Western Flower ThripsFrankliniella occidentalis

Frankliniella occidentalis,the western flower thrips, is a major worldwide pest, causing economic loss to a wide range of flower, fruit and vegetable cropssuch as chrysanthemum, pepper, cucumber, strawberry and raspberry.
Western Flower Thrips

The western flower thrips has spread around the world through international trade.  Its ability to breed on many species of host plants (>240 known hosts), and its ability to develop resistance to insecticides, has contributed to its success. Symptoms of plant damage by thrips feeding include: bud deformation, shape distortion of fruits or vegetables during growth and a range of leaf spots, scars, silvering and bronzing. Both adult and larvae feed throughout the plant and leave the crop susceptible to secondary fungal and bacterial infection resulting in moulding and wilting. The western flower thripsis a vector of some important virus diseases such as Tomato Spotted Wilt Virus (TSWV) and Impatiens Necrotic Spot Virus (INSV). Entire crops may be left unmarketable unless infestations are managed.

Russell IPM offers a range of strategies to improve management of thrips.  Mass-monitoring with Optiroll blue super plus with a species-specific aggregation pheromone and push-pull strategies combining Magipal with traps and lures contribute to reducing western flower thrips numbers and crop damage.  A range of traps can be used for monitoring including blue or yellow sticky traps and Ferolite light traps.  The Russell IPM kairomone thrips attractant, Thripnok, that attracts a range of thrips species, and the western flower thrips aggregation pheromone lures can be added to traps to increase trap catch.

Biology

Thrips have six life stages which includes the egg, two larval, prepupal, pupal and adult stages. Eggs are laid inside leaves, flower structures or fruit. In some cases this can result in wart-like growths but in others it is undetectable.

Larvae feed on leaves and pollen, maturing through two instars. They are often concealed in well-protected plant parts such as within flowers or under the calyx of fruits. Most pupae fall to ground to pupate.

Adult thrips emerge with slender, fringed wings in order to take flight.  Males and female aggregate in prominent positions for mating.

Larvae mature through two instars in concealed and well-protected plant parts such as within flower petals or under the calyx of fruits. In heavy infestations the larval will become mobile as they attempt to nourish upon all parts of the plant that are above ground. Most thrips, including western flower thrips, fall to the ground in order to pupate.

Finally, the adult thrips will emerge with slender and fringed wings in order to take flight and seek a partner for reproduction.

Nature of Damage

Western flower thrips feeding can result in severely damaged crops. Growers may notice visible signs of damage such as bud and fruit deformities and a blackening of the skin. Female thrips lay their eggs on crops and fruits, resulting in bronzing and silvering on fruit, leaves and petals.

Both adult and larvae feed throughout the plant and leave the crop susceptible to secondary fungal and bacterial infection resulting in moulding and wilting. The western flower thrips is a vector of some important virus diseases such as Tomato Spotted Wilt Virus (TSWV) and Impatiens Necrotic Spot Virus (INSV).

Monitoring

Installation of blue sticky traps such as Optiroll sticky roller traps and Impact Blue boards from Russell IPM can provide a simple and effective monitoring system for the western flower thrips.  Adding lures increases trap catch, selecting the western flower thrips aggregation pheromone for a species-specific lure, or Thripnok, to attract a range of thrips species.

Menu