Editor’s Note
How to choose the right mesh to prevent whiteflies, thrips, aphids—and the viruses they carry.
This article is part of the Insect Netting Knowledge Series and focuses on applying insect netting specifically for tomatoes and peppers.
Because these crops suffer heavy virus pressure from insect vectors, mesh selection must prioritize virus management, not only insect exclusion.
For the full framework, visit the Insect Netting Hub Page.
Introduction
Tomatoes and peppers are among the most profitable vegetable crops globally—but also among the most vulnerable to virus diseases. The true enemy is rarely the insect itself, but the viruses insects transmit.
- Whiteflies spread TYLCV and ToCV
- Thrips transmit TSWV
- Aphids transmit CMV and several non-persistent viruses
Virus outbreaks can lead to:
- 40–90% yield loss
- Severe deformation of new leaves
- Reduced fruit set
- Loss of marketable quality
Because viruses cannot be “cured,” prevention is the only strategy. Insect netting—when correctly selected and installed—becomes a powerful physical barrier that stops virus vectors before they reach the crop.
This guide explains the best mesh sizes, colors, and installation methods for tomatoes and peppers across different climates and production systems.
Why Tomatoes and Peppers Need Insect Netting (Virus Perspective)
Tomato and pepper growers often underestimate one fact: in these crops, insects don’t just damage plants—they introduce viruses that persist for the entire growing season.
The real threat: virus diseases, not direct insect feeding
Common viruses include:
- TYLCV (Tomato Yellow Leaf Curl Virus)
- ToCV (Tomato Chlorosis Virus)
- TSWV (Tomato Spotted Wilt Virus)
- CMV (Cucumber Mosaic Virus)
These viruses cause irreversible damage. Once introduced, removal of infected plants is the only remedy.
Three major insect vectors to control
| Pest | Virus Transmitted | Notes |
| Whiteflies | TYLCV, ToCV | Primary threat worldwide |
| Thrips | TSWV | Very small, hard to block |
| Aphids | CMV, non-persistent viruses | Short feeding time enough for transmission |
Tomatoes and peppers must block all three groups—especially thrips and whiteflies.
The “virus window period” for tomatoes & peppers
Virus transmission risk is highest:
- During transplant establishment (first 4 weeks)
- During flowering and early fruit set These periods require maximum exclusion.
Key Pests & Required Aperture Sizes (Based on Thorax Width)
Choosing the right insect net begins with understanding pest size. Aperture—not mesh number—determines exclusion ability.
Whiteflies (TYLCV carriers)
Thorax width: 0.24–0.29 mmRequired aperture: ≤0.25 mm Recommended mesh: 40–50 mesh
Whiteflies are the #1 threat to tomato crops globally.
Thrips (TSWV carriers)
Thorax width: 0.19–0.25 mmRequired aperture: ≤0.20 mm Recommended mesh: 50–75 mesh
Thrips are extremely small and require the finest mesh used in horticulture.
Aphids (CMV carriers)
Thorax width: 0.50–0.70 mmRequired aperture: ≤0.50 mm Recommended mesh: 40–50 mesh
Aphids can transmit virus even after a single brief probe. Blocking them reduces CMV spread significantly.
Summary Table: Pest → Aperture → Mesh
| Pest | Thorax Width | Max Aperture | Recommended Mesh |
| Thrips | 0.19–0.25 mm | ≤0.20 mm | 50–75 mesh |
| Whiteflies | 0.24–0.29 mm | ≤0.25 mm | 40–50 mesh |
| Aphids | 0.50–0.70 mm | ≤0.50 mm | 40–50 mesh |
Expert Insight: Tomato and pepper virus management should “follow the smallest pest”—which is always thrips.
Best Mesh Size for Tomatoes & Peppers (By Production System)
Different climates and infrastructures require different netting strategies.
High virus-pressure greenhouses
Recommended: 50–75 mesh
Suitable for:
- Middle East
- Africa
- Mediterranean climates
- Warm tropics
- Areas with intense thrips pressure
Why 75 mesh? Because TSWV transmission is a severe threat, and preventing thrips entry is non-negotiable.
Medium-pressure greenhouses
Recommended: 40–50 mesh
Benefits:
- Blocks whiteflies and aphids effectively
- Provides better ventilation than 75 mesh
- Ideal for plastic-film greenhouses with natural ventilation
Open-field tomatoes & peppers
Recommended: 25–40 mesh
Factors:
- Higher wind exposure
- Heat dissipation more important
- Whiteflies and aphids dominate over thrips
In windy environments, 50–75 mesh may cause heat stress.
Mesh Size, Ventilation & Heat Management
A major challenge in tomatoes and peppers is balancing pest exclusion and ventilation.
Smaller aperture = greater airflow resistance
Fine mesh (50–75 mesh):
- Slows air exchange
- Raises inside temperature by 2–5°C
- Increases humidity
If unmanaged, this leads to blossom drop and poor fruit set.
Heat thresholds for tomatoes & peppers
- Tomatoes:
- ≥32°C → Pollen viability decreases
- ≥35°C → Blossom drop
- Peppers:
- ≥38°C → Flower organ damage
- ≥40°C → Severe yield loss
This is why ventilation must be engineered carefully.
How to keep crops cool while using fine mesh
Practical strategies:
- Coarse mesh on roof + fine mesh on sidewalls
- Add mechanical ventilation (fans or exhaust)
- Increase total vent area by 20–40%
- Use evaporative cooling (wet wall systems)
- Build an air-tight structure to avoid pressure loss
Correct engineering prevents overheating while maintaining exclusion.
Recommended Mesh Size by Scenario (Decision Matrix)
| Scenario | Main Pest | Virus Risk | Recommended Mesh | Notes |
| High-pressure greenhouse | Thrips + whiteflies | Very high | 50–75 mesh | Best virus protection |
| Standard greenhouse | Whiteflies | High | 40–50 mesh | Balance airflow |
| Tomato open field | Whiteflies + aphids | Medium | 25–40 mesh | Wind resistance required |
| Pepper open field | Thrips lower risk | Medium | 25–40 mesh | Photoselective nets optional |
Technical Interpretation
If TSWV exists in the region → always choose 50–75 mesh.
Photoselective Nets for Tomatoes & Peppers
Color nets influence insect behavior and crop microclimate.
Silver / Pearl nets repel whiteflies
Silver-gray nets reduce virus incidence by reducing insect landing frequency.
They are commonly used in:
- Fresh-market tomato production
- Virus-prone pepper regions
Yellow nets attract thrips (use carefully)
Yellow increases thrips activity— Not recommended as full-cover netting.
Best used as:
- Localized strips
- Attraction sites near sticky traps
Red nets can enhance tomato coloration
Red light spectrum influences fruit pigmentation.
Useful in:
- Greenhouses aiming for high fruit quality
- Cool climates seeking better coloration
Importance of Air-tight Installation for Virus Control
Mesh size solves half the problem; installation solves the other half.
Doorways are the source of viruses
Entering workers carry insects on:
- Clothing
- Crates
- Tools
A double-door vestibule dramatically reduces risk.
Bottom sealing prevents whitefly bypass
If the net is not buried:
- Whiteflies enter through wind-lifted edges
- Soil erosion creates new gaps
Ground-level sealing is essential.
Fans and vents must be fully sealed
Negative pressure pulls insects in.
Seal all fan frames using:
- Fine-mesh sleeves
- Rubber gasket strips
- Continuous profiles
Recommended Netting Products for Tomatoes & Peppers
50–75 Mesh (high virus pressure)
Benefits:
- Blocks thrips (TSWV)
- Strong UV protection
- Suitable for greenhouse doors and sidewalls
40–50 Mesh (balanced greenhouse option)
- Good airflow
- Effective against whiteflies and aphids
- Suitable for most climates
25–32 Mesh (open-field tomatoes & peppers)
- Strong wind resistance
- Virus control through reduced vector landing
- Works with shading systems
IPM Recommendations for Tomatoes & Peppers Using Insect Netting
Netting works best when integrated into a full IPM plan.
Best practices:
- Install yellow/blue sticky traps
- Remove virus-infected plants immediately
- Rotate crops and avoid planting near solanaceous weeds
- Monitor pest pressure weekly
- Enforce strict entry hygiene in greenhouses
- Use reflective mulching to reduce whitefly landing
Conclusion
For tomatoes and peppers, virus management must drive mesh selection—not insect size alone. Thrips and whiteflies are the leading virus vectors, making 50–75 mesh the gold standard in high-pressure regions. In moderate climates, 40–50 mesh offers excellent protection with improved ventilation. For open fields, 25–40 mesh balances airflow with vector suppression.
When combined with air-tight installation and strong IPM practices, insect netting becomes one of the most effective tools for reducing virus incidence and stabilizing tomato and pepper yields.
Ready to Choose the Right Insect Net for Your Tomato or Pepper Farm?
Selecting the correct mesh size is critical for preventing virus outbreaks in tomatoes and peppers.
If you need expert guidance or want tailored recommendations for your climate, structure type, or pest profile:
👉 Contact EyouAgro for a personalized mesh selection guide or a free quotation. We help growers design complete insect-exclusion systems—mesh, installation method, ventilation strategy, and IPM integration.
📩 Get in touch: https://eyouagro.com/contact-us/
FAQ – Best Insect Netting for Tomatoes & Peppers
What is the best mesh size for preventing viruses in tomatoes and peppers?
The ideal mesh depends on your local virus pressure.
In high-pressure regions where TSWV and TYLCV are common, 50–75 mesh is recommended to block thrips and whiteflies.
In moderate-pressure greenhouses, 40–50 mesh provides a strong balance between virus prevention and ventilation.
Can insect netting completely eliminate virus diseases like TYLCV or TSWV?
No net can eliminate viruses entirely, but it can dramatically reduce the number of virus-carrying insects entering the crop. Combined with strict door hygiene, double-door vestibules, sticky traps, and removal of infected plants, insect netting becomes one of the strongest IPM tools for virus management.
Does finer mesh cause overheating in tomato and pepper greenhouses?
Yes. Finer nets (50–75 mesh) reduce ventilation, which can increase temperature by 2–5°C. To avoid heat stress, growers can expand vent areas, use fans or evaporative cooling, or apply coarse mesh on the roof and fine mesh on the sidewalls.
What color insect net is best for tomatoes and peppers?
Silver or pearl-colored nets can repel whiteflies, reducing virus pressure. Red nets may help enhance tomato coloration in some climates. Yellow nets attract thrips and should be used carefully—preferably only as trap aids, not full-coverage nets.
Can open-field tomatoes use insect netting?
Yes. Open-field tomatoes often use 25–40 mesh, which provides good vector suppression without excessive heat buildup. This is effective against whiteflies and aphids, the dominant virus vectors in open environments.
Do installation methods affect insect netting performance?
Absolutely. Even the best mesh fails if installation is not air-tight. Door frames, bottom edges, fans, and vent openings must be sealed properly. A double-door vestibule and buried edges are essential for preventing virus-carrying insects from bypassing the mesh.
