Diaprepes Root Weevil and Other Pests of Regulatory

ConcernCatharine Mannion

University of Florida, IFAS,

Tropical Research and Education Center

Diaprepes Root Weevil

• Native of the Caribbean Islands

• Sugarcane rootstalk borer, Apopka weevil, citrus root weevil

• First reported in Florida in 1964 in a nursery in Central Florida

• Major pest of citrus, sugarcane, ornamentals, root crops

Diaprepes Root Weevil on Ornamentals

• Little information on the effect of adult and/or larval feeding on ornamental plants

• Many ornamental plants can support advanced larval injury before external symptoms (leaf yellowing, defoliation, wilting) are observed

• Some ornamental plants such as oaks appear to be susceptible to root diseases such as Phytophthora root rot following larval feeding

• Most of the research focus has been in citrus

Feeding Damage by Adult Weevils• Adults feed on the foliage of

numerous plants causing a typical notching on the leaf margins

• Adults can be found year round in southern Florida with peak flights in the spring and fall

Oviposition

• 30 – 264 eggs per mass (approximately 5,000 eggs in a lifetime)

• Neonates hatch and fall to the soil surface

• Neonates are very active and begin moving into the soil where they feed on plant roots but can survive for numerous days without feeding

• Females lay their eggs between two leaves or fold a single leaf

Larvae can cause severe damage to roots ultimately killing the plant

No larvae Larvae

Preliminary Plant Host Survey for Egg Masses, Damage, or Adults in a Field Nursery -

(September 1998)

• Ti (Cordyline terminalis)• Dahoon holly (Ilex cassine)*• Silver trumpet tree (Tabebuia

caraiba)• Jacaranda (Jacaranda

mimosifolia)• Geiger tree (Cordia sebestena)• Gumbo limbo (Bursera

simaruba)• Cocoplum (Chrysobalanus

icaco)• Silver and green buttonwood

(Conocarpus erectus)*• Black olive (Bucida buseras)*• Live oak (Quercus virginiana)*

• Brazilian beauty leaf (Calophyllum braziliense)

• Autograph tree (Clusia rosea)• Bauhinia sp.• Cassia sp.• Crape myrtle (Lagerstroemia

sp.)*• Mahogany (Swietenia

mahogani)*• Privet (Ligustrum sp.)• Coconut palm (Cocos nucifera)*• Pygmy date palm (Phoenix

roebellini)*• Satin leaf (Chrysophyllum

olivivorme)

Risk of Movement

• Adults are fairly strong fliers, but most widespread distribution is attributed to movement of plant material

• Immature stages in soil or containers of nursery plants

• Egg masses on foliage– Neonate larvae are active and can survive for

numerous days without feeding

• Adults on foliage– Although adults are large and somewhat obvious, they

can hide

• Movement of adults in trucks or equipment

Texas Shipping Requirements

• All nursery stock not grown in a greenhouse must be sprayed for adults with an approved insecticide within 14 days of movement

• The soil must be drenched with bifenthrin or have bifenthrin incorporated in the mix.– Soil incorporation for fire ants meets the required

levels for Diaprepes, however, if the plants are older than 6 months, another treatment will be necessary

– Soil drench – the high drench rate for fire ant meets the required levels for Diaprepes (25ppm)

Approved Insecticides for Foliar Sprays

• Talstar (bifenthrin)*

• Orthene (acephate)

• Sevin (carbaryl)

• Dursban (chlorpyrifos)

Texas Diaprepes Quarantine

Infested CountiesApril 2001

Establishment in Container Ornamentals

• Isolated populations

• Ability to establish

• External factors

Larval Establishment in Container Ornamentals

Larval Establishment in Container Ornamentals

• 0 egg masses• 5 egg masses• 20 egg masses

Larval Establishment in Container Ornamentals

Treatment Total Larvae Recovered

Percent Larval Establishment

Talstar – 0 eggs 0 0

Talstar – 400 eggs 0 0

Talstar – 1300 eggs 0 0

Control – 0 eggs 0 0

Control – 400 eggs 1 1.0

Control – 1300 eggs 4 0.3

Percent Reduction of Diaprepes Larvae in 1-Gallon Containers

Drenched with Talstar(7 DAT)

Treatment Percent Reduction

9th instar (65 days old) 47.6

8th instar (51 days old) 80.0

7th instar (41 days old) 82.4

Soil RemovalLocation: Commercial nursery, Broward County

Host Plant: Ficus alli45 gallon container

Diaprepes: Natural infestation

Treatments (7 replications): 1. Field soil2. Potting mix3. Potting mix + Talstar @ 25 ppm

Evaluation: 5 weeks after treatment

The trees were removed from the field and placed in 45 gallon containers. In treatments 2 and 3, the field soil was removed and replaced with potting mix. The Talstar drench was applied in 9 gallons per container.

0

0.5

1

1.5

2

2.5

Mea

n N

o.

Liv

e D

iap

rep

es

Soil Potting Mix Potting Mix+Talstar

F=1.6; df=2,18; P=0.229

Trees: Ficus alli 45 gallon containers

The Effect of Soil Removal and Bifenthrin on Natural Populations of Diaprepes abbreviatus

Talstar + Nematodes – 3 tests

Location: Commercial nursery or the research center Diaprepes: Artificially infested Treatments: Interaction of entomopathogenic nematodes

and Talstar

Test 1 - 45-gallon containers

Test 2 – 3-gallon containers

Test 3 – 8-ounce containers

Test 1 - MethodsLocation: Commercial nursery,

Broward County

Host Plant: Bucida buceras (big leaf black olive), 45

gallon container

Diaprepes: Artificially infested Treatments (7 replications):

1. Talstar @ 25 ppm2. Heterorhabditis indica @ 9.8 billion/A3. Talstar @ 25 ppm + H. indica @ 9.8 billion/A4. Control

Evaluation: 5 weeks after treatment

The trees were potted in 45 gallon containers with a potting media. Each container was infested with 15-fifth and ninth instar Diaprepes (approximately half of each age in each container). One week after infestation, treatments were applied. Talstar was drenched in 9 gallons per container. Nematodes were applied in approximately 2 gallons per container.

1.9 b

3.0 b

0.0 c

7.4 a

0

1

2

3

4

5

6

7

8

Me

an N

o. L

ive

D

iap

rep

es

Talstar Nema Talstar+Nema Control

Trees: Bucida buceras (big leaf black olive) 45 gallon containers

F=55.130; df=3,24; P <0.000

The Effect of Bifenthrin and Heterorhabditis indica on Diaprepes abbreviatus

Test 2 - Methods

Location: Tropical Research and Education Center, Homestead

Host Plant: Conocarpus erecta (buttonwood), 3 gallon containers

Diaprepes: Artificially infested

Treatments: Next slide

Evaluation: 2 weeks after treatment

Five larvae were buried in each container with potting mix and one plant. Ten days after the larvae were added to the containers, treatments were applied. Insecticides were drenched with 0.53 gallons per container. Nematodes were applied in 25.5 oz. per container.

Test 2Treatments (5 replications)

1. Talstar @ 25 ppm – 5th instar2. Talstar @ 25 ppm – 7th instar3. Talstar @ 25 ppm – 9th instar4. H. indica @ 2 billion/A – 5th instar5. H. indica @ 2 billion/A – 7th instar6. H. indica @ 2 billion/A – 9th instar7. Talstar @ 25 ppm + H. indica @ 2 billion/A – 5th instar8. Talstar @ 25 ppm + H. indica @ 2 billion/A – 7th instar9. Talstar @ 25 ppm + H. indica @ 2 billion/A – 9th instar10. Flagship (thiomethoxam) @ 17 oz/A – 5th instar11. Flagship @ 17 oz./A – 7th instar12. Flagship @ 17 oz./A – 9th instar13. Control – 5th instar14. Control – 7th instar15. Control – 9th instar

0

1

2

3

4

5

Mea

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o. L

ive

Lar

vae

Talstar Nema Talstar+Nema Flagship Control

b

a

c

a

aTree: Conocarpus erectus (buttonwood) 3 gallon containers

F=56.441df=4,70

P <0.000

The Effect of Bifenthrin and Heterorhabditis indica on Diaprepes abbreviatus

Test 3 - Methods

Location: Tropical Research and Education Center, Homestead

Host Plant: None (carrot provided for food); 8 oz. plastic cups

Diaprepes: Artificially infested

Treatments: Next slide

Evaluation: 2, 3, 4, 5, and 6 days after application

Diaprepes larvae (9th instar) were placed in cups containing potting media and one carrot for food. Nematode and chemical applications were made 4 days after larvae were placed in the cups.

Test 3 - Treatments

5. Nema-low + Talstar-low

6. Nema-low + Talstar-high

7. Nema-high + Talstar-low

8. Nema-high + Talstar-high

9. Control

1. Nema – low

2. Nema-high

3. Talstar – low

4. Talstar – high

Nematode: Heterorhabditis indica and Steinernema riobravis

(low rate = 1 billion/A; high rate = 2 billion/A)

Chemical: Talstar (bifenthrin)

(low rate = 12.5 ppm; high rate = 25 ppm)

0

0.5

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1.5

2

2.5

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2 DAT 3 DAT 4 DAT 5 DAT 6 DAT

Mea

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arva

e

9. Control

Talstar + Heterorhabditis indica (Grubstake)

0

0.5

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1.5

2

2.5

3

2 DAT 3 DAT 4 DAT 5 DAT 6 DAT

Mea

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o. L

ive

Lar

vae

1. Nem (L) 2. Nem (H) 9. Control

Talstar + Heterorhabditis indica (Grubstake)

0

0.5

1

1.5

2

2.5

3

2 DAT 3 DAT 4 DAT 5 DAT 6 DAT

Mea

n N

o.

Liv

e L

arva

e

1. Nem (L) 2. Nem (H) 3. Talstar (L) 4. Talstar (H) 9. Control

Talstar + Heterorhabditis indica (Grubstake)

0

0.5

1

1.5

2

2.5

3

2 DAT 3 DAT 4 DAT 5 DAT 6 DAT

Mea

n N

o. L

ive

Lar

vae

1. Nem (L) 2. Nem (H) 3. Talstar (L)

4. Talstar (H) 5. Nem (L) + Tal (L) 6. Nem (L) + Tal (H)

9. Control

Talstar + Heterorhabditis indica (Grubstake)

0

0.5

1

1.5

2

2.5

3

2 DAT 3 DAT 4 DAT 5 DAT 6 DAT

Mea

n N

o. L

ive

Larv

ae

1. Nem (L) 2. Nem (H) 3. Talstar (L)

4. Talstar (H) 5. Nem (L) + Tal (L) 6. Nem (L) + Tal (H)

7. Nem (H) + Tal (L) 8. Nem (H) + Tal (H) 9. Control

Talstar + Heterorhabditis indica (Grubstake)

0

0.5

1

1.5

2

2.5

3

2 DAT 3 DAT 4 DAT 5 DAT 6 DAT 9 DAT

Mea

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Liv

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arva

e

9. Control

Talstar + Steinernema riobravis (BioVector)

0

0.5

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1.5

2

2.5

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2 DAT 3 DAT 4 DAT 5 DAT 6 DAT 9 DAT

Mea

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Liv

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arva

e

1. Nem (L) 2. Nem (H) 9. Control

Talstar + Steinernema riobravis (BioVector)

0

0.5

1

1.5

2

2.5

3

2 DAT 3 DAT 4 DAT 5 DAT 6 DAT 9 DAT

Mea

n N

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Liv

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arva

e

1. Nem (L) 2. Nem (H) 3. Talstar (L) 4. Talstar (H) 9. Control

Talstar + Steinernema riobravis (BioVector)

0

0.5

1

1.5

2

2.5

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2 DAT 3 DAT 4 DAT 5 DAT 6 DAT 9 DAT

Mea

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Liv

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arva

e

1. Nem (L) 2. Nem (H) 3. Talstar (L)

4. Talstar (H) 5. Nem (L) + Tal (L) 6. Nem (L) + Tal (H)

9. Control

Talstar + Steinernema riobravis (BioVector)

0

0.5

1

1.5

2

2.5

3

2 DAT 3 DAT 4 DAT 5 DAT 6 DAT 9 DAT

Mea

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Liv

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arva

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1. Nem (L) 2. Nem (H) 3. Talstar (L)

4. Talstar (H) 5. Nem (L) + Tal (L) 6. Nem (L) + Tal (H)

7. Nem (H) + Tal (L) 8. Nem (H) + Tal (H) 9. Control

Talstar + Steinernema riobravis (BioVector)

Summary

• Strikingly similar results were obtained in all tests • In all cases, the combination treatment of Talstar and

nematode provided the best control suggesting a synergy or additive effect between treatments.

• The addition of nematodes may provide a way to reduce the amount of insecticide currently recommended.

Required Soil Treatment

• Incorporated Talstar for fire ant meets the requirement

• If it has been more than 6 months, a drench is necessary

• Drench – high drench rate for fire ants

• Rate is based on bulk density of planting media

Insect Pests of Concern in South Florida

• Pink hibiscus mealybug• Stellate scale• Cycad aulacaspis scale• Holopothrips• Myllocerus weevil• Lobate lac scale

Pink Hibiscus Mealybug

Photos by UF, Osborne

Stellate Scale (Vinsonia stellifera)

• Female is star-shaped and soft-bodied, 3/8 inch

• Introduced into Florida from Puerto Rico in the 1950’s but was eradicated

• Found in July 2002 at numerous sites

• Hosts: Numerous ornamental plants and fruit trees, coffee

Hunsberger

Hunsberger

Cycad aulacaspis scaleAulacaspis yasumatsui

• Pest of cycads of the Cycas sp.• Found in Miami, Florida in 1996• Spreading northward in the state• Threatened rare and endangered species of cycads

D. Caldwell

• Found in 2001 on trumpet trees, Tabebuia spp. • This insect is new to the United States • From a group of thrips

that are foliage feeders with some reported to cause galls.

• Currently in Miami-Dade, Broward and Palm Beach Counties.

Holopothrips near inquilinus

Myllocerus undatus

• Broward and northern Miami-Dade County

• From Sri Lanka• Little information

known about this species

• It likely has a very large host range including fruit and ornamentals

Lobate Lac ScaleParatachardina lobata

lobata

• First collected in Florida in August 1999 May become a pest on several tropical and subtropical fruits and ornamentals

• Native to India and Sri Lanka

• Currently in Palm Beach, Broward and Miami-Dade Counties

• More than 100 species of woody plants have been determined to be hosts

• Thirty-two are native plants• Some of the plants include

hibiscus, cocoplum, black olive, weeping fig, buttonwood, sand live oak, and wax myrtle

Lobate Lac Scale

Lobate Lac Scale

The adult female has two pairs of prominent lobes; dark reddish brown

Crawlers are elongate-oval; deep red and mobile

Small hole

Catharine MannionResearch and Extension Specialist

Ornamental Entomology

University of Florida, IFASTropical Research and Education Center

18905 SW 280th StreetHomestead, FL 33031

305-246-7000cmannion@mail.ifas.ufl.edu

Photo Credits

Myllocerus undatas photos are property of Department of Agriculture and Consumer Services (DOACS).

All other photos are property of Catherine Mannion.