Preserving Beneficial Predators in the Home Garden Mary Barbercheck and Jermaine Hinds Penn State Department of Entomology

Ladybeetle and Syrphid on Buckwheat Flowers Principles of IPM Manage system for productivity and beneficial processes Plant Positive vs. Pest Negative Use of decision-making criteria before action (or no action) Integration of all suitable control techniques in a compatible manner Limited pesticides, only as last resort Ladybeetle and Syrphid on Buckwheat Flowers

What are Natural Enemies? Spiders Ground Beetles Predators Parasitoids Pathogens Value of pest suppression estimated at $6 billion per year! Damsel Bug Parasitic Wasps Beneficial Predators are insects and other arthropods that suppress pests by feeding or parasitizing unwanted pest organisms. Large diversity of beneficial insects within and outside the insects. Includes mites, fungi, nematodes, and arachnida. Define each? Predators – typically consume multiple prey items whole Parasitoids – complete life cycle as a parasite within the host or pest insect. Pathogens – Disease causing organisms that kill pest insects can include fungal and bacterial pathogens (Seedcorn maggot parasite, Bacillus thuringencis). Insect-parasitic Nematode Predatory Mite Insect-parasitic fungi

Natural Enemies of Plant-Feeding Insects NESARE Soil Quality Workshop, 2006 Kutztown, PA Natural Enemies of Plant-Feeding Insects Predators – during development consume many insects Predatory mites, ground beetles, predatory bugs, spiders, daddy-longlegs, centipedes Ray R. Weil, University of Maryland

NESARE Soil Quality Workshop, 2006 Kutztown, PA Natural Enemies of Plant-Feeding Insects Parasitoids – during development consume one insect parasitoid wasps, tachinid flies Ray R. Weil, University of Maryland

NESARE Soil Quality Workshop, 2006 Kutztown, PA Natural Enemies of Plant-Feeding Insects Pathogens - cause disease in host organism fungi, bacteria, viruses, protozoa, nematodes Ray R. Weil, University of Maryland

NESARE Soil Quality Workshop, 2006 Kutztown, PA Biological Control Biological Control - Exploitation of natural enemies to hold pests below economically damaging levels Conservation Improve environment for existing beneficial organisms Augmentative & Inundative Purchase and release Usually not long-term Improve environment for applied beneficial organisms Pediobius wasp on Mexican Bean Beetle Organic growers depend biological control to help manage their pests – taking advantage of food web interactions. Conservation – using cultural methods to make the environment favorable for natural enemies. Aphid “mummies” after parasitoid emergence Ray R. Weil, University of Maryland

NESARE Soil Quality Workshop, 2006 Kutztown, PA Conservation Biological Control Goal: Improve environment for beneficial organisms and processes Habitat Management: provide resource plants or habitats, e.g., cover crops refuge strips of flowering plants pollen and nectar resources required by many insect natural enemies Adding plant diversity to a production system in space and time can help break pest cycles. Plants in the same family tend to have similar pests. Crop rotation, planting a series crops from different plant families in the same space in sequential seasons, helps deter the build up of pests that can occur when one crop species is planted continuously. Crop rotation, as described in Section 205.205 in the National Organic Standards, is fundamental to good organic management and serves several functions. As stated in the rule, the producer must implement a crop rotation including but not limited to sod, cover crops, green manure crops, and catch crops. Crop rotation provides the benefits in addition to providing pest management in annual and perennial crops, including: maintenance or improvement of soil organic matter content; management of plant nutrients; and erosion control. Spatial crop diversity can be achieved through crop rotation and various forms of polyculture, e.g., strip cropping, multiple cropping, or interplanting of plant species or varieties. A general effect of polyculture is a spatial mixing of crops, which can slow the build-up and spread of pests during the growing season. There are two main hypotheses to help explain how plant diversity acts to keep pest populations low. The first is based on plant apparency. It has been hypothesized that when a host plant is growing among non-host plants that the host plant is less apparent to an insect and, therefore, more difficult to locate. The second hypothesis is based on natural enemies. It has been hypothesized that plant diversity in a system increases the kinds of resources available to natural enemies of insects and encourages their occurrence, and predation and parasitism of insect pests. An interesting application of crop diversity to control insect pests is perimeter trap cropping. In perimeter trap cropping, the crop being protected (“main crop”) is surrounded completely by a planting of one or two rows of a trap crop. The perimeter trap crop encloses the main crop and intercepts and concentrates incoming pests, where they can be killed. The trap crop may also serve as habitat for beneficial organisms. Perimeter trap crops must be present before or at the same time as the main crop to intercept pests. If the trap crop is maintained in a vigorous condition, the pest may not leave it. However, for maximum effectiveness, the perimeter trap crop should be treated with an allowed substance as soon as pests appear or begin to build-up in numbers. Ray R. Weil, University of Maryland

Minimize Disturbance Excessive tillage and pesticides may threaten and disturb beneficial insects Destroy habitat Directly kill insects Insects use undisturbed areas for foraging, refuge and overwintering Provide areas free of disturbance Conservation borders/strips: Hedgerows, perennial wildfllower strips, etc

Choosing the right plants Compatible with growing system Diversify! Variety of flower colors, shapes and sizes Choose different flower structures, tall an short Choose species that ensure bloom throughout the growing season When choosing insectary plants to promote and conserve beneficial insects in farm or garden consider: Which plants are compatible with your operation annuals? Perrenials? Length of time in field? Secondary benefits (legume, weed suppression, reseeding) When choosing plants, it is important to diversify your selection. Different insects are attracted to different types of flowers based on color, size, scent, structure. Offer a variety of flowers that can service a variety of beneficial insects. Also diversify plant species based on length of flowering time. It is important to choose species that bloom throughout the growing season and whose flowers appear when the targeted beneficial insects emerge.

Additionally, Quene Anne’s Lace, sweet alyssum, phacelia, clovers (red, crimson, white), canola, etc.

Caution Pesticide Use Pesticides may harm beneficial insects! Avoid spraying when insects are active Pesticides should be used as a last resort Rely on cultural and biological control measures Use targeted/ least toxic pesticides

Some “Soft” Pesticides NESARE Soil Quality Workshop, 2006 Kutztown, PA Some “Soft” Pesticides Safest Insecticidal soap Diatomaceous earth Spinosad (Entrustr) Various microbials Particle films: bentonite, kaolinite (Surroundr) Plant extracts and oils Pheromones OK Dormant and summer oils (narrow range petroleum, fish, plant) Sulfur compounds Botanicals Pyrethrum (PyGanicr) Neem Ray R. Weil, University of Maryland

Considerations for pesticide use NESARE Soil Quality Workshop, 2006 Kutztown, PA Considerations for pesticide use Have a plan: How and when you will react to a pest outbreak Decide in advance your ‘action threshold’ Where possible, use biological controls Know your soft pesticide choices: what’s safe, what’s labeled, what works, cost. European Corn Borer Flea beetle Ray R. Weil, University of Maryland

NESARE Soil Quality Workshop, 2006 Kutztown, PA Microbial Controls Insect Control: B.t. var kurstaki Beuveria spp. (Mycotrol, Naturalis) Metarhizium spp. (Met52) Insect viruses Beauveria Insect Virus Ray R. Weil, University of Maryland

Minimize Pesticide Non-target Effects NESARE Soil Quality Workshop, 2006 Kutztown, PA Minimize Pesticide Non-target Effects Kaolin clay particle film Registered on a variety of fruits and vegetables Prevents insect feeding and oviposition Approved for organic production Ray R. Weil, University of Maryland

NESARE Soil Quality Workshop, 2006 Kutztown, PA Biological Control of Pests: Augmentative Apply large number of organisms in same manner as a pesticide Introduces large numbers of organisms for relatively fast-acting control May or may not become established Application of a biological agent much like a pesticide. Ray R. Weil, University of Maryland

NESARE Soil Quality Workshop, 2006 Kutztown, PA Dispersal of Beneficial Arthropods Consider the behavior of targeted beneficial insects. Farmscaping to conserve natural enemies assumes that beneficial organisms will move out of refuge/resource areas into the cash crop to control pests there. Different natural enemies have a tendency to disperse different distances. Ray R. Weil, University of Maryland

Summary Beneficial insects: How to conserve? Important for pest suppression! Require undisturbed and resource-rich habitat to thrive How to conserve? Minimize disturbance Provide resources Food (nectar, pollen) Foraging sites Overwintering sites Minimize pesticide use Rely on cultural and biological methods of control

Acknowledgements