Role of Pheromones and Plant Volatiles in Insect Pest Monitoring and Control Jaime C. Piñero

Transcription

1 Role of Pheromones and Plant Volatiles in Insect Pest Monitoring and Control Jaime C. Piñero Assistant Professor and State IPM Specialist Cooperative Research and Extension Lincoln University of Missouri

2 Presentation Layout 1. Importance of Pheromones and Plant Volatiles 2. Pheromone-Based Systems 3. Effective Monitoring Systems 4. Behaviorally-Based Insect Pest Management Cucurbits

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4 OLFACTION: A key aspect of insect behavior SEX PHEROMONES Pheromone lures can be used for monitoring and control (e.g., mating disruption) Male Ceanothus Moth PLANT VOLATILES Because plant volatile compounds play a critical role in the insect s life, they can be a useful tool in insect pest management programs Plant volatiles can be used in the form of synthetic attractants in traps for monitoring and control (e.g., mass-trapping) Most insects show a preference for particular plant species; therefore, plant volatiles emitted by preferred host plants represent the best attractant for insects

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6 Importance of Insect Sex Pheromones 1. Tomato pinworm (Keiferia lycopersicella) 2. Two-spotted spider mites 3. Fruit sunscalding

7 Tomato Pinworm Monitoring and Control Primary pest of tomatoes in regions of Florida, California, Texas, and Mexico Larvae are leafminers during early instars and then become leafrollers as they increase in size Although foliar injury can suppress growth of younger plants, greatest damage occurs when older larvae enter the tomato fruit Worms enter below the calyx and increase the likelihood of decay Monitoring: Pheromone-baited traps Control: Mating disruption

8 Mating Disruption Practice of dispensing synthetic species-specific sex attractants into a To achieve control, the grower crop to suppress pest reproduction by interfering with mate finding typically must apply the pheromone treatment as soon as the adult stage of the insect shows up While insecticides can control very heavy infestations, mating disruption works best when pest densities are low The effectiveness of mating disruption is measured by the extent that moths are prevented from finding pheromone traps (i.e., no male moths should be captured!). Typically one monitoring trap is deployed per 2-3 acres. competitive attraction Non-competitive means

9 100 EPA registrations of insect pheromones for use as pest control agents in agriculture and forestry Mating disruption for all insect pests encompasses 700,000 ha (1.7 million acres) worldwide, 160,000 of which target codling moth, Cydia pomonella (in the USA).

10 Tomato Pinworm Mating Disruption 1. MONITOR using pheromone-baited traps deployed in early April to determine first flight and continue throughout the season to help assess treatment effectiveness 2. Application of NoMate TPW should take place no later than two weeks after transplant OR if traps capture 2-5 tomato pinworms per day 3. Apply at a rate of spirals per acre (200 under low population pressure; 400 at high pressure levels 4. Minimum recommended area is 5 acres Spirals are applied directly by wrapping the spiral around stems, branches, stakes, wires, and strings

11 Effective Plant-Based Monitoring Systems Most effective lures involve a combination of pheromones and plant volatiles

12 Effective monitoring systems? The economic threshold for direct counting cucumber beetles on muskmelon is 1 beetle per plant, and using yellow sticky traps is 10 beetles per trap per day

13 2010 Eval. of lures using sticky cards Lure H most attractive to spotted and striped cucumber beetles * MEAN NUMBER CAPTURED PER TRAP TRAPS BAITED WITH FLORAL-BASED COMMERCIAL LURES * Funding provided by North Central IPM Center ( )

14 Behaviorally-Based Insect Pest Management

15 Push-Pull Strategy Behavioral manipulation of insect pests and their natural enemies via the integration of stimuli that act to: (1) make the protected resource unattractive or unsuitable to the pests (PUSH) while (2) luring them toward an attractive source (PULL) from where the pests are subsequently removed or killed REQUIREMENTS: Lures, traps, and repellents (or deterrents) IN SOME CASES, NON-TOXIC COMPONENTS

16 Perimeter Trap Cropping (PTC) Plants that are planted next to a higher value crop so as to attract pest as either a food source or oviposition site PTC: Functions by concentrating and/or killing the pest in the border area, while reducing pest numbers on the unsprayed cash crop Plant species or cultivar used needs to be more attractive to pest than crop is Advantages: 1. Decrease pesticide use and costs 2. Natural enemies can reproduce in trap crop plants (induced volatiles) 3. Improve crop s quality 4. Help conserve the soil and environment

17 An Example The diamondback moth (DBM) becomes resistant to insecticides quickly and is therefore difficult to control in cole crops Researchers in Florida were able to keep the DBM at low populations in 9 commercial cabbage fields by surrounding them with two rows of collards A naturally occurring parasitic wasp helped control the population. At low DBM populations: no insecticides were needed Cabbage fields surrounded by 2 rows of collards (in Florida) Parasitic wasps can reduce pest numbers in trap crop plants

18 Other Examples Insect Trap Crop Observations Colorado potato beetle Flea beetles European corn borer and fruitworm Potato variety Superior (grows well in cool weather) Chinese Southern Giant Mustard (Brassica juncea var. crispifolia) Corn (sweet or field) Plant the trap crop between last year s and this year s fields (near overwintering sites) Main crops: cabbage, broccoli, or cauliflower. Reseeding of the trap crop may be necessary Main crop: pepper (for European corn borer) and tomato (for fruitworm) Need to be validated in Missouri

19 Dead-End Trap Crops Highly attractive plants for egg-laying but larvae are not able to survive! Example: Yellow rocket (Barbarea vulgaris R. Br.), a wild crucifer, can be used as a trap crop for diamondback moth (cabbage, broccoli and cauliflower) In greenhouse trials, the egg-laying preference for yellow rocket varied between fold over cabbage; no larvae were able to develop on yellow rocket (presence of saponins) More research needed Although growers consider B. vulgaris a weed, it may have some advantages as a trap crop for management of diamondback moth.

20 Blue Hubbard squash: An Effective Trap Crop? Very attractive to adult cucumber beetles Not susceptible to bacterial wilt Diabrotica undecimpunctata howardi Acalymma vittatum Picture: Squash Bug Squash Vine Borer

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22 6 butternut growers planted a Blue Hubbard border around fields (2 to 6 acres). These 6 fields were compared to conventional butternut fields where beetles were controlled with full-field insecticide sprays Fields were scouted twice weekly until first leaves, then weekly until flowering. Borders were sprayed at the first arrival of the beetles CB were only found in the trap crop and insecticides were only applied to the perimeter trap crop Excellent performance of Blue Hubbard squash (cash crop was not sprayed). In addition, yield in PTC plots was 12.5% higher in plots surrounded by Blue Hubbard, lowest yield was in sprayed plots 85% less insecticide was applied

23 Two-row perimeter of buttercup squash around a main crop of butternut. Picture: Univ. of Massachusetts

24 Research at Lincoln University

25 Research Objectives 1. Develop mass trapping systems (spring and fall) Evaluation of synthetic volatile compounds Evaluation of various traps (including home-made) 2. Evaluate effectiveness of trap crop species (preliminary) 3. Evaluate (kaolin clay) Surround as a deterrent 4. Assess effects of trap type and color on cucumber beetle attraction

26 Push-Pull Strategy for Cucumber Beetles Traditional Lincoln University Kaolin Clay (Surround) Applied weekly Perimeter trap crop = 20% (to be sprayed) Usually not marketable Trap crop plants + mass trapping

27 Trap Crop Study: June-July 2011 Control (no trap crop) Buttercup squash Blue Hubbard squash Lemondrop squash Approach replicated twice Inter-plant distance: 1.5 ft; inter-plot distance: 20 ft NO INSECTICIDE APPLIED TO ANY PLANT INSECTS NOT REMOVED

28 Results Number (mean ± SEM) of insects counted Jun NO INSECTICIDE APPLIED TO ANY PLANT INSECTS NOT REMOVED Control (no trap crop) Buttercup squash Blue Hubbard squash Lemondrop squash

29 Results Number (mean ± SEM) of insects counted Jun Jul NO INSECTICIDE APPLIED TO ANY PLANT INSECTS NOT REMOVED Control (no trap crop) Buttercup squash Blue Hubbard squash Lemondrop squash

30 Results Number (mean ± SEM) of insects counted Jul NO INSECTICIDE APPLIED TO ANY PLANT INSECTS NOT REMOVED Control (no trap crop) Buttercup squash Blue Hubbard squash Lemondrop squash END OF TEST: SQUASH PLANTS IN VERY BAD SHAPE. BEETLE POPULATIONS VERY HIGH

31 On-farm Trap Crop Study Mr. Jose Fonseca (St. Peters, MO) 13 acres, mostly tomatoes (9 acres), cucurbits (3), cole crops (1), Conventional vegetable farmer, very interested in IPM

32 Problem: cucumber beetles get inside hoophouse and kill the seedlings Solution: Application of systemic insecticide Imidacloprid (Admire PRO)

33 2011 Trap Crop Approach: Mr. Fonseca planted Blue Hubbard squash, planted in pots, and placed 4 plants outdoors, on the corners of the hoophouse

34 May 8, 2011 Mr. Fonseca counted 121 striped cucumber beetles and 4 spotted beetles on the 4 Blue Hubbards Forgot to apply Imidacloprid. At this moment, the 4 plants were treated No beetles were seen inside the hoophouse (1,000 zuchinni seedlings) Suggested to grow more Blue Hubbards and plant 2 perimeter-rows to protect the zucchinis when transplanting to the field

35 June 6, 2011 Mr. Mbogho and I travelled to Mr. Fonseca s farm. Couldn t find the 2 rows of Blue Hubbards! Farmer indicated that was unable to grow more Blue Hubbard plants Conducted a random sampling of 25 Zucchinis; also counted beetles on the 4 Blue Hubbard plants that he had transplanted to the field Results?

36 June 6 - Results Insect Mean 4 BH Mean 25 Zuch. Striped Spotted Squash bugs

37 June/July - Results Date Insect Mean 4 BH Mean 25 Zuch Striped Spotted Squash bugs Date Insect Mean 4 BH Mean 25 Zuch Striped Spotted Squash bugs Date Insect Mean 4 BH Mean 25 Zuch Striped Spotted Squash bugs 0 0 Date Insect Mean 4 BH Mean 25 Zuch Striped Spotted Squash bugs 0 0 Date Insect Mean 4 BH Mean 25 Zuch Striped 0 0 Date Insect Mean 4 BH Mean 25 Zuch Striped Spotted Squash bugs Spotted Squash bugs 0 0 Sprayed!

38 WATERMELON VARIETY TRIAL (DR. GU) AT MU SW RESEARCH CENTER MT. VERNON, MO (TRAP CROPS PLANTED ON 17 JUNE, 2011)

39 Squash Bug Egg-laying 10 leaves sampled per plant 4 plants sampled per squash type IN RED: Percentage of sampled leaves that had squash bug eggs 12.5% 17.5% 22.5%

40 Conclusions Trap crops: a promising management tool for cucurbit pests Also represent an important monitoring tool Critical to plant 1- or 2-week old Blue Hubbard plants Critical to kill insects in trap crops Approach requires an understanding of several factors: Need to use mixtures (e.g., Buttercrop + Blue Hubbard)? Spatial layout of the trap crop Proportion of trap crops needed Organic systems

41 Outlook 1. Continue with 2011 studies 2. Compare Blue Hubbard with Red Kuri Hubbard squash 3. Evaluate effectiveness of trap crop in other crops (e.g., Solanaceous and Brassicas) 4. Evaluate plant extracts mixed with various insecticides incl. organic (USDA-ARS, Beltsville, MD) 5. Evaluate Vittatalactone, the newly identified striped cucumber beetle aggregation pheromone 6. Effects of trap crops on natural enemy abundance

42 Thanks to my students! Austen Dudenhoeffer Tom Vehige Aaron Mbogho Angelica Wells

43 Thank You! We can t solve problems by using the same kind of thinking we used Questions? when we created them - Albert Einstein