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Publication #ENY-843

Management of Insect and Mite Resistance in Ornamental Crops1

James F. Price, Elzie McCord, Jr., and Curtis Nagle2

Resistance of arthropods to crop management chemicals has been problematic since the early era of synthetic organic pesticides. During the 1970s and early 1980s leafminer (Liriomyza trifolii) outbreaks heavily damaged herbaceous ornamental crops such as chrysanthemum, gypsophila, aster, and marigold in fields, shade houses and greenhouses. Several effective insecticides including organophosphates, carbamates, pyrethroids, and a triazine were identified for leafminer control during the outbreak; however, control was short-lived as the leafminer developed resistance to each insecticide.

Poor performance of pesticides does not always indicate pest resistance. Such factors as pesticide degradation in storage, hydrolysis in acid or alkaline preparations, applications to an incorrect life stage, or other inadequate application procedures may contribute to poor control.

Definition of Resistance

Pest populations can be susceptible or resistant to a pesticide. Resistance occurs when a formerly susceptible pest population becomes significantly less susceptible to a pesticide and degradation of the pesticide or improper application is not a factor. Pesticide resistance is a population-based phenomenon in which the genetic composition shifts and the population becomes dominated by individuals possessing genes that confer resistance.

Establishment of Resistance

Resistant populations are protected from formerly effective pesticides through one or more means. For example, resistant pests may: (1) deactivate (break down), (2) sequester (safely store within their bodies), (3) avoid, or (4) excrete the toxin from their bodies more effectively, (5) have an altered target site that will not accumulate the toxin, or (6) reduce the permeability by the toxin through their exoskeletons (“shells”).

Individuals within a susceptible pest population often vary in their level of susceptibility; however, the non-susceptible type occurs only very rarely. When a pesticide is applied repeatedly, the susceptible pests die and the resistant ones survive, mate with other survivors and reproduce. Some of their offspring inherit the parents' characteristic for survival. Upon additional applications, the more susceptible of the offspring within the remaining population die and the less susceptible ones survive, mate with other survivors and produce more similar offspring. Further applications additionally select for the resistant individuals until that form (genotype) is common. The population then is regarded as resistant and the effectiveness of the pesticide is lost.

Resistance Management

Resistance can develop rapidly with pests that have many generations per year, when multiple generations are exposed to a pesticide, and when new individuals do not move into a treated area to dilute the frequency of the resistant genes. Ornamentals production, especially in greenhouses, often incorporates a combination of these factors that contribute to resistance and account for some of the leafminer problems experienced decades ago.

The main objectives of resistance management programs in ornamentals production should be to minimize the number of exposures of pests to pesticides with a similar mode of action and to use non-chemical approaches to arthropod management. (Mode of action is the specific activity of the toxin that results in the death of the pest. For instance, one mode of action is to inhibit mitochondrial complex I electron transport. This causes a failure of the pest to produce energy in affected cells and to die.)

Repeated exposures to a pesticide are the primary drivers of resistance but much can be done to manage pests by means other than chemicals. Care can be taken to rotate crops, establish new ones only after the older crops have been removed, use pest resistant species and varieties, set pest-free transplants, conserve and release natural enemies, etc. Pest-specific tactics are available for particular situations such as elimination of excessive moisture in order to kill fungus gnats in greenhouses.

Crops should be scouted on a regular, frequent schedule and pesticide applications should be made only when pest densities approach economic injury levels. When pesticide use is required, products should be rotated among the different modes of action indicated on many modern product labels. A list of modes of action can be found by selecting “MoA Classification Scheme” at the Insecticide Resistance Action Committee Website: http://www. irac-online.org/Crop_Protection/MoA.asp .

Tables 1-3 present a mode of action summary for insecticides and miticides intended for ornamentals production in Florida. Sound rotation plans often recommend pesticides of one mode of action for one pest generation and a pesticide of a different mode of action for another generation. If multiple pesticide applications are required, rotations should continue through all practical modes of action before returning to a previously used one. The use of certain unique products with known general modes of action (such as soaps and oils) is unlikely to result in pest resistance and no codes are assigned. These can be used without regard to a rotation plan for resistance management.

When pesticides are used, it is important to assure that fresh, fully potent pesticides are prepared and applied in accordance with label directions. Aqueous pesticidal preparations should be adjusted to near neutral pH (pH 7.0) or as specified by the label. Sprayer calibration, nozzle condition and pressure, and spray placement must be correct. Applications also should be timed and directed to contact the most susceptible life stage of the pest.

Conclusion

Episodes of pest resistance to popular pesticides can cause crop yield losses, crop quality reduction, added control costs, increased human exposure to toxins, and degradation of the environment. These consequences can be alleviated if resistance management is practiced throughout Florida's ornamentals industry. If growers minimize pesticide application by depending more on biological and cultural pest control measures, and reduce pest exposures to pesticides with identical modes of action, then resistance can become a rare phenomenon.

Tables

Table 1. 

Mode of action of insecticides and miticides registered for use in Florida's ornamental production (presented by active ingredient). (Insecticide Resistance Action Committee mode of action classification codes version 5.3).

Active Ingredient (Common Name)

Trade Name Examples

Mode of Action Code

1,3-dichloropropene

Telone

abamectin

Avid

Lucid

6

acephate

Orthene

Tame/Orthenea

1B

acequinocyl

Shuttle

20B

acetamiprid

TriStar

4A

azadirachtin

Aza-Direct

Azatin

18B

azinphos-methyl

Guthion

1B

Bacillus thuringiensis aizawai

Xentari

11B1

Bacillus thuringiensis israelensis

Gnatrol

11A1

Bacillus thuringiensis kurstaki

Dipel

Javelin

11B2

Beauveria bassiana

Botanigard

Mycotrol

Naturalis

bifenazate

Floramite

25

bifenthrin

Allectusb

Attain

Talstar

3

buprofezin

Talus

16

carbaryl

Sevin

1A

carbofuran

Furadan

1A

chlorfenapyr

Pylon

13

chlorpyrifos

Duraguard

Duraplexc

Dursban

1B

clarified hydrophobic extract of neem oil

Triact

clofentezine

Ovation

10A

clothianidin

Celero

4A

cryolite

Kryocide

Prokil Cryolite

9A

cyfluthrin

Decathlon

Discusb

Duraplexd

3

cyromazine

Citation

17

deltamethrin

Deltagard

3

diazinon

Diazinon

1B

diflubenzuron

Adept

Dimilin

15

dimethoate

Dimethoate

1B

dinotefuran

Safari

4A

disulfoton

Di-Syston

1B

endosulfan

Thionex

2A

esfenvalerate

Asana

3

ethoprop

Mocap

1B

etoxazole

Tetrasan

10B

fenbutatin oxide

ProMite

12B

fenoxycarb

Award Fire Ant Bait

Preclude

7B

fenpropathrin

Tame

Tame/Orthenee

3

fenpyroximate

Akari

21

fipronil

Chipco Choice

2B

flonicamid

Aria

9C

halofenozide

Mach 2

18A

hexythiazox

Hexygon

10A

hydramethylnon

Amdro

20A

imidacloprid

Allectusf

Discusc

Marathon

Merit

4A

iron phosphate

Sluggo

kaolin

Surround

lambda-cyhalothrin

Scimitar

3

malathion

Malathion

1B

metaldehyde

Deadline

Prozap

metam-sodium

Vapam

methidathion

Supracide

1B

methiocarb

Mesurol

1A

methyl bromide

67-33 Preplant Soil Fumigant

8A

naled

Dibrom

1B

novaluron

Pedestal

15

oxydemeton-methyl

MSR Spray Concentrate

1B

permethrin

Ambush

Astro

3

phosmet

Imidan

1B

piperonyl butoxide

Diatectg

Pyrenoneg

Pyreth-Itg

27A

polyhedral occlusion bodies of the nuclear polyhedrosis virsus of Spodoptera exugia

Spod-X

potassium salts of fatty acids

AllPro Insecticidal Soap

M-Pede

propargite

Omite

Ornamite

12C

pymetrozine

Endeavor

9B

pyrethrin

Diatecth

PyGanic

Pyrellini

Pyrenoneh

Pyreth-Ith

3

pyridaben

Sanmite

21

pyriproxyfen

Distance

7D

refined petroleum distillate

Ultra-Fine Oil

rotenone

Pyrelling

21

s-kinoprene

Enstar II

7A

s-methoprene

Extinguish

7A

spinosad

Conserve

Entrust

Justice Fire Ant Bait

Spintor

5

spiromesifen

Judo

23

tau-fluvalinate

Mavrik

3

tebufenozide

Confirm

Mimic

18A

thiamethoxam

Flagship

4A

a This product also contains fenpropathrin, see mode of action code 3 in table 2.

b This product also contains imidacloprid, see mode of action code 4A in table 2.

c This product also contains cyfluthrin, see mode of action code 3 in table 2.

d This product also contains chlorpyrifos, see mode of action code 1B in table 2.

e This product also contains acephate, see mode of action code 1B in table 2.

f This product also contains bifenthrin, see mode of action code 3 in table 2.

g This product also contain pyrethirn, see mode of action code 3 in table 2.

h This product also contain piperonyl butoxide, see mode of action code 27A in table 2.

i This product also contains rotenone, see mode of action code 21 in table 2.

Table 2. 

Mode of action of insecticides and miticides registered for use in Florida's ornamental production (presented by mode of action code). (Insecticide Resistance Action Committee mode of action classification codes version 5.3).

Mode of Action Code

Active Ingredient (Common Name)

Trade Name Examples

1,3-dichloropropene Telone

Beauveria bassiana

Botanigard

Mycotrol

Naturalis

clarified hydrophobic extract of neem oil

Triact

iron phosphate

Sluggo

kaolin

Surround

metaldehyde

Deadline

Prozap

metam-sodium

Vapam

polyhedral occlusion bodies of the nuclear polyhedrosis virus of Spodoptera exugia

Spod-X

potassium salts of fatty acids

AllPro Insecticidal Soap

M-Pede

refined petroleum distillate

Ultra-Fine Oil

1A

carbaryl

Sevin

carbofuran

Furadan

methiocarb

Mesurol

1B

acephate

Orthene

Tame/Orthenea

azinphos-methyl

Guthion

chlorpyrifos

Duragard

Duraplexa

Dursban

diazinon Diazinon

dimethoate

Dimethoate

disulfoton

Di-Syston

ethoprop

Mocap

malathion

Malathion

methidathion

Supracide

naled

Dibrom

oxydemeton-methyl

MSR Spray Concentrate

phosmet

Imidan

2A

endosulfan

Thionex

2B

fipronil

Chipco Choice

3

bifenthrin

Allectusb

Attain

Talstar

cyfluthrin

Decathlon

Discusb

Duraplexc

deltamethrin

Deltagard

esfenvalerate

Asana

fenpropathrin

Tame

Tame/Orthenec

lambda-cyhalothrin

Scimitar

permethrin

Ambush

Astro

pyrethrin

Diatectd

PyGanic

Pyrelline

Pyrenoned

Pyreth-Itd

tau-fluvalinate

Mavrik

4A

acetamiprid

TriStar

clothianidin

Celero

dinotefuran

Safari

imidacloprid

Allectusa

Discusa

Marathon

Merit

thiamethoxam

Flagship

5

spinosad

Conserve

Entrust

Justice Fire Ant Bait

Spintor

6

abamectin

Avid

Lucid

7A

s-kinoprene

Enstar II

s-methoprene Extinguish

7B

fenoxycarb

Award Fire Ant Bait

Preclude

7D

pyriproxyfen

Distance

8A

methyl bromide

67-33 Preplant Soil Fumigant

9A

cryolite

Kryocide

Prokil Cryolite

9B

pymetrozine

Endeavor

9C

flonicamid

Aria

10A

clofentezine

Ovation

hexythiazox

Hexygon

10B

etoxazole

Tetrasan

11A1

Bacillus thuringiensis israelensis

Gnatrol

11B1

Bacillus thuringiensis aizawai

Xentari

11B2

Bacillus thuringiensis kurstaki

Dipel

Javelin

12B

fenbutatin oxide

ProMite

12C

propargite

Omite

Ornamite

13

chlorfenapyr

Pylon

15

diflubenzuron

Adept

Dimilin

novaluron

Pedestal

16

buprofezin

Talus

17

cyromazine

Citation

18A

halofenozide

Mach 2

tebufenozide

Confirm

Mimic

18B

azdirachtin

Aza-Direct

Azatin

20A

hydramethylnon

Amdro

20B

acequinocyl

Shuttle

21

fenpyroximate

Akari

pyridaben

Sanmite

rotenone

Pyrellina

23

spiromesifen

Judo

25

bifenazate

Floramite

27A

piperonyl butoxide

Diatecta

Pyrenonea

Pyreth-Ita

a This product also contains an active ingredient with the mode of action code 3.

b This product also contains an active ingredient with the mode of action code 4A.

c This product also contains an active ingredient with the mode of action code 1B.

d This product also contains an active ingredient with the mode of action code 27A.

e This product also contains an active ingredient with the mode of action code 21.

Table 3. 

Mode of action of insecticides and miticides registered for use in Florida's ornamental production (presented by trade name). (Insecticide Resistance Action Committee mode of action classification codes version 5.3).

Trade Name Examples

Active Ingredient (Common Name)

Mode of Action Code

67-33 Preplant Soil Fumigant

methyl bromide

8A

Adept

diflubenzuron

15

Akari

fenpyroximate

21

Allectus

imidacloprid & bifenthrin

4A & 3

AllPro Insecticidal Soap potassium salts of fatty acids

Ambush

permethrin

3

Amdro

hydramethylnon

20A

Aria

flonicamid

9C

Asana

esfenvalerate

3

Astro

permethrin

3

Attain

bifenthrin

3

Avid

abamectin

6

Award Fire Ant Bait

fenoxycarb

7B

Aza-Direct

azadirachtin

18B

Azatin

azadirachtin

18B

Botanigard

Beauveria bassiana

Celero

clothianidin

4A

Chipco Choice

fipronil

2B

Citation

cyromazine

17

Confirm

tebufenozide

18A

Conserve

spinosad

5

Deadline

metaldehyde

Decathlon

cyfluthrin

3

Deltagard

deltamethrin

3

Diatect

pyrethrin & piperonyl butoxide

3 & 27A

Diazinon

diazinon

1B

Dibrom

naled

1B

Dimethoate

dimethoate

1B

Dimilin

diflubenzuron

15

Dipel

Bacillus thuringiensis kurstaki

11B2

Di-Syston

disulfoton

1B

Discus

imidacloprid & cyfluthrin

4A & 3

Distance

pyriproxyfen

7D

Duragard

chlorpyrifos

1B

Duraplex

cyfluthrin & chlorpyrifos

3 & 1B

Dursban

chlorpyrifos

1B

Endeavor

pymetrozine

9B

Enstar II

s-kinoprene

7A

Entrust

spinosad

5

Extinguish s-methoprene

7A

Flagship

thiamethoxam

4A

Floramite

bifenazate

25

Furadan

carbofuran

1A

Gnatrol

Bacillus thuringiensis israelensis

11A1

Guthion

azinphos-methyl

1B

Hexygon

hexythiazox

10A

Imidan

phosmet

1B

Javelin

Bacillus thuringiensis kurstaki

11B2

Judo

spiromesifen

23

Justice Fire Ant Bait

spinosad

5

Kryocide

cryolite

9A

Lucid

abamectin

6

M-Pede potassium salts of fatty acids

Mach 2

halofenozide

18A

Malathion

malathion

1B

Marathon

imidacloprid

4A

Mavrik

tau-fluvalinate

3

Merit

imidacloprid

4A

Mesurol

methiocarb

1A

MSR Spray Concentrate

oxydemeton-methyl

1B

Mimic

tebufenozide

18A

Mocap

ethoprop

1B

Mycotrol

Beauveria bassiana

Naturalis

Beauveria bassiana

Omite propargite

12C

Ornamite

propargite

12C

Orthene

acephate

1B

Ovation

clofentezine

10A

Pedestal

novaluron

15

Preclude

fenoxycarb

7B

Prokil Cryolite

cryolite

9A

ProMite

fenbutatin oxide

12B

Prozap

metaldehyde

PyGanic pyrethrin

3

Pyrellin pyrethrin & rotenone

3 & 21

Pyrenone piperonyl butoxide & pyrethrin

27A & 3

Pyreth-It piperonyl butoxide & pyrethrin

27A & 3

Pylon

chlorfenapyr

13

Safari

dinotefuran

4A

Sanmite

pyridaben

21

Scimitar

lambda-cyhalothrin

3

Sevin carbaryl

1A

Shuttle

acequinocyl

20B

Sluggo

iron phosphate

Spintor

spinosad

5

Spod-X

polyhedral occlusion bodies of the nuclear polyhedrosis virus of Spodoptera exugia

Supracide

methidathion

1B

Surround

kaolin

Talstar

bifenthrin

3

Talus

buprofezin

16

Tame

fenpropathrin

3

Tame/Orthene

fenpropathrin & acephate

3 & 1B

Telone

1,3-dichloropropene

Tetrasan

etoxazole

10B

Thionex

endosulfan

2A

Triact

clarified hydrophobic extract of neem oil

TriStar

acetamiprid

4A

Ultra-Fine Oil

refined petroleum distillate

Vapam

metam-sodium

Xentari

Bacillus thuringiensis aizawai

11B1

Footnotes

1.

This is document ENY-843 (IN715), a publication of the Department of Entomology and Nematology, Florida Cooperative Extension Service, IFAS, University of Florida. Publication date: November 2007. Please visit the EDIS Website at http://edis.ifas.ufl.edu.

2.

James F. Price, associate professor, Gulf Coast Research and Education Center; Elzie McCord, Jr., associate professor, Dept. of Biological Sciences, New College of Florida; Curtis Nagle, biological scientist, Gulf Coast Research and Education Center, Cooperative Extension Service, IFAS, University of Florida, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.