Cassava thrips

Systematic position. The cassava thrips (Corynothrips stenopterus) belongs to the order Thysanoptera and the family Thripidae. This insect is a significant specialist pest specifically associated with cassava plants, causing damage across various tropical agricultural regions.

Crops and economic importance. The primary host plant is cassava (Manihot esculenta). The pest infests the terminal buds and young leaves. Damage caused by this thrips species reduces the plant's photosynthetic capacity, which directly results in poor tuber development and reduced total yield, threatening food security in affected areas.

Biology and life cycle. The life cycle comprises eggs, two larval instars, prepupae, pupae, and adults. Both larvae and adults prefer the tender tissues of expanding leaves. The life cycle is accelerated by warm tropical climates, allowing for multiple generations throughout the year, especially during the dry season when populations tend to peak.

Nature of damage. Infestation results in stunted growth, leaf curling, and distortion of young foliage. Feeding punctures cause necrotic spots on the leaves, leading to chlorosis and premature leaf drop. In severe infestations, the apical meristem may die, leading to excessive lateral branching, a condition often described as witch's broom effect.

Control measures. Integrated Pest Management (IPM) is essential for controlling Corynothrips stenopterus. Key strategies include:

• Planting resistant or tolerant cassava varieties.
• Ensuring proper crop hygiene and weed management to remove alternative hosts.
• Biological control using natural predators.
• Applying systemic insecticides only when infestation levels exceed economic thresholds to protect beneficial insects.