Sugarcane white grub facts for kids

Holotrichia serrata, also known as the sugarcane white grub or cockchafer grub, is a type of dung beetle. You can find these beetles in countries like India, Bangladesh, and Sri Lanka. They are known for being a pest, especially in sugarcane fields.

Life Cycle of the Sugarcane White Grub

The adult female beetles lay white, almost round eggs. These eggs hatch into young grubs.

Grub Stages

The first two stages of the grub (called instars) are clear and yellowish-white. They have a special 'C' shape. The third stage grub is a dirty white color. It can grow to be about 34 to 39 millimeters long.

The grub's head is brownish-orange and easy to see. It has strong mouthparts called mandibles. Its thin antennae are long and brown. The grub stage lasts for 60 to 70 days. After this, there is a short two-day period before it becomes a pupa.

Pupa Stage

The third stage grub burrows deep into the soil. There, it makes a small chamber out of earth. Inside this chamber, it turns into a pupa. This pupa is about 25 to 27 millimeters long. The pupa stage lasts for 13 to 19 days.

Adult Beetles

After the first rains, the adult beetles come out of the ground within 3 to 4 days. Adult beetles are brown. Female beetles are usually bigger than males. They are about 23 to 25 millimeters long. In a controlled environment, adult beetles can live for 12 to 26 days.

Why Sugarcane White Grubs are a Problem

The grub stage of Holotrichia serrata is a serious pest. It causes damage to sugarcane plants. Farmers use many ways to control these grubs. These methods include cultural, mechanical, biological, chemical, and combined approaches.

Controlling the Grubs

• Biological Control: One way to fight the grubs is by using a special fungus. This fungus, called Metarhizium anisopliae, can destroy the grubs. Another fungus, Beauveria brongniartii, also attacks the grubs. Some tiny worms called nematodes (like Heterorhabditis indica) can also be used against pupae and adult beetles. A bacterium called Paenibacillus popilliae can also help.
• Chemical Control: Farmers sometimes use special bug-killing chemicals called insecticides. These help to get rid of grubs in sugarcane fields.
• Natural Repellents: Smells from plants like Acacia nilotica and Azadirachta indica leaves can attract adult beetles. This helps farmers to trap them.
• Farming Methods: Simple farming practices can help. These include plowing, harrowing, and hoeing the fields. Flooding the fields or leaving them unplanted for a while can also reduce grubs. Planting different crops each season (crop rotation) also helps.
• Resistant Plants: Some plants, like sunflower, are less affected by the grubs. Farmers can also plant "trap crops" like sorghum, maize, or onion. These plants attract the grubs away from the main crop.

Outbreaks and Damage

In September 2012, many of these beetles appeared in soybean, cotton, and pigeon pea fields in India. This was a big problem for farmers. Besides sugarcane, these grubs also harm many vegetables, groundnuts, and coconuts. In Sri Lanka, grubs have been seen eating the roots of teak seedlings. This causes the young teak plants to wilt and die.

In 2009, there was a very large infestation in Maharashtra State, India. About 9 million adult beetles were collected by hand and destroyed. This helped protect rice, chili, sorghum, and sugarcane crops.

Main Host Plants

The sugarcane white grub can feed on many different plants, including:

• Areca catechu (Areca palm)
• Arachis hypogaea (Peanut)
• Cajanus cajan (Pigeon pea)
• Cocos nucifera (Coconut palm)
• Gossypium arboreum (Tree cotton)
• Hevea brasiliensis (Rubber tree)
• Nicotiana tabacum (Tobacco)
• Oryza sativa (Rice)
• Pennisetum glaucum (Pearl millet)
• Saccharum officinarum (Sugarcane)
• Solanum tuberosum (Potato)
• Sorghum bicolor (Sorghum)
• Tectona grandis (Teak)