Pesticides work in two ways to reduce bee populations. First, many pesticides necessary in crop production are highly toxic to honey bees. Second, the use of herbicides reduces the acreages of attractive plants for the bees to forage on. Pesticide damage to colonies takes many forms. Bees may be poisoned when they feed on nectar or pollen contaminated with certain pesticides. Bees may also be poisoned when they fly through a cloud of pesticide dust or spray or walk on treated parts of a plant. Bees may be overcome by the fuming action of certain pesticides, either in the field or in the hive if the material has drifted there. Colonies may be completely destroyed, but most commonly only field bees are killed. Loss of field bees can be serious because the ability to build up strongly populated colonies is the beekeeper's most vital key to successful honey production or pollination. If the field force is destroyed by pesticides, the whole colony will be weakened and may remain weak for some time; the queen may reduce egg laying or be killed by the workers; and the colony may fail to survive the winter, produce a crop of honey, or be useful for crop pollination.