The influence of different weather front types for light trapping of European Corn Borer (Ostrinia Nubilalis Hbn)

The influence of different weather front types were analysed for light-trap catch of the European Corn Borer (Ostrinia nubilalis Hbn.) getting from the data of national light-trap network in Hungary. This data originated from 114 ob-serving stations operated between 1st April and 31st October from 1962 to 1998. There were 61906 observing data of 205536 samples during 5030 nights exam-ined in our work. Daily catches mean the collecting result at one station at one night independently of the catch size.

The location of warm-, cold- and occluded front types were determined for each days from Daily Weather Report published by the Hungarian National Meteorological Service. We classified the fronts on basis of their quality and location compared to the territory of Hungary. These nine front groups were used in the examination:

1. on-coming cold front (OCF),
2. cold front (CF),
3. on-coming warm front (OWF),
4. warm front (WF),
5. on-coming occluded front (OOF),
6. occluded front (OF),
7. on-coming cold- and warm fronts (OCWF),
8. cold- and warm fronts (CWF),
9. simultaneous cold, warm- and occluded fronts (CWOF).

Every types of weather fronts were separated according to which kind of weather fronts were observable on the previous day.

We calculated relative catch (RC) values from daily light-trap results for all observing stations so we could process the values of different light-trap stations and different dates contractedly. Relative catch is the quotient of the number of individuals caught during the sampling interval (1 night) and the mean values of the number of individuals of one generation counted for the sample in-terval. In this way in the case of expected mean number of individuals, the value of relative catch is 1.

Then we summarised the values of relative catches coming from different observing stations for each night. We made an average from these values for all the types of fronts. There was made comparison between the values of relative catch belonging to the different front types and the average values of catch of all the other days.

It is concluded, the different weather fronts modify the catch of light traps according to their specific characters (main types) and according to their successions. It was established the weather fronts do not always modify the success of light trapping in the same way according to their types, the modifications are caused by the different types coming after one another.