Integrated Pest Management for Herbaceous Perennials
fact sheet and image gallery- August 2004

Integrated pest management (IPM) is a sustainable approach to managing pests by combining cultural, physical, biological and chemical tactics in a way that minimizes economic, health and environmental risks.

To implement an IPM program specific for your particular operation requires commitment, planning and management skills. The major components of an IPM plan include:

• Becoming knowledgeable about the cultural needs of the specific herbaceous perennials being grown.
• Becoming familiar with the key pests and their associated natural enemies.
• Preventing pest problems by using proper sanitation and cultural practices.
• Scouting on a regular basis to promptly identify cultural problems, access crop health, pest activity and locations, set action thresholds and predict pest activity. Growing degree days and plant phenology can also be used to help predict pest activity. Your goal is to maintain pests at a level acceptable to your customer's expectations.
• Considering all available pest management options, weighing their advantages and disadvantages before making a decision.
• Evaluating each treatment decision and reviewing your entire pest management plan at the end of each season.
• Keeping accurate scouting and pesticide usage records to help in long-term management.

Sanitation
Begin with a clean greenhouse and outdoor production yard and train employees on proper sanitation procedures. Eliminate weeds that may be reservoirs for insects and diseases. Discard old stock plants and unsold plants that may harbor unwanted pests.

Place outdoor grown perennials in a level, well-drained field. Use a porous weed block fabric to prevent weed growth while providing good drainage. Space plants to allow for adequate air circulation. Keep the perimeter free of weeds to discourage weed seeds and insects from migrating into the growing area. Keep cull piles as far away from your growing area as possible. When mixing your own growing media, use a concrete pad to keep the mix separate from field soil. During storage, cover the media to prevent contamination with windblown weed seeds and fungal spores. Before overwintering perennials, cut back foliage and remove any diseased or dead tissue. Apply a protectant fungicide to prevent Botrytis blight, especially on those perennials prone to Botrytis. Produce stock plants under strict sanitary protocols. Inspect any incoming plants before they are placed in your production areas.

Monitoring
Regular, consistent monitoring or scouting is needed to set action thresholds, predict pest activity and evaluate the effectiveness of your treatments. Some of the advantages of regular scouting include: a more efficient pest management program (treatments are applied only when needed), treatments can be directed against the target pest at its most susceptible life stage, with an enhanced ability to use softer, more environmentally friendly materials that help conserve natural enemies because problems are detected early and regular evaluations are conducted. There is also an increased sense of security when pest problems are properly identified, and effectively managed with follow-up evaluations.

Yellow Sticky Cards
Yellow sticky cards can be used in propagation areas to detect adult thrips, whiteflies, fungus gnats, shore flies and leafminers. Yellow sticky cards can also be used outdoors to help identify fast-moving leafhoppers.

Key Pests and Key Plants
Identify the key pests and key plants specific to your operation. Key pests are those pests that cause persistent problems year after year. Many key pests have rapid generation times and attack a wide range of herbaceous perennials. In outdoor production, aphids, two-spotted mites, black vine weevils, beetles, lace bugs, thrips, four-lined plant bugs, tarnished plant bugs, leafhoppers, leafminers, iris borers and slugs can be important pests. In greenhouse production, aphids, fungus gnats, whiteflies, thrips, two-spotted mites and whiteflies are important pests.

Plant Inspections
Randomly inspect plants by looking on the underside of leaves for insects and signs of their damage. Walk through the fields in a regular pattern, such as a "W" or "X" or "Z " and randomly inspect the plants. By tapping foliage over a sheet of white paper, you can detect aphids, mites, thrips and other small pests. A 10 to 20X hand lens is useful for making proper identification of key pests and their life stages.

Plant Inspections for Diseases
Regular monitoring of the environmental conditions (temperature, humidity, light, etc.) and cultural practices helps to prevent many diseases. Check plants weekly for symptoms of stress, symptoms and signs of disease including leaf spots, wilting, abnormal leaf color, fungal spores, mycelium and bacterial ooze. Look at the entire plant, both above and below ground. Examine the roots to see if they are white and healthy with adequate root hair growth. Become familiar with the characteristic growth habit of the individual plant species you are growing. Experienced growers recognize the difference between plants not actively growing compared to diseased plants.

Plant Inspections for Weeds
Survey the site to identify the types of weeds (broadleaf or grasses), their life cycle (annual, biennal or perennial) and record the level of weed pressure. Scout weed populations during and after the growing season to assess the success of your weed control program. Knowing the life cycle of the weeds is necessary to determine optimal timing for cultural or chemical management.

To effectively manage weeds, integrate the use of cultural controls (prevention and sanitation), mechanical controls (hand weeding, especially any escaped weeds before they flower and set seed), physical barriers (fiber cloth and other mulches) with the selective application of herbicides. Before applying any herbicide, read the label carefully, for many herbicides only control certain weeds and may injure herbaceous perennials that are closely related to those weeds you are trying to control. To prevent herbicide injury, avoid using pre-emergence herbicides on very young plant material with poorly developed roots. (There are no pre-emergence herbicides labeled for use in the greenhouse due to the potential for severe crop injury). For more specific information, refer to "Weed Management Guide for Herbaceous Ornamentals" by Dr. Senesac, which describes the herbicides registered for use on herbaceous ornamentals, and weed susceptibilities to herbicides, that is available from either Cornell University or the University of Maryland – see reference list).

Natural Enemies
When scouting, record the presence of common natural enemies including ladybird beetles, aphid mummies, syrphid fly larvae, lacewing larvae, big-eyed bugs, damsel bugs, predatory mites, and minute pirate bugs. Refer to A Guide to Natural Enemies of North America and other references to help with identification. If natural enemies are present, your tolerance level for pest activity needs to be higher, so these beneficial arthropods will have a food source. Many beneficials do best in a diverse plant environment where they have access to food, water and overwintering sites. Knowing when natural enemy populations are high can allow you to either eliminate or delay treating a pest population that would otherwise require treatment.

By avoiding the use of long-lasting broad spectrum pesticides, you can help conserve those natural enemies already present. Certain pesticides, for example, many pyrethroids and organophosphates, may be harmful to natural enemies for up to 3 months after their application. Koppert Biological Systems has compiled as list of pesticides and their effect on natural enemies. Become familiar with using insecticides that are more compatible with natural enemies such as horticultural oils, insecticidal soaps, insect growth regulators and other selective materials.

Evaluation and Record-Keeping
Evaluate the effectiveness of each of your treatments and review your pest management plan at the end of each season.

View the gallery of photos for this article.

View Scouting and Management Guidelines for Herbaceous Perennials

Information on our site was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

menu