Corn Earworm A Review of Corn Earworm and Other Insect Problems in 211 Rick Foster Purdue University Corn Earworm Biology Females prefer to lay eggs on green silks Corn Earworm Control Must have insececide present on silk when larvae hatches from egg Pyrethroids have been primary control opeons, especially Capture, Mustang Max, Hero, and Warrior Some concerns about resistance Coragen and Radiant appear to be good alternaeves Pest of sweet corn, seed corn and tomato Two generaeons per year where it overwinters 2nd is usually most important Does not overwinter in large numbers in northern 2/3 of Indiana Corn Earworm Biology Females prefer to lay eggs on green silks When larvae hatch, they move directly into the ear Ep Once inside the ear, the larvae are protected from insececides Corn Earworm Management Treat when fresh, green silks are present (start at 7%) Treat if catching more than 1 moths per night 1
Corn Earworm Management Make treatments every 2-5 days from 7% silks unel silks are brown; generally 3-4 treatments Shorten interval if temperatures are high Shorten interval if moth catches are high Corn Earworm Management First generaeon populaeons may or may not reach economic levels During much of the season, few earworms present Once the second generaeon hits, populaeons will likely be high for the rest of the season Date of arrival of second generaeon is variable A pheromone trap is a criecal management tool 28 Meigs Farm CEW Pheromone Trap Catches 26 Meigs Farm CEW Pheromone Trap Catches 3 12 25 1 Moths per Week 8 6 4 Moths per Week 2 15 1 2 5 6/15/26 6/22/26 6/29/26 7/6/26 7/13/26 7/2/26 7/27/26 8/3/26 Week Ending 8/1/26 8/17/26 8/24/26 8/31/26 9/7/26 9/14/26 6/16/28 6/23/28 6/3/28 7/7/28 7/14/28 7/21/28 7/28/28 8/4/28 8/11/28 8/18/28 8/25/28 9/1/28 9/8/28 Week Ending 2
CEW Management Tips The first applicaeon (7% silks) is the most criecal, with each succeeding spray being less important Ge[ng good coverage of the silks is imperaeve consider drop nozzles. Test with water sensieve paper. High gallonage is preferred 2 gallons per acre or more RELATIONSHIP BETWEEN CORN EARWORM PHEROMONE TRAP CATCH AND EGG LAYING RelaEonship Between Pheromone Trap Catch and Egg Laying Nightly RelaEonship Between Trap Catch and Egg Laying What Affects Trap Catch? Full moon suppresses trap catch High relaeve humidity (5 8%) increased trap catch What Affects Egg Laying? Egg laying was suppressed during full moon High humidity suppressed egg laying Egg laying was increased (per moth caught in pheromone trap) in early season sweet corn 3
So, how do we use threshold? CEW Pheromone Trap Catch - 21 In general, we should conenue to use 1 moths per night as the threshold for most of the season For early season sweet corn (before nearby field corn in silking, use a threshold of 1. Moths Per Week 14 12 1 8 6 4 2 Pinney Lafayette 3 CEW Pheromone Trap Catch - 211 25 CABBAGE CATERPILLARS Moths Per Week 2 15 1 Pinney Lafayefe 5 6- Jun 13- Jun 2- Jun 27- Jun 4- Jul 11- Jul 18- Jul 25- Jul 1- Aug 8- Aug 15- Aug 22- Aug 29- Aug 5- Sep Diamondback Moth Diamondback Moth Most serious pest worldwide - $1 billion annually Resistant to many insececides in some places Appear early in growing season Larvae are small (5/16 inch), light- green, tapered, and wiggle when disturbed 4
Imported Cabbageworm Imported Cabbageworm Adults are white buferflies Larvae are velvety green, 1 inch long RelaEvely easy to control Cabbage Looper Cabbage Looper Does not overwinter; late season pest Larvae loop when they crawl Pale green; 1 1/2 inch long RelaEvely difficult to control Caterpillar Damage Chew holes in leaves; bore into head Young plants killed Older plants stunted Heads abort or are unmarketable ContaminaEon Management OpEons Method DBM ICW CL Natural enemies +++ ++ + Early planting --- + ++ Bt insecticides +++ +++ ++ Chemical insecticides +++ +++ +++ Overhead irrigation ++ --- --- Crop destruction --- + --- 5
Cabbage Thresholds Broccoli, Cauliflower Thresholds Stage Diamondback Moth ICW and Loopers Transplant to cupping 5% with > 5 larvae/plant 3% Cupping to early head 5% with > 5 larvae/plant 2% Early head to harvest 1% with > 1 larva/plant 1% Stage Diamondback Moth ICW and Loopers Seedbed 1 % 1% Transplant to first curd 4% 2% First curd to harvest 1% 1% InsecEcides Pyrethroids Ambush, Asana, Baythroid, Brigade, Hero, Mustang Max, Pounce, Warrior Bt Avaunt Confirm, Intrepid, Rimon Coragen Radiant, Entrust, SpinTor Proclaim Larvin, Lannate Cabbage InsecEcide Trial - 211 Chemical Rate/acre Loopers ICW DBM Yield Untreated - - - - - 3. ab 13.25 a 24. ab 1.8 e Coragen 5 fl. oz. 4.25 c 8.5 c 14.25 bc 85. a Radiant 1 fl. oz. 7. c 8.5 c 8.5 c 77.5 abc Proclaim 4.8 oz. 2.25 abc 16.25 bc 17. abc 81.7 ab Agree 2 lb. 35.25 a 9. c 12.25 c 71.7 bcd Avaunt 3.5 oz. 16.5 abc 14.75 bc 15.75 bc 65.8 cd Entrust 2. oz. 27.5 ab 21.25 b 1.5 c 64.2 d Intrepid 1 fl. oz. 13.75 bc 13.75 bc 3.5 a 65. cd Mustang Max 4 fl. oz. 21.25 abc 16.5 bc 18.5 bc 65.8 cd Crymax 2 lb. 23. abc 1.5 bc 17. bc 67.5 cd Hornworms TOMATOES HIGH TUNNELS Hornworms are generally a minor problem in field grown tomatoes 6
Insects in High Tunnels Popular literature says that most insects will be less serious in high tunnels than in field Hightunnels.org decreased incidence of pest and disease problems Vermont High Tunnel Guide Insect pests generally cause less damage in high tunnels than they do in the field Not supported by research data Our research shows that most insects can be as bad or worse in high tunnels 7
Hornworms High Tunnels vs. Field Brown Marmorated SEnk Bugs Found in Indiana Hornworms/ Plant 1.8 1.6 1.4 1.2 1.8.6.4.2 -.2 A 1.15 HT A.32 Field Hornworms / Plant 7 6 5 4 3 2 1 A 4.73 High Tunnel A 1.88 Field Plot First discovery in Elkhart County in November, 21 Confirmed in 6 counees Likely present in many other locaeons All confirmed counees are along interstate 21 211 Brown Marmorated Stinkbug, Halyomorpha halys (Stal) Why should we care about brown marmorated senk bugs? Serious pest of vegetables such as tomatoes, peppers, sweet corn, green beans, etc. Serious pest of fruit crops such as peaches, apples, grapes, etc. Pest of corn and soybeans Pest of many ornamental plants They like to overwinter inside homes They are difficult to control They senk 8
History Important pest in naeve range of Korea, China, and Japan First detected in Allentown, PA in 21 Now a serious problem along most of the eastern seaboard Problems usually appear in homes for several years prior to becoming a serious crop pest Find in Elkhart Co. was in a home large numbers Biology Overwinters as adult (inside) Become aceve in May First afack trees and orchards Later vegetables and soybeans Probably 2 or more generaeons per year IdenEficaEon Management No good sampling methods available yet Blacklight traps Pyramid trap Direct observaeons No economic thresholds No cultural methods No biological control No organic control solueons Several pyrethroids and a number of older insececides seem to provide good control Brown Marmorated Stink Bug Trapping 211 9
Brown Marmorated Stink Bug Trapping 211 Blacklight Trap and Pyramid Traps Blacklight Trap Only Pyramid Trap Only Brown Marmorated Stink Bug Trapping 211 Blacklight Trap and Pyramid Traps Blacklight Trap Only Pyramid Trap Only ImplicaEons We probably have a few years before BMSB becomes a serious crop pest Growing organic fruits and vegetables will become increasingly difficult Vegetable growers will likely increase pesecide use What should you do? Stay calm; it s not a problem yet If you think you see BMSB, collect some and report to your county Extension educator QuesEons? 1