Did Colorado beetle stay over for the winter in Finland?

6.10.2011

<p>Commercial and subsistence potato farmers reported sightings of Colorado beetles commendably in the summer. A clear picture of the areas of occurrence could be formed on the basis of the sightings, although reports came from an exceptionally wide area. It is probable, however, that not all infestations were detected, so eradication measures will be necessary also next summer.</p>

All in all, 38 infestations were found in potato crops during the summer. Twelve of the sightings were made in commercial farms, and most of the occurrences detected in subsistence crops were also in agricultural farms. The sightings were reported within a period of two months, the latest in connection with potato harvesting in mid-September.

Eradication measures were carried out on all infestation sites, using methods best suited to each particular case. The reproduction biology of the beetle creates a challenge to eradication. Also this summer, all the development phases of the beetle could be found during a two-month period on a single infestation site: eggs, larvae, pupae and new adult beetles. The exceptionally warm and long summer promoted the efficient reproduction of the beetle.

The sightings made early on in the summer represented the larvae stage, when eradication is relatively easy. The occurrences found in August-September were mainly new-generation beetles and it is possible that part of the new adults had already burrowed underground to winter. There are therefore grounds to suspect that the Colorado beetle stayed over for the winter in Finland. It is also probable that not all infestations were detected this summer. This means that next year reporting of sightings will be of even greater importance in the eradication of the beetle.

This is Evira's last Colorado beetle news release this summer. Evira wishes to thank all the parties for the work carried out to prevent the spreading of the pest. The active participation of the media, farmers and citizens has been extremely important for the eradication efforts.

Should any beetles still be found during harvesting of potato, this should be immediately reported to Evira. Contact information as well as more information about the incidence of the beetle this summer can be found on Evira's web site at http://www.evira.fi/portal/en/plants/cultivation_and_production/plant_pests_and_diseases/quarantine_pests_and_diseases/potatoes/colorado_beetle/

For more information, please contact:
Atro Virtanen, Senior Officer, Evira, tel. +358 20 77 25047
Raija Valtonen, Section Head, Evira, tel. +358 20 77 25040

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