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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
n N
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
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
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) 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
n N
o.
Liv
e L
arva
e
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
o.
Liv
e L
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
o.
Liv
e L
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
3
2 DAT 3 DAT 4 DAT 5 DAT 6 DAT 9 DAT
Mea
n N
o.
Liv
e L
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
n N
o.
Liv
e L
arva
e
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
Photo Credits
Myllocerus undatas photos are property of Department of Agriculture and Consumer Services (DOACS).
All other photos are property of Catherine Mannion.