The maize shoot fly, also known as the stem fly, is an insect pest that attacks maize (corn) crops. The larvae of the fly feed on the stem and shoots of the plant, causing significant damage and reducing yield. Let’s check out more information on Maize Shoot Fly management below.
Maize (corn) is one of the world’s most important staple crops, providing food and feed for millions of people and livestock. It’s a versatile crop that can be grown in many regions of the world, including South America, North America, Europe, Africa, and Asia. Maize is a valuable crop due to its high yield potential and versatility, with uses ranging from human consumption to livestock feed and biofuel production.
Maize Shoot Fly management
The life cycle of Maize Shoot Fly
- Eggs: A female lays an average of 40 eggs single on the lower surface of the leaves and tender stem.
- The incubation period lasts about 2-3 days.
- Larvae have a larval period of 10 to 12 days. There are four larval instars present.
- Pupa: Stem pupation. The pupal period lasts about a week.
- The average adult lifespan is 12-1 4 days.
- The life cycle takes about 2-3 weeks to complete.
- A year with multiple generations.
- Carryover – The pest spends the winter as an adult on grasses.
Occurrence of Maize Shootfly
- On hatching from the eggs, larvae bore into the central shoots of seedlings and kill the growing point, producing “dead hearts.”
- They eat the decaying cores of shoots. Following the death of the central shoot, the plant produces tillers and develops a bushy appearance.
Identification of Shootfly in Maize field
- The eggs are white. Eggs are laid on the underside of seedling leaves 7 to 8 days old or on young tillers; one to three eggs are laid per leaf. The white eggs are elongated in shape.
- Crawl down inside the sheath base of the young shoot and kills the growing point and the youngest leaf.
- The fully developed (third instar) larvae are 8 to 10mm long and yellowish.
- Puppa usually occurs at the base of a dead shoot but can also occur in the soil.
- The pupal period lasts about seven days.
- Adult flies are about 4mm long. It resembles a tiny housefly.
- The female’s head and thorax are pale greys. The abdomen is yellowish with two brown patches on it. The male is darker in color.
Damage symptoms of Shootfly in Maize field
- The maize shoot fly larva migrates to the upper side of the maize leaf and moves along the leaf whorl until it reaches the growing point. Once there, the larva incisions at the growing point, causing the central leaf to dry up. The larva then feeds on the decaying tissue of the central leaf inside the shoot, producing a “deadheart.” These symptoms are typically visible 2-3 days after infestation.
- Maize plants between 5-30 days old are the most susceptible to shoot fly damage. However, older plants may also be infested by the shoot fly under high humidity conditions during the rainy season, but without producing the typical “deadheart” symptoms. The damaged leaf becomes thin and papery and wraps around the other leaves, leading to stunted plant growth.
- Late infestations by maize shoot flies can also damage the panicle in its formative stage, causing it to rot or dry up in the affected areas. This can result in reduced grain yield.
- Shoot fly-damage maize plants often produce axillary tillers as a means of recovery unless they are exposed to another episode of shoot fly infestation while still in the susceptible stage. In such cases, the tillers may also become damaged, and the plant may not fully recover.