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Flea Beetle: Organic Control Options

Flea Beetle: Organic Control Options

Sustainable Agriculture A program of the National Center for Appropriate Technology • 1-800-346-9140 • www.attra.ncat.org : Organic Control Options

By George Kuepper, This publication focuses on organic control of fl ea , one of the more serious vegetable crop pests. NCAT Agriculture Cultural and biological options are discussed along with alternative pesticidal materials. Specialist Published March 2003 Updated by Rex Dufour, NCAT Agriculture Specialist April 2015 ©NCAT IP389

Contents Introduction ...... 1 Cultural/Physical Controls ...... 2 Biological Control ...... 2 Alternative ...... 3 References ...... 4 Further Resources ...... 4

Typical damage of fl ea beetle on brassicas—likely the Crucifer . Photo: Rex Dufour, NCAT Introduction lea beetles are one of the most diffi cult-to- considered general feeders, though many species manage pests of and cole crops. attack only one plant or closely related kinds of FTh ey are also a problem on seedlings of plants (Metcalf and Metcalf, 1993). tomatoes, potatoes, peppers, turnips, , Life history varies somewhat with species, but and corn. Th ere are various genera and species most appear to pass the winter in the adult stage, of fl ea beetles, all members of the Chrysomeli- ATTRA (www.attra.ncat.org) sheltering under plant debris in the fi eld, fi eld is a program of the National dae . Th e adults are active -feeders that margins, and adjacent areas. Th e adults emerge in Center for Appropriate Technology can, in large numbers, rapidly defoliate and kill (NCAT). The program is funded spring and may feed on and less-desirable through a cooperative agreement plants. Symptoms of fl ea beetle feeding are small, vegetation until crop plants become available. As with the Department rounded, irregular holes; heavy feeding makes a result, they are frequent pests in seedbeds and of Agriculture’s Rural Business- look as if they had been peppered with Cooperative Service. Visit the on new transplants (Metcalf and Metcalf, 1993). NCAT website (www.ncat.org) fi ne shot. Some species also vector serious dis- Th ey may become especially troublesome when for more information on eases such as potato blight and bacterial wilt of weedy areas begin to "dry up." Flea beetles cause our other sustainable agriculture and corn. Further damage may be done by the larvae, the greatest damage by feeding on cotyledons, energy projects. which feed on plant roots. Some fl ea beetles are stems, and foliage (Hines and Hutchinson, 1997). www.attra.ncat.org Page 1 In organic systems, the preferred approaches to preferred by the —at 6- or 12-inch intervals pest management are those that enhance the among cole crops. In one trial, this measurably diversity of the farm system, such as cover crop- reduced damage to broccoli (Byczynski, 1999). ping, rotation, and interplanting; those that use special knowledge of pest , such as delayed Row-cover materials such as Reema™ can be used planting; and those that take advantage of exist- to cover seedlings and provide a barrier to adult ing on-farm resources. Th ese approaches are typi- beetles. It is advisable to get the row cover in place fi ed by cultural and biological controls, which will at or before emergence for maximum protection. be discussed fi rst. Alternative pesticides, while Th e covers can be removed once the pest popu- frequently necessary for some crop pests and con- lation subsides (Ellis and Bradley, 1992). To be ditions, can be treated as "rescue chemistry" to most eff ective, row covers should be used in con- be used when and if other strategies fall short. junction with a planned crop rotation in which the crop to be protected follows a non-suscepti- ble crop. Th is reduces the chance that pests will Cultural/Physical Controls emerge under the row cover (Caldwell, 1998). Flea beetles are favored by stable, warm spring ATTRA has additional information on row cov- weather and hampered by alternating periods ers, including manufacturers and distributors, in of hot and cold temperatures with intermittent the publication Season Extension Techniques for rains. Seedlings of crops are most vulnerable to Market Gardeners. Related ATTRA fl ea-beetle feeding when stressed, particularly by Growers report some level of fl ea-beetle control Publications inadequate moisture. Providing good nutrition using white and yellow sticky traps (Byczynski, www.attra.ncat.org and favorable growing conditions aids in shorten- 1999; Anon., 1996). Reference is made to indi- ing the vulnerable early-growth stages and helps vidual traps placed every 15 to 30 feet of row. Bug Vacuums for plants survive fl ea-beetle attack. Th e literature Encircling the fi eld with continuous sticky tape Organic Crop suggests that organic fertilization may make crops Protection less attractive to fl ea beetles (McKinlay, 1992). is also mentioned. Sources of sticky traps include ARBICO and Golden Harvest Organics (see Cole Crops and Other Brassicas: Organic Because the pest is so mobile, and because so many Further Resources). Production genera and species are involved, crop rotation, by itself, has little eff ect as a control strategy. How- Since the adults overwinter in plant debris, there Organic ever, living mulches or polycultures are known to is value in sanitation procedures that destroy ref- Production reduce fl ea-beetle damage (McKinlay, 1992; Anon., uge sites. Plowing or rototilling weeds and crop residues in the fall is often recommended, as is Organic IPM Field 2000). One reason for this is that the individual crop Guide plants are not silhouetted against a bare-soil back- destruction of grassy and solanaceous ( ground and are less obvious to the pest (McKin- family) weeds adjacent to the fi eld (Flint, 1990). Specialty Unfortunately, these procedures are often in con- and Greens: Organic lay, 1992). Th e ATTRA publication elaborates further on this subject. fl ict with good sustainable practices that strive to Production maintain soil cover and fi eld buff ers. When such Season Extension Trap cropping, in which attractive plant spe- confl icts occur, growers can view sanitation pro- Techniques for Market cies are planted near the main crop to draw the cedures as transitional strategies only and look for Gardeners pest away, off ers some possibilities for fl ea-- more sustainable practices to use in the future. tle management. Apparently the most practical trap crop is Chinese Southern Giant Mustard Anecdotal reports have suggested that catnip (Brassica juncea var. crispifolia), seed of which is might repel fl ea beetles. Research by organic gar- widely available. Research has shown that plant- deners in 1997 failed to confi rm this information, ing this trap crop about every 55 yards between however. Th e gardeners reported that catnip used rows of cabbage, broccoli, or caulifl ower (or as a as a mulch or sprayed as an extract tea did a gen- border around the fi eld) can do an exceptional erally poor job of repelling the pest (Long, 1998). job of protecting them. To retain eff ectiveness, reseeding of the trap crop may be necessary, Biological Control especially if the pest destroys the fi rst planting. In healthy agroecosystems, there are populations Th e trap is less eff ective in protecting crops that of benefi cial predators and parasites that work to are almost as attractive to fl ea beetles as Giant control the number of fl ea beetles and other pests. Mustard is, such as Nappa cabbage, gai choy, One example is Microcotonus vittage Muesebeck, and choy sum (Chaput, 1999). a native braconid that kills the adult fl ea Another approach to trap cropping is to interplant beetle and sterilizes the female fl ea beetle (Hines radishes—Chinese Daikon and Belle are and Hutchinson, 1997). Growers can manage the

Page 2 Flea Beetle: Organic Control Options diversity of their farms and gardens to support Not a botanical and not often populations of benefi cials. Specifi c information mentioned in this regard, dia- on such strategies is provided in the ATTR A pub- tomaceous earth has been lication Farmscaping for Biological Control. observed to reduce fl ea-beetle populations and is sometimes Commercial formulations of entomopathogenic recommended (Anon., 1999; nematodes are eff ective agents for controlling fl ea Spring and Day, no date). beetles (Ellis and Bradley, 1992). Applied to the soil, the nematodes attack the beetle's larval stage, Th e kaolin-clay-based product reducing root feeding and helping to prevent the Surround™ has undergone some next cycle of adults from emerging. ATTRA’s preliminary evaluation for fl ea- Ecological Pest Management Database (https:// beetle control on eggplant. While attra.ncat.org/attra-pub/biorationals/index.php) eff ective in reducing fl ea-beetle has information about formulations of benefi cial damage, Surround™ degraded nematodes. Search in “Active Ingredients” under fruit yield and quality; there also Steinernema or Heterorhabditis. were problems removing the clay- An assassin bug preying on a fl ea beetle, residue coating from the fruit. with typical fl ea beetle damage on Alternative Pesticides Th e use of this product will likely eggplant leaf. Likely Western Potato Flea be limited to the early part of the Beetle. Photo: Chris Hay Botanical pesticides recommended for control- season, before fruit set (Maletta et ling fl ea beetles include neem, rotenone, pyre- al., 2002). thrin, sabadilla, and formulations of these in some combination (Ellis and Bradley, 1992). Th e Uni- Fields should be regularly monitored to deter- versity of California mentions insecticidal soap mine if and when any pesticidal agents should be as an organic option for fl ea beetles, but indi- applied. Th is is especially critical with fl ea beetles, cates that it "may provide partial control" only since a small population can do signifi cant dam- (Anon., 1997; Nielsen, 1997). Sprays combining age to a crop in the cotyledon or fi rst-leaf stages. rotenone with insecticidal soap are considered Th e University of California recommends that very eff ective (Flint, 1990). Other sources sug- treatment begin when several damaged rows are gest that garlic sprays are useful (Rateaver and observed, and that spot treatment of rows and Rateaver, 1993). Research in Colorado showed borders be attempted fi rst (Anon., 1997). Small that garlic extracts are successful in suppressing growers, whose whole crop may comprise just a fl ea beetles, but effi cacy may trail off later in the few rows, will need to act more quickly. Once cole season (Anon., 1998). In addition to garlic, the crops reach the fi ve-leaf stage, they are generally USDA Natural Resources Conservation Service able to tolerate a moderate level of damage; older (NRCS) recommends onion and mint as natural plants are even more tolerant. fl ea-beetle repellants (USDA, no date). Pyola™ is a natural product that com- bines with pyrethrins. It is recom- mended for use on fl ea beetles, cucumber bee- tles, Mexican bean beetles, squash bugs, , mites, and . However, since much of the canola oil on the market is derived from genetically engineered plants, this product may or may not be acceptable for organic pro- duction. Growers should contact their certifying agent before purchase and use. To learn more, visit www.gardensalive.com. Botanical and soap-based pesticides should be considered a last resort in organic management. Like synthetic pesticides, most of these materi- als are broad-spectrum and kill many benefi cial, non-target organisms, including predators and Flea beetles attempting to graze on plant leaf coated with Surround kaolin parasites that help keep the fl ea beetle population clay. Surround may provide some protection against fl ea beetle feeding. in check naturally. Photo: Rex Dufour, NCAT www.attra.ncat.org Page 3 References Anon. 1997. UC IPM Pest Management Guidelines-Cole Farming Research Foundation. http://ofrf.org/sites/ofrf.org/ Crops. University of California, Davis, CA. December. p. fi les/docs/pdf/ib08.pdf A.7-A.8. www.ipm.ucdavis.edu/PMG/r108300511.html An overview of research that studied trap crops and their Anon. 1998. Flea Beetle IPM. IPM Practitioner. September. p. 16. eff ectiveness for controlling fl ea beetles. Anon. 1999. and fl ea beetles. IPM Practitioner. July. p. 14. Flea Beetles by W.S. Cranshaw. Colorado State University Extension. www.ext.colostate.edu/pubs/insect/05592.html Byczynski, Lynn. 1999. Tips, but no easy answers to fl ea Provides information on history and habits of fl ea beetles, as beetle invasions. Growing for Market. March. p. 12. well as cultural and chemical controls. Caldwell, Brian. 1998. Flea beetles. Organic Farms, Folks & Flea Beetles on Vegetables by Center for Integrated Pest Foods. May-June. p. 14. Management, North Carolina State University. http://ipm. Chaput, Jim. 1999. Managing fl ea beetles in cole crops. ncsu.edu/AG295/html/fl ea_beetles.htm Eco-Farm & Garden. Summer. p. 31-32. Provides a useful profi le of fl ea beetles, including their biology and habits, host plants, damage, distribution, and control. Ellis, Barbara W. and Fern Marshall Bradley. 1992. Th e Organic Gardener’s Handbook of Natural and Disease Control. Rodale Press, Emmaus, PA. 534 p. Webinars Diversity by Design: Using Trap Crops to Control the Flint, Mary Louise. 1990. Pests of the Garden and Small Crucifer Flea Beetle by J. Parker and W. Snyder. 2014. Farm. University of California, Oakland, CA. p. 82-83. http://www.extension.org/pages/71255/diversity-by-design:- Hines, Rebecca and W.D. Hutchinson. 1997. Flea Beetles. using-trap-crops-to-control-the-crucifer-fl ea-beetle-webinar#. Minnesota Extension Service. January. VR777OFd-TZ www.vegedge.umn.edu/vegpest/colecrop/fl ea.htm A webinar exploring the use of trap crops, stands of plants Long, Cheryl. 1998. Organic Gardening gardeners’ report. grown to attract pest away from target crops. Organic Gardening. April. p. 16. Maletta, M. et al. 2002. Evaluation of Surround for Pest Suppliers Control on Eggplant. Plant & Pest Advisory. Rutgers Coop- ARBICO erative Extension, University of New Jersey, Brunswick, NJ. P.O. Box 4247, Tucson, AZ 85738-1247 January 31. p. 1-2. Tel: 800-827-2847 McKinlay, Roderick G. 1992. Vegetable Crop Pests. CRC Fax: 520-825-2038 Press, Boston, MA. p. 98-101. E-mail: [email protected] Metcalf, R.L. and R.A. Metcalf. 1993. Destructive and Golden Harvest Organics Useful Insects, 5th edition. 404 N. Impala Drive, Fort Collins, CO 80521 Tel: 970-224-4679 McGraw-Hill Book Co., New York, NY. p. 14.6-14.9. Fax: 413-383-2836 Nielsen, G.R. 1997. Flea Beetles. University of Vermont E-mail: [email protected] Extension. EL71. www.uvm.edu/pss/ppp/pubs/el71.htm www.ghorganics.com/StickyTrap.html Rateaver, Bargyla and Gylver Rateaver. 1993. Th e Organic Method Primer, Update Special Edition. Rateavers, San Diego, CA. p. 137. Flea Beetle: Organic Control Options Spring, Alexandra, and Eric Day. No date. Flea Beetles. By George Kuepper, NCAT Agriculture Specialist Dept. of , Virginia Tech, Blacksburg, VA. Published March 2003 https://pubs.ext.vt.edu/3104/3104-1549/3104-1549_pdf.pdf Updated by Rex Dufour, NCAT Agriculture Specialist USDA. No date. Lawn and Garden Care.Natural Resources April 2015 ©NCAT Conservation Service. www.nrcs.usda.gov/wps/portal/nrcs/ Cathy Svejkovsky, Editor • Amy Smith, Production detail/national/home/?cid=nrcs143_023497 This publication is available on the Web at: Further Resources www.attra.ncat.org IP389 Websites Slot 109 Evaluating trap crops for controlling fl ea beetle in brassi- Version 042815 cas, and an organic trial by Mary Scott. Organic

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