Thrips on Plumeria: Causes, Treatment, & Prevention

If you’ve got thrips on your plumeria it can be hard to get rid of them, but the good news is that they rarely cause significant damage to these tropical flowering plants. However, if you’ve found yourself with a significant infestation we’ve got all the tips about thrip causes, and how to treat and prevent thrips on plumeria plants.

What are Thrips?

Thrips (Thysanoptera) are tiny flying insects usually measuring less than 1mm (0.05″). The genus, Thysanoptera, is made up of around 6000 species of thrip all with different habits and habitats.

Most thrips are actually beneficial to have in the garden as they predate herbivorous thrips and aphids, but the herbivorous thrips eat the leaves of tender plants like plumeria, meaning that thrips on plumeria can cause significant damage.

How to identify thrips on plumeria leaves

Thrips are winged insects, with elongated abdomens measuring less than 1mm from head to tail. Their bodies can be translucent brown or translucent green and they typically gather in groups of 1-200 on the underside of leaves.

If you notice clusters of small brown spots on the surface of plumeria leaves, the chances are that there are pests underneath. The brown patches are infected spots on the leaf surface and should be removed to prevent spread, or treated with a natural fungicide like neem oil to kill any spores or bacterial infection.

Signs of thrips of plumeria leaves

Depending on the severity of thrip infestation, there are a few different signs to look out for on your plumeria leaves:

  • Curled leaves
  • Black tip fungus
  • Wrinkles plumeria leaves
  • Puckered plumeria leaves

Below, we’ll look at each problem, and how to identify it.

Plumeria leaves curled

Curling plumeria leaves are a sign of stress. If your plumeria leaves are curling at the edges, or curling completely in on themselves it is usually a sign of pests gathered at the base of the leaf. When thrips gather at the base of a leaf they suck water, sap and chlorophyll out of the cells along the base of the leaf surface, tightening and hydrating the leaf above.

Occasionally, this will not cause any fungal or bacterial infection as that relies on the insects already having come into contact with other infected plants. If this is the case, simply spray off the thrips, or scrape them into the bin.

Black tip fungus

Black tip fungus can be caused by new plant growth, through is more commonly caused by spider mites. Black tip fungus is caused by insects damaging new growth and eating into the fresh tips of plumeria. Remove the affected tips, then discard the waste in the trash. If any thrips remain on the plant, treat them with rubbing alcohol which will also help to dry out any remaining fungal spores.

Wrinkled plumeria leaves / Puckered plumeria leaves

Wrinkled plumeria leaves are usually caused by smaller infestations of thrips when just a small number have landed on your plant. Indoor plumeria in particular is more likely to get puckered or wrinkled leaves, rather than curled leaves of black tip fungus. This is due to more regulated watering.

Thrip lifecycle

The thrip lifecycle is fairly common, but the way they protect their young is particularly unusual and causes more damage to plants than the adult thrips.

Adult thrips lay their eggs directly into plant tissue in winter, in cuts and crevices on the leaf surface. As the first larvae emerge from their eggs in spring they eat directly into the leaf, causing further damage. The larvae transform into wingless nymphs, which stay on one plant, traveling along the stem to healthy leaves, leaving tiny black droppings that stick to the leaf.

As they mature, they develop wings and fly off to other plants to expand the gene pool. Female thrips live for around 45-50 days, while male thrips live for just 30 days. In warm climates, thrips can hatch up to forty generations in a single year.

What causes Thrips on Plumerias?

There are plenty of plant pests that prefer dry or suffering plants, but some are actually a sign (albeit an unwanted one) that your plants are happy and healthy.

Thrips are attracted to healthy plants and will land on any plant they find that has a good supply of nutrients held in its leaves and buds. Because of this, it can be very hard to discourage thrips without using pest control measures, so below, we’ll look at the best ways to treat thrips on frangipani plants.

How to Treat Thrips on Plumeria

There is a big difference between pesticides and pest treatments. Pesticides kill insects, either by drying out their hard shells, damaging their nervous system, or cutting off oxygen. Pest treatments can include anything from washing your plants to manually removing insects and are generally safer for other beneficial insects.

However, there are some pesticides and insecticides which can be used safely with minimal risk for other wildlife.

Organic pesticides

Below, we’ve got three of our favorite organic pesticides which will treat and kill thrips on any plumeria plant. Follow the guides below to use them safely and reduce the risk to other wildlife.

1. Castile Soap

Castile soap works by suffocating insects, and small invertebrates. Castile is a natural plant material that is high in saponins – the compounds that make all soaps foam. By mixing and suspending in water, the soap creates an airtight film over the insects it is sprayed onto or insects that try to bite through it while it is wet.

Once dry, castile soap is ineffective. To use castile soap safely and effectively, spray it directly onto thrips, in the evening when other insects are less likely to be around.

 

 

2. Organic Neem Oil

Neem oil is, like castile soap, a natural material harvested from neem trees. The trees have natural pesticidal qualities and when the oil is extracted it is an incredibly effective pest deterrent as well as an insecticide. The oil works the same way as castile soap, by suffocating insects when sprayed or dabbed directly.

The extra benefit of neem oil is that it soaks into plants, and remains as an effective deterrent to insects for several weeks after application.

 

 

3. Horticultural Oil

Horticultural oil is a general term for mixtures of both castile soap and neem oil, but the best horticultural oils will usually contain methol, lemongrass and other essential oils that will dry out and deter insects.

Like neem oil and castile soap, horticultural oil should only be sued in the evening to avoid accidentally coating beneficial insects.

 

 

Organic Pest Treatments

As well as using insecticides, there are a whole host of ways to directly treat thrips on frangipani plants without harming other wildlife. If you notice thrip droppings on plant leaves but can’t see thrips, scrape them off and rinse the leaves, and their droppings contain chemicals that deter predators. this way, natural thrip predators like ladybugs will find them and eat them for you.

For most pests, simply rinsing your plant with a strong water jet can help, but thrip nymphs will crawl back onto your plants, so scrape them off, directly into the trash if you can.

Thrips on plumeria, FAQs

What kills plant thrips?

Neem oil, horticultural soap or castile soap are very effective at killing thrips if applied directly, but it’s also worth introducing natural predators like ladybugs who feast o thrips. As well as ladybugs, one of the thrip’s most common predators is actually other thrips!

Can you save a plant from thrips?

Thrips are less voracious than aphids or spider mites and do not gather in the same numbers, so rarely cause significant or lasting damage to plants. If thrips have carried infection to your plumeria from other plants, simply remove the infected material and burn, it or bin it.

Are thrips harmful?

Thrips are harmful to plants but less so than other plumeria pests. In terms of ecosystem balance, thrips are beneficial insects as they provide food for larger insects, which, in turn, provide food for birds and small mammals.

Can thrips bite humans?

There are over 6000 different species of thrip, but most will not bite humans other than by accident. Thrip bites are not known to carry diseases and are not a common allergen so cause just minor skin irritation. It is rare to be bitten by a thrip.

Conclusion

thrips are definitely one of the easiest pests to manage on plumeria leaves, so if you follow our guide above you should have an easy time getting rid of these irritating plumeria pests.

for more tips on treating and preventing plumeria pests, check out our guide to aphids on plumeria, plumeria scale, and mealybug on plumeria. All are regularly mistaken for thrips on plumeria.

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