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Barnacle Scales and Cannabis Plants

barnacle scales on cannabis plant
Posted by: Samuel Thomasino Category: Plant Problems Comments: 0

Barnacle Scales and Cannabis Plants

Barnacles on cannabis plants are often scale insects that are thriving on the plants for juice and nutrients. These little pesky creatures enjoy many crop types though are known for migrating to cannabis plants as if to them it were a delicacy.

Scale insects are small in size and belong to the Hemiptera family from which eighty-thousand species exist. They come in many shapes and sizes and at first, may appear as a growth from the plant itself instead of bug infestation.

Typically colonizing on stems and under leaves, it is important growers keep watchful eyes for signs of their unwelcomed visit. Once these pests attack, infected plants soon show signs of nutrition problems with curling leaves usually being the first.

Slow-growing, poor-postured plants with small bumps that look like warts or barnacles attached to the stems or leaves are likely to be infected by scale bugs. Just like aphids, they suck the nutrients and life from crops which leaves the plant weak and incapable of growing. Nutrient deficiency symptoms will often arise as these scale insects remove the nutrients from the plant, leaving it inbalanced.

Untreated attacks can lead to all crops becoming infected and depending on severity could kill them all. No grower investing hard-earned money and months of sweat-equity effort wants to encounter a dying harvest, but fortunately, avoiding that is possible when steps, such as the ones in this Sticky Seeds guide, make removing barnacle scales from cannabis plants efficiently easier.

Fortunately for growers, there are several ways to combat these pests which this guide will insightfully review. Though first, let us discuss the dangers and behaviours of these pesky little creatures to see why they are a concern for both in and outdoor growers around the world.

What are Cannabis Barnacles

scale insects on leaves

Cochineals (AKA Scale Insects) are one of the most damaging insects to cannabis plants and are known as barnacle scales. These small parasites can become a nightmare for growers as they can cause crops to sicken and die. Plants with curling leaves or signs of malnutrition may be due to scale insects that colonize on the main stalk or branch sides and appear as bumps or warts.

Many people call these scale insects ‘barnacles’ as the formation the colony takes on the plant’s stems is very similar. Scale insects are like the barnacles you can find on rocks, but in this case, they are on plants. The behavior is very similar, they do not move, and appear as scales. They move before grouping on stems and leaves but are stationary once their resting spot is found.

Some prefer to live on leaves while others on stems. The ones pictured at the bottom have made themselves at home, are well settled, and exhibit just how badly infiltration can become.

honeydew deposits from scale insects

They come in many shapes and sizes and despite their small stature are among the most damaging of pests to cannabis plants. Varying in form, they at first may be hard to identify as they look similar to dark-colored aphids, so if bugs resembling aphids appear, the grower should not rule out scale insects as the intruding culprit.

Similar to aphids, they thrive on plant nutrients though left untreated can cause the entire harvest to become infected. As aphids do, these bugs release honeydew on plants too.

Honeydew is a liquid waste causing fungus known as sooty mold to form on the cannabis plant. Sooty mold thrives on honeydew deposits, quickly compounds on leaves, and can turn plants black. This mold not only discolors plants and hinders growth but makes buds less safe to consume too.

Furthermore, sweet honeydew attracts new insect species to crops making it all that much harder for growers to recover crops from infestation.

Damage to plants and months of wasted effort can occur if proper preventative care is not given as scale insects not only deplete nutrients from cannabis plants but can transmit diseases to them too. Some viruses not only slow the growth of plants but the plant’s production of flowers too. Some cochineal species even inject toxins into crops which further endangers the health of the plant.

Fortunately for growers, barnacle scales are fairly easy to get rid of when using the removal solution shared down below.

bad cannabis barnacle scale investation

Safe Bugs for Cannabis Plants

The use of natural predators is, and for quite some time has been, one of the best methods to combat pests. Coccinellids, or Coccinellidae, or ladybugs as commonly known, are strong allies in the fight against bugs.

With over forty-five hundred species, they are often found on plants on which their prey feeds and are natural predators to mites and insects, including cochineal and aphids, that both pose major threats to cannabis crops.

Used most by outdoor growers, successfully attracting ladybugs to plants will help keep cochineals far away from plants. They have become so essential to growers in their fight against ridding pests from plants that nurseries specializing in breeding ladybirds have started popping up.

With ladybugs, especially the seven-spotted ladybird, growers can achieve speedily-impressive results. You can buy ladybugs for cannabis plants but is best they arrive on their own and reproduce on plants.

As such, growers needing to rid cochineals or mealybugs from their plants should avoid using pesticides as these could kill ladybugs or keep them from showing up altogether.

Where do Cannabis Barnacles come from

These pests enjoy warm climates and stressed plants. They come from outdoors and are, most of the time, transmitted to plants from ones that are already infected. They can also migrate from pets, soil, and clothing.

As such, indoor cultivators should ensure clothes are free of bugs before entering their grow space. Not letting animals into grow areas is advised as well as this prevents another means of migration by which they travel.

These resilient little bugs travel any way they can and protect themselves well along their way. One defense mechanism and way to identify them is the gooey-armored hard plate they develop over their bodies once settled on a plant. This is one way they make it difficult for growers to rid them as their shell makes them more resistant to pesticide sprays than other species.

If a plant with wax scale insects were sprayed to the point that all barnacles and bugs were removed the plant itself would suffer due to the water pressure that would be needed to eliminate them. Damage needs to be avoided so barnacle removal from cannabis plants should be done with care using a solution that is gently sprayed on to plants, we will share safe removal solutions further into the guide.

Due to the damage these pests can cause, growers should take preventative measures before attacks even begin, though if not, being able to identify them quickly when they do arrive is the next best thing. Learning the forms they come in are essential to prevention and removal as identifying attacking pests lets the grower choose a removal solution suitable to the species.

Cannabis Plant Barnacles and Parasites

brown warts on stem

Barnacles on cannabis plants are actually the result of scaled insect infestation though small white parasites are likely to be mealybugs.

There are many cochineal species that growers combat though the one posing the greatest threat to cannabis crops are soft scale insects that feed on cannabis crops as their host plant.

Soft-scale insects are common cannabis cultivation pests usually inhabiting the plant’s main stem. Measuring no more than four-millimeters, their dome-shaped, scale-like form distinct them from aphids which makes them easy to identify.

Bugs that appear similar yet white instead are mealybugs and can be removed just as easily, but what are mealybugs and how can they be removed from cannabis plants?

Mealybugs and Cannabis Plants

Mealybug translates to ‘cotonet’ in Spanish due to their cotton-like texture. They average three-millimeters in length and lay fifty to five-hundred eggs at a time on plants. This causes harm to crops as mealybugs protect eggs with a powdery-wax layer that cements to stems and leaves, which makes removing them while avoiding plant damage a tedious process.

Once hatched, new-born cochineal will search for a place on the plant to suck juices and nutrients so growers should act swiftly if eggs are found. These bugs thrive best in warm climates and in temperatures over sixty-five degrees Fahrenheit. Mealybugs come in many shapes and sizes.

Interesting Fact: Female mealybugs die after laying eggs and have life spans averaging eighty-eight days.

mealy bugs
mealy bugs different shapes

How to Remove Barnacle Scales AKA Scale Insects from Cannabis Plants

Mealybugs and scale insects prefer dry and hot climates and are most active during summer. Growers can keep cannabis barnacles and bugs away by keeping grow spaces sanitary and ensuring they do not allow pets or wild animals around the plants.

Growers can get rid of cannabis barnacles by spot-cleaning the infected areas of the plant with one of the liquids below, followed by direct sunlight exposure. This works well as it creates a hostile environment in which they cannot live, so they either die or flee the plant, if alive long enough to do so. The below options are best applied by misting both sides of the leaves and stems with a spray bottle.

There are many ways to get rid of cannabis bugs and below we review the best ways to remove cannabis plant barnacles.

6 Ways to Rid of Cannabis Barnacles and Scales Safely

power sprayer for removing scales

#1 – Remove Barnacle Scales Using a Power Sprayer

Removing insects and barnacles from the infested plant is the first step to treating it. This is a delicate process as damage to plants should be avoided during the process.

Removing barnacles from cannabis plants is often safely done using a one-handed pressure sprayer filled with water at ph level 6.0 (remember, the plants will absorb this water so the ph should be optimised) to simply blast the bugs off. In some cases, growers will remove badly infected areas of the part altogether though nearly all bugs can be removed using a sprayer.

For better results, some growers use insecticides, such as option #2 below, to rid bugs and future-proof crops from additional attacks.

#2 – Insecticidal soaps

Fatty acid and insecticidal soaps are effective in removing cannabis barnacles and wax scale insects. These soaps weaken the outer shells of bugs, are safe for crops, and leave no residue.

When using insecticidal soaps, coverage is very important as it does not stay on plants for long. As such, to ensure the complete absence of pests and barnacles found on stems and leaves, growers should apply the soap at least twice but should avoid contact between the spray and flowering buds.

neem oil

#3 – Neem Oil

Neem oil is a naturally-occurring pesticide helpful for combating pests. It is a solution popular among growers though cinnamon, lemon, eucalyptus, and rosemary-based oils work effectively well too.

These oils have properties that affect scale insects upon contact though growers should avoid using aromatic oils as these often alter the smell and taste of harvested flowers.

The best way to remove barnacles from cannabis plants is to prevent the insects that cause them from arriving in the first place. One good way to do this is to use a vegetable-based solution, such as canola, soybean, or cottonseed oil as these will not impact the smell or taste of harvested buds.


#4 – Spinosad

Spinosad products are organically-made and pose no harm to plants. Spinosad sprays should be sprayed under leaves and to areas infested with scale insects, which again are the bugs responsible for the barnacles growers see.

While Spinosad sprays are not as strong as harsher pesticides, it works well when liberally applied and is contact-safe for plants and humans too. Growers using this spray, to ensure its effectiveness, may need to spray the plant a few times as the hard shell wax insects use to protect themselves is a good defense against repellants.

Spinosad is an organic insecticide created from the fermentation of soil bacteria and kills scale insects upon ingestion or contact once it has entered the insect’s nervous system.

It is a good product for in and outdoor growers to have on hand as it is toxic to scales and barnacles but not to beneficial bugs, such as spiders and ladybugs, that help growers to naturally rid these pests from their garden.

Note: Once mixed with water, Spinosad products are only effective for twenty-four hours. Growers should only mix the amount they need per application as excess spray becomes waste.

Properly dressing the plant in spray is done best using a one-handed pressure sprayer/mister as they make it easier to evenly distribute spray to stems and leaves.

#5 – Essentria IC3

This insecticide contains a mix of various horticultural oils, is organic, and safe for plants and humans.

Often marketed as a “bed bug killer”, it also works well for plants infected with aphids, barnacles, spider mites, whiteflies, and mealybugs and should be applied once daily as it stays active on plants for only eight to twelve hours.

#6 – Beneficial Insects

Lacewigs, ladybugs, and lady beetles are welcomed guests to any cannabis garden as they prey on bugs that damage plants.

While some growers buy ladybugs online to release in the garden, they usually fly away within a day which does not give them the time to reduce infestation as growers would hope.

One thing to consider is the reproductive abilities of scale insects as they multiply in volumes natural predators cannot keep up with. As such, bugs that are good for cannabis plants may not be able to resolve infestation alone but can make a noticeable difference and will help, to an extent, to restore order to the garden once again.

beneficial insects

highly resistant strains

Cannabis Strains and Seeds Resistant to Bugs

Growers not wanting to worry about pest prevention and management should grow genetics known to be inherently defensive to pest attacks. There are many measures a grower can take to prevent pests, and for those with limited time, this means choosing pest-resistant cannabis seeds, such as Afghan Kush, which is available in our store.

Pests are most likely to attack during summer which is when barnacles on cannabis plants usually show. As such, growers, especially ones outdoors, should buy cannabis seeds for strains that are easy to grow as these are known to be naturally resistant to attacks from agricultural predators.

Growers that buy autoflowering seeds are usually safe as these are more resilient to attacks as they are better adapted to the effects of poor growing environments.

Some of the best strains to grow outdoors for repelling scale insects and barnacles include:

Safeguarding plants from barnacles and scale insects can be difficult for growers, especially for the ones growing outdoors, though with the steps shared in this guide, they are easier to combat and rid from plants.

Thank you for visiting Sticky Seeds, we appreciate your support and look forward to serving your needs with weekly cannabis posts and fantastic cannabis seed deals enjoyed by thousands of enthusiasts each month.

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