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Diaprepes Root Weevil and Other Pests of Regulatory Concern. Catharine Mannion University of Florida, IFAS, Tropical Research and Education Center. Native of the Caribbean Islands Sugarcane rootstalk borer, Apopka weevil, citrus root weevil.
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Diaprepes Root Weevil and Other Pests of Regulatory Concern Catharine Mannion University of Florida, IFAS, Tropical Research and Education Center
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
Diaprepes Root Weevilon 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 • Females lay their eggs between two leaves or fold a single leaf • 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
No larvae Larvae Larvae can cause severe damage to roots ultimately killing the plant
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) Preliminary Plant Host Survey for Egg Masses, Damage, or Adults in a Field Nursery - (September 1998)
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 Counties April 2001
Establishment in Container Ornamentals • Isolated populations • Ability to establish • External factors
Larval Establishment in Container Ornamentals • 0 egg masses • 5 egg masses • 20 egg masses
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 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.
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 3 – 8-ounce containers Test 2 – 3-gallon containers
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 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.
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 instar 2. Talstar @ 25 ppm – 7th instar 3. Talstar @ 25 ppm – 9th instar 4. H. indica @ 2 billion/A – 5th instar 5. H. indica @ 2 billion/A – 7th instar 6. H. indica @ 2 billion/A – 9th instar 7. Talstar @ 25 ppm + H. indica @ 2 billion/A – 5th instar 8. Talstar @ 25 ppm + H. indica @ 2 billion/A – 7th instar 9. Talstar @ 25 ppm + H. indica @ 2 billion/A – 9th instar 10. Flagship (thiomethoxam) @ 17 oz/A – 5th instar 11. Flagship @ 17 oz./A – 7th instar 12. Flagship @ 17 oz./A – 9th instar 13. Control – 5th instar 14. Control – 7th instar 15. Control – 9th instar
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.
Nema-low + Talstar-low Nema-low + Talstar-high Nema-high + Talstar-low Nema-high + Talstar-high Control Nema – low Nema-high Talstar – low Talstar – high Test 3 - Treatments 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)
Summary • Strikingly similar results were obtained in all tests • In all cases, the combination treatment of Talstar and nematodeprovided 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
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 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
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
The adult female has two pairs of prominent lobes; dark reddish brown Crawlers are elongate-oval; deep red and mobile Lobate Lac Scale Small hole
Catharine Mannion Research and Extension Specialist Ornamental Entomology University of Florida, IFAS Tropical Research and Education Center 18905 SW 280th Street Homestead, FL 33031 305-246-7000 cmannion@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.
