Trap Cropping: a Simple, Effective, and Inexpensive Organic IPM Approach to Manage Cucumber Beetles and Squash Bugs in Cucurbit Crops Jaime C

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Trap cropping: A simple, effective, and inexpensive organic IPM approach to manage cucumber beetles and squash bugs in cucurbit crops Jaime C. Piñero and Jacob T. Wilson Lincoln University Cooperative Research and Extension, Jefferson City, MO 65101 RESULTS (cont’d.) ABSTRACT The relative attractiveness of Blue Hubbard, Red Kuri Hubbard, METHODS (cont’d.)  In 2013, RK was 6.7 – 11 times more attractive than the cash crop to and Buttercup squash plants (trap crop plants) to adult spotted cucumber Each treatment plot was replicated 4 times. Two trap crop plants of the • spotted cucumber beetles (Fig. 6A) and 2.4 – 23 times more attractive than beetle (Diabrotica undecimpunctata howardii), striped cucumber beetle assigned variety were planted in each of the outermost rows (1 and 6) of (Acalymma vittatum), and squash bug (Anasa tristis) were evaluated using a the cash crop to striped cucumber beetles (Fig. 6B). each sub-plot. The 4 inner rows in each comparative behavioral approach. In addition, the ability of trap crop plants to replicate consisted of the cash crop, sBH wa 6.7 – 11 times more attractive than the cash crop to spotted

prevent pest numbers from exceeding economic thresholds in the cash crop zucchini, for a total of 16 cash crop beetles and 2.4 – 23 times more attractive than the cash crop to striped was assessed. These insects have consistently been identified as the most beetles (Fig. 6A,B). plants per replicated sub-plot (Fig. 2A). 5 Red Kuri Hubbard damaging insect pests of cucurbits in areas of the US where the crops are cash crop Blue Hubbard 2013: Four 2-week old seedlings of the appropriate treatment (Blue Hubbard 4 A grown and truly effective organic management approaches are lacking. Results • cash crop Buttercup indicate that all three squash varieties suppressed squash bugs from cash = BH, Red Kuri Hubbard = RK, or Buttercup = BC) were planted at each end of 3 cash crop control crops, but for spotted and striped cucumber beetles Red Kuri squash and Blue every row (Fig. 2B). The cash crop, Zephyr summer squash, was direct seeded 2 at the same time at 18 inch intervals which resulted in about 65 plants per Hubbard squash performed best throughout the growing season. Therefore 1 Red Kuri Hubbard and Blue Hubbard squash represent excellent trap crop row. This resulted in a cash crop to trap crop ratio of ca. 8:1. 0 plants to manage key insect pests of cucurbits in organic systems. • For all evaluations, data were collected 3 times per week for 6-8 weeks. The 24-Jun 25-Jun 26-Jun 27-Jun 28-Jun 29-Jun 30-Jun 1-Jul 2-Jul 3-Jul 4-Jul 5-Jul 6-Jul 7-Jul number of insect pests (by species) was counted for all trap crops and INTRODUCTION The concept of trap cropping fits into the ecological 1.50 Red Kuri Hubbard B randomly selected cash crop plants per row. All insects and egg masses were cash crop framework of habitat manipulation of an agro-ecosystem for the purpose of 1.25 Blue Hubbard removed by hand from the field as they were counted. cash crop 1.00 Buttercup pest management (Shelton and Badenes-Perez, 2006). Trap crops function cash crop Mean number of insects removed insects of number Mean 0.75 control Control A B by delivering pest-behavior-modifying stimuli that attract the pest to the (no trap crop) Red Kuri Hubbard Buttercup Blue Hubbard CASH CROP: ZEPHYR SQUASH Blue 0.50 Hubbard squash CASH CROP: ZEPHYR SQUASH border areas thereby reducing – or even eliminating, pest numbers in the 0.25 CASH CROP: ZEPHYR SQUASH Red Kuri cash crop, resulting in a reduced or eliminated need for chemical Hubbard 0.00 squash application to the crop (Cook et al., 2007). Due to its high attractiveness to CASH CROP: ZEPHYR SQUASH CASH CROP: ZEPHYR SQUASH Buttercup squash cucumber beetles and low susceptibility to bacterial wilt, Blue Hubbard CASH CROP: ZEPHYR SQUASH Fig. 6: Occurrence of (A) spotted cucumber beetles, and (B) striped cucumber beetles on trap crop and cash crop plants in experimental plots at the LU Carver farm in 2013. squash has been shown to perform well as a perimeter trap crop for striped Fig. 2: Layout of the experimental plots used in the (A) 2012, and (B) 2013 field evaluations at two cucumber beetle, Acalymma vittatum (Coleoptera: Chrysomelidae), in Lincoln University (LU) research farms in Jefferson City, Missouri. ON-FARM RESEARCH summer squash (Pair, 1997), cantaloupe (Boucher and Durgy, 2004), and  Seven farmer cooperators, including a NCR-SARE FR grant recipient, have butternut squash (Cavanagh et al., 2009). Perimeter trap cropping, however, RESULTS adopted the trap cropping approach in their vegetable farms. Four of these needs to be improved and adapted to the current size and conditions of  Overall, the most attractive trap crop for striped cucumber beetles was RK, but farms are certified organic. AZERA™ insecticide (pyrethrins + azadirachtin) organic farms, and tested against multiple pest species. This study aimed at for spotted cucumber beetles both RK and BH were equivalent (Figs. 3 and 4). has been their method of choice for killing insects on trap crop plants. Fig . 7 illustrates the level of season-long insect pest suppression achieved at assessing the attractiveness of Blue Hubbard, Red Kuri Hubbard, and  At both farms, all trap crops were equally effective at suppressing all three pest the EarthDance organic farm by planting BH squash in 2 perimeter rows. Buttercup squash to adult spotted cucumber beetle, (Diabrotica species from cash crops (Figs. 3, 4, and 5). Insect pest: Squash Bug Insect pest: Spotted cucumber beetle Insect pest: Striped cucumber beetle Earth Dance Farms Earth Dance Farms Earth Dance Farms 0.20 0.08 0.24 AVG_Striped_TrapCrop 0.18 AVG_SB_TrapCrop AVG_Spotted_TrapCrop 0.22 0.07 AVG_Spotted_CASH_Crop AVG_Striped_CASH_Crop undecimpunctata howardii) striped cucumber beetle, (A. vittatum, and AVG_SB_CASH_Crop 0.20 A 4.5 A 0.16 0.9 Diabrotica undecimpunctata howardii 0.06 0.18 0.14 4.0 0.16 0.8 Acalymmavittatum SEM) of 0.05 A ± 0.12 squash bug (Anasa tristis) 0.7 AB 3.5 0.14 A A A 0.10 0.04 0.12 0.6 3.0 A A (mean 0.08 0.10 2.5 0.03 0.5 0.08 0.06 (Heteroptera: Coreidae), as well insects removed 2.0 0.02 0.06 0.4 B A 0.04 0.04 1.5 Number 0.01 0.3 0.02 0.02 as the plant’s ability to suppress 1.0 0.2 0.00 0.00 0.00 a a a a a a 5/8/2014 5/15/2014 5/22/2014 5/29/2014 6/5/2014 6/12/2014 6/26/2014 5/8/2014 5/15/2014 5/22/2014 5/29/2014 6/5/2014 6/12/2014 6/26/2014 5/8/2014 5/15/2014 5/22/2014 5/29/2014 6/5/2014 6/12/2014 6/26/2014 0.5 a a 5/12/2014 5/19/2014 5/26/2014 6/2/2014 6/9/2014 6/16/2014 6/30/2014 5/12/2014 5/19/2014 5/26/2014 6/2/2014 6/9/2014 6/16/2014 6/30/2014 5/12/2014 5/19/2014 5/26/2014 6/2/2014 6/9/2014 6/16/2014 6/30/2014 0.1 0.0 Date Date Date pest numbers in various cash 0.0 Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini control TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP Fig. 7: Season-long evaluation of Blue Hubbard squash as trap crop to suppress key insect pests from the cash crops in multiple farms over TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP control crops at EarthDance Farms (Ferguson, MO). Website: http://www.earthdancefarms.org. Diabrotica undecimpunctata howardii

insects removed SEM) of insects A SEM) removed of insects 21 Spotted Fig. 1. Cucumber beetles and the squash bug are key insect 27 A Diabrotica undecimpunctata howardii A A A Acalymmavittatum ± ± Striped several years. pests of cucurbit crops in many areas of the U.S. 24 Acalymma vittatum B 18 21 A B For one conventional farmer that now practices 15 A (Mean 18 A 15 12 Integrated Pest Management, use of trap cropping 12 B METHODS 9 9 A has saved him about $ 400 per acre in labor, Number 6 B (Mean Number 6 B 3 a a a Field studies were conducted at the Lincoln University (LU) George a a a a a a a a 3 a a a pesticide, and fuel, per growing season. He has not 0 a a Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini control 0 sprayed his cash crops for 3 years in a row. Washington Carver (2011-2014) and Alan T. Busby (2012-2014) certified- TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini control TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP organic research farm, in Jefferson City, Missouri. Reported here are the Fig. 3: Number of cucumber beetles in experimental plots Fig. 4: Number of cucumber beetles in experimental plots CONCLUSIONS approaches followed for the years 2012 and 2013. at the LU Carver farm on (A) week 1, and (B) weeks 2-3 at the LU organic Busby farm on (A) week 1, and (B) weeks after transplanting during 2012. 2-3 after transplanting during 2012. Trap cropping is an effective IPM tool for organic cucurbit growers.  Trap crop transplants were grown in the greenhouse using soilless, peat For both figures (3 and 4): For each beetle species (blue: spotted, red: striped cucumber beetle), bars with same uppercase letters are not dBH, RK, an BC are all attractive trap crop varieties to cucurbit pests. significantly different (ANOVA and Fisher-protected LSD tests, P > 0.05). Letters in lower case denote comparisons made across cash crops. based, potting media. All trap crop and cash crop seeds were certified Cucurbit trap cropping is effective at suppressing pests in the cash crop

0.20 0.9 3.0 3.0 organic and were purchased from Johnny’s Selected Seeds. A A with as few as 11 % of the total plants being trap crops. 0.8 A 2.5 C 2.5 D A 0.7 B 0.15 A

SEM) of A 0.6 A After field preparation, raised, plastic mulch-covered beds with drip ± 2.0 2.0 ACKNOWLEDGMENTS We thank G. Ndunguru, K. Kliethermes, J. Miller, E. Ovwielefuoma, A. Dudenhoeffer, T. 0.5 0.10 A 1.5 1.5 A Hussain, A. Hemwall, D. Newman, L. Hunter, and D. Panday for assisting with data collection. Funding for this study was (mean A 0.4 irrigation were installed. In most cases, rows were 35 m long. 0.3 provided by USDA-NIFA Capacity Building Grant program and the Ceres Trust: An Organic Initiative.

insects removed insects 1.0 1.0 0.05 0.2

Number A 0.5 A 0.5 0.1 a a a REFERENCES 2012 : Evaluations were conducted in 16 small-scale plots. Each plot was a A a a a a 0.00 0.0 0.0 0.0 Boucher, T.J. and Durgy, R. 2004. Demonstrating a perimeter trap crop approach to pest management on summer squash in New England. J. Extension Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini control Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini control Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini control Red Kuri Zucchini Buttercup Zucchini Blue Hubbard Zucchini Zucchini control (http://www.joe.org/joe/2004october/rb2.php) TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP TRAP CROP CASH CROP randomly assigned one of the following treatments: (1) Red Kuri Hubbard Cavanagh, A., Hazzard, R., Adler, L.S., and Boucher, J. 2009. Using trap crops for control of Acalymma vittatum (Coleoptera: Chrysomelidae) reduces insecticide use Fig. 5: Number of squash bugs in experimental plots at (A) LU Carver farm, weeks 1-3, (B) LU Carver farm, weeks 4-6, (C) LU organic in butternut squash. J. Econ. Entomol. 102: 1101-1107. squash, (2) Blue Hubbard squash, (3) Buttercup squash, and (4) control (no Cook, S.M., Khan Z.R., and Pickett, J.A. 2007. The use of push-pull strategies in Integrated Pest Management. Annu. Rev. Entomol. 52: 375-400. Busby farm, weeks 1-2, and (D) LU organic Busby farm, weeks 3-4. Bars with same uppercase letters are not significantly different Pair, S. D. 1997. Evaluation of systemically treated squash trap plants and attracticidal baits for early-season control of striped and spotted cucumber beetles (ANOVA followed by Fisher-protected LSD tests, P > 0.05). Letters in lower case denote comparisons made across cash crops. (Coleoptera: Chrysomelidae) and squash bug (hemiptera: Coreidae) in cucurbit crops. J. Econ. Entomol. 90: 1307-1314. trap crop). Shelton, A.M. and Badenes-Perez, F.R. 2006. Concepts and applications of trap cropping in pest management. Annu. Rev. Entomol. 51: 285–308.