensified in 1999 due to the findings in Italy. Trapping was carried out at 50 locations, mainly near the Hungarian and Croatian borders, but also near the Italian border and Ljubljana international airport. So far, D. virgifera has not been found in Slovenia. The spread in Europe will determine the future monitoring programmes in Slovenia.

It must be recalled that D. virgifera was reported for the first time in Europe in Surčin, near Belgrade airport (Serbia) in 1992-1993. In 1998, 900 pheromone traps were used and it was observed that D. virgifera continued to spread towards the south. In 1998, damage was only reported near Belgrade, Pozarevac, Novi Sad, and Vršac, this area extending towards the borders with Croatia (on the west) and Romania (on the east). In 1998, the area where damage was observed covered 45525 ha. Monitoring done in southern Backa (region around Novi Sad) in 1998 showed that populations levels were still increasing. High infestations occurred in the eastern part of southern Backa as in 1997, and differences previously observed between the east and west parts of this region tended to disappear. Symptoms in maize fields were visible ("gooseneck" symptoms). In 1998, D. virgifera was also found for the first time in Montenegro. A few adults have been trapped at three localities (near Bijelo Polje in the north of Montenegro) along a railway track. In 1999, trapping was done at 282 sites. Populations were denser in the north-east than in the hilly areas of the centre. D. virgifera continued to spread southwards along the rivers Ibar (approximately 60 km) and Morava (approximately 20-30 km, to Leskovac). Damage occurred in the same counties as in 1998, and also in the neighbouring areas of Middle Banat and Middle Backa. The mean yield reduction was estimated at 30% (from 5 to 80% damage was observed).

Spread of Western Corn Rootworm in Europe from 1992-1999 (by C. R. EDWARDS, J. KISS and Gy. BARNA; based on data from Igrc-Barcic, Festic, Furlan, Ilovai, Ivanova, Maceljski, Princzinger, Sivcev and Vonica)

The situation of Diabrotica virgifera virgifera (referred to here as D. virgifera for convenience) in Central Europe was reviewed during the 4th meeting of the EPPO ad hoc Panel on Diabrotica virgifera held jointly with the 6th International IWGO Workshop on Diabrotica virgifera in Paris, 1999-11-04/05. In summary, the spread of D. virgifera continues in Central Europe, and, in 1999, it has mainly spread northwards and southwards. An additional area of about 31000 km² was infested. D. virgifera has not spread to new countries but is approaching the borders of Slovakia, Slovenia, Austria and Ukraine. Economic damage has been seen on maize in Serbia, as in previous years. The numbers of insects caught in some parts of Romania, Bosnia & Herzegovina and Croatia (close to the area in Serbia where economic damage is observed) suggest that economic damage may be expected in the near future. The map below shows the spread of D. virgifera in Europe from 1992 to 1999.

A monitoring programme was carried out for the first time in Albania, in the district of Shkodra (north of Albania, near the Former Yugoslav Rep. of Macedonia), in Tirana (near the international airport) and in the area of Durres, with pheromone traps and yellow sticky traps at 12 locations. D. virgifera has not been found in Albania.

In 1999, pheromone traps had been placed along the borders with Hungary (in Burgenland and Styria) and near Vienna international airport. D. virgifera has not been found in Austria. In 2000, monitoring will extend to counties with less maize-growing.

In Bosnia & Herzegovina, maize is an important crop covering approximately 250.000 ha, mainly in the north and north-east parts of the country. D. virgifera was first found in 1997 in areas bordering Serbia and Croatia. In 1998, the monitoring was done in the cantons of Posavina and Tuzla-Podrinje (which are situated in the north near the borders of Croatia and Serbia) and Una (western part). It was found only in the first two, in the region around Tuzla (near Doboj, Gracanica and around Zvornik) and in the north along the river Sava (near Orasje). Populations had increased compared to the previous year, particularly in the region near the river Sava (border with Croatia). Minor damage caused by adults on maize silks had been observed in 1998 near Orasje (along river Sava).

In 1999, in the Federation of Bosnia & Herzegovina, the survey was done using pheromone traps, yellow sticky traps, PALs traps (with flower volatile bait) and colour traps in the cantons of Posavina, Tuzla, Zenica-Doboj and Una. D. virgifera was not found in canton Una. It was found for the first time in the canton Zenica-Doboj (municipalities of Tešanj and Doboj Jug Zenica). Most captures concerned the cantons of Tuzla and Posavina. In canton Tuzla, it was found around Tuzla, Živinice and Lukavac. In canton Posavina (Oraske, Odsak), densities were especially high and it is expected that economic damage may occur in the near future, although no larval damage has been seen this year. The pest is spreading from eastern and northern parts towards the centre of the county, now passing from the plains to more mountainous areas. Future control will mainly be based on avoidance of monoculture.

In the Serbian areas of Bosnia & Herzegovina, in 1998, the greatest numbers of D. virgifera were trapped in the eastern part (Bijeljina, Brčko). Only one adult was found in a single locality near Banjaluka. It was felt that the insect was spreading more rapidly along the river Sava towards the west than southwards. In 1999, pheromone and yellow sticky traps were placed in pairs at 51 locations of 24 communities. 3749 adults were caught at 31 locations. At some of them, populations had reached the level of economic damage and such damage might be observed in 2000, especially at Amajlija, Brodac, Bijeljinan Brezovo Polje and Karakaj, and to a lesser extent at Trnovi, Dragljevac, Tabus and Plazulja. The pest has now reached the central region of Banjaluka.

After the first IWGO Workshop in Graz (AT) in 1995, a trapping programme was initiated in Bulgaria. Cucurbitacin traps were used in 1995 and 1996, and pheromone traps were used in 1997. Field inspections were also carried out. During the period 1995-1997, results were all negative. In 1998, the insects were found in the north-west near the borders of with Serbia (YU) and Romania (along the Danube). The highest numbers of insects were caught near Bregovo. The estimated infested area was 200 km². In 1999, 300 pheromone traps and yellow sticky traps were used. The first three adults of D. virgifera were trapped on August 2nd (the last one was caught in October 4^th). In total, 303 adults were caught (against 156 in 1998). The insect has moved between 25 and 35 km inwards from the Serbian and Romanian borders.

D. virgifera was first found in the east of Croatia in 1995. One adult was caught in a cucurbitacin trap, but now it is considered that the pest was probably already present on an area extending about 30 km from the Yugoslav border and situated to the south of the river Bosut. In 1996, the pest spread westwards (80 km from the Yugoslav border) and adults were trapped in approximately 6000 km². In 1997, the area where adults were trapped reached 9000 km² and the front line of the outbreak was situated 100 km from the Yugoslav border. In 1998, D. virgifera spread towards the west (found in two new localities Nova Gradiška and Gornji Varoš) and over a distance of 37 km along the river Sava (up to the village Gornji Varoš; situated at 150 km from the Yugoslav border and 150 km from Slovenia). In the middle part of the front line (in the middle of Croatia), D. virgifera spread only 8 km to the west. In the northern part of Croatia, along the border with Hungary, no further spread was observed. In the north of Croatia, there is a marshland area (Kopački Rit) near Hungary where beetles were found for the first time in 1998. This marshland may have slowed down the spread of D. virgifera but it has not prevented it.

In 1999, pheromone and yellow sticky traps were placed in pairs on 117 sites and were replaced every 25 days. 30% of traps were situated in areas which were not infested in June 1999. About 12000 adults were caught (preliminary results). The Infested area is evaluated at 12750 km² in 1999 (against 10500 in 1998, 9000 in 1997, 6500 in 1996) on which 165000 ha of corn are grown. The population densities were much higher and high densities (25 adults) were trapped at locations where the pest was not present last year. Two more counties have been infested in 1999: Koprivnicko-Krizevacka next to Hungary and at its south, Bjelovarsko-Bilogorska. D. virgifera spread mainly in the North of the country next to Hungary, and in the middle part of the frontline. It spread to the west along the rivers Sava (120 km from Slovenia) and Drava (100 km from Austria). Despite a very strong traffic from east to west, no spread by vehicles was registered. Damage was assessed in a trial on insecticides carried out at the border with Yugoslavia. The highest damage was 5.5 (Iowa scale), with yield losses of 15-20% in this plot. However, it should be stressed that no economic damage has been reported on farmers' crops in 1999.

Maize is grown on approximately 3 million hectares in France (both for grain and silage), with about 25% in monoculture. In 1999, official monitoring was carried out at 16 locations at risk, near airports and in representative maize-growing areas. D. virgifera has not been found in France.

Monitoring for D. virgifera started in Germany in 1998 in Baden-Württemberg. In 1999, it extended to Bayern, Sachsen, Nordrhein-Westfalen, Baden-Württemberg, using 161 pheromone traps and 18 MCA (plant kairomone) traps at 53 locations. D. virgifera has not been found in Germany.

D. virgifera was first found in Hungary in 1995 in the south of the country. In 1997, D. virgifera spread towards the north (up to 100-120 km from the Yugoslav border). In 1996-1997, it was estimated that the pest has moved 40 km to the north and that approximately 10 000 km² were potentially infested by D. virgifera. The pest was present in the following counties: Baranya (Villány, Boly), Bács-Kiskun (Kecskemét), Csongrád (Szeged, Csanádpalota, Maroslele-Makó) and Békes (Mezökovacsháza, Mezöhegyes, Battonya, Csnádapáca). The highest population numbers were found in Békes and Czongrád counties. Larvae were seen for the first time, slightly damaging maize roots near Szeged (Czongrád county), but without any impact on maize yield. In 1998, the monitoring programme was carried out in infested areas, non-infested areas (according to 1997 results) and along the front line of the spread. It showed that the spread was very slow but that populations increased in the following areas: Baranya (Villány, Boly), Bács-Kiskun (Kunbaja, Bácsalmás), Csongrád (Szeged, Csanádpalota, Nagylak) and Békes (Mezöhegyes). In the area of Szeged, slight larval damage was observed but no impact on yield was recorded. D. virgifera did not spread towards the north in 1998 (the front line is still approximately at 120 km from the Yugoslav border), but it has slowly moved towards the west.

In 1999, the permanent monitoring network was set up at 19 sites of 9 infested counties with pairs of pheromone and yellow sticky traps. Scout trapping was also done in areas previously not infested using pheromone traps at 105 locations. The two trapping systems caught 9304 adults in total (against 1895 in 1998). D. virgifera was trapped in 12 counties: Bács-Kiskun, Baranya, Csongrád, Békes, Fejer, Somogy (up to the southern shore of lake Balaton), Pest, Jász-Nagykun-Szolnok, Hajdú-Bihar, Nógrád (close to the river Ipoly, near the Slovakian border), Budapest, Tolná, Komaróm-Esztergom (northern part of the country; not far from the Danube and the Slovakian border). D. virgifera spread northwards through the valleys and along the Danube. Larval damage was observed in Békés and Csongrád counties, and the economic damage level was reached near Szeged (Csongrád county) in an experimental field grown in monoculture. No damage was reported in farmers' fields in Hungary.

Following the establishment and spread of D. virgifera in Yugoslavia, an alert programme was set up in Italy in order to be able to take containment and eradication measures as soon as the pest is found. A monitoring programme was set up in the north-eastern part of Italy with 12 trapping sites in 1997 and 20 sites in 1998 (1 to 10 pheromone traps per site). Maize fields were selected in regions where maize is often grown continuously and also near potential points of entry (airports, firms trading with infested countries etc.). In 1997, no D. virgifera was found. In 1998, the first 7 specimens of D. virgifera were trapped between 21st July and 13th August in maize fields in Tessera, near the international airport of Venezia (Marco Polo). It was unexpected in the sense that, if the pest is spreading westward from the outbreak in the Danube basin, it would have been expected to occur first in Slovenia, Austria or western Croatia. In fact, the origin of this introduction is not known. Air-borne transport from USA or road-borne transport from the Danube basin are both possibilities.

After this finding an eradication programme was immediately set up. A focus area was delimited where D. virgifera had been found (1100 ha) and a safety area was defined in the surroundings (7-14 km around the focus, 35000 ha in all). In the focus area, a trapping grid (0.5 km ´ 0.5 km) was set up using pheromone traps. It was planned that, in this area, treatments would be applied to all the maize if D. virgifera was found early in the season, and treatments would nevertheless be applied at the beginning of July. Finally, continuous cropping of maize would be prohibited. In the safety area, a second trapping grid (1 km ´ 1 km) was established. It was planned that maize fields would be treated within 1 km of the trap if adults were caught and trapping would be intensified.

In 1999, official checks were made to verify that specific restrictions on maize cropping had been respected. Fenitrothion and chlorpyrifos were used for the above-mentioned treatments. In addition, it was prohibited to move fresh parts of maize and soil in which corn was grown in the previous year outside the focus area. It was also forbidden to thresh corn before the 1st of October to prevent possible spread of adults. These measures were funded through regional funds to cover farmer's costs caused by the prohibition and costs of treatment and monitoring.

In 1999, only 2 adults were caught, in one trap on July 6th and 26th near the airport. This trap was situated at the limit of the focus area and 11 ha of maize in the safety area was also treated. The eradication strategy therefore seems to have been effective. There was no increase in the number of males captured, and no spread outside the focus area. In the rest of the country, 26 traps were set up in the Veneto region, and 26 in Friuli Venezia Giulia, and no D. virgifera was caught. Monitoring in Lombardia, Emilia Romagna and Piemonte also gave negative results.

The first find of D. virgifera was made in 1996 at Nadlac (district of Arad – west of the country near Hungary) on yellow sticky traps. In 1997, D. virgifera was caught mostly in Arad, Timis, Caras-Severin and Mehedinti districts and it was estimated that an area of approximately 10000 km² was potentially infested. In 1998, approximately 12000 km² was potentially infested. Increase in population densities was recorded. In 1999, 241 sites were studied (each site having both pheromone and yellow sticky traps). The spread continued towards the east and the north-east within the districts of Bihor, Arad and Hunedoara. In the south, D. virgifera spread towards the south-east, along the Danube, near the Bulgarian border, and it reached the district of Dolj. The potentially infested area is approximately 14000 km². Although it was noted that in some areas the numbers of adults caught were approaching the economic thresholds, no economic damage has yet been observed in Romania.

In 1998, 37 traps were placed along the border with Hungary and no D. virgifera were caught. In 1999, 39 traps were used along the southern border of Slovakia and near Bratislava and Kosice airports. No Diabrotica virgifera were caught. D. virgifera has not been found in Slovakia.

A monitoring programme has been in place in Slovenia since 1995 in the north-east and south-east of the country, which are two intensive maize-growing areas near Hungary and Croatia. The monitoring programme was intensified in 1999 due to the findings in Italy. Trapping was carried out at 50 locations, mainly near the Hungarian and Croatian borders, but also near the Italian border and Ljubljana international airport. So far, D. virgifera has not been found in Slovenia. The spread in Europe will determine the future monitoring programmes in Slovenia.

It must be recalled that D. virgifera was reported for the first time in Europe in Surčin, near Belgrade airport (Serbia) in 1992-1993. In 1998, 900 pheromone traps were used and it was observed that D. virgifera continued to spread towards the south. In 1998, damage was only reported near Belgrade, Pozarevac, Novi Sad, and Vršac, this area extending towards the borders with Croatia (on the west) and Romania (on the east). In 1998, the area where damage was observed covered 45525 ha. Monitoring done in southern Backa (region around Novi Sad) in 1998 showed that populations levels were still increasing. High infestations occurred in the eastern part of southern Backa as in 1997, and differences previously observed between the east and west parts of this region tended to disappear. Symptoms in maize fields were visible ("gooseneck" symptoms). In 1998, D. virgifera was also found for the first time in Montenegro. A few adults have been trapped at three localities (near Bijelo Polje in the north of Montenegro) along a railway track. In 1999, trapping was done at 282 sites. Populations were denser in the north-east than in the hilly areas of the centre. D. virgifera continued to spread southwards along the rivers Ibar (approximately 60 km) and Morava (approximately 20-30 km, to Leskovac). Damage occurred in the same counties as in 1998, and also in the neighbouring areas of Middle Banat and Middle Backa. The mean yield reduction was estimated at 30% (from 5 to 80% damage was observed).