Diaprepes Root Weevil Native of the Caribbean Islands


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Diaprepes Root Weevil

  • Native of the Caribbean Islands

  • Sugarcane rootstalk borer, Apopka weevil, citrus root weevil



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







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)*



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

  • 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)





Establishment in Container Ornamentals

  • Isolated populations

  • Ability to establish

  • External factors



Larval Establishment in Container Ornamentals



Larval Establishment in Container Ornamentals



Larval Establishment in Container Ornamentals



Percent Reduction of Diaprepes Larvae in 1-Gallon Containers Drenched with Talstar (7 DAT)



Soil Removal

  • Location: Commercial nursery, Broward County

  • Host Plant: Ficus alli

  • 45 gallon container

  • Diaprepes: Natural infestation

  • Treatments (7 replications):

  • 1. Field soil

  • 2. Potting mix

  • 3. Potting mix + Talstar @ 25 ppm

  • Evaluation: 5 weeks after treatment





Talstar + Nematodes – 3 tests

  • Location: Commercial nursery or the research center Diaprepes: Artificially infested

  • Treatments: Interaction of entomopathogenic nematodes and Talstar



Test 1 - Methods

  • Location: Commercial nursery, Broward County

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

  • Diaprepes: Artificially infested

  • Treatments (7 replications):

  • 1. Talstar @ 25 ppm

  • 2. Heterorhabditis indica @ 9.8 billion/A

  • 3. Talstar @ 25 ppm + H. indica @ 9.8 billion/A

  • 4. Control

  • Evaluation: 5 weeks after treatment





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



Test 2 Treatments (5 replications)





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



Test 3 - Treatments

  • Nema-low + Talstar-low

  • Nema-low + Talstar-high

  • Nema-high + Talstar-low

  • Nema-high + Talstar-high

  • Control























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



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



Cycad aulacaspis scale Aulacaspis 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



Holopothrips near inquilinus

  • 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.



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 Scale Paratachardina 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



Lobate Lac Scale

  • 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

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







Photo Credits

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

  • All other photos are property of Catherine Mannion.




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