insect pests of sorghum and pearl millet in the semi-arid tropics and their management

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  • Insect Pests of Sorghum and Pearl Millet in the Semi-Arid Tropics and their Management

    Dec 2009

    HC Sharma1, BVS Reddy1, MK Dhillon1 and VR Bhagwat21International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Andhra Pradesh, India.

    2Directorate of Sorghum Research (DSR), Rajendranagar 500 030, Hyderabad, India.

    Strategies for Pest ManagementSynchronous and timely/early sowings of cultivars with similar maturity over large areas reduce damage by shoot fly, midge and head bugs.

    M 35-1, Phule Yashoda, ICSV 700 and ICSV 93046 are relatively less damaged by shoot fly and stem borers, while ICSV 745 and ICSV 88032 are resistant to sorghum midge. Malisor 84-7 and CSM 388 are resistant to head bugs. In pearl millet, Zongo, INMB 106 and INMB 155 exhibit moderate levels of resistance to stem borer, and Souna, IBV 8001 and HKB tif to head miner.

    Treat seeds with carbofuran (5% a.i.), thiamethoxam (9.0 ml kg-1 seed), or imidacloprid (0.165 mg kg-1 seed) to reduce damage by shoot fly.

    Spray cypermethrin (750 ml ha-1) or endosulfan (350 g a.i. ha-1) to control foliar pests or apply carbofuran granules (5 to 7 granules plant-1) in the leaf whorls to control shoot fly and stem borer. For panicle feeding insects, the crop may be sprayed with endosulfan or cypermethrin at the 50% flowering, post-anthesis, and milk stages to control midge, head bugs and head caterpillars.

    Plate 7: Head caterpillars, Helicoverpa armigera (7a), Eublemma spp (7b), and Heliocheilus albipunctella (7c) feeding on sorghum and pearl millet.

    Plate 8: White grub, Holotrichia spp. (8a) and Blister beetle, Cylindrothorax tenuicollis feeding on pearl millet.

    3

    4a 4b

    1a 1bPlate 1. Shoot flies: Atherigona soccata damage in sorghum (1a) and A. approximata damage in pearl millet (1b).

    Shoot fliesShoot flies, Atherigona soccata/ A. approximata females lay cigar shaped eggs singly on the lower surface of the leaves. The larva cuts the growing point of sorghum (Plate 1a) and pearl millet (Plate 1b), resulting in wilting and drying of the central leaf known as deadheart. The damaged plants produce side tillers, which may also be attacked.

    Plate 2. Leaf scarification (2a), deadheart (2b), and stem tunneling (2c, 2d) by Chilo and Busseola in sorghum, and stem tunneling by Coniesta larvae in pearl millet (2e).

    Stem borers, Chilo, Busseola and Coniesta Stem borers, Chilo partellus and Busseola fusca damage sorghum, while Coniesta ignefusalis is specific to pearl millet. Stem borer larvae feed on whorl leaves, resulting in leaf scarification (Plate 2a). The grown up larvae damage the growing point resulting in the production of a deadheart (Plate 2b). Stem borer larvae also cause extensive stem tunneling (Plate 2c,d,e).

    Sugarcane aphid

    Head bugs

    Shoot bug

    Other important pests

    Midge

    Sugarcane aphid, Melanaphis sacchari adults and nymphs suck the sap from the lower surface of leaves resulting in yellowing of leaves and stunted plant growth (Plate 3). The aphids secrete honeydew, which falls on the lower leaves and the ground, on which sooty molds grow.

    Plate 3. Sugarcane aphid, Melanaphis sacchari damage in sorghum.

    Plate 4. Shoot bug, Peregrinus maidis damage in sorghum.

    Plate 5. Midges: Stenodiplosis sorghicola damage in sorghum (5a) and Geromyia penniseti damage in pearl millet (5b).

    Shoot bug, Peregrinus maidis adults and nymphs suck sap from the leaf whorls (Plate 4a). In case of severe infestation, the top leaves start drying first, and at times results in plant mortality (Plate 4b).

    Midge, Stenodiplosis sorghicola larvae feed on the developing ovaries of sorghum (Plate 5a) and pearl millet (Plate 5b) resulting in the production of chaffy spikelets. Females lay eggs in panicles at flowering during morning hours.

    5a 5b

    Head bugs, Calocoris angustatus (Plate 6a) and Eurystylus oldi (Plate 6b) nymphs and adults suck sap from the developing grain. High levels of bug damage lead to tanning and shriveling of the grain. Calocoris angustatus is an important pest in India, while E. oldi is important in western Africa.

    6a 6b

    Plate 6. Head bugs, Calocoris angustatus (6a) and Eurystylus oldi (6b) damage in sorghum.

    Head caterpillarsHead caterpillars, Helicoverpa armigera (Plate 7a) and Eublemma spp. (Plate 7b) feed on the developing grain of sorghum, while head miner, Heliocheilus albipunctella (Plate 7c) and pearl millet larvae feed on inflorescence and developing grain of pearl millet.

    7a 7b

    7c

    2a 2b 2c

    2d 2e

    White grub, Holotrichia spp. (Plate 8a) is a serious pest of pearl millet planted in the sandy soil and blister beetle, Cylindrothorax tenuicollis (Plate 8b) is an important pest of pearl millet in dry tropic regions of India.

    8a 8b

    For more information, contact: HC Sharma, Principal Scientist (Entomology), e-mail: h.sharma@cgiar.org

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