Ghujhia Weevil, Tanymecus indicus, is a small beetle that feeds on wheat grains and is native to the Indian subcontinent, belonging to the Family Curculionidae of the Order Coleoptera. It is also known as the Indian or South Asian wheat weevil. This is a major pest of wheat crops and is considered one of the most destructive insect pests in the world.
It is not only a pest of stored grains but also of wheat crops in fields. To effectively manage this pest, it is important to understand its life cycle, its preferred habitats, and the best methods for controlling it. This article will provide an overview and discussion of the Ghujhia weevil pest in wheat crops, including its symptoms, identification techniques, and control.
Wheat Ghujhia Weevil Management in Wheat
Life Cycle of Ghujhia Weevil in Wheat Crop
The life cycle of the Ghujhia weevil pest in wheat crops consists of four stages: egg, larva, pupa, and adult. The female Ghujhia weevil lays eggs in the wheat crop, usually at the base of the stem. These eggs hatch within 8 to 10 days. The larvae that arise from these eggs are known as grubs. They feed on the wheat plant’s grains, leaves, and stems. They feed for about 3 to 4 weeks before they enter the pupal stage. The pupa stage is a resting stage in which the larvae form a protective cocoon in the soil.
This cocoon comprises soil particles and bits of the wheat plant. The pupa remains in the cocoon for 4 to 5 weeks before emerging as an adult weevil. The adult weevil feeds on the wheat plant by puncturing the stems and leaves and sucking out the fluids. The adult weevils can live up to 3 weeks and lay more eggs in the wheat crop. The life cycle of the Ghujhia weevil can be completed in 6 to 8 weeks, depending on the weather conditions. This pest has only one generation in a year.
Occurrence of Ghujhia Weevil in Wheat Fields
- Location of Wheat Ghujhia Weevil: The Ghujhia weevil is a major pest of wheat in India, Bangladesh, Pakistan, Sri Lanka, and some parts of Africa.
- Host Range: Ghujhia Weevil pest is known to feed on various crops, including wheat, barley, gram, and mustard.
Factors Favoring Population Increase of Ghujhia Weevil in Wheat Fields
- Weather conditions – The optimum temperature for the weevil’s activity is 21-27°C, and moderate to high humidity and adequate rainfall favor the growth and spread of the pest.
- Lack of natural enemies – The lack of natural enemies of the Ghujhia weevil in the wheat fields, such as predators and parasites, allows the weevil population to grow and increase.
- Higher reproductive rate – The weevils reproduce quickly and can lay up to 350 eggs in a single season, which can rapidly increase their population.
Identification of Ghujhia Weevil in Wheat Fields
- Egg: The eggs are white, oval, and laid in clusters of up to 30 eggs.
- Larva: The newly hatched larvae are pale yellow and have distinctive brown head.
- Adult: The Ghujhia weevil is a black beetle with yellowish-brown marking on its back, and an oval shape of 2-3 mm in length. It has a long snout used to puncture the wheat grains and feed on them. They have wings but cannot fly.
Damage Symptoms of Ghujhia Weevil in Wheat Fields
- The larvae feed inside the stem and head of the wheat plant, causing them to become weakened and discolored, and the leaves may die off.
- In severe infestation, they can cause the stem and head of the plant to become pitted and distorted, resulting in reduced seed production.
- The adult weevils feed on and cause significant damage to the plant’s foliage, resulting in yellowing and wilting of the leaves.
- The infestation will be at its peak level between October – November.