Extension Bulletin 2719, New, October 2000 Natural Enemies in Your Garden: A Homeowner’s Guide to Biological Control MICHIGAN STATE UNIVERSITY EXTENSION Cover Photos Front cover, clockwise from top left • Ladybug larva, Coccinella septempunctata (USDA). • Green lacewing adult (Karim Maredia). • Ladybug, Hippodammia parenthesis1. • Tachinid fly adult (Dave Smitley). Back cover, from top • Tomato hornworm covered with braconid parasitoid cocoons1. • Carabid beetle adult, Calosoma spp. (Dave Smitley). • Virus infected cabbage looper1. Text Illustrations • Pages 21 ‘Orius’, 23, 25, 26, 28, 29, 32, 33, 35, 38, 44-46, and 48 (Michelle Schwengel, Midwest Biological Control News). • Pages 15-20, 21 ‘true bug’, 24, 33, 36, 40, and 42 (Jana Lee). • Page 29 ‘Multicolored Asian lady beetle’ (William F. Lyon, O.S.U. Extension factsheet HYG-215-94: Multicolored Asian lady beetle). • Page 37 (J.J. Culver, 1919, USDA Bulletin 766, plate 1). • Page 47 (P. Berry, 1938, USDA Circular 485). • Pages 34, 411. 1 (Michael P. Hoffman and Anne C. Frodsham, 1993, “Natural Enemies of Vegetable Insect Pests”, Cornell University). Natural Enemies in Your Garden: A Homeowner’s Guide to Biological Control Jana C. Lee Douglas A. Landis Department of Entomology Michigan State University This publication is a product of the Michigan State University Biological Control Program within the Center for Integrated Plant Systems. Funding was provided by the Michigan Agricultural Experiment Station, Project GREEEN and Michigan State University Extension. MICHIGAN STATE MICHIGAN UNIVERSITY AGRICULTURAL EXPERIMENT EXTENSION STATION Table of Contents Introduction Who are Our Friends in the Garden?. 4 Making Biological Control Work for Us . 5 Conserving Natural Enemies Conservation Step 1: Don't Reach for the Pesticide Spray . 6 Conservation Step 2: Make a Home for Natural Enemies (Habitat Manipulation) . 6 Augmenting Natural Enemies Natural Enemies for Hire . 11 What to Consider When Ordering Natural Enemies. 11 Making Augmentation Successful . 12 Discovering Natural Enemies in Your Backyard — How to Sample . 14 Natural Enemies of Common Pests . 15 Predators Minute Pirate Bugs . 21 Stink Bugs . 22 Assassin Bugs . 24 Damsel Bugs. 24 Bigeyed Bugs . 25 Green Lacewings . 26 Ladybugs . 27 Rove Beetles . 31 Ground Beetles. 32 Hover Flies . 34 Robber Flies . 35 Spiders . 36 Parasitoids Tachinid Flies . 37 Trichogramma Wasps . 40 Aphidius Wasps . 42 2 Table of Contents Cotesia glomerata. 43 Cotesia melanoscelus . 44 Pteromalus puparum . 45 Diadegma insulare . 45 Tiphia vernalis and T. popilliavora . 46 Elm Leaf Beetle Parasitoids . 47 Ooencyrtus kuvanae . 48 Pathogens Nematodes . 50 Beauveria bassiana . 52 Entomophaga maimaiga. 54 Bacillus thuringiensis . 55 Trichoderma harzianum, Strain T-22 . 59 Gliocladium virens . 60 Acknowledgements This book summarizes information from the Midwest Biological Control News that is of interest to homeowners and gardeners. The newsletter source and contributing authors are given at the end of each section. If you are interested in learning more about a particular topic, you many find the original article and other articles of interest to you in the newsletter online index at <http://www.entomology.wisc.edu/mbcn/mbcn.html> We thank the following people for their help and comments: Chris DiFonzo, Deborah McCullough, Susan Mahr, Dean Krauskopf, Ralph Heiden, Angela Eichorn, Jerry Draheim and Jeanne Himmelein. We also thank Susan Mahr from Midwest Biological Control News, Michael Hoffman, Dave Smitley and Karim Maredia for use of their illustrations and photos. Many illustrations from Midwest Biological Control News were drawn by Michelle Schwengel. 3 Introduction he home landscape is a complex Who are Our Friends habitat possibly consisting of in the Garden? T vegetables, flowers, turf, woody ornamentals and other desired, and in some Most of us are familiar with spiders, cases, undesired plants. For most of us, our ladybugs and praying mantids and know garden is a relaxing place where we tailor the they eat a lot of bad bugs. Luckily, many environment to our aesthetic and physical other natural enemies are also taking care of needs. Yet the garden is also home to pests. There are three major groups of creatures we consider pests when we find natural enemies: predators, parasitoids and them in our broccoli or apples or on our pathogens. prized rose bushes. As a result, the home landscape has become the repository of Predators, such as nearly 11 percent of the conventional ladybugs and spiders, pesticides used in this country. Indeed, acre eat many prey in a for acre, your cousin Vinny's tomato patch lifetime. Often they are has more pesticides than farmer Joe's larger and stronger than soybean field! Fortunately, the garden is also their prey and the most home to our friends, the natural enemies of visible natural enemies pests. in our garden. Some are C. maculata quick running hunters, Most gardeners learn a great deal about their while others sit and wait for a victim to plants' growth needs, but they often know pounce on. little about the insects in their gardens. Most of the insects in a garden are not harmful Parasitoids are pests. The vast majority of insect species in specialized insects North America are either beneficial or that develop as harmless to humans and garden plants. young in one host, To take advantage of the work that natural eventually killing enemies do (kill pests), we must first know it. Unlike which ones we have and help them flourish. predators, they Using natural enemies to control pests usually kill only reduces your need to use pesticides and lets one prey during you take a bite from cousin Vinny's tomatoes, Wasp on an egg their immature right off the vine! stage. Many flies and wasps are parasitoids, but they are — MBCN, v.4, n.4, Bryan Schmeiser and Bob usually small and therefore go unnoticed. O'Neil, Purdue University. 4 Introduction Pathogens homeowners will not be importing natural — nematodes, enemies into our backyards, some of the viruses, natural enemies described in this book were bacteria, fungi brought from other countries and and established here. The importation of parasitic protozoans — wasps to control alfalfa weevil in the cause diseases. Midwest has been a widely successful nematode Many of these classical biological control program. naturally occur in our gardens; others need to be Conservation biological control introduced. Commercial companies have encourages existing natural enemy begun to develop many of these pathogens populations to flourish in the area and as bait or spray formulations, making them suppress pests. This involves reducing easier for us to use. practices that harm natural enemies as well as implementing practices that improve natural enemy longevity, reproductive rate Making Biological and effectiveness. Control Work for Us Augmentation biological control Biological control uses natural enemies to is the release of natural enemies into the keep unwanted pests at low levels. environment in high numbers. This is done To practice biological control in the yard, you when natural enemies do not thrive well in the environment or are not active during the should know the three basic approaches. time of pest activity. Conservation and Classical biological control is used augmentation of natural enemies are the when pests are exotic in origin and exotic home gardener's tools to subdue pests, so natural enemies are imported and released let's get started! to bring about control. This is conducted by federal and state agencies. Although we 5 Conserving Natural Enemies word of caution: not all traps are effective (see section on electric traps). • When all other measures have failed, very Conservation Step 1: selective and well timed spot treatments of Don't Reach for the individual plant parts with a low-impact Pesticide Spray insecticide (such as insecticidal soaps or horticultural oils, which are relatively safe To conserve natural enemies in the home compounds for beneficials) may be landscape, first and foremost, we need to considered. reduce insecticide use. The chemicals we • Tolerating a modest level of insect feeding spray to get caterpillars off broccoli also kill on your garden vegetables will reduce the or reduce the livelihood of natural enemies. need for chemical inputs. If cabbageworms Natural enemies take longer to re-establish eat part of your cabbage head, you can themselves than pests do. Using pesticides always cut off the nibbled part and use the may also create new pests because it kills rest. natural enemies that are suppressing minor pests without our knowledge. When the — MBCN, v.2, n.4, John Obrycki, Iowa State natural enemies are killed by a pesticide, University, and Susan Mahr, University of these minor pests can become major Wisconsin - Madison. problems. Kinder Options Conservation Step 2: Home gardeners have many insect pest Making a Home for management options other than insecticides. Adopting these options with attention to the Natural Enemies life cycles of pest and beneficial insects is a (Habitat Manipulation) key component of integrated pest Natural enemies require more than just food management (IPM). Some IPM practices (pests to eat) to complete their life cycles. include preplant cultural operations, such as Predators and parasitoids may need an selecting insect-resistant varieties, crop overwintering site, protection from heat and rotations and companion plantings. After the desiccation, plant food sources and early- garden has been planted,