More Colorado beetles found in two domestic plots
The summer’s findings are in Taipalsaari, Savitaipale and Hirvensalmi. One of the new occurrences is a colony that has wintered on the same site and was not spotted in last year’s potato crop. The other is a colony consisting of a single adult beetle and its offspring in the larval stage.
The findings give rise to a suspicion that further new overwintered colonies may be found in the 2011 and 2012 distribution areas. On the other hand, it is quite possible that new adult beetles have already been carried to Finland with the warm south-eastern currents of early June.
Report findings immediately to hotline number
Independent checking of potato crops by professional and amateur growers in the whole of southern Finland is now particularly important, especially in the distribution areas of 2011 and 2012. The Finnish Food Safety Authority Evira requests that all suspected Colorado beetle findings are reported immediately by phone to the hotline number.
The reporting hotline number is 040 801 4407 (safest 9-20, including weekends).
Inspections and control are the responsibility of inspectors from Evira and the Centres for Economic Development, Transport and the Environment. You should not take independent action to eradicate the pest, as it may compromise the control measures taken by the authorities.
Recognise the adult beetle and larva
At this time of the year, you may find adult Colorado beetles, egg clusters and larvae in potato haulms. The adult beetle is about a centimetre long with 10 black stripes lengthwise along its yellow back. An adult female lays eggs all summer. The beetle’s yellowish-orange eggs are the size of semolina grains in dense clusters on the underside of leaves. The eggs quickly develop into darkish larvae, 1-2 millimetres long at first, that grow in a few days to a little over a centimetre and turn reddish-orange. There are two rows of black spots along each side of the central larval body.
For control measures to be effective, it is important that any occurrence is detected as early as possible, before the larvae have eaten their fill and burrowed in the soil to pupate.
At first, adult beetles and larvae eat holes into the potato leaves. The real destruction is wrought by the larvae, which consume the leaves almost completely, if they occur in masses. The stripped haulms indicate more easily identifiable colonies in the foliage.
More on the subject:
Incidence map 2011-2013, photos of the Colorado beetle, and instructions for monitoring and action on the Evira website: www.evira.fi/koloradonkuoriainen (in Finnish)
Senior Inspector Arto Virtanen, t. 040 704 9607