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Damage Potential of Earhead Bug on Sorghum Panicle

  • N. Natarajan
  • P. C. Sundara Babu
Research Article

Abstract

The intensity of damage to sorghum panicle caused by the sorghum earhead bug, Calocoris angustatus Lethierry (Heteroptera:Miridae) was studied under laboratory and field conditions. Laboratory studies showed that among the five nymphal instars, fourth instars consumed maximum food (5.06 mg/day). In adults, the consumption was thrice that of the fourth instar nymphs. Male and female consumed on average 250.68 and 305.56 mg of food respectively from their second instar nymphal stage till their death. In the field, 1–3 days old panicles were preferred for oviposition when compared with panicles at later stages. Grain weight losses upto 31.54 g/panicle infested with three adults were recorded. Similarly the grain weight per panicle decreased as the number of ovipositing females increased; grain weight losses of 9.72-42.02 g were recorded.

Key Words

Sorghum earhead bug Calocoris angustatus damage potential 

Mots Cléfs

Punaise du sorgho Calocoris angustatus dégât potentiel 

Résumé

L’intensité du dégât provoqué par la punaise du sorgho, Calocoris angustatus Lethierry, (Heteroptera: Miridae) sur l’êpi du sorgho fut etudiée au laboratoire et sur le terrain. Les etudes faites au laboratoire demontrent que parmis les cinq stages de developpement des nymphes, le quatrième consomma un maximum de 5.06 mg/jour de nourriture. Chez les adultes la consommation fut trois fois plus elevée que celle des nymphes au quatrième stage. Les mâles et femelles ont consomme respectivement en moyenne 250.68 et 305.56 mg de nourriture à partir de leur deuxième stage de developpement des nymphes jusqu’à leur mort. Sur le terrain les êpis ages de 1 a 3 jours etaient preferes pour la ponte. Des pertes de poids des graines jusqu’a 31.54 g par êpi infecté par trois adultes furent enregistrées. D’autre part on a noté une dimuniton du poids de graines par êpi lorsque le nombre des femelles en état de ponte augmente. Une dimunition du poids des graines allant de 9.72 a 42.02 g provenaient de l’effet de femelles supplementaires.

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Copyright information

© ICIPE 1988

Authors and Affiliations

  • N. Natarajan
    • 1
    • 2
  • P. C. Sundara Babu
    • 1
  1. 1.Department of Agricultural EntomologyTamil Nadu Agricultural UniversityCoimbatoreIndia
  2. 2.National Pulses Research CentrePudukkottaiIndia

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