The early shoot borer, also known as Chilo infuscatellus, belongs to the order Lepidoptera’s Crambidae family. It is a serious pest of sugarcane, usually attacking the crop in the first few weeks of cane development. The insect is endemic to Southeast Asia and is present in many nations, including Bangladesh, India, and Thailand. Early shoot borer larvae eat through the sugarcane stalk, resulting in severe damage and decreased output.
The pest must be managed effectively using resistant varieties, cultural practices, biological control methods, and chemical control with insecticides. Sugarcane is an important cash crop grown worldwide in tropical and subtropical regions. It is primarily grown for its high sugar content, extracted from the stalks of the plant. Sugarcane produces sugar, molasses, ethanol, and other industrial products.
Early Shoot Borer Management in Sugarcane
Life Cycle of Sugarcane Early Shoot Borer
The length of the life cycle of early shoot borer is determined by temperature. Larval development typically takes 25-30 days in warm weather and about five days longer in cool weather.
- Flat-scale eggs are deposited in masses of 4–100 in 3-5 rows on the underside of leaves during the egg stage. Like tiles, the masses are barely overlapping. Within 4-6 days, the eggs emerge.
- Larval stage: The larvae are dirty white with five longitudinal bands of deep violet color and a dark brown head. 16 to 30 days are spent in this period.
- Pupal stage: Within the passage, the pupal stage is experienced. The caterpillar drills a sizable escape hole in the stem before pupating and then covers it with silken discs.
- Adult stage: The adult moth has white hind wings and a light greyish-brown body with black spots close to the forewings’ coastal margins.
Host range: The sugarcane early shoot borer (Chilo infuscatus) primarily feeds on sugarcane, but it can also infest other related plants, including sorghum, maize, and wild relatives of sugarcane. However, sugarcane is the preferred host for this pest, and it causes the most significant damage to sugarcane crops.
Factors Favoring Growth/ Causes of Early Shoot Borer in Field
- The causal organism of the early shoot borer in sugarcane is the larvae of Chilo infuscatus, which primarily attacks the crop during the early stages of cane growth before internode formation.
- It also infests the cane stalks in years of scanty rainfall, causing heavy yield losses as it affects the plant stand and unit area.
- This pest results in canes of different ages with less cane weight and poor juice quality.
- When the early shoot borer infects cane stalks, yield and quality are reduced.
- Factors that favor the growth of early shoot borer in fields include warm temperatures, high humidity, and the presence of weeds, which provide alternate hosts and breeding grounds for the pest.
Identification of Early Shoot Borer in Sugarcane in Field
Flat-scale-like eggs laid in masses on the lower surface of leaves, dirty white larvae with dark violet stripes, and the emergence of pale greyish-brown moths with black dots and white hind wings also indicate the presence of this pest. And the appearance of dead hearts in infected canes.
Damage Symptoms of Early Shoot Borer in Sugarcane
- The larvae of the borer enter the cane laterally through one or more holes in the stalks and bore downwards as well as u