Thrips in the Home Vegetable Garden
Thrips are easily recognized apart from other common garden pests because, regardless of species, thrips all share the same longer body shape which is neither found in aphids, mealybugs, nor spider mites.
And with more than 6,000 known species, thrips have taken preference to some of the most popular vegetables, fruit trees, and ornamental flowers grown in the home garden as possible host plants.
But like most other small and soft-bodied insects, thrips can always be safely and effectively eradicated via some of the most common treatment methods including homemade solutions and a simple high-pressure hose. Thrips are perhaps most easily recognized by their elongated body-length wings which do not actually support thrips in flight but merely propels them from plant to plant like a grasshopper.
Facts About Thrips Garden Pests
- Thrips Distribution: More than 6,000 species found on 6 continents throughout spring and summer
- Thrips Host Plants: Root vegetables, brassicas, fruit trees, legumes, ornamental bulbs and flowers
- Thrips Damage: Flecked with pale and white splotches from plant tissue having been depleted
- Thrips Lifespan: 30-45 days
- Thrips Eggs Laid per Lifetime: 150-300 eggs
- Thrips Removal: Pruning, high pressure hose, isopropyl alcohol, neem oil, dish soap spray
- Thrips Predators: Ladybugs, mites, wasps, lacewings, spiders
- Most Common Thrips in North America: Onion Thrips (Thrips tabaci)
What Do Thrips Look Like?
Thrips are long and slender for their negligible size and, despite having very prominent wings that extend the length of their bodies, are not actually sustainable fliers for long distances.
Similar to many winged insects, thrips’ wings merely help them from plant to plant and are not intended for actual flight like a butterfly or bee.
With more than 6,000 species of thrips known, they’re found in just about every possible color but generally all share the same shape, size, and features. Even the most common varieties such as onion thrips, gladiolus thrips, and melon thrips all share a light translucent tan and brown.
Thrips Damage to Garden Vegetables
Signs of thrips in the garden can be difficult to identify because affected crops are often damaged from pathogens or disease rather than as a direct result of feeding.
Damage left behind from thrips has a noticeably silver and iridescent streaking on the underside of the leaf, which can often be the biggest clue as to a possible thrips infestation. Like other sap-sucking pests, damaged host plants will show signs of white mottling before beginning to yellow, curl, and eventually wilt from the plant.
One of the most common diseases transmitted from thrips is tomato spotted wilt, a common virus among nightshade crops which leaves affected hosts stunted, deformed, and yellow and mottled.
What Do Thrips Eat in the Garden?
Like other miniscule garden pests, thrips do not directly consume the leaves and foliage but, instead, pierce the skin to feed on the numerous essential fluids. The most common species are onion thrips which are found on Allium crops and a wide range of leafy greens, Brassicas, and vegetables.
Gladiolus thrips are generally exclusive to ornamental flowers and have been found to feed on just about anything colorful in the flower bed including gladiolus, iris, lily, snapdragon, carnation, and freesia.
Melon thrips are rampant through much of the tropics and have even been found in parts of Florida on various squash, cucumber, and melon crops.
Thrips eggs are quick to hatch in no more than 3 to 7 days and ready to begin a brief, yet complete, 45-day lifecycle.
Thrips eggs are best described as looking like a small pinto bean in both shape and color and can usually be found in clusters anywhere from 10-200 eggs under leaves and nestled along stems.
Most eggs found beneath leaves and vegetation are likely those of onion thrips while other species of thrips that feed on ornamentals such as gladiolus thrips are known to lay their eggs within flower buds, old and new. Soft fruits such as tomato, pear, and privet berry are always at risk for housing even the smallest cluster of eggs.
How To Rid Thrips from the Home Garden
When first noticing a thrip infestation, isolate the plant if possible and search nearby plants for thrips as well.
Affected plants that have the possibility of being salvaged should be pruned of damaged stems since the growth will never rebound from the loss of essential sap and tissue. Thrips and eggs can be simply sprayed off with a hose to remove any infestation.
For a more passive and long-term treatment, add about a tablespoon of either dish soap, neem oil, or 70% isopropyl alcohol to a liter of water and heavily spray affected areas.
Solution does not work as immediately as a high-pressure hose but will keep the host plant from being inviting.