Thrips of hibiscus

Disease Information

Thrips

Symptoms

Bud Drop: The typical sign of thrips is a bud that grows large, turns an off-color before opening, and then falls from the plant at the slightest pressure. Buds may sometimes fall before turning color, but often that sort of rotten color happens before the buds fall. The reason for this change in the big, healthy bud is that the thrips have been scratching around inside the bud as well as laying eggs inside of it. When the bud falls, the young thrips are then able to leave the bud and burrow into the ground where they change into adult thrips that are capable of flying back up to new buds to continue the cycle.

Scratch Marks: Some varieties of hibiscus do not react to thrips by losing their buds. In that case you can see the thrips damage as scratch marks on the flower petals. Sometimes it looks almost natural, like the spots and markings that some of our varieties produce as part of their interesting flower coloring. Other times you can see how it badly mars the beauty of the flowers. Even though these varieties do not lose their buds they can still be treated in order to obtain flawless blooms free of thrips scratches.

COMMENTS on disease

Thrips are insects that lay their eggs inside the buds of hibiscus, roses, and other species that make big buds before flowering. The thrip is small but visible if you look for it. The easiest way to see thrips is to take an open flower and shake it over a white piece of paper. Thrips will fall out of the flower onto the paper, looking like small, black pencil lines on the paper. They are much longer than they are wide, and their dark color stands out against a piece of white paper.

Management

For fast and full results, it is best to remove all rotten buds from the plants and the ground and dispose of them in the trash. In order to keep thrips under control, you will need to use a product called Spinosad. This chemical needs to be sprayed over the tops of the plants, covering the buds and upper leaves of the plants. Use Spinosad for three treatments, 5-7 days apart. but you may repeat this treatment series if you need to. You can also drench the potting mix or soil around a hibiscus with a systemic pest control product. This will kill most of the live thrips that are living in the ground in the juvenile form, and it will speed up control of this pest.

Organic Treatment: If you don`t want to use pesticides, an organic approach is to spray in the same way with any product containing "Neem oil," a natural product obtained from the Neem tree. It may require more treatments to control thrips, but is a good alternative approach if combined with gathering up all rotten buds and spent flowers so the thrips do not reach the ground around the plant                .

 

 



Share this article