Biology Technical Note 01 - Habitat Development for Beneficial Insects

by United States Department of Agriculture

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TECHNICAL NOTES

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Habitat Development for Beneficial Insects

for conservation biological control of agricultural insect pests

Provided is guidance on the conservation biological control of agricultural insects pests, by creating habitat to support beneficial predators and parasitoids that attack those insect pests.

Conservation biological control is a science-based pest management strategy that seeks to integrate beneficial insects back into cropping systems for natural pest control, ultimately reducing and in some cases eliminating the need for pesticides.

In addition to enhanced crop pest control, this conservation practice can provide additional farm benefits, including:

Improved water quality and soil health ₰ Replacement of under-used areas for those that work to support the farm ₰ Farm beautification by establishment of wildflowers and other blooming plants ₰ Support conservation standards for various farm certification programs

Ecology of Native Beneficial Insects and the Pests they Control

The foundation of using conservation biological control for agricultural insect pests is understanding the interrelationships between organisms and their environment. Appendix 1 provides a table to help determine what native beneficial insects should be targeted for habitat development based on the ecology of the species, its habitat requirements and the pest it controls.

What pest species is of concern?

Photo identification and information on “pests to be controlled” can be found using USDA-APHIS’ Identification Technology Program (ITP), ID Tools: http://www.idtools.org/

What beneficial insects would you like to target?

Often there are several beneficial insects to control the pest species of concern, your strategy may be to target all of them or just to focus on one species or group of species (i.e. predatory bugs).

Designing the Insectary or Trap Crop The insectary is a habitat area established primarily of perennial plants that provides long-term habitat. The trap crop is a yearly habitat area established by creating a cover of primarily annual plants. Both serve useful purposes and it’s recommended to plan for both types on the farm. The insectary will provide a longer term sanctuary to keep the insects on the farm, while the trap crop will focus their presence on a specific field where they are needed to control the pest insects.

Habitat areas are planned on field borders or other odd or unused areas adjacent or near-to the cash crop fields. Take an inventory of the farm to locate these potentially suitable areas. They can be as small as quarter acre but the generally recommended minimum size is 0.5 acre.

If any insecticides are used on the farm or known to be used on adjoining farms, ensure that the habitat areas are protected from potential drift or runoff, and consider posting signs around the habitat areas to prevent accidental spaying on the habitat areas. A useful resources can be found online provided by the NRCS and Xerces Society: Preventing or Mitigating Potential Negative Impacts of Pesticides on Pollinators Using Integrated Pest Management and Other Conservation Practices.

Plants Suitable for Beneficial Insect Habitat Review Appendix 1 for the plant families and requirements that create habitat for the desired beneficial insects. The plants listed are referred to by their family grouping (i.e., mint family). Use Appendix 2 to obtain a listing of plant species (sorted by their family grouping) that are suited to Colorado.

• Select a mixture of species that consist of at least three plant species for each blooming period (spring, summer, fall); to ensure that habitat will sustain the beneficial insects.
• Plantings should consist of a diversity of plants with at least six species in the mix.
• Provide consideration for incorporating as many native species as possible.

Appendix 2 is a starting point for determining which plants to use. To find species adapted to the habitat area consult the Soil Survey and other resources such as climate data (planting zones). Use the USDA PLANTS database (http://plants.usda.gov/) to further refine the selection.

Selecting Suitable Plants based on Blooming Periods As a general rule, insectary bloom periods are defined for Colorado in Table 1. The intent of providing boom periods is to help select plants that will blooming throughout the growing season. This is particularly helpful for selecting insectary plants. However, for trap crops you may only want to select the bloom periods that precedes and coincides with the cash crop.

Table 1: Insectary Bloom Periods

Early Season Bloom Period: April 15th - June 15th

Mid-Season Bloom Period: June 15th - July

Late Season Bloom Period: August - September

Establish Beneficial Insect Habitat NRCS provides several conservation practices that may be used to establish habitat for beneficial insects. For the selected practice, the purpose and associated criteria will be for Pollinators/Beneficial Insects. Table 2 lists the most appropriate and commonly used practices.

Table 2: Conservation practices commonly used to establish beneficial insect habitat.

For Insectaries (permanent cover)	For Trap Crops (annual cover)
327 - Conservation Cover 386 - Field Border 393 - Filter Strip 332 - Contour Buffer Strips 342 - Critical Area Planting 422 - Hedgerow Planting	340 - Cover Crop 328 - Conservation Crop Rotation

Manage Beneficial Habitat

The following conservation practices are commonly used to ensure that the habitat area functions as intended for the lifespan of the insectary or trap crop.

Table 3: Conservation practices commonly used to manage beneficial insect habitat.

645 - Upland Wildlife Habitat Management

Commonly used to provide a management & monitoring plan, which often includes: strategies for early detection of factors that may adversely affect the habitat area (i.e. scouting for newly emerging invasive weeds); a contingency plan for stressors such as drought; best management practices such as promoting insect overwintering areas; and a plan for record keeping.

472 - Access Control

This management practice may be useful for sites that require additional planning and thought regarding how to protect the habitat area from accidental spraying, mowing, grazing etc.

315 - Herbaceous Weed Control

Where weeds may become an issue, this practice can help to differentiate between beneficial “weeds” and those that could threaten the integrity of the habitat area or cause a concern for the adjoining cash crops. When control is needed, it will provide a weed suppression strategy to minimize the adverse effect to the non-target plants (such as spot spraying/wick application or by using non-chemical control methods).

Measures for a Successful Beneficial Insect Habitat Area

• Prevent insecticide use within the habitat areas and if used on nearby fields ensure that measures are in-place to prevent chemical drift onto the habitat areas (i.e., create a buffer, check wind directions before application, avoid application upslope from the habitat area, etc.).
• Prevent disturbances that could affect blooming or insect health, such as grazing, mowing, tillage, burning, or herbicide application. If they are necessary to manage for the health of the habitat area, then use mitigation techniques such as spot treatments and/or waiting until after the bloom periods.
• Have a contingency plan in place for unexpected events such as drought or if the habitat area is lost.
• Maintain the beneficial “weeds” that establish naturally within the habitat areas, such as milkweed, sunflowers, asters, and yarrow. As a general rule, maintain plants unless they are on the Colorado Noxious Weed List (lists A, B, or C) or they have the potential to cause an issue for the cash crops.
• Consider keeping a record to evaluate the effectiveness of promoting beneficial insects on the farm and to watch for when adaptive management may be needed to improve habitat conditions.

(i) Dates of when flowering starts and ends for each of the habitat plants.

(ii) Observations of the type and quantity of beneficial insects found in the habitat area.

(iv) Crop records or observations of pest type and quantity in the cash crop field.

Additional Resources
Hopwood, J. et. al. 2017. Habitat Planning for Beneficial Insects. Guidelines for Conservation Biological Control. The Xerces Society for Invertebrate Conservation. Portland, Oregon. http://www.xerces.org

Lee-Mäder, E. et. al. 2014. Farming with Native Beneficial Insects. The Xerces Society for Invertebrate Conservation. Portland, Oregon. http://www.xerces.org

Vaughn, M. et. al. Agronomy Technical Note No. 9: Preventing or Mitigating Potential Negative Impacts of Pesticides on Pollinators Using Integrated Pest Management and Other Conservation Practices. USDA Natural Resources Conservation Service and The Xerces Society. http://www.xerces.org

Appendices (not listed in original)

1. Appendix 1
2. Appendix 2