 Pesticides are chemicals used to control a pest. There are many types of pesticides. Herbicides kill plants, disinfectants remove germs, fungicides kill fungi, insecticides kill insects, and repellents repel pests. Many other pesticides control other arthropods, birds, fish, mammals, bacteria, and viruses. This video will focus on the most commonly used pesticides. Herbicide, insecticides, fungicides, and bactericides, and some of their basic mode of action. Mode of action is the way a pesticide exerts a toxic effect on the target plant, animal, or microorganism. Pesticide mode of action can be divided into two categories, systemic and contact. Systemic involves the pesticide penetrating the plant or animal and translocating within its system with the intent to protect it from bacteria, viruses, or other pests. In plants, it translocates throughout the plant and kills the leaves and also the root system. Contact pesticides do not penetrate the host while controlling the pests. It acts as a barrier or repellent in a plant. Or by killing any green tissue present. Broad spectrum pesticides can kill or harm a wide variety of organisms, both beneficial and harmful pests, and then there are those that target a specific trait in a pest. Herbicides are pesticides used to control or kill unwanted plants. There are close to 5,000 herbicides registered for use in the United States, all with various mode of actions and formulations. In this video, we will cover five groups of herbicides. Those are oxins, enzyme blockers, photosynthetic inhibitors, amino acids, and cell growth inhibitors. Growth regulators are commonly referred to as synthetic oxins. These chemicals mimic natural plant hormones and interrupt plant cell growth in newly forming stems and leaves. They affect protein production and normal cell division, leading to malformed growth. Synthetic oxins also kill plants by causing the cells in the tissue that carry water and nutrients to divide and grow without stopping. This is often called growing itself to death, which is seen by one side of the stem being longer than the other. Sulfonylurea, phenylpyralazine, and imidazolanone are examples of ALS inhibitors or enzyme blockers. They are chemicals that block the normal function of an enzyme called acetylactate synthase, or ALS. This enzyme is essential in amino acid or protein synthesis. Without proteins, plants starve to death. Enzyme blockers kill a wide range of plants, including broadleaf weeds, nut sedges, and grasses. ACCase inhibitors mainly kill grasses. This enzyme helps the formation of lipids or fats in the roots of grass plants. Without lipids, susceptible weeds die. Photosynthetic inhibitors, such as bipyridinium and traizines are chemicals that interfere with photosynthesis, a plant's natural ability to make food, and disrupt plant growth, ultimately leading to death. There are also amino acid synthesis inhibitors, shoot-and-root growth inhibitors, and PPO inhibitors. Several herbicides fall into these groups, including glyphosate, acetylchlor, and trifluorilin. These herbicides stop or interrupt cell growth and a vision. Pigment inhibitors or bleachers are herbicides that cause the tissue of a plant to turn white after treatment. Examples include oxazolidinone, isoxazole, and trichotone. They interrupt the chlorophyll production in the plant, turning the plant tissue white and interrupting photosynthesis. The photosynthesis system can easily be damaged by sunlight without carotenoids. Insecticides control insects and other arthropods. Nerve and muscle poisons and insecticides disrupt, inhibit, block, terminate, or activate various channels, enzymes, and receptors within pests. Examples include carbamates, organophosphates, pyrethroids, pyrethrins, fibronil, chloridane, DDT, and neonicotinoids. This results in a range of symptoms such as paralysis, hyper-acceptation, system shutdowns, and overly-stimulated muscle contraction. Mid-gut poisons are poisons that attack the guts of insects via protein toxins leading to unbalanced ions, or salts in other minerals, and septicemia, or blood poisoning. Examples include BT toxins such as bacillus thuringiensis and bacillus ferricus. Insect growth regulators inhibit the normal life cycle of insects by copying one of these hormones, directly interrupting cuticle development, or loss in fat building. These would make insects die from staying in the immature life stage indefinitely. Respirators can be inhibitors of mitochondrial ATP synthase, uncouplers of oxidative phosphorylation via disruption of the proton gradient, or mitochondrial complex electron transport inhibitors. These insecticides stop the insect from functioning by reducing the energy output that controls the cellular processes. Examples of this are muscle weakness, breathing issues, visual issues, and loss of muscle coordination. Other unknown or non-specific target insecticides are known to affect less well-described target sites or functions, or to act non-specifically on multiple targets.