role of pheromones and plant volatiles in insect pest...

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

1. Importance of Pheromones and Plant Volatiles

2. Pheromone-Based Systems

3. Effective Monitoring Systems

4. Behaviorally-Based Insect Pest Management

• Cucurbits

Presentation Layout

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OLFACTION: A key aspect of insect behavior

SEX PHEROMONES Pheromone lures can be used for monitoring

and control (e.g., mating disruption)

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

Male Ceanothus Moth

Importance of Insect Sex Pheromones

1. Tomato pinworm (Keiferia lycopersicella)

2. Two-spotted spider mites

3. Fruit sunscalding

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

Mating Disruption Practice of dispensing synthetic species-specific sex attractants into a crop to suppress pest reproduction by interfering with mate finding

To achieve control, the grower 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

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).

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 200-400 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

Effective Plant-Based Monitoring Systems

Most effective lures involve a combination of pheromones and plant volatiles…

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”

MEA

N N

UM

BER

CAPT

URE

D P

ER T

RAP

TRAPS BAITED WITH FLORAL-BASED COMMERCIAL LURES

Lure “H” most attractive to spotted and striped

cucumber beetles *

* Funding provided by North Central IPM Center (2010-2011)

2010 Eval. of lures using sticky cards

Behaviorally-Based Insect Pest

Management

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

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

Perimeter Trap Cropping (PTC)

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

An Example

Cabbage fields surrounded by 2 rows of collards (in Florida)

Parasitic wasps can reduce pest numbers in trap crop plants

Insect Trap Crop Observations Colorado potato

beetle Potato variety Superior

(grows well in cool weather) Plant the trap crop between last year’s and this year’s fields (near overwintering sites)

Flea beetles

Chinese Southern Giant Mustard (Brassica juncea

var. crispifolia)

Main crops: cabbage, broccoli, or cauliflower. Reseeding of the trap crop

may be necessary

European corn borer and fruitworm

Corn (sweet or field)

Main crop: pepper (for European corn borer) and tomato (for fruitworm)

Need to be validated in Missouri

Other Examples

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 24-66 fold over cabbage; no larvae were able to develop on yellow rocket (presence of saponins)

More research needed

Dead-End Trap Crops

Although growers consider B. vulgaris a weed, it may have some advantages as a trap crop for management of diamondback moth.

Picture: http://bugguide.net

Diabrotica undecimpunctata howardi

Acalymma vittatum

Very attractive to adult cucumber beetles Not susceptible to bacterial wilt

Blue Hubbard squash: An Effective Trap Crop?

Squash Vine Borer Squash Bug

85% less insecticide was applied

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

Two-row perimeter of buttercup squash around a main crop of butternut.

Picture: Univ. of Massachusetts

Research at Lincoln University

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

2010-2011 Research Objectives

Traditional

Perimeter trap crop = 20% (to be sprayed) Usually not marketable

Lincoln University

Trap crop plants + mass trapping

Kaolin Clay (Surround) Applied weekly

Push-Pull Strategy for Cucumber Beetles

Control (no trap crop)

Buttercup 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

Blue Hubbard squash

Trap Crop Study: June-July 2011

Num

ber (

mea

n ±

SEM

) of i

nsec

ts c

ount

ed

Control (no trap crop) Buttercup squash Blue Hubbard squash Lemondrop squash

Jun. 21 + 22 + 24 + 27 NO INSECTICIDE APPLIED TO ANY PLANT

INSECTS NOT REMOVED

Results

Num

ber (

mea

n ±

SEM

) of i

nsec

ts c

ount

ed


Jun. 29 + Jul. 1 + 6 + 8 NO INSECTICIDE APPLIED TO ANY PLANT

INSECTS NOT REMOVED

Results

Num

ber (

mea

n ±

SEM

) of i

nsec

ts c

ount

ed


Jul. 11 + 13 + 15 NO INSECTICIDE APPLIED TO ANY PLANT

INSECTS NOT REMOVED

END OF TEST: SQUASH PLANTS IN VERY BAD SHAPE.

BEETLE POPULATIONS VERY HIGH

Results

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

Problem: cucumber beetles get inside hoophouse and kill the seedlings

Solution: Application of systemic insecticide Imidacloprid (Admire PRO)

2011 Trap Crop Approach:

Mr. Fonseca planted Blue Hubbard squash, planted in pots, and placed 4 plants outdoors, on the corners of the hoophouse

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

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?

June 6 - Results Insect Mean 4 BH Mean 25 Zuch.

Striped 16.5 0.00

Spotted 1.0 0.04

Squash bugs 3.5 0.00

June/July - Results Date Insect Mean

4 BH Mean

25 Zuch. 06.20 Striped 3.0 0

06.20 Spotted 1.2 0

06.20 Squash bugs 0.0 0

Date Insect Mean 4 BH

Mean 25 Zuch.

06.27 Striped 0 0

06.27 Spotted 0.5 0

06.27 Squash bugs 0 0


Mean 25 Zuch.

07.05 Striped 0 0

07.05 Spotted 0.75 0



Mean 25 Zuch.

07.11 Striped 0.25 0

07.11 Spotted 0.50 0

07.11 Squash bugs 0.75 0


Mean 25 Zuch.

07.18 Striped 0 0

07.18 Spotted 0.75 0



Mean 25 Zuch.

07.25 Striped 0.5 0

07.25 Spotted 2.0 0.04


Sprayed!

WATERMELON VARIETY TRIAL (DR. GU) AT MU SW RESEARCH CENTER MT. VERNON, MO

(TRAP CROPS PLANTED ON 17 JUNE, 2011)

Squash Bug Egg-laying

12.5%

17.5% 22.5%

• 10 leaves sampled per plant • 4 plants sampled per squash type • IN RED: Percentage of sampled leaves that had squash bug eggs

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

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

Outlook

Angelica Wells

Thanks to my students! Austen Dudenhoeffer

Aaron Mbogho Tom Vehige

Thank You! Questions?

“We can’t solve problems by using the same kind of thinking we used

when we created them”

- Albert Einstein

role of pheromones and plant volatiles in insect pest...

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