Extrafloral nectaries

Caring for house plants often leads to surprising discoveries. If you've ever spotted mysterious drops of sap on your plant's leaves and are worried about diseases or pests, fear not. More often than not, it's just your plant doing its natural thing. Those tiny sap drops? They might be a sign of something fascinating called Extra Floral Nectaries (EFN).

EFN is specialized nectar production units strategically placed on various parts of plants, excluding the flowers. Rather than indicating trouble, these small structures serve a crucial purpose by generating sweet nectar to attract beneficial insects.

Symptoms of pests or EFN?

When encountering drops of sap on your plant's leaves, it's essential to rule out the possibility of pest infestations, which can sometimes manifest as sap leakage or drops of honeydew on and around your plant. Common culprits include spider mites, thrips, and honeydew-producing pests such as aphids, scale insects, and mealybugs.

Potential Pests

1. Spider Mites and Thrips:These tiny creatures may cause minuscule punctures in the leaves, leading to sap leakage. The presence of webbing, stippled leaves, grey areas and tiny black spots are other indications of spider mites or thrips.

2. Honeydew-Producing Pests (Aphids, Scale Insects, Mealybugs):These pests excrete a sugary substance called honeydew, often observed as sticky drops on and around infested plants.

Distinguishing EFN from Pests

1. Location:EFN are typically located on specific plant parts, excluding flowers. Undersides of the leaves, the petioles and stems of the plant are common areas where EFN is usually located. Some plants even have visible glands where the EFN is produced.

2. Appearance of Sap Drops:EFN-produced sap is usually clear and odorless. Sometimes surrounded by distinctive borders, which may manifest in colors such as yellow, black, purple, green, or red-colored. In contrast, honeydew from pests may have a stickier consistency, covering a larger area and can attract sooty mold over time - turning it black in color.

Detecting and Addressing Issues

1. Regular Inspection:Routinely inspect your plants for signs of pests. Look for webs, discolored leaves, or the presence of insects on the plant.

2. Wiping Leaves:Gently wipe the leaves with a damp cloth to remove any sticky residue.

By understanding the distinctive features of Extra Floral Nectaries and the potential signs of pest infestations, you can better care for your plants and address issues promptly.

Is EFN treatable?

In many cases, when EFN appears, your best course of action might be to simply appreciate the unique defense mechanism your plants have. However, there are instances where factors contribute to EFN that you can actively address:

Watering:Imbalanced watering, either too much or too little, can stress plants and trigger EFN activation.

Solution: Maintain a consistent watering routine, following both the schedule and the guidelines provided by Planta for optimal plant care.

Nutrients:Just like us, plants need the right nutrients. Both lacking nutrients and being fed too much can cause stress to your plants.

Solution: Ensure your plants receive the correct type and amount of fertilizer to prevent nutrient stress.

Climate:Extreme temperature and humidity conditions can stress plants and lead to EFN activation.

Solution: Create a comfortable environment by monitoring and controlling temperature and humidity levels.

Pests:Bugs can be disruptive troublemakers, potentially causing stress-induced EFN activation.

Solution: Manage pests diligently to keep your plants healthy and less likely to call in the insect cavalry.

Does all plants produce EFN?

Many aren't familiar with Extrafloral Nectaries. But it's actually discovered in over 4000 plant species across more than 90 families.

Most known are cherry trees with visible glands on their leaf petioles. Initially recognized for aiding in plant identification, these tiny glands turned out to have a crucial ecological role.

The appearance of EFN can vary widely among different species. Here's a few examples of some houseplants known to produce EFN:

• Philodendron

• Goeppertia (Calathea)

• Hibiscus

• Passiflora

• Aglaonema

• Opuntia

• Rhipsalis

• Dioscorea