Weeds, Bugs and other Pest. Weeds. Weed-plants that are considered to be growing out of place. What is a weed to some is not a weed to others The key is where it is growing Undesirable plants They compete with desired plants for water, nutrients, light and space. They decrease crop quality
Perennial Weeds-can live for more then two years and may reproduce by seed and/or vegetative growth.
Rhizomes-a stem that runs underground and gives rise to new plants at each joint (node).
Stolen-a stem that runs on the surface of the ground and gives rise to new plants at each node.
Noxious Weed-a plant that causes great harm to other organisms by weakening those around it.
Most states have a noxious weeds list.
Great effort is made to control or eradicate
Can be very difficult to kill and need several treatments of herbicides
Spread by various methods
Seeds become airborne
Seeds enter flowing waterways
Seeds become attached to humans or animals and travel
Seeds are eaten and distributed by birds
Idaho Department of Agriculture has a list of 64 noxious weeds. The State is divided into 30 Cooperative Weed Management Areas (CWMA).
In each of these areas land owners and government agencies work together to ensure that noxious weeds are controlled and eradicated.
Yellow Devil Hawkweed
Plant disease is ANY abnormal plant growth.
Plant diseases are more the rule then exception
Most plants tolerate the diseases
There are two types of disease causing agents
Combination of water and temp stress
It is important to understand the difference between infectious diseases caused by biotic agents and noninfectious diseases caused by abiotic diseases.
There are various symptoms caused by the pathogens on plants:
Dwarfing of growth Yellowing of foliage
Leaf spotting Blasting of grain heads
Stem cankers Fruit rot
Seed decay Destruction of seedlings
Root rot Galls
Growers need to know what the symptoms are and the causes to be able to effectively treat and eradicate the disease.
The occurrence and severity of the plant disease is based on the following factors:
1. A susceptible plant or host must be present
2. The pathogen organism, or causal agent, must be present. A casual agent is an organism that produces a disease.
3. Environmental conditions conducive to support the causal agent must occur.
The relationship between these factors is known as the disease triangle
*Understanding how the relationship works is how we can effectively treat plant diseases and learn to stop the growth of the new diseases.
Fungi are plants that lack chlorophyll.
Fungi causes diseases by producing spores or mycelium
These spores can be dispersed by wind, water, insects and humans.
Bacteria can enter a plant only through wounds or natural openings.
Bacterial diseases are the causes for things like stem and root rot as well as many blights.
Viruses are composed of nucleic acids surrounded by protein sheaths. They effect the plant’s metabolism by effecting protein synthesis. Plant viruses are transmitted by seeds, insects, nematodes, fungi, grafting and mechanical means, including sap contact. Produces several well-known symptoms- a visible change to the host. Symptoms include ring-spots, stunting, malformations and mosaics-light and dark green leaf patterns.
Nematodes: tiny roundworms that live in the soil or water, within insects, or as parasites of plants or animals. These parasites are very small and produce damage by feeding on the host plant. Main symptom is plant growth issues from feeding on the roots and stems.
Invertebrate pest: organisms that do NOT have a vertebrate.
Insects, nematodes, snails and slugs
Insects have three body parts: head, thorax and abdomen and have 6 legs.
Ticks, mites and spiders have only two body parts and 8 legs.