Pest & Disease Control for Rhubarb Plants

Every plant has the future potential for disease and insect damage. Factors such as location and weather will play a part in which issues your plants encounters. If available, disease-resistant varieties are the best option for easy care; and for all types of plants, proper maintenance (such as watering, pruning, spraying, weeding, and cleanup) can help keep most insects and diseases at bay.

NOTE: This is part 7 in a series of 11 articles. For a complete background on how to grow rhubarb plants, we recommend starting from the beginning.

Leaf Spot

These fungi cause circular, or angular spots, variable in size having beige centers surrounded by a red zone. When affected tissue dies, it may drop out, leaving large ragged holes in the foliage. Fungi overwinter in infected plant debris and in infected propagation stock.

Natural Control

  • Remove and destroy leaves following the first heavy frost.
  • During harvest, remove stems with spotted leaves first.

Other Control Options

  • Consult County Extension Agent

Botrytis Rot

May cause a leaf, stem and crown rot of forced rhubarb. Disease intensifies where there is poor air circulation and high humidity.

Natural Control

  • Practice strict sanitation.

Other Control Options

  • Consult County Extension Agent

Root and Crown Rot

Plants become unthrifty. Leaves may turn yellow to red and collapse. The crowns, when sectioned, exhibit a brown-black decay. Large roots lack small feeder roots. Larger roots may have large brown-black lesions present.

Natural Control

  • Purchase healthy propagation stock.
  • Select well-drained fields.
  • Remove and destroy diseased plants.

Other Control Options

  • Consult County Extension Agent

Virus

Several viruses are known to occur in rhubarb. Reports from British Columbia and UK indicate that turnip mosaic; arabis mosaic and cherry leaf roll virus is the most common. These viruses have wide host ranges and cause mottling and ring spotting of leaves. They may be introduced in infected planting stock.

Natural Control

  • Obtain and plant healthy nursery stock.
  • Avoid planting virus free crowns near virus-contaminated crowns.

Other Control Options

  • Consult County Extension Agent

Potato Stem Borer

The potato stem borer is a caterpillar, which when fully grown is about 3.5 cm in length and pinkish-white in color. The first stages of the insect attack only weeds, couch grasses in particular. Later they move into the centre of the stalk. The adult moths lay their eggs on the stems of grasses in August. The eggs do not hatch until the following spring. Damage can be expected in June and July. Serious infestation can lead to an unmarketable crop.

Natural Control

  • This pest is not a problem when couch grass and other weeds are controlled in and around the rhubarb plant.
  • Weeds should be controlled to make the area less attractive for egg lying by the adult moth.
  • Early spring burning of affected fields or field margins will effectively control this pest.

Other Control Options

  • Consult County Extension Agent

Tarnished Plant Bug

Adult tarnished plant bugs are light brown to reddish brown in color and about 5-6 mm in length. They occur throughout the season. They are very active and quick moving. They can damage rhubarb by feeding on young leaves. Tarnished plant bugs are mainly a pest of new plantings.

Natural Control

  • Keep plantings and adjacent areas weed free.
  • Avoid planting adjacent to legumes.

Other Control Options

  • Consult County Extension Agent

Slugs

Slugs may be a problem in plantings with heavy soils, poor drainage and in weedy situations. Slugs feed at night, by rasping the surface of stems, leaving unsightly scars, which reduce the salability of the stem. Keep weeds under control.

Natural Control

  • Remove leaves and trash from the field when harvesting.
  • DO NOT use manure and/or mulches in areas of field prone to slug damage.

Other Control Options

  • Consult County Extension Agent

Black Bean Aphid

Black bean aphid aphis fabae has caused problems on occasion. Large infestations may cause curling or wilting of leaves. There is also potential for the spread of virus by aphids. Provide good weed control.

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer

Flea Beetle

Flea beetle can cause damage to new plantings by their feeding activity on the leaves. They are especially active during periods of hot dry weather. Provide good weed control.

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer

Cutworms

Larvae appear as smooth skinned caterpillars to the naked eye. Frequently roll into a C-shape when disturbed. Variegated is yellow to brown, little over an inch long with 4-6 yellow or pink diamond-shaped spots down its back. Dark sided cutworm somewhat larger, gray to greenish gray with irregular longitudinal stripes. Larvae feed at night.

Natural Control

  • Hi-Yield® Vegetable & Ornamental Insect Control

Latest Articles & Videos

Rooted in ServiceRooted in Service The Stark Bro's Story of Leadership in Gardening Excellence At Stark Bro’s, we’re proud to be veteran-owned and veteran-operated, bringing the values of service and dedication directly into the heart of gardening. With over 200 years of history, we know that the strongest roots grow from a commitment to quality, integrity, and community. Our leadership upholds these principles, guiding every plant we nurture and every customer we serve. Here, we don’t just grow fruit trees; we grow relationships and legacy.
Harvest basket full of applesHarvest basket full of apples Preparing Your Garden for a Successful Fall and Winter As summer comes to an end, it’s time to give your fruit trees and berry plants the care they need to thrive through the colder months. Proper fall maintenance not only protects your plants from winter damage but also lays the foundation for healthy growth come spring. Here’s your fall checklist to help ensure a smooth transition into the next season.
Preparing a garlic bedPreparing a garlic bed How to Prep a Garlic Bed for Planting Preparing a garlic bed properly is essential for growing healthy, productive garlic plants. Garlic is usually planted in the fall, as it needs a cold period to establish strong roots before spring growth. Here’s a step-by-step guide to help you prepare your garlic bed for planting.
citrus treescitrus trees How to Care for Citrus Trees in Containers & Successfully Grow Citrus Indoors Imagine filling your home with the vibrant scent of citrus blossoms, while enjoying fresh fruit all year long—even if you live outside the ideal growing zones for citrus! Growing citrus in containers makes this possible, allowing you to bring the beauty and flavor of citrus into any climate. With optimal care, citrus trees can bloom and bear fruit multiple times a year, adding both color, fragrance and flavor to your living space.