**Kikuyu Thrips** (*Thrips newmani*) are minute, specialized insect pests that feed exclusively on **Kikuyu grass** (*Pennisetum clandestinum*), a common turfgrass and fodder crop in warmer climates. They feed by rasping the plant cells on the leaves and sucking up the exuded sap, causing the grass blades to turn silvery, then brown, giving the turf a dry, scorched, or desiccated appearance. They are a significant pest of high-value lawns, sports fields, and golf courses where Kikuyu grass is used.
Taxonomy and Classification
Kikuyu Thrips belong to the order Thysanoptera (thrips). They undergo a unique metamorphosis involving two pupal-like stages in the soil. They are highly specific feeders, relying on the growth of Kikuyu grass. Thrips are characterized by their fringed wings and their unusual rasping mouthparts.
Physical Description
Adult Kikuyu Thrips are tiny, slender insects, 1/20 to 1/16 inch long.
- **Appearance:** Dark brown to black, cigar-shaped body with fringed wings (difficult to see).
- **Nymphs:** Yellowish and resemble smaller versions of the adult, lacking fully developed wings.
- **Location:** Found feeding within the protected, rolled-up, new growth of the grass blades and sheaths, making them difficult to detect and treat.
- **Damage Sign (Key ID):** The turf turns a characteristic **silvery or bleached color**, especially on the tips of the grass blades, followed by browning and a general “scorched” appearance that is not relieved by watering.
Distribution and Habitat
Kikuyu Thrips are found globally wherever Kikuyu grass is widely cultivated, particularly in Australia, New Zealand, South Africa, and parts of the U.S. (e.g., California, Hawaii). Their habitat is restricted to the grass canopy and the soil beneath (where the pupal stages occur).
Behavior and Conflict
The conflict is aesthetic damage and loss of turf vigor.
- **Hidden Feeding:** Their feeding deep within the protected, newly emerging blades shields them from environmental pressures and many contact insecticides.
- **Stress:** Heavy feeding severely reduces the grass’s ability to photosynthesize, leading to death of the blade tips and a general decline in the aesthetic quality of the turf.
- **Rapid Reproduction:** They reproduce quickly, leading to rapid population explosions, particularly in warm, dry weather.
Management and Prevention
Control is integrated pest management (IPM), often requiring the use of systemic products.
- **Cultural Control:** Maintain optimal turf health with appropriate irrigation and fertilization to help the grass tolerate damage. Mowing at a taller height may reduce stress.
- **Chemical Control (Key):** Due to their protected feeding site, **systemic insecticides** (absorbed by the grass and transferred to the thrips as they feed) are often necessary for effective control.
- **Contact Sprays:** Contact insecticides must be applied with large volumes of water and sufficient pressure to ensure the spray penetrates deep into the grass canopy where the thrips are hiding.
- **Monitoring:** Use blue or yellow sticky traps placed near the turf to monitor adult population levels.
Conservation and Research
Kikuyu Thrips are managed as a specialized turfgrass pest. Research focuses on optimizing systemic insecticide delivery for deep canopy penetration, identifying resistant Kikuyu grass varieties, and exploring natural enemy augmentation.