Dr. S.K. Dutta

1
Identification, symptoms and nature of damage
beetles and wireworms
Dr. S.K. Dutta Dr. Badal Bhattacharyya Departmen
t of Entomology Assam Agricultural
University,Jorhat-13
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Epilachna Beetles
Identification

• The adult beetle is medium sized (8-9 mm in
  length), yellowish brown globular insect bearing
  12-28 spots on the elytra
• The grubs are about 6 mm long, yellowish in
  colour and bear spines all over the body

Fig. Grubs of Epilachna beetle Fig.
Adults of Epilachna beetle Source
http//www.infonet-biovision.org
Source http//www.agroatlas.ru/pests/
/default/ct/116/crops
Epilachna_vigintioctomaculata_en.htm

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Symptoms

• Scrapping of epidermis leading to skeletonised
  leaves

Fig. Leaf skeletonization caused by
Epilachna beetle Source http//www.ipmimages.org
/browse/detail.cfm?imgnum1326153
4
Nature of Damage

• Both adults and grubs feed on the upper surface
  of the leaves. They eat up regular areas of leaf
  tissue, leaving parallel bands of uneaten tissue
  in between
• The infested leaves are skeletonized which later
  turn brown, dry up and fall off

Fig. Leaf skeletonization caused by
Epilachna beetle Source
http//www.organicgardeninfo.com /mexican-
bean-beetle.html
Fig. Epilachna beetle Sourcehttp//www.avrdc.org
/LC/eggplan t/epilachna.html
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Wireworms/ Click Beetle
Identification

• Wireworms are very thin, yellow, pink or orange
  worms (larvae) of click beetles. Young wireworms
  are initially white and about 1.5 mm long
• Adults are slender beetles whose appearance
  varies greatly according to the species

Fig. Grub of wireworm
Fig. Adult of wireworm (click beetle )
Source www.bayercropscience.co.uk
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• Symptoms

• Small feeding scars or feeding tunnels in potato
  tubers

Fig. Wireworm infested potato plant
Fig. Wireworm infested potato tuber
Source instruct1.cit.cornell.edu/pest
_defects.html
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Nature of Damage

• The larvae (wireworms) damage potato by feeding
  primarily on tubers. The damage appears as
  straight, round holes with smooth walls
• Wireworm can also feed on young sprouts,
  underground stems and roots
• Wireworm infestation may also lead to secondary
  infection by soft rot disease

Fig. Potato tuber infected with soft
rot Sourcehttp//www.omafra.gov.on.ca/english/cr
ops/hort/news/hortmatt/2003/20hrt03a7 .htm