Winter breaks the cycle of pests, or at least some of them. Flies, mosquitos and ticks that carry diseases all go dormant during freezing temperatures. Their life cycles are short and while eggs do over-winter, they must start from zero every spring versus building up continually over time.
Farther south, where temperatures never reach freezing , more pest management is needed. Intestinal and lung worms need an intermediate host,or are picked up from the manure which is frozen in our winters, thus making a fall deworming program a very effective management technique. it usually takes until later the next spring until the eggs are able to re-infest the stock. Some regions must deworm their livestock more frequently than in Canada and must rotate the products used for internal worms to avoid or at least delay resisance to the dewormers that are used.
Livestock and pest management are not the only reason winter is a Canadian advantage. There are some plant bugs that thrive in warm climates but can’t survive in our winters. These can be airborne and only come to Canada on storms that bring them up from warmer climates to the south. But this means they only come with storms and do not pose a risk to crops every year.
But not every pest goes dormant or dies in winter. Some actually like cooler weather. Lice for example, tend to spread during winter months. Populations begin to increase with cooler temperatures, reaching maximum levels in late winter. Treatments should be timed to coincide with the beginning of population growth (i.e. autumn or early winter). We usually take advantage of anytime we are handling cows in the fall to do this, like preg-checking heifers or when we are sorting for Body Condition Score as cows are being moved from fall grazing on pasture to winter feeding grounds.
While we gripe about the weather; there are benefits that come with it.