DATE. OF OUT IS iiimminti A GUIDE TO immam. information: PEPPERMINT IDENTIFICATION AND MANAGEMENT PUBLICATIONcurrent most THIS For http://extension.oregonstate.edu/catalog 4 PNW 182 OREGON WASHINGTON IDAHO Ordering Instructions If you would like additional copies of PNW 182, A Guide to Peppermint Insect and Mite Identification and Management, send $5.00 per copy to: Publications Orders DATE. Agricultural Communications Oregon State University Administrative Services A422 OF Corvallis, OR 97331-2119 Bulletin Office Cooperative Extension Cooper Publications Building OUT Washington State University Pullman, WA 99164-5912 IS Both universities offer discounts on orders of 100 or more copies of a single title. For price quotes in Oregon, please call (503) 737-2513; in Washington, please call (509) 335-2857. information: PUBLICATIONcurrent most THIS For http://extension.oregonstate.edu/catalog DATE. OF OUT IS information: A Guide to Peppermint Insect and Mite IDENTIFICATION AND MANAGEMENT current PUBLICATION PNW 182 Ralph E. Berry, professor of entomology, and Revised February 1993 most Glenn Fisher, Extension entomologist, THIS For Oregon State University http://extension.oregonstate.edu/catalog Due to constantly changing labels, laws, and regulations, the Extension Service can assume no liability for the suggested use of chemicals contained herein. The pesticide label is a legal document. The user is required by law DATE.to use the pesticide in a manner consistent with label direc- tions. OF The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products imiplies noOUT endorsement by the authors or the Extension Services of Oregon, Washington, or Idaho. Criticism of productsIS or equipment not listed is neither implied nor intended. information: PUBLICATIONcurrent most THIS For http://extension.oregonstate.edu/catalog Contents Introduction 1 DATE. Insect and Mite Identification on Peppermint 2 Pests Chewing on Leaves 2 Pests on Rhizomes, Roots, or Stems 2 OF Pests Sucking on Leaves or Stems3 Beneficial Insects and Mites3 Predators 3 OUT Parasites5 Parasitic Nematodes 5 IS Life Ccs ar 7 Pests Chewing on Leaves7 Var:egated Cutworm 7 iedbackectnworm (castinformation: of the Cascade Mountains)7 Alfalfa and Cc :bage I.,00rs 8 FalseCele- Leaflier8 .urange Mint Moth8 Grasshopptss9 Pests oncurrent Rhizomes, Roots, or Stems 9 PUBLICATIONRoot Weevil9 Mint Flea Beetle 10 Mint Root Borer 11 most Garden Symphylan (west of the Cascade Mountains) 11 THIS Wireworms 12 Mint Stem Borer (east of the Cascade Mountains) 12 For Pests Sucking on Leaves or Stems 13 Twospotted Spider Mite 13 http://extension.oregonstate.edu/catalogMint Aphid 13 Management and Control 21 Detection and Population Sampling 21 Monitoring 22 Treatment Thresholds or Action Levels 22 DATE. Pests Chewing on Leaves 22 Variegated Cutworm 22 Redbacked Cutworm (east of the Cascade Mountains)OF 25 Alfalfa and Cabbage Loopers 26 False Celery Leaftier 27 Grasshoppers 27 Pests on Rhizomes, Roots, or StemsOUT 27 Strawberry Root Weevil 27 Mint Flea Beetle 29IS Mint Root Borer 30 Garden Symphylan (west of the Cascade Mountains)31 Wireworms 32 Mint Stem Borer (east of the Cascade Mountains) 32 Pests Sucking on Leavesinformation: or Stems 33 Twospotted Spider Mite 33 Mint Aphid 34 References 35 PUBLICATIONcurrent most THIS For http://extension.oregonstate.edu/catalog Introduction Introduction Correct pest management decisions depend on an Much of the information contained in this guide was understanding of many related factors, including: taken from the results of studies conducted by 1) stage(s) of the pests, 2) their density and distribu- graduate students and others at Oregon State Univer- tion in the field, 3) presence or absence of beneficial sity, and we particularly wish to acknowledge Len insects and mites, 4) occurrence of other pests such as Coop, Craig Hollingsworth, Steve Danielson, Jack plant diseases and weeds, 5) the stage and health of DeAngelis, Mike Talkington, Joe Cacka,DATE. Mark the crop, and 6) the alternatives available to control Morris, Gary Parsons, Don Emmenegger, Joyce the pest(s), if and when necessary. Takeyasu, and Elson Shields for their contributions. We also wish to thank Craig Baird, University of Pest management begins with accurate identification Idaho, Southwest Idaho ResearchOF Center, Parma; of insects and mites. Incorrect identification can result Mark Morris, A. M. Todd Company, Salem, OR; in the needless use of an insecticide and destruction of Keith Pike, Washington State University Irrigated beneficial predators and parasites. Mint fields must be Agriculture Research and Extension Center, Prosser; inspected on a regular basis to establish population and Jim Todd, Willamette Agriculture Consulting, trends and to determine whether or not control is Salem, OR,OUT for their assistance in reviewing this necessary. The use of treatment thresholds will reduce manuscript. Support for research on peppermint has the unnecessary use of insecticides, which will save beenIS provided by the Oregon Mint Commission, the money, protect natural predators and parasites and Oregon Essential Oil Growers League and the Mint delay the development of insecticide resistance. Industry Research Council. Natural parasites and predators may be sufficiently abundant in some mint fields to suppress pest popula- Some of the information contained in this publication tions without the use of insecticides or miticides. This was taken from the manual used to support the guide was prepared to help individuals accurately computer software for Insect Pest Management on identify and sample mint pests and beneficial insects information:Peppermint (IPMP), OSU Extension Service Special and mites, and to develop sound pest management Report 834 (1989, 1993). For more information on decisions based on treatment thresholds. It emphasizes using the IPMP decision support program on a insects and mites on peppermint, but several of the computer, write Ralph E. Berry, Department of same pests and beneficial insects and mites also occur Entomology, Oregon State University, Corvallis, OR on spearmint. Identification of pests and sampling 97331-2907. procedures are similar in peppermint and spearmint, but additional research is needed to developcurrent treatment thresholds for pestsPUBLICATION on spearmint. most THIS For http://extension.oregonstate.edu/catalog 1 A Guide to Peppermint Insect and Mite Identification and Management !9Ma. ect and Mitede ItifiAtion )1. PerIpermint Before using any insecticide in your fd, be sure you Pests on Rtmrdes, Roots, or Stems have accurately identified the insects and mites. If you need help call your county agent, someone at the I. Plants cut-off at or slightly below the soil surface university, or an experienced individual who is in the spring (Apr..11.May, early June). Lower foliage familiar with insects and mites on mint. with ragged-edged holes. Cutworms found beneath soil surface during the dayDATE. and feeding on above- Pests Chewing on Leaves ground foliage at night.Redbacked cutwormand other Euxou species (Figs. 1 and 2) andblack cut- Plants cut-off slightly below or above the soil Redbacked cutworm occurs only east of the surface; leaves with ragged-edged holes and above Cascade Mountains.OF ground stems with notches eaten out.Cutworms including variegated cutworm (Figs. 3 and 4), spotted Plants show wilted appearance above ground cutworm (Fig. 5), black cutworm, Bertha armyworm, during late August, September, and early October. western yellowstriped armyworm (Fig. 6), and others. Rhizomes with tunneling around the nodes or Damage from redbacked cutworm (Figs. 1 and 2) and OUTrhizomes hollow. MintrcH.)ot borer larvaif 1/2 inch long black cutworm usually occurs in April, May, and June. with three pairs of true legs (Fig. 9,adultFig. 10). If Other cutworms typically cause injury during JulyIS larvae smaller, 1/8 inch long, C-shaped, white legless and August. grub found feeding inside mint stems near the soil surface in Idaho or eastern Oregon, thenmint stem Ragged-edged holes eaten through the leaves and borer(Figs. 15 and 16). around the leaf margins, particularly on leaves mid- way and higher on the plant.Loopersincluding alfalfa Plants slow to grow in the fall and early spring. looper (Figs. 7 and 8) and cabbage looper. Surface feeding injury on the rhizomes, roots and information:stems. Small C-shaped white legless larvae 1/4 to Terminal leaves and buds tied together with silk. 1/2 inch long with brown heads in the soil around the Upper surface of leaves skeletonized or with small roots.Larvae of strawberry root weevil(Fig. 13) and holes.False celery leaftier larva(Fig. 17, adult Fig. 18). other weevil species such as black vine, obscure, and rough strawberry root weevils. Ragged or completely eaten leaves present on plants around the field margins at first, later entire Plants slow to grow in the spring. Feeding injury field with a ragged appearance.currentGrasshoppers evident on surface of the roots or just beneath root (Fig. 22).PUBLICATION epidermis, brown "tracking" evident just beneath root epidermis. Very small white larvae 1/8 inch long with Small semicircular or irregularly shaped notches three pairs of legs and a brown head may be found chewed in the leaf margins.Strawberry root weevil inside the roots or in the soil around the roots.Mint adults(Fig.most 14). Adult feeding is inconspicuous and is flea beetle larvae(Fig. 11). not economically important. THIS Plants stunted in irregular spots in the field, often Very small holes in leaves giving a shot-hole very slow-growing in the spring. Small, 1/8 to 1/4 Forappearance to the leaves.Mint flea beetle adults inch long, white centipede-like animals feeding on (Fig. 12). small roots leaving few root hairs, roots stunted and discolored with pruned appearance. Found principally http://extension.oregonstate.edu/catalogwest of the Cascade Mountains.Symphylans(Fig. 21). t anu Mite Identification on Peppermint 6. Plants appear s_unted r a Ac ,avis [ ist feeuing injury on rcasDots an1-. ard rhvorirws. 'tan"an orJr dark c: .A*17; 7- LP I ii it'ID we :ern and C.