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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 of the pest, 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 when properly applied. 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 or increased tolerance to the pesticide that results in reduced insecticidal activity.

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” at the Insecticide Resistance Action Committee Website: http://www.irac-online.org/teams/mode-of-action/.

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 products 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 exposing pest populations to pesticides with identical modes of action, then resistance can be avoided.

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 7.2).

Active Ingredient (Common Name)

Trade Name Examples

Mode of Action Code

1,3-dichloropropene

Telone

no codea

abamectin

Avid

Lucid

6

abamectin & bifenazate

Sirocco

6 & un b

acephate

Orthene

1B

acephate & fenpropathrin

Tame/Orthene

1B & 3A

acequinocyl

Shuttle

20B

acetamiprid

TriStar

4A

azadirachtin

Azahar

Azatin

un

Bacillus thuringiensis aizawai

Jackpot

Xentari

11B

Bacillus thuringiensis israelensis

Gnatrol

11A

Bacillus thuringiensis kurstaki

Dipel

Javelin

11B

Beauveria bassiana

Botanigard

Mycotrol

Naturalis

no code

bifenazate

Floramite

un

bifenazate & abamectin

Sirocco

un & 6

bifenthrin

Attain

Talstar

OnyxPro

3A

buprofezin

Talus

16

carbaryl

Sevin

1A

carbofuran

Furadan

1A

chlorfenapyr

Pylon

13

chlorpyrifos

DuraGuard

Dursban

1B

chlorpyrifos & cyfluthrin

Duraplex

1B & 3A

Chromobacterium subtsugae

MBI-203

no code

clarified hydrophobic extract of neem oil

Triact

Trilogy

no code

clofentezine

Ovation

10A

cryolite

Kryocide

un

cyfluthrin

Decathlon

3A

cyfluthrin & chlorpyrifos

Duraplex

3A & 1B

cyfluthrin & imidacloprid

Discus

3A & 4A

cyromazine

Citation

17

deltamethrin

Deltagard

3A

diazinon

Diazinon

1B

diflubenzuron

Adept

Dimilin

15

dimethoate

Dimethoate

1B

dinotefuran

Safari

4A

disulfoton

Di-Syston

1B

esfenvalerate

Asana

3A

etoxazole

Tetrasan

10B

fenazaquin

Magus

21A

fenbutatin oxide

ProMite

Vendex

12B

fenoxycarb

Award

Preclude

7B

fenpropathrin

Tame

3A

fenpropathrin & acephate

Tame/Orthene

3A & 1B

fenpyroximate

Akari

21A

fipronil

Chipco Choice

2B

flonicamid

Aria

9C

hexythiazox

Hexygon

Onager

10A

hydramethylnon

Amdro

20A

imidacloprid

Marathon

4A

imidacloprid & cyfluthrin

Discus

4A & 3A

iron phosphate

Sluggo

no code

Isaria fumosorosea

PFR-97

no code

kaolin

Surround

no code

lambda-cyhalothrin

Scimitar

3A

malathion

Malathion

1B

metaldehyde

Deadline

Durham Metaldehyde

no code

metam-sodium

Vapam

no code

metam-potassium

Metam KLR

no code

methidathion

Supracide

1B

methiocarb

Mesurol

1A

milbemectin

Ultiflora

6

naled

Dibrom

1B

novaluron

Pedestal

15

orthoboric acid

Niban

8D

oxydemeton-methyl

MSR Spray Concentrate

1B

permethrin

Ambush

Astro

3A

phosmet

Imidan

1B

polyhedral occlusion bodies of the nuclear polyhedrosis virsus of Spodoptera exigua

Spod-X

no code

potassium salts of fatty acids

AllPro Insecticidal Soap

M-Pede

no code

pymetrozine

Endeavor

9B

pyrethrins

Diatect

PyGanic

Pyrenone

Pyreth-It

3A

pyrethrins & rotenone

Pyrellin

3A & 21B

pyridaben

Sanmite

21A

pyridalyl

Overture

un

pyriproxyfen

Distance

7C

refined petroleum distillate

Ultra-Fine Oil

no code

rotenone & pyrethrins

Pyrellin

21B & 3A

s-kinoprene

Enstar II

7A

s-methoprene

Extinguish

7A

sodium ferric EDTA

Dr.T’s

no code

sorbitol octanoate

SorbiShield

no code

spinosad

Conserve

Entrust

5

spiromesifen

Judo

23

spirotetramat

Kontos

Movento

23

sucrose octanoate

SucraShield

no code

tau-fluvalinate

Mavrik

3A

tebufenozide

Confirm

Mimic

18

thiamethoxam

Flagship

4A

tolfenpyrad

Hachi-Hachi

21A

a When no mode of action code is present, there is no code established and the product can be used without regard to mode of action.

b ”un” means this compound has an unknown or uncertain mode of action.

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 7.2).

Mode of Action Code

Active Ingredient (Common Name)

Trade Name Examples

No codea

1,3-dichloropropene

Telone

Beauveria bassiana

Botanigard

Mycotrol

Naturalis

clarified hydrophobic extract of neem oil

Triact

Trilogy

iron phosphate

Sluggo

Isaria fumosorosea

PFR-97

kaolin

Surround

metaldehyde

Deadline

Durham Metaldehyde

metam-sodium

Vapam

metam-potassium

Metam KLR

polyhedral occlusion bodies of the nuclear polyhedrosis virus of Spodoptera exigua

Spod-X

potassium salts of fatty acids

AllPro Insecticidal Soap

M-Pede

refined petroleum distillate

Ultra-Fine Oil

sodium ferric EDTA

Dr.T’s

sorbitol octanoate

SorbiShield

sucrose octanoate

SucraShield

1A

carbaryl

Sevin

carbofuran

Furadan

methiocarb

Mesurol

1B

acephate

Orthene

chlorpyrifos

DuraGuard

Dursban

diazinon

Diazinon

dimethoate

Dimethoate

disulfoton

Di-Syston

malathion

Malathion

methidathion

Supracide

naled

Dibrom

oxydemeton-methyl

MSR Spray Concentrate

phosmet

Imidan

1B & 3A

acephate & fenpropathrin

Tame/Orthene

chlorpyrifos & cyfluthrin

Duraplex

2B

fipronil

Chipco Choice

3A

bifenthrin

Attain

Talstar

OnyxPro

cyfluthrin

Decathlon

deltamethrin

Deltagard

esfenvalerate

Asana

fenpropathrin

Tame

lambda-cyhalothrin

Scimitar

permethrin

Ambush

Astro

pyrethrins

Diatect

PyGanic

Pyrenone

Pyreth-It

tau-fluvalinate

Mavrik

3A & 1B

cyfluthrin & chlorpyrifos

Duraplex

fenpropathrin & acephate

Tame/Orthene

3A & 21B

pyrethrins & rotenone

Pyrellin

4A

acetamiprid

TriStar

dinotefuran

Safari

imidacloprid

Discus

Marathon

thiamethoxam

Flagship

4A & 3A

imidacloprid & cyfluthrin

Discus

5

spinosad

Conserve

Entrust

Justice

6

abamectin

Avid

Lucid

milbemectin

Ultiflora

6 & un b

abamectin & bifenazate

Sirocco

7A

s-kinoprene

Enstar II

s-methoprene

Extinguish

7B

fenoxycarb

Award

Preclude

7C

pyriproxyfen

Distance

8D

orthoboric acid

Niban

9B

pymetrozine

Endeavor

9C

flonicamid

Aria

10A

clofentezine

Ovation

hexythiazox

Hexygon

10B

etoxazole

Tetrasan

11A

Bacillus thuringiensis israelensis

Gnatrol

11B

Bacillus thuringiensis aizawai

Jackpot

Xentari

11B

Bacillus thuringiensis kurstaki

Dipel

Javelin

12B

fenbutatin oxide

ProMite

Vendex

13

chlorfenapyr

Pylon

15

diflubenzuron

Adept

Dimilin

novaluron

Pedestal

16

buprofezin

Talus

17

cyromazine

Citation

18

tebufenozide

Confirm

Mimic

20A

hydramethylnon

Amdro

20B

acequinocyl

Shuttle

21A

fenazaquin

Magus

fenpyroximate

Akari

pyridaben

Sanmite

tolfenpyrad

Hachi-Hachi

21B & 3A

rotenone & pyrethrins

Pyrellin

23

spiromesifen

Judo

spirotetramat

Kontos

Movento

un

azadirachtin

Azahar

Azatin

bifenazate

Floramite

Sirocco

cryolite

Kryocide

pyridalyl

Overture

un & 6

bifenazate & abamectin

Sirocco

a When no mode of action code is present, there is no code established and the product can be used without regard to mode of action.

b ”un” means this compound has an unknown or uncertain mode of action.

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 7.2).

Trade Name Examples

Active Ingredient (Common Name)

Mode of Action Code

Adept

diflubenzuron

15

Akari

fenpyroximate

21A

AllPro Insecticidal Soap

potassium salts of fatty acids

no code a

Ambush

permethrin

3A

Amdro

hydramethylnon

20A

Aria

flonicamid

9C

Asana

esfenvalerate

3A

Astro

permethrin

3A

Attain

bifenthrin

3A

Avid

abamectin

6

Award

fenoxycarb

7B

Azahar

azadirachtin

unb

Azatin

azadirachtin

un

Botanigard

Beauveria bassiana

no code

Chipco Choice

fipronil

2B

Citation

cyromazine

17

Confirm

tebufenozide

18

Conserve

spinosad

5

Deadline

metaldehyde

no code

Decathlon

cyfluthrin

3A

Deltagard

deltamethrin

3A

Diatect

pyrethrins

3A

Diazinon

diazinon

1B

Dibrom

naled

1B

Dimethoate

dimethoate

1B

Dimilin

diflubenzuron

15

Dipel

Bacillus thuringiensis kurstaki

11B

Di-Syston

disulfoton

1B

Discus

imidacloprid & cyfluthrin

4A & 3A

Distance

pyriproxyfen

7C

DuraGuard

chlorpyrifos

1B

Duraplex

cyfluthrin & chlorpyrifos

3A & 1B

Durham Metaldehyde

metaldehyde

no code

Dursban

chlorpyrifos

1B

Endeavor

pymetrozine

9B

Enstar II

s-kinoprene

7A

Entrust

spinosad

5

Extinguish

s-methoprene

7A

Flagship

thiamethoxam

4A

Floramite

bifenazate

un

Furadan

carbofuran

1A

Gnatrol

Bacillus thuringiensis israelensis

11A

Hachi-Hachi

tolfenpyrad

21A

Hexygon

hexythiazox

10A

Imidan

phosmet

1B

Jackpot

Bacillus thuringiensis aizawai

11B

Javelin

Bacillus thuringiensis kurstaki

11B

Judo

spiromesifen

23

Kontos

spirotetramat

23

Kryocide

cryolite

un

Lucid

abamectin

6

M-Pede

potassium salts of fatty acids

no code

Magus

fenazaquin

21A

Malathion

malathion

1B

Marathon

imidacloprid

4A

Mavrik

tau-fluvalinate

3A

MBI-203

Chromobacterium subtsugae

no code

Mesurol

methiocarb

1A

Metam KLR

metam-potassium

no code

Mimic

tebufenozide

18

Movento

spirotetramat

23

MSR Spray Concentrate

oxydemeton-methyl

1B

Mycotrol

Beauveria bassiana

no code

Naturalis

Beauveria bassiana

no code

Niban

orthoboric acid

8D

Onager

hexythiazox

10A

OnyxPro

bifenthrin

3A

Orthene

acephate

1B

Ovation

clofentezine

10A

Overture

pyridalyl

un

Pedestal

novaluron

15

Preclude

fenoxycarb

7B

PFR-97

Isaria fumosorosea

no code

ProMite

fenbutatin oxide

12B

PyGanic

pyrethrins

3A

Pyrellin

pyrethrins & rotenone

3A & 21B

Pyrenone

pyrethrins

3A

Pyreth-It

pyrethrins

3A

Pylon

chlorfenapyr

13

Safari

dinotefuran

4A

Sanmite

pyridaben

21A

Scimitar

lambda-cyhalothrin

3A

Sevin

carbaryl

1A

Shuttle

acequinocyl

20B

Sirocco

bifenazate & abamectin

un & 6

Sluggo

iron phosphate

no code

sodium ferric EDTA

Dr. T’s

no code

SorbiShield

sorbitol octanoate

no code

Spod-X

polyhedral occlusion bodies of the nuclear polyhedrosis virus of Spodoptera exigua

no code

SucraShield

sucrose octanoate

no code

Supracide

methidathion

1B

Surround

kaolin

no code

Talstar

bifenthrin

3A

Talus

buprofezin

16

Tame

fenpropathrin

3A

Tame/Orthene

fenpropathrin & acephate

3A & 1B

Telone

1,3-dichloropropene

no code

Tetrasan

etoxazole

10B

Triact

clarified hydrophobic extract of neem oil

no code

Trilogy

clarified hydrophobic extract of neem oil

no code

TriStar

acetamiprid

4A

Ultiflora

milbemectin

6

Ultra-Fine Oil

refined petroleum distillate

no code

Vapam

metam-sodium

no code

Vendex

fenbutatin oxide

12B

Xentari

Bacillus thuringiensis aizawai

11B

aWhen no mode of action code is present, there is no code established and the product can be used without regard to mode of action.

b”un” means this compound has an unknown or uncertain mode of action.

Footnotes

1.

This document is ENY-843, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date November 2007. Revised November 2012. 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., professor, Department 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 use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition. Use pesticides safely. Read and follow directions on the manufacturer's label.


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 UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.