**5.12** *Plutella xylostella* **(L.) (Lepidoptera: Plutellidae)**

**Identification:** Diamondback moth is small greyish with three white triangular spots along the inner-margin of the forewings. At rest the triangular markings of opposite wings appear as diamond shaped markings and hence the name. The larvae are pale green, body tapering slightly at both ends (TIFP, n.d.-b).

**Life cycle and damage**: females lay eggs on the lower leaves. The first instar larvae make tiny, irregular holes in the leaves. Diamondback moth is the most destructive pest of brassicasea throughout the world. Caterpillars feed on the foliage and make the leaves a withered appearance. Moths of later generations lay eggs higher on the plant and the larvae feed first on leaves, moving later to buds, flowers and developing seedpods. In later stages larvae bore holes in the leaves and the leaves may be eaten up completely. They also bores into pods and feeds developing seed (TIFP, n.d.-b).

**Monitoring:** monitor the presence of *P. xylostella* by pheromone traps or yellow sticky traps*.*  Traps should be checked weekly and count the number of moths (TIFP, n.d.-b).

**Economic and action thresholds:** economic threshold is when 25-30 larvae observed per square foot or 1-2 larvae per plant, and there is significant evidence of damage to flowers or pods (Knodel et al., 2010).

**Control**: bio-control agents such as *Cotesia plutellae* (Kurdjumov), *Diadegma mollipla*  (Holmgren), *Oomyzus sokolowski* (Kurdjumov)*,* and *Apanteles* sp. can control diamondback moth. When the threshold exceeded application of malathion, Trichlorfon, Endoslfan 35 EC, Diazinon 20 EC or triazophos is recommended (Manyangarirwa et al., 2009; TIFP, n.d.-b).
