At this time of year my house is always packed to overflowing with delightful and exotic winter immigrants from the great outdoors: herbs from the Mediterranean, succulents from Central America, ferns from Brazil, and tropicals from Asia and Africa. In they come ---arriving on hand trucks, garden carts and wheelbarrows--- ready to settle into their seasonal, winter homes. Right now, my "port-of-entryway" is so full of migrating plants, that it's become something of a horticultural Ellis Island. And while I joyfully welcome plant species from all zones and nations, like any busy border crossing agent, I do have to be cautious; keeping my eyes open for those troublesome stowaways trying to sneak through customs.
Many gardeners bring plants indoors over winter, and during the autumn rush, they end up transporting insects into their homes as well. While it's true that some stowaways ---particularly the ladybugs--- may be beneficial insects, most are quite bad. And when those 'bad bugs' sneak indoors undetected ---beneath pots, in soil or on the plants themselves--- they can quickly grow out of control, damaging and eventually destroying plants altogether. So how does a gardener protect plants during seasonal migration? I recommend a two step approach. Keep new arrivals in a quarantine area for a period of adjustment, and thoroughly inspect all containers for known 'bad guys' and unwelcome guests.
The vast majority of my large tropical plants over-winter in a special room I've set up in my walk-in cellar. When I pull these plants indoors each year, I carefully monitor them for pests and if I find insect eggs or larvae, I eliminate them with organic pesticides like neem, horticultural oil or insecticidal soap. But unless you are familiar with the life cycle of problem insects, it can be difficult to spot pests and differentiate between the 'good bugs' and the 'bad'. Ladybug larvae can look a bit intimidating, and if a gardener is unfamiliar with its ugly duckling stage, it may be inadvertently killed. The ultimate guide to backyard bugs, Garden Insects of North America by Whitney Cranshaw is a great book to have on hand. Studying up on a bit of entomology over winter will also help you defend your outdoor garden in spring. The close-up photos of larvae and eggs are definitely not glamorous, but if you want to keep your plants healthy and beautiful, you really need to become familiar with the sometimes ugly side of nature in order to keep your plants pest-free.
Do you move outdoor plants inside for winter?