SWD in strawberries, blueberries and

raspberries

Carlos García-Salazar, Rufus Isaacs, Steve Van Timmeren, and

Anamaría Gómez-Rodas

MSU Department of Entomology

MSU Extension Agriculture and Agribusiness Institute

Gemma Calabria et al. 2012

Problems hampering SWD controlControl strategy directed to adult control.

Selection of insecticides with limited effect on life

stages inside the fruit.

Limited number of insecticides available for the SWD

in blueberries, raspberries and strawberries.

Limited knowledge of the behavior of the pesticide in

the habitat of the insect.

Organophosphate, Pyrethroids, Neonicotinoids, etc.

Insecticide delivery system and deposition of the

product in the insect habitat.

Problems hampering SWD control..

Limited understanding of how to adjust insecticide

applications to pest behavior and current weather

conditions has lead growers to take MSUE

recommendations as “prescriptions” rather than

adjustable and more dynamic (changing)

recommendations.

A systems approach for Managing SWDThe purpose of the spray application is to put the pest in contact with the pesticide

(García et al. 2011)

A Systems Approach to SWD Management

Pest Biology and Behavior. Under a Systems Approach growers

and IPM practitioners need to understand the biology and behavior of

the pest. In the case of the spotted wing Drosophila (SWD) there was

no data available until 2013.

Critical Points of the SWD Life Cycle. Knowing its biology and

behavior is not enough. For a successful control, growers need to

identify critical points in its life cycle where control actions should be

applied to optimize the effectiveness of an insecticide.

Pesticide: Physical and Chemical characteristics. Under a Systems

Approach one of the most important aspects of pest control is to

understand how insecticides behave once they leave the sprayer. Their

behavior depends on their chemical characteristics, their toxicological

group, current weather and target crop conditions.

A Systems Approach……cont...Host Plant Structure and Pest Habitat. Plant structure and

type of canopy affect the performance of pest management in

berries.

Affect penetration and deposition of insecticides into the

habitat of the pest (Pruning vs. Not Pruning).

Also, affect the temperature and relative humidity (rH) in the

habitat of the insect; where in the host plant the insect

spends the most critical stages of its life cycle. This also

helps direct the insecticide’s application.

Spray Systems and Pesticide Deposition. Different spray

systems produce different types of depositions on the plant.

Depending on the range of droplets produced by the sprayer the

insecticide will reach the insect or its habitat affecting the quality

of pest control.

A Systems Approach..continuation

Biological Monitoring. SWD’s management under a Systems

Approach requires:

Current information on the conditions of the pest at target

site.

Presence of Natural Enemies and other pests that may

influence the success of our SWD control.

Also provides information on the success of our IPM actions.

Environmental Monitoring. Under a Systems Approach the

environment is the driving force behind the entire IPM program.

Current & forecasted weather conditions at the target site

affect all of the above parameters, including pest biology and

insecticide behavior used for SWD management.

Biology and Behavior of SWD

Reproduction strategy; “r” Type

High reproduction potential > 300 eggs/female.

Multiple generations in a short period of time.

Behavior:

Highly mobile in the adult stage; most of its biological cycle

spent inside the fruit protected from insecticide

applications.

Eggs and larvae near the surface of the fruit breathing

through modified breathing tubes.

Resistance to Insecticides:

High potential for developing resistance to insecticides,

specially to Pyrethroid insecticides.

Females oviposit eggs under the fruit’s skin

Isaacs et al., MSU Extension 2012

SWD ovipositor

and eggs Serrated

Ovipositor

Fresh egg showing breathing

tubes

Recently laid eggs on cherries. Notice

the white breathing tubes protruding

out of the oviposition scare.

Pictures by E. H. Beers, Timothy J. Smith, and Doug Walsh. http://jenny.tfrec.wsu.edu/opm/displaySpecies.php?pn=165

Examples of breathing tubes of SWD eggs

Eggs laid in

blueberries (left) and

cherries (bottom right)

Pictures by E. H. Beers, Timothy J. Smith, and

Doug Walsh.

http://jenny.tfrec.wsu.edu/opm/displaySpecies.php?

pn=165

Larva: feeds and grows superficially in the fruit

Notice

breathing

tubes and

lungs

Isaacs et al., MSU Extension 2012

SWD Life Cycle

WSU, Whatcomb County

Optimal development at

65-70 degrees Fahrenheit,

about 12 day generation

time.

Adult flies live for 3-6

weeks, and females can

lay over 300 eggs.

Limited by high heat in

summer and by winter

cold.

Female fly lays eggs into

ripening fruit.

Unlike blueberry maggot,

no delay before egg

laying.

Biological Monitoring

Spotted wing

Drosophila - male

Spotted wing

Drosophila - female

Blueberries with a hole and a depressed area may indicate infestation

Oviposition scar

Isaacs et al., MSU Extension 2012

SWD damage on

Strawberries

SWD females lay their eggs

under the skin after cutting a

slit in the skin of intact

ripening fruit.

Larvae feed on the flesh of the

fruit, causing soft spots on the

surface and wrinkling the skin.

The fruit will subsequently

collapse, scarring of the tissue

appears and mold increases.

Tanigoshi, et al 2010. Insecticide Management of Spotted Wing Drosophila, Drosophila suzukii (Matsumura) In

Pacific Northwest Small Fruits. IOBC Budapest, Hungary 2010.

SWD damage on Strawberries..continuation

Figure 1. Damage 3

days after egg laying.

Figure 2. Damage 5

days after egg laying.

Strawberries

deteriorate

quickly and mold

may appear 3

days after egg

laying.

The fruit will

subsequently

collapse, scarring

of the tissue will

occur and mold

will increase.

Photo: Parent, Whitney, Lee; USDA-ARS, Corvallis

SWD Fruit infestation in Strawberries

Figure 1 - SWD egg (pale form) on strawberry, indicated

by yellow arrow. The two yellow objects are achenes

(“seeds” indicated by black arrows).

Figure 2 - SWD Larva on Raspberry-whitish, indicated by

arrow.

Photos: Phil Pellitteri, UW-Madison Insect Diagnostic Lab

SWD damage in raspberriesThe same

berries are

shown below

after

inspection for

SWD

infestation

Removing the

peduncle it

shows SWD

larvae feeding

inside the

receptacle; the

juice stains the

cone.

SWD in Raspberries

These pictures show SWD larvae emerging from infested fruit after

being submerged in water with salt

Monitoring of adult SWD

1. For earliest detection – yeast-sugar mix bait.

2. For easiest use – commercial lure (Trece or

Scentry).

3. Place traps at field edges, check weekly.

4. Risk is greatest adjacent to woods.

5. Know what you’re looking for!!

Use MSU Guide to identifying SWD

http://tinyurl.com/m7ra75w

Pictures by E. H. Beers, Timothy J. Smith, and Doug Walsh.

WSU.

Rufus Isaacs, MSU Extension.

SWD monitoring with synthetic lures Plastic container with

ten 3/8 inch diameter

holes.

Hang in shade near

fruit.

Bait the trap and

change the lure once a

month.

Two options…..

1. With sticky trap:

check trap and

liquid.

or

2. No trap and check

insects sifted from

liquid (add soap).Pictures by C. Garcia-Salazar, MSU Extension

SWD on sticky insert and in liquid bait of a yeast trap

0

10

20

30

40

50

60

70

80

90

100

Avg

. no

. of

D. s

uzu

kii p

er

trap

Insert

Liquid

Checking yeast traps is

time consuming and

messy.

More SWD caught

earlier on the insert

than in liquid.

Checking inserts only

would reduce trap

assessment time.

Number of traps to detect SWD early

0

1

2

3

4

5

6

7

8

9

10

8/26/2011 9/7/2011 9/13/2011 9/21/2011 9/28/2011 10/3/2011 No Detection

Nu

mb

er o

f ti

mes

po

siti

ve f

or

SWD

1 Trap Average

6 Traps Average

13 Traps Average

ACV-baited traps

spread across

large (50 acre)

farms

Monitored weekly

Analysis of first

catch

One trap per 5-10

acres

Environmental Monitoring

The weather

The weather effect on insect phenology and

reproduction potential.

We expected Michigan’s harsh winter would kill the

population and would take care of the problem.

Temperatures suitable for optimum reproduction.

Relative humidity affects SWD survival and reproduction.

Effect on insecticide behavior.

Summer heat inactivates main insecticide tools.

Summer rains affect insecticide persistence on crop.

Effect of Relative Humidity (rH) on survival

Perc

enta

ge

of surv

ivin

g p

op

ula

tion

Tochen et al. 2015. Humidity affects populations of Drosophila suzukii (Diptera:

Drosophilidae) in blueberry.

Effect of Relative Humidity (rH) on egg layingA

vg

. e

gg

s la

id p

er

da

yTochen et al. 2015. Humidity affects populations of Drosophila suzukii (Diptera: Drosophilidae)

in blueberry.

Effect of plant structure and canopy

Bush height

Canopy structure

Canopy and water management:

Prune plants to maintain an open canopy.

Reduce relative humidity (rH) to make plantings

less attractive to SWD and to improve spray

coverage.

Leaking trickle irrigation lines should be repaired,

and overhead irrigation should be minimized.

Allow the ground and mulch surface to dry before

irrigating.

Spray Deposition in Blueberry Fields

This slide shows 3 different

types of spraying equipment for

blueberries, and the spray

deposition patterns. Upper left:

Cannon sprayer. Upper right:

airblast sprayer. Lower left:

fixed-wing plane application.

Factors Influencing Pesticide Behavior

Pesticide behavior means the manner in which the insecticide acts once

it is released onto the crop as a result of the prevailing weather

conditions.

(Image by Marlene Cameron)

Environmental degradation of Mustang Max

Cypermethrin

quickly

dissipated, with

29–43%

degradation

occurring within

the first 2 days

after the pesticide

application.

The half-lives for cypermethrin:1.6–3.1 daysPest Manag Sci 2009; 65: 189–196

Insecticide comparison – effect of rainBushes were protected from rain or had 0.81 inches of rain 24 hours after

application. Protected from all other rainfall over 7 days.

0

20

40

60

80

100

Perc

en

t co

ntr

ol

3 DAT 5 DAT 7 DAT No Rain

38.3

97.5100

25

75

0

24.3

70.8

97.9

32.6

83.3

23.6

Pe

rce

nt

co

ntr

ol

3 DAT 5 DAT 7 DAT Rain

Isaacs, et al. 2012

Pest habitat and behaviorThe purpose of the application is to put the pesticide

in contact with the pest.

Placement of pesticide in the habitat:

Use the maximum volume of water; 40 galons per

acre.

Use fine to medium spray; droplet size 100-250

microns ( 20 to 40 droplets per square centimeter).

Taking advantage of pest behavior:

Eggs and larvae need to breath fresh air; egg

breathing tubes are exposed.

Larvae remain feeding under the fruit skin in the

outer flesh.

Ratings of insecticides for key blueberry pestsInsecticide Class REI (h) PHI (d) CBFW Aphids JB BBM SWD

Imidan Organophos

.

24 3 **** ** **** **** ****

Malathion Organophos

.

12 1 ** ** ** *** ***

LannateCarbamate

48 3 ** *** ** ** ****

Asana Pyrethroid 12 14 **** ** *** *** ****

Brigade Pyrethroid **** ** *** *** ****

Mustang Max Pyrethroid 12 1 **** ** *** *** ****

Danitol Pyrethroid 24 3 **** ** *** *** ****

AssailRR Neonic. 12 1 *** **** ** **** ***

DelegateRR Spinosyns 4 3 *** - - ** ****

Entrust▲ Spinosyns 4 3 ** - - ** ***

Pyganic ▲ Pyrethrum 12 0 * * * * **

Evergreen Pyrethrum 12 0 * * ** ** **

RR = reduced risk, ▲ = organic Prepared by R. Isaacs, J. Wise, K. Mason and D. Trinka 2012

Insecticides against SWD in caneberries

Take-home messages: Maintain your current IPM program but make the necessary

modifications to incorporate the SWD management.

For early warning of SWD:

One trap per 5-10 acres, monitor for SWD from just before first ripening.

Yeast traps with yellow sticky card for easy adult ID.

Trap in woods for early warning.

Choose effective insecticides for SWD (Coverage! Rotation!)

Broad spectrum: Lannate, Malathion, Imidan, Brigade, Mustang Max,

Hero (Brigade+Mustang Max).

Reduced-risk: Delegate/Radiant.

Organic: Entrust, Pyganic.

Sample fruit using salt solution, in-field, before and after insecticide

applications, and at processors.

Understand the labels (PHIs, REIs, season limits) and residual activity.

SWD Resources from MSU

www.ipm.msu.edu/SWD.htm

What to do to learn & understand the

“Systems Approach to SWD Management”

ATTEND online and face to face trainings that will

be offered in Traverse City during 2017 (dates to

be announced).

For more information contact:

Dr. Erwin 'Duke' ElsnerMSUE Small Fruit / Consumer Horticulture Educator

520 W. Front Street, Suite A, Traverse City, MI 49684

Phone: 231 922-4822 fax: 231-947-6783

email: elsner@msu.edu