Final answer:
The forestry department is employing a chemical control method, specifically a foliar application, to manage pests by spraying pesticide on tree leaves.
Step-by-step explanation:
The forestry department is using a chemical control method. This involves using a foliar application method, in which department personnel will spray pesticide directly on the trees’ leaves.
Chemical control is a method employed to manage weed and pest populations with the use of pesticides, including herbicides, insecticides, and fungicides. While biological control uses other organisms, such as herbivores or pathogens, to control invasive species, and mechanical control involves physical removal or destruction of the pest, chemical control relies on chemical substances to reduce pest populations.
Pesticides can have both target and non-target effects, meaning they can affect other species in addition to the intended pests. Furthermore, long-term reliance on chemical control may lead to issues like resistance, increased costs, and environmental disruption. Therefore, it is often recommended to use chemical control methods wisely and as a last resort when other ecologically based controls are inadequate.