Carambola Pests
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Adult diaprepes root weevil, Diaprepes abbreviatus (Linnaeus)
Fig. 1
Adult diaprepes root weevil, Diaprepes abbreviatus (Linnaeus)

Red Banded Thrip, Selenothrips rubrocinctus
Fig. 6
Red Banded Thrip, Selenothrips rubrocinctus

Red Banded Thrip Pupa(e)
Fig. 7
Red Banded Thrip Pupa(e)

Southern Green Stink Bug, Nezara viridula (Linnaeus)
Fig. 9
Southern Green Stink Bug,
Nezara viridula
(Linnaeus)

Brown soft scale (Coccus hesperidum) Linnaeus
Fig. 16
Brown soft scale,
Coccus hesperidum
(Linnaeus)

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Carambola trees are attacked by a number of scale insects including plumose (Morganella longispina) and philephedra (Philephedra tuberculosa) scales, which attack leaves and twigs, causing defoliation and stem dieback. The diaprepes weevil (Diaprepes abbreviatus) causes damage to the roots, which may lead to root and shoot dieback. 1
Fruit damage caused by stink bugs (Nezara sp.) and squash bugs (Acanthocephala sp.) results in pinhole-sized markings on the fruit surface and dry areas of the flesh under the puncture wounds. This may lead to infection by fungi which cause soft rot of the fruit. Fruit blotch miner (Lepidoptera: Gracillaridae) causes a superficial damage to the waxy cuticle and can be identified by meandering brownish colored trails on the fruit surface. Brown scales (Coccus hesperidum) and red-banded thrips (Selenothrips rubrocinctus) have also been observed feeding on carambola fruit. 1



Diaprepes Root Weevil
Diaprepes abbreviatus (Linnaeus)

Female root weevils generally oviposit eggs in clusters between two leaves on newly flushed foliage. After ten or twenty days, eggs hatch and larvae fall to the ground. The larvae begin feeding on the fibrous feeder roots. Successively larger larval instars feed on larger roots. The final larval stages (of at least eleven) proceed to the tap root and major lateral roots of the tree. Even if direct feeding does not girdle these roots, lesions provide entry to debilitating fungi such as Phytophthora. Adult weevils emerge over a three month period which may begin as early as March. Larval development time ranges from nine to 18 months, which includes an inactive pupal stage of one to three months.
Dry weather delays development and emergence. 2
Notching (Fig. 4) along the margins of young leaves is a telltale symptom of the presence of Diaprepes abbreviatus adults, or other related root weevils. However, other pests such as grasshoppers and caterpillars may produce similar damage. Therefore, it is best to look for a sign, such as the pest doing the damage. Look for Diaprepes abbreviatus adults during the day on the foliage. Shaking the plant may aid in detection as adults fall off of the plant onto the ground.
The larvae of Diaprepes abbreviatus are found in the soil where they feed on the roots of the host (Fig. 5). They will often girdle the taproot, impeding the ability of the plant to take up water and nutrients resulting in plant mortality. In addition, this type of injury provides an avenue for root rot infections by Phythophora fungus. Young hosts can be killed by a single larva, while several larvae can cause serious decline of older, established hosts. Because larvae are below ground, it is difficult to detect them before decline of above ground potions of the host is observed. 3

Egg mass of Diaprepes abbreviatus (L.), on citrus leaf. Young (right) and older (left) larvae of the diaprepes root weevil, Diaprepes abbreviatus (Linnaeus) Damage - notching on leaves - by Diaprepes abbreviatus (L.)
Fig. 2 Fig. 3 Fig. 4
Damage to citrus tree roots by Diaprepes abbreviatus (L.)
Fig. 5

Fig. 2. Egg mass of Diaprepes abbreviatus (L.), on citrus leaf
Fig. 3. Young (right) and older (left) larvae of the diaprepes root weevil, Diaprepes abbreviatus (Linnaeus)
Fig. 4. Damage notching on leaves by Diaprepes abbreviatus (L.)
Fig. 5. Damage to citrus tree roots by Diaprepes abbreviatus (L.)

Further Reading
Diaprepes Root Weevil from the University of California pdf 8 pages
Diaprepes root weevil, Diaprepes abbreviatus (Linnaeus) from the University of Florida pdf 4 pages



Red Banded Thrip (Fig. 6)
Selenothrips rubrocinctus

The redbanded thrips is ubiquitous in its distribution throughout Florida, but it is generally found in damaging numbers from Orlando to Key West. Female redbanded thrips are slightly greater than 1 mm in length, and have a dark brown to black body underlain by red pigment, chiefly in the first three abdominal segments. The larvae is light yellow to orange, with the first three and last segments of the abdomen bright red. The life cycle of this thrips is about three weeks in Florida, and several generations are possible each year. Redbanded thrips prefer young foliage, which may lead to leaf drop, at times totally denuding trees. The frass and associated sooty mold from thrips feeding may give rise to fruit which is out-of-grade. 2

In Florida, this species is found from Key West to Macclenny (Baker County in north Florida), but more generally it is found from the Orlando area south. The larvae and adults feed on the foliage and the fruit by piercing the epidermis with their mouthparts. Redbanded thrips prefer young foliage and their feeding and causes leaf silvering, leaf distortion, and leaf drop. The thrips destroys the cells on which it feeds, causes some leaf distortion, injury to the fruit, and leaves unsightly dark colored droplets or blotches of excrement on the leaf surface. A more serious injury is leaf drop, which may denude trees. Honeydew excretory products from red-banded thrips and other insect infestations fall to leaves, fruits or objects beneath, giving rise to the objectionable fruit-degrading, black sooty mold. 4

Typical thrips damage
Fig. 8

Fig. 8.  Typical thrips damage

Further Reading
Redbanded Thrips, Selenothrips rubrocinctus from the University of Florida pdf 4 pages



Southern Green Stink Bug
Nezara viridula (Linnaeus)

The southern green stink bug has piercing-sucking mouthparts. The mouth consists of a long beak-like structure called the rostrum. Salivary fluid is pumped down the salivary duct and liquefied food is pumped up the food canal. All plant parts are likely to be fed upon, but growing shoots and developing fruit are preferred. Attached shoots usually wither or, in extreme cases, may die. The damage on fruit from the punctures is hard brownish or black spots. These punctures affect the fruit's edible qualities and decidedly lower its market value. Young fruit growth is retarded and the fruit often withers and drops from the plant.
Biological control: Parasites, usually wasps and flies, provide biological control of the southern green stink bug. In Florida a tachinid fly, Trichopoda pennipes, parasitizes adults and nymphs; and a wasp, Trissolcus basalis, parasitizes eggs. 5

Eggs of the Southern Green Stink Bug 1st instar nymphs Second instar nymph
Fig. 10 Fig. 11 Fig. 12
Third instar nymph of the southern green stink bug Fourth instar nymph of the southern green stink bug Fifth instar nymph of the southern green stink bug
Fig. 13 Fig. 14 Fig. 15

Fig. 10. Eggs of the southern green stink bug
Fig. 11. 1st instar nymphs
Fig. 12. Second instar nymph
Fig. 13. Third instar nymph of the southern green stink bug
Fig. 14. Fourth instar nymph of the southern green stink bug
Fig. 15. Fifth instar nymph of the southern green stink bug



Soft Brown Scale (Fig. 16)
Coccus hesperidum

The scale body is flat and oval, light brown to yellowish in color with brown stippling, and 2.5 to 4 mm long (Fig. 16). This scale gives birth to pale yellow crawlers. Males are uncommon. Soft brown scales secrete large amounts of honeydew and the adjoining foliage becomes heavily coated with sooty mold. On occasions young citrus trees can be killed by high populations of soft brown scale from feeding and honeydew production. Scale feeding on older trees results in reduced tree vigor, twig dieback, reduced yields, and lower fruit grades due to heavy sooty mold. Soft brown scale can be found infesting a wide range of ornamental plants.
The scale is heavily parasitized by several different species of parasitic wasps. 6

Further Reading
A guide to Scale Insect Identification from the University of Florida pdf 5 pages



Further Reading
Growing Carambola in the Florida Home Landscape from the University of Florida pdf 8 pages
Florida Crop/Pest Management: Carambola from the University of Florida pdf 5 pages

Bibliography

1 Crane, Jonathan, H. "Carambola Growing in the Florida Home Landscape." edis.ifas.ufl.edu. This document is HS12, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date April 1994. Revised Nov. 2016. Web. 21 Apr. 2017. Web. 28 Jan. 2014.
2 Mossler, Mark A. and Crane, Jonathan. "Florida Crop/Pest Management Profile: Carambola." edis.ifas.ufl.edu. One of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Sept. 2002. Reviewed July 2013. Web. 1 Oct. 2014.
3 Weissling, T. J., Peña, J. E., Giblin-Davis, R. M. and Knapp, J. L.Jr. "Diaprepes Root Weevil, Diaprepes abbreviatus (Linnaeus) (Insecta: Coleoptera: Curculionidae)." edis.ifas.ufl.edu. This document is EENY-024 (IN151), one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: Feb. 1998. Revised: Nov. 2012. Web. 2 Oct. 2014.
4 Denmark, H.A. and Wolfenbarge, D.O. "Redbanded thrips Selenothrips rubrocinctus (Giard)." edis.ifas.ufl.edu. One of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. June 1999. Revised May 2016. Web. 21 Apr. 2017.
5 Squitier, Jason M. "Southern Green Stink Bug, Nezara viridula (Linnaeus)." edis.ifas.ufl.edu. This document is EENY-016 (IN142), one of a series of Featured Creatures from the Entomology and Nematology Department, UF/IFAS Extension. Published Nov. 1997. Revised Nov. 2013.
6 Futch, S.H., McCoy, C.W. and Childers, C.C. "A Guide to Scale Insect Identification." edis.ifas.ufl.edu. This document is HS-817, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published Sept. 2001. Reviewed June 2012.

Photographs

Fig. 1,6 Giblin-Davis, R. M. Adult diaprepes root weevil, Diaprepes abbreviatus (Linnaeus) and Red Banded Thrip, Selenothrips rubrocinctus. N.d. entnemdept.ufl.edu. 28 Jan. 2014.
Fig. 2 Butler, Jerry F. Egg mass of Diaprepes abbreviatus (L.), on citrus leaf. N.d. University of Florida. edis.ifas.ufl.edu. Web. 2 Oct. 2014.
Fig. 3 Grub, Peggy. Young (right) and older (left) larvae of the diaprepes root weevil, Diaprepes abbreviatus (Linnaeus). N.d. USDA. edis.ifas.ufl.edu. Web. 2 Oct. 2014.
Fig. 4 Pena, Jorge. Damage - notching on leaves - by Diaprepes abbreviatus (L.). N.d. University of Florida. edis.ifas.ufl.edu. Web. 2 Oct. 2014.
Fig. 5 Pena, Jorge. Damage to citrus tree roots by Diaprepes abbreviatus (L.). N.d. University of Florida. edis.ifas.ufl.edu. Web. 2 Oct. 2014.
Fig. 7 Buss, Lyle J. Red Banded Thrip Pupa(e). N.d. University of Florida. edis.ifas.ufl.edu. Web. 2 Oct. 2014.
Fig. 8 Castner, J. Typical thrips damage. N.d. University of Florida. edis.ifas.ufl.edu. Web. 28 Jan. 2014.
Fig. 9 Castner, J. Adult Southern Green Stink Bug, Nezara viridula (Linnaeus). N.d. University of Florida. edis.ifas.ufl.edu. Web. 28 Jan. 2014.
Fig. 10 Castner, J. Eggs of the Southern Green Stink Bug, Nezara viridula (Linnaeus). N.d. University of Florida. edis.ifas.ufl.edu. Web. 2 Oct. 2014.
Fig. 11,12,13,14,15 Pilcher, Herb. Lyfe cycle of the Southern green stink bug, Nezara viridula (Linnaeus). N.d. USDA-ARS. edis.ifas.ufl.edu. Web. 2 Oct. 2014.
Fig. 16 Cranshaw, Whitney. Brown soft scale (Coccus hesperidum) Linnaeus. 2003. bugwood.org. Under (CC BY 3.0 US). Colorado State University. Web. 25 Apr. 2016.

Published 1 Oct. 2014 LR. Last update 21 Apr. 2017 LR
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