We’ve once again reached the worst part of the growing season here in South Florida.
The heat is unbearable, the humidity levels are high and the roses are stressed. To add to the chaos of mid-summer come the chilli thrips, here to put the icing on the cake; but don’t worry there is GOOD news on the way.
Chilli thrips are BAD little buggers that eat the brand new growth on the rose canes. They suck all the water out of new leaves and completely stunt the growth of new shoots and blooms. They do terrible damage to leaves, canes and will usually result in an aborted bud or a deformed bud if you get a bud at all.
They are nearly microscopic and are usually always missed by even the most vigilant gardeners leaving them to question what could possibly be wrong with their rose. The damage is UGLY, and almost looks like chemical burn or some sort of chemical damage, but alas, it’s the tiny chilli thrips doing their work.
I first came across chilli thrips about 5 years ago. I had never dealt with them before, but that year, after a road trip to a specialty rose nursery in Tampa, I seem to have come home with more than just 6 gorgeous bushes. I brought back the dreaded chilli thrip. Either way they were bound to find my garden, but that year I dealt with them for the first time.
I don’t even remember how it was that I finally figured out it was chilli thrips that were damaging my roses. I do know that for a long time I thought it was the South Florida heat suddenly wreaking havoc on my new roses. But eventually I figured it out. Most likely through the now defunct website Garden Web (now Houzz), where I learned so much wonderful info on rose-growing.
After much research, I learned that the only way to get rid of them is to use a product called Spinosad. Spinosad is a natural substance made by a soil bacterium that can be toxic to insects. It is used to control a wide variety of pests, including thrips, leafminers, spider mites, mosquitos, ants, fruit flies and other pests.
Spinosad is organic, so it can be used in organic gardening, but it is still harmful to bees and other beneficial insects. When I do spray, I do it in the evenings after the bees and butterflies have gone in for the day. And, instead of bombing the entire garden with pesticide, I only spray the tips of the rose growth, which is the only place the chilli thrips are found. This way, I limit my entire garden being exposed to the compound.
If you are not a pesticide sprayer, like I sometimes am, there is another, less effective, method to get rid of them. You can cut off the affected growth and put it in a plastic bag away from your garden. By doing this you will remove about 80% of the population, however there is nothing preventing them from re-infesting the roses. But, this is something you can do as a temporary way to keep them at bay until the cooler months, when chilli thrips disappear with the first cool nights come fall.
My roses are usually looking quite bad by the end of summy either way, from the heat, the black spot and the chili thrips, so some years I don’t do anything at all until fall when I prune them back hard and let the new growth come in without the pressure of pest and disease. In the end it’s not much different than having no roses during the winter months up north.