The spined predatory shield bug, Oechalia schellenbergii (Guerin-Meneville) and the glossy shield bug, Cermatulus nasalis (Westwood) are both important predators of pests in cotton including Helicoverpa and looper larvae. Adults and nymphs are usually abundant in cotton from December to February.

Identification: The spined predatory shield bug - adults are 12mm long and have a grey-brown, shield-shaped body with a light marking in the middle of the back and a pair of prominent spines on either side of the shoulder. Nymphs are dark grey with a characteristic red ring on the back. Eggs are laid in irregular-shaped rafts and are black with short white spines around the rim.

The glossy shield bug - adults are 12mm long and have shiny brown, shield-shaped bodies. Patterns include darker brown and small yellow markings. Nymphs are dark red and brown with the early instars being bright red. The black eggs, which are laid in 'rafts' of 50 or more, have short, white spines around the rim. The development of the glossy shield bug from egg to adult takes about 3 weeks.

Habitat: They are found all year round on weeds and other crops especially on crops infested with larvae of insects.

Targeted prey: Shield bug adults and older nymphs use piercing/sucking mouthparts to feed on insects. They prey on moth larvae, including Helicoverpa and loopers.

Shield_07_TSmith (Mick can we zoom in a bit)
“Shield bug eggs are laid in irregular-shaped rafts and are black with short white spines around the rim.” 20mm Photo: T. Smith

  
“The Spined predatory shield bug has prominent spines on either side of the shoulder.” 12mm Photo: L. Wilson

 
The Glossy shield bug has a large appetite for a large range of caterpillars.” 12mm Photo: J. Wessels DEEDI