Thrips
Onion Thrips (Thrips tabaci)
Western Flower Thrips (Frankliniella occidentalis)
Thrips damage on hemp.
Thrips damage on hemp.
Thrips adult and nymphs on the neck of onion.
Thrips adult, feeding damage, and excrement (black specks) on early season curcurbit.
Microscopic view of onion thrips.
Microscopic view of wester flower thrips.
Hosts
- Field-grown and greenhouse-grown hemp
- Artichoke
- Beans
- Cabbage
- Cauliflower
- Corn
- Curcurbits
- Eggplant
- Garlic
- Leafy greens
- Leeks
- Onion
- Peas
- Peppers
- Tomatoes
- A variety of grasses, flowers, and weeds
Description
Adults are minute with elongated yellow or yellow-brown bodies and two pairs of fringed (hairy) wings. Larvae are a creamy-yellow color, and wingless.
Life Cycle
Egg | Larva | Pupa | Adult
- 5-8 generations per year.
- Overwinter as adults in plant debris and protected areas.
Damaging Lifestage(s): Larvae and adults.
Damage Symptoms
Thrips feed with a punch-and-suck behavior causing white flecks or silvery scars on foliage in combination with dark fecal spots. Thrips feeding on developing leaves may cause distortion.
Time for Concern
Populations are favored by hot, arid conditions and decrease with heavy rain or overhead irrigation.
When and Where to Scout
- Monitor foliage for feeding damage (white spots or flecks) that usually occurs along the leaf veins.
Threat Level
Low to medium. Damage to field-grown hemp is usually minor and insignificant to overall plant health. Economic damage is more likely to occur in indoor-grown hemp.
Occurrence in Utah
Both species of thrips are common in Utah. They have been found in field-grown hemp, but not causing economic damage.
Management
- Plow plant debris under after harvest and remove volunteer host plants.
- Inspect transplants for thrips infestations (using a 10x hand lens) and discard or manage infested plants.
- Remove weeds within hemp fields and around greenhouses.
- Approved insecticides are available.
When to Consider Treatment
When thrips damage is seen on multiple plants (no threshold exists for industrial hemp).
Look-alikes
Beneficial thrips (e.g. black hunter thrips, banded thrips or Aeolothrips)
Thrips Insecticides
| Utah-Registered Product | Active Ingredient(s) | Notes |
|---|---|---|
| Ancora | Isaria fumosorosea | Toxic to bees. |
| Aza-Direct Biological Insecticide | azadirachtin | |
| Ullamco | azadirachtin | |
| AzaGuard | azadirachtin | |
| AzaSo | azadirachtin | |
| Azatin O Biological Insecticide | azadirachtin | |
| Azatrol EC Insecticide | azadirachtin | |
| Azera Insecticide | azadirachtin | |
| Bonide All Seasons Horticultural & Dormant Spray Oil Concentrate; Ready to Spray | mineral oil | Greenhouse use only (for commercial). |
| Bonide Insecticidal Soap MultiPurpose Insect Control Ready To Use | potassium laurate | Greenhouse use only. |
| Botanigard Maxx | pyrethrins | Greenhouse use only. |
| Brandt Ecotec Plus | rosemary oil | Greenhouse use only. |
| Bug Buster-O Extinguish Ant Bait | pyrethrins | Greenhouse use only. |
| Captiva | capsicum oleoresin extract | |
| Captiva Prime | capsicum oleoresin extract | |
| EcoWorks EC | neem oil, cold pressed | |
| Garden Safe Brand Insecticidal Soap Insect Killer | potassium laurate | |
| Grandevo CG; WDG | Chromobacterium sub strain PRAA4-1 Cells |
|
| Leaf Life Gavicide Green 415 | mineral oil | Greenhouse use only or transplants intended for field planting. |
| Mammoth Cancontrol | thyme oil | |
| Mite-E-Oil | mineral oil | Greenhouse use only. |
| Molt-X | azadirachtin | |
| M-Pede Insecticide Miticide Fungicide | potassium laurate | |
| Natural Guard Brand by Ferti-lome Insecticidal Soap Concentrate | potassium salts of fatty acids | |
| Omni Supreme Spray | mineral oil | |
| Organocide 3-in-1 Garden Spray RTU; Concentrate | sesame oil | |
| Organocide Bee Safe 3-in-1 Garden Spray Concentrate | sesame oil | |
| Organocide Bee Safe 3-in-1 Garden Spray RTU | potassium sorbate | |
| Ortho Tree & Shrub Fruit Tree Spray Concentrate | clarified hydrophobic extract of neem oil | |
| Prizefighter | ammonium nonanoate | |
| PureCrop1 | soybean oil | |
| Pycana | pyrethrins | Greenhouse use only. |
| Pyganic Crop Protection EC 1.4 II; 5.0 II | pyrethrins | |
| Pyrethrum TR Total Release Insecticide | pyrethrins | |
| Rango | neem oil, cold pressed | |
| Safer Brand Insect Killing Soap Concentrate II | potassium salts of fatty acids | |
| Safer Brand Insect Killing Soap with Seaweed Extract II | potassium salts of fatty acids | |
| Safer Brand Yard & Garden Insect Killer II | potassium salts of fatty acids | |
| SaferGro Pest Out | cottonseed oil | |
| Spear T Liquid Concentrate | gs-omega/kappahxtx-hv1a | |
| SuffOil-X | mineral oil | |
| Surround WP Crop Protectant | kaolin | |
| Trilogy | sulfur | |
| TriTek | mineral oil | |
| Venerate CG; XC | Burkholderia sp strain A396 | |
| Whitney Farms Insecticidal Soap | potassium laurate | |
| Xpectro OD | pyrethrins |
Photo Credits
- USU Extension IPM Program
- Microscopic western flower thrip - Jack T. Reed, Mississippi State University, Bugwood.org