A new plant pest detected in Australia is highlighting the importance of regular crop monitoring, good biosecurity practices and effective insecticide resistance management across the nursery and greenlife industry.

Intonsa flower thrips (Frankliniella intonsa) is a small, fast-moving pest that feeds on flowers, buds and young foliage. While new to Australia, the species is already widespread internationally and has a broad host range that includes ornamental plants, vegetables, berries, fruiting crops, field crops and numerous weed species.

For Queensland nurseries, both wholesale and retail, awareness and early detection will be important.

What is Intonsa flower thrips?

Intonsa flower thrips is native to East Asia and parts of Europe and is now found across Asia, Europe and the Middle East, as well as Australia.

Adults are small (generally around 1–2mm long) and cigar-shaped, ranging from yellowish to dark brown depending on their life stage.

Their small size means they can be difficult to detect during routine crop inspections.

Feeding and egg-laying activity can cause browning, scarring, distortion and bud abortion, reducing the quality and marketability of affected plants.

Intonsa flower thrips is also a known vector of plant viruses, including Tomato spotted wilt virus and Impatiens necrotic spot virus.

Managing the risk of insecticide resistance

Australia’s nursery industry is already experienced in managing thrips, and a range of treatment options is available. However, effective resistance management is critical.

Thrips can reproduce quickly, allowing resistant traits to spread through a population in a relatively short period. Eggs embedded within plant tissue and pupae in soil may also avoid contact with chemical treatments.

Repeatedly using insecticides with the same mode of action can further increase resistance pressure.

Nurseries using chemical controls should therefore:

• Rotate between different insecticide modes of action rather than repeatedly relying on the same chemical class.
• Follow all label and permit directions, including application and coverage requirements.
• Regularly monitor crops to identify pest activity early.
• Consider an integrated pest management (IPM) approach combining chemical, cultural and biological controls.

Nurseries requiring access to additional modes of action can search the nursery industry’s Minor Use Permits available through Nursery Production Farm Management System.

Monitoring and biological control

Regular monitoring is an important part of managing thrips populations.

Yellow or blue sticky traps can help monitor flying adults, while frequent crop inspections can assist with identifying activity before populations become established.

Biological controls can also form part of an IPM program. Beneficial organisms such as predatory mites may help target thrips eggs and immature stages while reducing reliance on chemical controls.

When combining biological and chemical controls, growers should understand the potential toxicity of pesticides to beneficial organisms and seek appropriate technical advice.

Stay informed and get support

Good crop monitoring, early identification and a well-planned IPM and resistance management program can help nursery businesses respond effectively to emerging pest threats.

Greenlife Industry Queensland membership gives you access to free biosecurity alerts and member-only rates on our expert nursery advisory services.

Explore the Nursery Production FMS for industry resources, including Minor Use Permits, or join Greenlife Industry Queensland to access ongoing biosecurity information and support.