Géza RIPKA¹ and Gábor PRINCZINGER^2
1 Plant Health and Soil Conservation Station of Budapest, Hungary
² Ministry of Agriculture and Regional Development, Budapest, Hungary

The Hungarian Plant Protection Organisation has carried out a nation-wide survey of Western corn rootworm (WCR) (Diabroticavirgiferavirgifera LeConte) in Hungary since 1996. The Plant Health and Soil Conservation Stations in all counties have participated in the study. As in the previous year in 2000 the WCR monitoring system was based on two basic examinations:

1. Scout trapping
On 71 locations where the WCR was absent in 1999, Hungarian sex-pheromone traps (Csalomon®) were placed out in maize fields. In the non-infested areas of 14 counties, the traps were monitored from 20 June till the end of September at 10-day intervals. Within 30 days the traps were replaced by new ones.

2. Permanent Monitoring Network
To determine WCR population build-up Hungarian pheromone traps and Multigard® yellow sticky traps placed out in pairs on 27 sites of 12 WCR-infested counties. The distance between pheromone and Multigard® traps was 50 m. In maize fields the traps were monitored from 20 June to early October. From 22-26 June Pherocon® AM yellow sticky traps were also placed in each monitoring field and checked as the two other trap types. All traps were changed at intervals of 30 days. Catches were recorded decadely.

WCR was trapped in 16 out of 19 Hungarian counties till late August. Out of 71 scout traps, 25 ones had catches over WCR-infested area. These traps caught a total of 671 beetles. The average number of catches was 26,8 adults/trap.

Out of 27 permanent monitoring pheromone traps, 25 ones had catches. A total of 9612 beetles were caught. The average catch was 384,5 beetles/trap. Out of 27 Multigard® traps catches were observed on 20 traps. 4577 WCR adults were trapped. The average catch was 228,8 beetle/trap. 17 traps had catches out of 27 Pherocon® AM traps. Total catch was 923 imagoes, and the average value was 54,3 beetles/trap. The two trapping systems caught a total of 15 783 WCR adults, much more than in 1999 (9 304 beetles). The highest population density was at Szeged (Csongrád county). WCR population considerable increased in counties Csongrád, Baranya and Békés. At county level most beetles were caught in July, viz. 9 082 adults (60 %), but the catch in June was remarkably high, with 1 945 beetles (12,9 %). In August 4 085 (27 %) imagoes were trapped only. Due to warm and dry weather, the life-cycle was WCR was rapid.

In Transdanubia, in county Veszprém and Zala, this year WCR reached the northern shore of lake Balaton. The invasive species was found in counties Heves and Borsod-Abaúj-Zemplén. In county Nógrád of norther Hungary WCR was trapped close to the river Ipoly, near the Slovakian border, too. The pest is spreading northward along the river Tisza.

In 10WCR-infested counties WCR larval damages were surveyed in 969 maize fields on 41 357 ha. It is approximately 10 % of total maize fields of these counties. Majority of the inspected fields was continuous corn. The Iowa scale was used for the evaluation. In counties Békés, Baranya, Bács-Kiskun and Csongrád larval damages were observed on 3 103 ha. In counties Bács-Kiskun and Csongrád root damages reached the economic level.