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Fungicide & Insecticide - Protecting your fields and your investments

What is a fungicide and why use one?

Fungicides are a pesticide that either kills or prevents the growth of fungi and their spores. Fungicides control fungi that damage plants, including mildews, blights, and rusts. Fungicides work in a variety of ways, but most interfere with energy production inside fungal cells or damage fungal cell membranes.

Fungi damage plants by killing cells and/or causing plant stress. By doing so fungi can greatly reduce yield and quality of harvest. Applying a fungicide before symptoms occur is usually best as it gives the desired plant the help it needs to fight off the fungi and has been shown to help increase yield and drought tolerance in some studies.

What is an insecticide and why use one?

Insecticides are pesticides used to kill, harm, repel, or mitigate one or more species of insect. Insecticides work in many ways. Some disrupt the nervous system, while other may damage the insect’s exoskeletons, repel them, or control them by some other means. 

Insects damage plants in different ways. For example, insects with chewing mouthparts, such as grasshoppers and beetles, cause feeding damage such as holes or notches
in plant parts, leaf defoliation, and cutting plants off at the soil. Insects with sucking mouthparts like aphids feed by sucking sap from plant tissues.

Some insect damage can be minimal but if the infestation is above the economic threshold, they can cause significant yield loss.

Use of an insecticide

Unlike herbicides and fungicides, use of most insecticides needs to be taken with precaution as there are several beneficial insects such as bees and ladybugs that don’t need to be harmed if the infestation of the problem insect or insects isn’t above the economic threshold. The economic threshold is the insect’s population level or extent of crop damage at which the value of the crop destroyed exceeds the cost of controlling the pest.


Questions about applying fungicide or insecticide in Bozeman, Belgrade, Dillon, Townsend, or other parts of Southwest Montana? Call Rocky Mountain Supply’s agronomy division at a convenient location near you!

Belgrade Agronomy
406-388-6242

Dillon Agronomy
406-660-3124

Townsend Agronomy
406-266-3422