Glossary of Words used by Tree Services

Absorption. Penetration from the surface to below the surface.

Alternate host. One of the two types of horticulture plants on which fungus must develop to complete its life cycle.

Antibiotic. A chemical compound made by microorganisms that are harmful to other microorganisms.

Arborist. A professional in the management of trees and shrubs.

Attractant. A substance that lures insects to traps or bait stations.

Bacteria. Microscopic, single-celled organisms that can cause disease in plants, and counteract disease.

Bark. The corky substance covering the outer layer of the tree or shrub.

Beneficial insects. Predators, parasites, parasitoids that feed on or destroy pest insects.

Biological control. Control of pests by predators, parasites, or disease.

Blight. Disease with rapid killing of leaves, flowers, or stems.

Botanical pesticide. A pesticide extracted directly from plants.

Branch. A secondary shoot or stem coming from one of the main trunk or leader.

Broad spectrum pesticide. A pesticide used for a wide range of pests.

Canker. A sunken or abnormal part of a woody plant.

Canopy. The entire part of the tree under the crown.

Chlorophyll. Pigment in plants used to make sugar.

Chlorosis. Yellowing of plant tissue that should be green.

Cone. A fruit carrying seeds, with overlapping scales.

Conifer. A cone-bearing tree of the pine family. Usually an evergreen.

Crown. The branches, twigs, and leaves at the top of the tree.

Deciduous. A tree or shrub that sheds leaves seasonally.

Diagnosis. The nature or cause of damage to plant species by identifying the pest.

Dormant. The stage of no active growth in horticulture plants.

Drench. Soil saturating.

Entomology. The science of insects and organisms related to insects.

Epidemic. Widespread disease or insect problem.

Eradicate. To completely remove a pest from the host and area.

Flower. The reproductive part of the tree or shrub. Includes petals and sepals.

Fruit. A mature ovary of a flower containing one or more seed.

Fungicide. A pesticide made organically or traditionally to control diseases.

Fungus. A microscopic organism that lacks chlorophyll and lives as a parasite on a plant. Reproduces by spores.

Gall. An outgrowth or swelling on a horticulture plant.

Host. A plant that houses a parasite and provides food for it.

Inoculum. A pathogen capable of starting disease in horticulture plants.

Inorganic pesticide. A mineral pesticide that does not contain carbon.

Insect. An invertebrate animal usually with 6 legs and antennae.

Insect growth regulators. Natural insect hormones or chemicals that confuse an insect.

Insecticide. An organic or traditional pesticide used to control insects.

Integrated pest management. Using all necessary and available approaches to the plant management. A management program of the pests to avoid economic damage, not to eradicate the pests. Minimal environmental side effects are attempted.

Larva. The immature stage of an insect before it goes through metamorphosis.

Leader. The highest main shoot of a plant.

Life cycle. The different stages that an organism lives through.

Limb. A big branch. 15 inches or bigger coming off the main trunk or leader.

Metamorphosis. The change of shape, size, or form of an insect.

Microbial pesticide. Fungi, bacteria, or virus that create adverse conditions for pests to live.

Mildew. Fungal disease where spores are visible on the plant surface.

Miticide. Pesticide for mites.

Mold. Woolly fungal growth or decaying organic matter developing on the plant.

Molting. The changing of external shells, so insects can grow bigger.

Narrow-spectrum pesticide. Pesticide that is targeted only to a few pests.

Natural enemies. Predators and parasites that are not friendly towards horticulture pests.

Necrosis. Death of entire portions of plants.

Needle. The pine family leaves.

Nematode. Small worms that survive in soil, water, or plants.

Nymph. A young insect that does not go through extensive metamorphosis.

Organic pesticide. Pesticide created from plants.

Parasite. A living organism that lives off other living organisms.

Parasitoid. An insect the feeds off bigger or same sized insects. Usually only eats one type of insect.

Pathogen. A living organism that can cause disease in other hosts.

Pest. Any unwanted organism (insect, disease, or even an animal) that competes for food.

Pesticide. A chemical made to control, prevent, or reduce unwanted pests.

Pheromone. A substance produced to communicate with other members of a species.

Plant disease. A harmful condition to the physiology or morphology or a plant. Host, pathogen, and environment must come together to develop disease.

Predator. An animal that feeds on other animals.

Protectant. Pesticide used to prevent a pest problem.

Resistance. The ability of an organism to tolerate a pesticide.

Rust. Disease by fungi creating red, brown, or orange spores.

Scab. Rough diseased area of a horticulture plant.

Shrub. A tree of multiple, smaller, lower branches.

Species. A taxonomic classification of a group.

Spore. A reproductive part of a fungus.

Systemic pesticide. Pesticide absorbed and translocated throughout the plant.

Target pest. An organism a particular program is trying to control.

Translocation. The internal plant movement of water, food, nutrients, and minerals throughout the plant.

Vector. A living organism capable of transmitting a pathogen or organism.

Wilt. Drooping of plant parts.