Sorghum Shoot Fly – A Destructive Pest

Sorghum shoot fly, scientifically known as Atherigona soccata, is an insect pest that causes significant damage to sorghum crops. This small insect resembles a housefly and poses a threat particularly during the seedling stage of the crop.

Hosts

The primary host of the sorghum shoot fly is sorghum itself. However, it can also infest other crops such as maize, finger millet, bullrush millet, rice, wheat, and various other grass species.

Life Cycle

The female sorghum shoot fly lays white eggs individually on the central surface of the leaves, typically on the underside. Within 1-3 days, the eggs hatch, and the yellow-colored maggots move to the upper surface of the leaf. They then enter the space between the leaf sheath and the axis and make a clean cut at the base of the leaf. The growing point of the plant dies, providing a food source for the maggots.

The larval stage lasts for about 6-12 days, followed by pupation, which takes approximately 7 days. Pupation occurs in the base of the dead shoot or occasionally in the soil. Finally, adult flies emerge from the pupae. A single female fly can lay up to 30 eggs during its lifetime. The entire life cycle of the sorghum shoot fly is completed within 17-20 days.

Identification

The eggs of the sorghum shoot fly are whitish, elongated, and measure around 0.8 x 0.2 mm. The fully grown larva is 8-10 mm long and appears white or yellowish. The adult fly is approximately 4 mm in length and resembles a small house fly. The female has a pale grey head and thorax, while the abdomen is yellowish with brown patches. Male flies are generally darker in color.

Feeding and Damage

The larva of the sorghum shoot fly migrates to the upper side of the leaf, moving along the leaf whorl until it reaches the growing point. It creates an incision at the growing point, causing the central leaf to dry up. The larva feeds on the decaying tissue inside the shoot, leading to the production of a condition known as “deadheart.” These symptoms usually appear 2-3 days after infestation.

Plants between 5-30 days old are most susceptible to shoot fly damage. However, in humid conditions during the rainy season, older plants may also experience infestation, although they may not exhibit typical deadheart symptoms. The damaged leaves become thin and papery, wrapping around other leaves and hindering normal growth. In some cases, late infestations can damage the panicle during its formative stage, resulting in rotting or drying of the affected portion.

Control

Chemical Control Method

To combat the sorghum shoot fly, the following insecticides are recommended:

  • KINGCODE ELITE 50EC: Mix 10ml with 20 liters of water.
  • LEXUS 247SC: Mix 8ml with 20 liters of water.
  • PENTAGON 50EC: Mix 10ml with 20 liters of water.
  • PRESENTO 200SP: Mix 5g with 20 liters of water.
  • BACIGUARD 16WDG: Mix 15g with 20 liters of water.
  • SINOPHATE 750SP: Mix 20g with 20 liters of water.
  • EPITOME ELITE 500SP: Mix 10g with 20 liters of water.
  • ESCORT 19EC: Mix 10ml with 20 liters of water.
  • LEGACY 50EC: Mix 15ml with 20 liters of water.
  • PROFILE 440EC: Mix 30ml with 20 liters of water.
  • TRUMPET 200SC: Mix 15ml with 20 liters of water.

Note

When using any insecticide, it is advisable to mix it with INTEGRA at a ratio of 3ml per 20 liters of water. INTEGRA improves the effectiveness of the insecticide as a sticker, spreader, and penetrant. Timely application of the insecticide is crucial for successful shoot fly control. To prevent resistance, it is recommended to alternate between different insecticides throughout the crop season rather than relying on a single one.

Non-Chemical Methods

In addition to chemical control, several non-chemical methods can be employed:

  • Early sowing.
  • Planting shoot fly-resistant varieties.
  • Encouraging natural enemies like parasitic wasps and various species of spiders that prey on the shoot fly eggs.
  • Collecting and destroying crop residues after harvest to reduce carry-over from one season to another.
  • Implementing proper weed control.
  • Maintaining field hygiene and sanitation.
  • Rotating crops with non-host species.

Conclusion

The sorghum shoot fly is a highly destructive insect pest that causes significant damage to sorghum crops, especially during the seedling stage. Identifying the pest, understanding its life cycle, and implementing appropriate control measures, such as chemical and non-chemical methods, can help minimize the impact and protect the sorghum crop from severe losses.

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