Original Down East

In some cases you should consider replacing your stock with new plants after a few years. Strawberries, for example, will lose their vigor after a while. This is often a sign that they have become infected with virus diseases and anything you propagate from them will also be infected. Potatoes too can become infected with virus diseases spread by aphids. The seed potatoes you buy are generally grown in areas where aphid attack is rare, so they are likely to be free from virus. So, unless you can be quite sure that your crop has not been attacked by aphids, it is worthwhile buying in new potato tubers every year.

Different varieties of the same plants may have varying degrees of resistance to pests and disease. Some varieties of potato, for example, are less susceptible to slug damage, while others show resistance to potato eelworm. There is quite a distinct variation in resistance to fungus diseases.

Plant breeders are constantly trying to breed pest- and disease-resistant plants, so it is worthwhile checking the current position on new varieties before buying anything that is notoriously disease-prone. There are, for example, several varieties of snapdragon that have been bred specifically to resist rust