Introduction to Plant Pests Original Created By Margaret Chapman For AgEd 410 Spring 1999 Cal Poly, San Luis Obispo Copied from Cal Poly Modified by Georgia Agriculture Education Curriculum Office June 2002

Four main groups of plant pests: 1. Weeds 2. Invertebrates 3. Vertebrates 4. Disease Agents

Plant Pests * Organisms that compete with people for food or fiber, interfere with raising our crops and livestock. * Proper identification is important in controlling pests.

Weeds * Undesirable plants, sometimes defined as “any plant growing out of place.” * Adapt well to local climates and soils and can compete successfully with cultivated plants.

* Most weeds produce a large number of seeds. * Some weed seeds can remain dormant for 20 years before germinating.

* Weeds compete with agricultural crops for water, nutrients, light and space. * Weeds can be persistent and difficult to eradicate, because some have vegetative means of reproduction in addition to seeds.

* Weeds can interfere with farming operations, and can harbor insects and plant diseases. * Some weeds are toxic to livestock.

* A simple way to identify weeds is to compare them to colored photographs and drawings. * Become familiar with plant classification system and the weeds physical features, developmental stages,and life cycles.

* We will discuss weed and other pest control measures in upcoming lessons.

Invertebrate Pests * Includes insects and their relatives, nematodes, snails and slugs. * “Invertebrate” signifies animals without backbones (no vertebrate).

* Insects have three body parts: head, thorax and abdomen and six legs.

* Ticks, mites and spiders have only two body parts and eight legs. Mite Spider Tick

* Nematodes are a large group of unsegmented worms that can be plant parasites.

* Snails and slugs are mollusks that prefer cool, moist surroundings.

Vertebrates * Animals with backbones * Includes fish,amphibians, reptiles, birds and mammals. * Most of our concern is with birds and mammals.

* Harbor pathogens, disease causing organisms * Eat or damage crops Pest birds * Cause damage to buildings * Make too much noise

* Rodents are mammals that interfere with people, or cause harm to crops and livestock. * Animal pests are similar to weeds, those that are out of place are considered pests.

* Rats * Mice * Squirrels Most of our vertebrate problems are caused from:

Disease Agents * Cause disease in plants and animals. * Many are submicroscopic, making identification difficult. * If you can’t see the pest, then it may be identified by the type of symptoms caused or damage done.

* Included in this group of pests are: 1. Bacteria Bacterial citrus canker symptoms on citrus leaves

2. Fungi * Scab symptoms on orange fruit caused by the fungus Elsinoe fawcetti

3. Viruses * Potato Virus on veins and shoots * Citrus tristeza Virus on grapefruit

Problems growers face * Energy, time and expense to combat problems. * Losses of food to our world food supply can become disastrous. * Farmers are focusing on controlling pests while dealing with environmental pollution problems.

* New methods and concepts continue to evolve each day to keep our crops healthy and abundant.