Thrips are common pests found in various houseplants, greenhouses, and outdoor gardens. The scientific name is Thysanoptera.
These pests are slender, tiny insects with distinctive asymmetrical mouthparts, and fringed wings.
There are around 264 thrips species in Northern America alone, and 6000 and more around the globe.
Most of the species feed on plants, but there are some thrips species which are beneficial insects as they only consume Hibiscus spider mites and other pests.
The common names include:
- Harvest Bugs
- Freckle Bugs
- Corn Lice
- Corn Flies
- Storm Bugs
- Corn Fleas
- Thunder Blights
- Storm Flies
- Thunder Bugs
- Thunder Flies
Thrips love to feed on hibiscus plants and other woody plants during their growing period, including:
- Viburnum – more on Doublefile Viburnum
- Gardenia varieties
- Azalea plant
Many thrips damage the plants by sucking all their contents, leaving them weak.
Thrips Are Attracted To Hibiscus
The thrips are attracted to hibiscus plants and typically lay their eggs in the hibiscus buds.
Since these insects are rather small, it is easy to miss them on the plants.
The best way to see the thrips which look like small black lines is either by:
- Using a magnifying glass
- Cutting the hibiscus flowers open and shaking the contents on the white piece of paper.
These pests are long and dark in color, which will make them stand out against white paper.
The wingless larvae and adult thrips cause some damage to hibiscus, but the damage worsens if they transfer certain viruses to the plant.
They are known to spread necrotic spot virus, and tomato spotted wilt virus.
What Damage Do Thrips Cause To Hibiscus?
Thrips feed and damage hibiscus plants by puncturing the surface and sucking in all the juices from the leaves, flowers, and fruits.
- The host plants become scarred, discolored, and twisted.
- The leaves become slivery, splotchy and pale before completely dying.
- The major sign of thrips infestation is the bud drop.
The hibiscus bud gets enlarged and changes color before opening and the bud drop starts at the slightest pressure.
The buds might even begin to fall before their color changes.
This usually happens because the thrips scratch the insides of the hibiscus flowers and lay eggs.
When hibiscus buds fall to the ground, the young pests hide in the soil until they become adults, and fly back to the new hibiscus plants and continue the cycle.
A few hibiscus plants don’t lose their buds but instead gets scratch marks on the petals and leaves.
The earliest sign of damage is the bleached or yellow spots on the leaves or the dead blotches on hibiscus flowers.
The damage progresses when the leaves start turning silvery with black spots, caused by fecal matter or excrement.
Gradually, the flowers and leaves start thinning and wilting.
Pest Control To Control Thrips
The most effective and easy way to get rid of and control thrips attacking hibiscus plants is to cut off all the rotten buds from the ground and the plant.
Carefully dispose of them in the trash, making sure none of the buds breaks on the ground to prevent the eggs from reaching the ground.
The organic way of treating the thrips infestation is to spray the hibiscus plants with products containing neem oil.
This treatment may take more time but is still an effective alternative method to eliminate these plant pests.
Sticky traps may also be used to trap the adults on the branches or stems before they reach the hibiscus flowers or buds.
If the infestation is too much to control through organic treatments, it is best to start using insecticidal soaps and sprays.
Spray Malathion or Acephate on the surface of the plants, making sure to cover the upper leaves and buds of the hibiscus.
A systemic insecticide, like Imidacloprid, may also be used by mixing it in the soil.
Typically, it takes three insecticidal treatments to eliminate the infestation, including the adult thrips, eggs, and pupae.
It is recommended to maintain a regular pest management and prevention action plan to reduce the likelihood of thrips infestation on hibiscus plants.
NOTE: Always follow label directions when applying am pest control product.
Be sure to inspect the plants regularly for signs of thrips, and immediately prune the infested and damaged leaves and buds.