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Preventing plant diseases on farms

Preventative practices can reduce disease pressure on farms

Illustration of a vegetable farm with workers performing farm tasks. The title text on the image says “Preventing plant disease problems on farms”. There is another text box on the right side of the image that says "Plant pathogens move through farm landscapes in many ways. Can you spot practices that help reduce disease pressure?"


Water management

Illustration of pumpkins (both green and orange) growing on straw mulch.
Mulch (either straw or plastic) prevents pathogens from splashing up from the soil when it rains.
Illustration of black drip irrigation lines running through a field of various vegetables, connected to a larger PVC irrigation line.
Use drip irrigation when possible to add water near the roots of plants without splashing water onto the leaves.
Illustration of beans supported by a trellis.
Proper spacing and the use of trellises for to support vertical growth provide better airflow through the canopy.
Illustration of green shrubs on a grassy slope between two fields.
Grassy walkways between plots can prevent water movement across fields. In areas with slopes, use deep-rooted perennials to absorb water.
Illustration of a stream running through a field, surrounded by flowers, shrubs, and grassy vegetation.
Maintain natural bodies of water, and surround them with deep-rooted perennial plants. Avoid surface water for irrigation when possible.


Illustration of healthy broccoli plants growing in dark brown dirt.
Use clean seed to prevent new pathogens from entering the farm. If using saved seed, treat it with hot water.
Illustration of a worker hoeing in small Brassica plants, with rows of larger, more mature plants in the foreground.
Start your days in the youngest, healthiest plants. After working in a field with disease pressure, wash your boots, tools and clothing.
Illustration of a person washing their hands near a portable restroom.
Wash your hands, clothes and shoes. Clean your shoes with high pressure water as you move between fields, and especially after visiting other farms.
Illustration of a high tunnel with tomatoes growing inside, and a nearby toolshed with boots and tools.
High tunnels are high value environments: keep separate tools and boots to use only in tunnels.
Illustration of a man washing the wheels on a red tractor. The tractor is on a concrete pad in the middle of the farm.
Wash your tools and equipment often, especially after working in diseased plots. Make a central washing station that is conveniently located so you remember to use it

Residue management

Illustration of distinct groups of crops in different beds.
Rotate the plots where crop families are planted. For example, after planting beans, wait 3 years until you plant beans again in the same spot.
Illustration of a close-up image of lettuce plants with spots on the leaves.
Look for diseased plants at least weekly, and identify all diseases. Once you have a diagnosis, seek resistant varieties the following year.
Illustration of a 3-bin compost system set away from the rest of the farm.
Keep compost away from fields and make sure it is fully composted before applying back to production fields.
Illustration of weeds growing near the edge of a broccoli field.
Manage weeds in and around fields; they can serve as hosts for various diseases.
Illustration of two workers. One is bending down and removing a plant from the soil.
Remove infected plants and their neighbors to prevent the spread of pathogens to healthy plants. Only remove diseased leaves when plants are dry, and no rain is forecasted.

Author: Natalie Hoidal, Extension educator, local foods and vegetable crops

Illustration: Urban Ecosystems & Stardust Interactive

Reviewed in 2021

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