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Can thrips survive winter?

Thrips are tiny insects that can cause major damage to plants. As cold-blooded organisms, their ability to survive the winter depends on the climate where they live. Here’s what you need to know about thrips and winter survival:

Do thrips die in winter?

Thrips do not necessarily die off completely during winter. However, their numbers are significantly reduced as cold temperatures slow down their development and reproduction. Adult thrips are more vulnerable to winter mortality than eggs or pupae that overwinter in protected sites.

How do thrips survive winter?

Thrips have adapted several strategies to improve their chances of surviving winter:

  • Seeking sheltered sites – Thrips migrate to protected areas like under bark, in leaf litter, or greenhouses to escape winter extremes.
  • Life stage – Eggs and pupae are more resilient to cold than adult thrips. Some eggs undergo diapause, a period of suspended development, to ride out winter.
  • Cold hardening – Exposure to gradually cooling temperatures triggers physiological changes that improve cold tolerance.
  • Migration – Some species migrate to warmer areas in fall to avoid severe winters.

What conditions are needed for thrips to survive winter?

Thrips survival depends on the following key conditions:

  • Shelter – Protected microclimates reduce exposure to extreme cold, wind, rain, and snow.
  • Insulation – Leaf litter, plant debris, and snow cover moderate temperature swings.
  • Above-freezing temperatures – Prolonged or frequent sub-freezing temperatures increase winter die-off.

Which species are most cold tolerant?

Some thrips species are better adapted to survive cold conditions, including:

  • Western flower thrips
  • Onion thrips
  • Chilli thrips
  • Fig thrips

These species can overwinter in colder regions where temperatures may dip below freezing. However, their populations decline over winter compared to warm regions.

Can thrips survive in northern climates?

Thrips can survive winters in northern latitudes, though populations crash when it gets extremely cold. Areas with moderate winters, like the Pacific Northwest, allow higher overwintering success. Harsher winters with prolonged below-freezing temperatures limit survival.

Greenhouses also enable northern overwintering as they maintain above-freezing temperatures. Some species like western flower thrips heavily infest greenhouses year-round.

Can insecticides control overwintering thrips?

Insecticide treatments are often ineffective for controlling thrips that overwinter in protected sites. However, they may help limit populations in greenhouses or on outdoor plants before thrips migrate to sheltered overwintering sites. Rotation of insecticide modes of action is key to preventing resistance.

How can I limit thrips survival over winter?

Here are some tips to reduce overwintering thrips on your property:

  • Remove leaf litter, piles of dead plants, and weed debris to eliminate protected sites.
  • Prune trees and shrubs to open up dense canopies and remove branches in contact with the ground.
  • Apply insecticidal drenches to container plants before bringing them indoors.
  • Use insect exclusion screens on greenhouse vents to prevent migration indoors.
  • Introduce biological control agents like predatory mites early in greenhouse crops.

Conclusion

Thrips can successfully survive winter in many temperate regions by seeking sheltered microclimates and undergoing physiological adaptations. While populations are reduced, thrips often rebound quickly in spring when founders emerge from protected sites. Careful sanitation and preventive insecticide applications can help limit damaging population spikes after winter.