Even potatoes, if grown for two consecutive years on the same plot, are surely affected by colorado potato beetle, as the colorado potato beetle is an insect that winters underground. Once the potatoes are put in the ground in the second year the colorado potato beetle awakens and attacks. There are three steps to avoid this:
1) open the furrows in the soil at least 15 days before the sowing of potatoes and sprinkle with a juice, diluted in water, obtained from shoots of potatoes. This reawakens the insects which emerge from the "lethargy" and, not finding the potatoes in the ground, will die of hunger. It is important that the spraying is carried out at least 15 days before sowing, since the colorado potato beetle can withstand even 7-10 days without food.
2) spread some lithotamnium algae powder in the sowing furrow , and then sow. This powder, in addition to being a fertilizer, will damage the jaw of the insects
3) collect and mix colorado potato beetle larvae in jars of water exposed to the sun for about 10 - 15 days until the larvae lose their form. Sprinkling this liquid (diluted) takes away the colorado potato beetle for a fortnight.
There is also an inhibitory action brought by growing some marigolds in the row of potatoes.