As much fun as it is to say the word “thrips”, this little critter is anything but fun for the gardener. They sound relatively harmless when you read descriptions: feather wings; tiny, thin bodies; can be translucent, white, brown or black. The young or juvenile thrips don’t have wings. Because thrips are so tiny, oftentimes described as looking like little black threads, and because they come in so many colors, with or without wings, it can be a challenge to identify them. It is easier to figure out if you need to get rid of thrips by looking for the signs of damage in your garden.
Someone forgot to tell thrips that they are sooooo 2010 and the new rage is zombies. Thrips are the little vampires of the garden (without the glitter). Thrips do most of their damage by sucking plants dry or scraping at the developing fruit. Fortunately, in most cases, thrip damage is cosmetic. Plants infested with thrips will exhibit any combination of symptoms: leaves can become spotted, lose color, become discolored (yellow/brown/black) where the thrips have sucked them dry, and/or they can roll up. Developing fruits and vegetables may be malformed or scarred. Plants may develop in a twisted manner. Flower petals will have crusty edges upon blooming (damaged caused by feeding larvae when the flower is still in bud stage). Even though the damage is unsightly, thrips rarely pose a serious threat to a plant, shrub, or tree’s survival. There are exceptions, however, such as when thrips attack tomato plants and spread the tomato spotted wilt virus.
Getting rid of thrips is a multi-layered process
Before we start, it is important to note that you don’t necessarily need to get rid of thrips. There are some thrips that are predatory to other thrips, thereby offering natural population control. Other thrips feed only on the pollen of a plant. It is very difficult to know which thrips you are dealing with unless a plant sample is sent to horticultural lab for testing. When faced with getting rid of thrips, you should start with the least aggressive approach and go from there.
Get rid of weeds. This is really the first line of defense. Remove all garden debris, weeds, grasses, and dead blooms, which all play host to thrips. Get rid of damaged foliage; cropping and pruning thrip damaged leaves and branches on an infected plant is important to get rid of thrips. In some situations, it might be best to permanently remove a damaged plant by digging it up and disposing of it in order to get rid of thrips, and keep them from spreading to healthy plants.
The next strategy in the battle to get rid of thrips is to use sticky traps. There are a number of types of sticky traps. Some experts recommend using a blue sticky trap because the color attracts thrips. To get rid of thrips, hang sticky traps around the infected plants, spacing the traps at the recommended intervals (usually 5-7 feet/1.5-2 meters). You can get blue Hydrofarm Sticky Traps from Amazon. Gently shake the foliage to dislodge the thrips, causing them to take flight and get stuck on the adhesive. This method uses no pesticides, poses very little threat to other wildlife, and is relatively weatherproof. It will require changing out the tape after it’s captured a lot of thrips, though.
After you get rid of thrips using sticky traps, you can bring in natural predatory insects that eat thrips and feed on the developing larvae. You can actually buy bugs, have them shipped to you, and release them into your garden to do the dirty work for you. Ladybugs, and Minute Pirate Bugs are two of the most effective predatory insects used to get rid of thrips. Just a heads-up, buying bugs is not cheap, but it is extremely environmentally friendly. There are conflicting camps regarding the use of natural predators to get rid of thrips. It would be most effect to use this strategy in a greenhouse setting where the environment would be a little more controlled in regards to the release of purchased predatory insects. Also, you will want to remove the sticky traps before you release your pillaging bugs so they don’t become victims of the adhesive too.
If you have a heavy infestation, you will need to get rid of thrips with a more aggressive approach such as an insecticidal soap. There are many brands, so choose one that fits your budget. Safer BioNeem® makes a concentrate that can be diluted and sprayed on infected plants, or poured around the plant base, offering protection systemically. When spraying it on the plant, test a small patch first, just to be on the safe side. While this product is relatively safe to use, there are some plants that don’t respond well to it. Once tested, you can then spray your infected plants, paying close attention to the underside of the leaf. The brand of insecticidal soap isn’t as important as is the active ingredient, neem oil. You can get a jug of Natria Neem Oil from Amazon.
Neem oil will help you get rid of thrips at all stages of development, but should not pose a threat to beneficial insects, bees, birds, fish, or other wildlife. Follow the directions on the packaging for proper dilution and application. If you are using this product on fruits and vegetables, it is important to look for OMRI-listed somewhere on the label. OMRI-listed means that The Organic Material Review Institute has certified that product for use in organic gardening. Even with this assurance, you will still want to wash your fruits and vegetables before eating them.
A Word of Caution
There are a couple of insecticides to avoid. DO NOT USE: organophosphate insecticides or systemic organophosphate acephate. Really. In comparison to thrips, these insecticides do more damage than the thrips. Neither of these treatments will discriminate between which bugs (or birds, or wildlife) will be eliminated. Basically, you’ll be using a flame thrower to light a candle. The backlash will be an environment that is out of balance, you will not only get rid of thrips, but you will eliminate the good, predatory insects, leaving a vacuum for spider mites to flourish.
Most damage caused by thrips is relatively harmless to your plants. If you’re going to get rid of thrips in your garden there are a lot of different, low-impact ways to approach this problem. Being patient and taking one step at a time is the key to success.