Kochia (Kochia scoparia), also called Mexican fireweed, burning bush, and summer cypress, is an annual plant in the goosefoot family (Chenopodiaceae). Kochia has recently been reclassified into the genus Bassia. Kochia stems are erect, highly branched, and can grow up to 7 feet tall. Plants growing on dry or infertile sites average 2 feet tall. Leaves are simple, alternate, and linear to lanceolate in shape. Leaves are 1 to 2 inches long with hairs on the bottom, but smooth on top. Leaves are green, but turn yellowish, red, or brown as plants senesce. Flowers are small and green and without petals. They develop in clusters in the axils of upper leaves and in terminal spikes. Seeds are 1/16 inch long, brown and flattened, and develop in star shaped fruit. Kochia has a main taproot and a network of finer roots.

Habitats

Kochia is highly adaptable and efficient at using water. Kochia thrives in low rainfall regions. Plants can tolerate a wide variety of soil types, and is found in grasslands, pastures, prairies, roadsides, wastelands, floodplains, riparian habitats, and cultivated fields.

Impacts

Kochia can spread long distances and competes for light, nutrients, and soil moisture. Kochia reduces crop yields, contaminates crops, and can reduce growth of nearby plants by releasing chemicals into the soil. Kochia contains oxalates, alkaloids, and nitrates that can be toxic to some grazing animals if large quantities are consumed.

Biology and Ecology

Kochia reproduces from seeds. Under ideal growing conditions, a single plant can produce over 50,000 seeds. Dead plants break off at the base and are blown by the wind as tumble weeds to spread seed.

Management Approaches

Biological Control

There are no biological controls available for kochia.

Mechanical and Cultural Control

Seedlings can be controlled by tilling in early spring. Repeated mowing prior to flowering can reduce seed set.

Chemical Control

Kochia has developed resistance to a number of herbicides including photosystem II inhibitors, ALS inhibitors, and synthetic auxins. For a complete list of reports of kochia resistance to herbicides, please see http://www.weedscience.org/Summary/USpeciesCountry.asp?lstWeedID=101&FmCommonName=Go Rotating herbicides with different modes of action can help slow development of resistance.

For herbicide recommendations for specific grain rotations and weeds in Montana, please see the MSU Herbicide Chooser Tool.

Examples of herbicides that can be used to manage kochia

Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.

Herbicide Active Ingredient trade name	Mode of Action	Product per Acre	Application Time or Growth Stage
Rangeland and Pasture
2,4-D	Action like indole acetic acid (synthetic auxins)
*Weedmaster		1 - 2 pints	Use lower rates for kochia plants 1-6 inches tall, and higher rates for plants between 10 and 20 inches tall.
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		8 - 24 ounces	Apply 8-16 ounces to small actively growing weeds and 16-24 ounces for established weeds.
Alfalfa
Imazethapyr	Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS)
*Pursuit		4 - 6 ounces	Apply to non-ALS resistant kochia when less than 3 inches tall. For stand establishment, apply when alfalfa has 2 fully expanded trifoliate leaves.
Peas and Lentils
Imazamox	Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS)
*Raptor		4 ounces	Apply post-emergence when weeds are actively growing and before they exceed the maximum recommended size stated on label. Delay application until the majority of the weeds are at the recommended growth stage. Apply when peas have at least 3 pairs of leaves, but before the bloom stage.
Grass Grown for Seed
2,4-D; clopyralid	Action like indole acetic acid (synthetic auxins)
*Curtail		2 - 4 pints	Apply to well established grass prior to the boot stage. Weeds should be actively growing and in the 2-4 leaf stage.
Small Grains
Carfentrazone	Inhibition of protoporphyrinogen oxidase (PPO)
*Aim EW		1 ounce	Apply to actively growing kochia less than 4 inches in height.
Clearfield® Wheat
Imazamox	Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS)
*Beyond + 2,4-D		4 ounces	In Clearfield crops, only controls ALS susceptible types.

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

References

For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=kochia&Start=1&results=48

HPIPM:Kochia

Taxonomy

Scientific Name

Scientific Name Synonyms

Common Name

Contents

Kochia (Kochia scoparia)

Identification and Life Cycle