patterns forming longitudinal stripes. The hindwings of males are a pale straw colour and in females the hindwings are white. Similar species such as Chilo orichalcociliellus located in East Africa may be confused with Chilo partellus. Reproduction and life cycle Eggs are laid in batches of 10–80 on the upperside and underside of leaf surfaces, usually close to the midrib. They hatch after 4–10 days. Younger larvae (caterpillars) feed on the leaf whorl. Older larvae tunnel into the stems, and it is within these tunnels that they feed and grow for about 2–3 weeks. When these larvae grow completely, they pupate and remain in the stem of the maize. After 1–2 weeks, the adults evolve from the pupae stage and emerge from the stem. They mate and lay eggs on other maize plants and continue to cause damage to the crop. During dry seasons, larvae may enter a state of diapause or a period suspended development for several months and will pupate once it the dry season is over and there is rain. Adults can emerge from pupae in the late afternoon or early evenings and are active at night. Adults will rest on plants during the day. The whole life cycle takes about 3–4 weeks, however it can vary due to temperature, humidity and other factors. Five or more successive generations may develop in favourable conditions and in regions where there is warm temperatures, high relative humidity, sufficient water and an abundance of host plants. C. partellus can reproduce and develop all year-round. Host relationship This pest causes US$334 million annual loss to sorghum alone in the semiarid tropics. C. partellus attacks several grass species which can be both cultivated and wild. Cultivated crop hosts include but are not limited to maize, sorghum, pearl millet, rice, and sugarcane. Wild hosts include elephant grass (Pennisetum purpureum), reeds (Phragmites) and vossia (Vossia cuspidata). In nature, an insect locates a host plant through a sequence of behavioural and biological responses such as the following: Orientation and setting Feeding Metabolism of ingested food Growth Survival and fecundity Oviposition If one or more of these categories of insect responses are not met by the host plant, the plant would therefore be rendered as unsuitable or unfavourable for insect establishment. Therefore, the extent of insect establishment depends on the interaction of insect responses to various plant characteristics. Numerous factors can enhance the insect pest problem,