Green stink bug

  • green stink bug egg raft, eggs are olive green
    green stink bug egg raft, eggs are olive green
  • green stink bug nymph, mossy green with dark markings on the back
    green stink bug nymph, mossy green with dark markings on the back
  • green stink bug adult, green shield-shaped body with brown wing covers
    green stink bug adult, green shield-shaped body with brown wing covers
Scientific name

Plautia affinis

Description

The eggs are similar to those of the green vegetable bug but are olive-green (as opposed to cream). They are laid in small loose rafts with only 5-15 eggs. Nymphs are cream and yellow with prominent dark markings, or are mossy green with dark markings on their back. Adults are only 8 mm long and have a green shield-shaped body with brown wing covers.

Similar species

The two-tone colouring of adults distinguishes the green stink bug from other stink bug pests in Australia. The nymphs and eggs are also distinctive.

Distribution

Native to Australia where it is reported from New South Wales and Queensland, but is most likely more widely spread.

Crops attacked

All summer legumes. Other hosts include sorghum, horehound and raspberry.

Life cycle

Green stink bugs typically invade summer legumes at flowering and commence feeding and egg laying. Females can lay over 400 eggs. Nymphs usually reach a damaging size during mid to late podfill. There are five nymphal stages. Usually only one generation develops per summer legume crop, but more than one generation is possible if temperatures are high.

The risk period is at podding.

Damage

The green stink bug is the least damaging of all the podsucking bugs, damaging only 10% as many seeds as the green vegetable bug.

Monitoring and action level

Crops should be inspected twice weekly from budding until close to harvest. Beat-sheeting is the preferred sampling method. Sample crops in the early to mid-morning when bugs are more likely to be at the top of the crop. Look for the distinctive small egg rafts, which indicate the presence of green stink bugs.

Control methods

Chemical control: Synthetic pyrethroids give effective control of podsucking bugs but these insecticides are incompatible with integrated pest management (IPM) and the management of easily flared pests such as silverleaf whitefly. Not all registered products give effective control of all life stages and during all crop stages (e.g. methomyl is less effective in densely canopied crops because of its short residual activity). The organophosphate trichlorfon gives only moderately effective control. Spraying is best done in the morning when the bugs are basking at the top of the canopy. Consult Pest Genie or APVMA for the latest pesticide options.

Cultural control for podsucking bugs on summer pulses: Where possible avoid sequential plantings of summer legumes, and avoid cultivar and planting time combinations that are more likely to lengthen the duration of flowering and podding. Spring plantings are at less risk than summer planted crops.

Conservation of natural enemies

Spiders, ants and predatory bugs are major predators, particularly of eggs and young nymphs with mortality of these stages sometimes exceeding 90%. Eggs may be parasitised by the tiny wasps Trissolcus basalis, T. oenone and Telenomus cyrus.

Last updated 12 October 2011