Pests, Bugs & Viruses

Identifying Plant Pest

For growers one of the worst issues to deal with are insects or other pest that survive off your plant and will more then often kill it or reduce its health/yield.

In IPM, Integrated Pest Management, like many facets of growing prevention is normally a simple process but when your preventative controls fail often growers are not sure where to go next.  Identifying your invaders and their population size will give you an idea of how far you will need to go to control.

Here we will run through a simple guide of what kind of pest you might commonly see affecting your plants.

Pests that can affect Cannabis include bug that pierce and scratch, infectious diseases and fungi’s. Pest can attack your leaves or roots or borrow into your plants, so identification is key. Becoming familiar with aphids, fungus gnats, thrips, green flies, black flies, mosaic virus, spider mites, caterpillars, inchworms, whiteflies, white powdery mildew / white powdery mold, stem rot, and the damage they can cause will help in identification and subsequently control. 

Aphids can live and wreak havoc in both your root zone and the underside of your leaves & have different forms depending on their stage of life called instars. These invasive pests will create necrotic spots from their leavings called “honey dew “ and leave a white husk when molting, a tell tale sign of their population size and growth. Adults with wings only seen in populations big enough that their food source is in low supply. 

Barnacles / Scale Insects
These bugs look like barnacles and stick to the plant on stems and underneath leaves. They are plant burrowers and can be a big issue depending on population size for your plants overall health. 

Broad Mites or Russet Mites
Both of these mites will most often be found after the damage they leave is seen, brown glossy and rusty looking dead leaves curled and moving up the plant often from the ground. Up.

These mites are very, very,  small but that doesn’t stop them from taking over your garden and slowing your growth reducing bud and plant health and eventually killing your plants.

Bud Rot or Mold
Bud rot can be a real issue for many outdoor or indoor hydro farmers. It appears to happen seemingly overnight but is often the end result of many factors that overall mean buds are full of moisture with nowhere to go.

It can be very invasive so if you find buds that all of a sudden are dying and look off, check for bud rot and remove the infected material immediately. Being very diligent to cut more then just infected material out and to find any smilar buds nearby and do the same, Mold is very infectious so be careful to make it a clean process of removing and discarding of infected material.

Caterpillars, Inchworms & Cabbage Loopers
Caterpillars and worms eat holes in your leaves and leave droppings that look like black specks. The damage tends to look random, but often a culprit is not far away and can be caught and ID’ed.

“Regular” crickets will munch on your leaves while “mole crickets” can tunnel under your plants and disturb their roots!

“Regular” Crickets

Mole Cricket – these can tunnel under your cannabis plants like moles

Fungus Gnats
Fungus gnats are little black bugs with long wings and long bodies that breed in your media and subsist of your plants roots and algae that forms on the media surface. Their larvae can even burrow into roots and hibernate for a period. You will often see very bad infestations with swarms around your plants or wet damp areas living off of algae.

You’ve probably seen these before, but unless you are growing outdoors probably never seen them as a pest. These critters will eat your leaves and make an overall mess of things.

These bugs come in almost every color known to man so sometimes it can be tough to tell what they are just from looking. However, their piercing and sucking method of feeding will leave your leaves with spots that become drained thin and translucent and kill your leaves.

Leaf Miners
If you notice a maze pattern imprinted in your plant’s leaves starting at the edges you probably have leaf miners these little pests are easily identifiable by the pattern their larvae leave.

Leaf Septoria / Yellow Leaf Spot
This fungus causes round yellow or brown spots, with symptoms often starting on lower parts of the plant

These little bugs are soft oval and are usually covered in white gray mealy wax. They can in high numbers be a big nuisance and their leaving or “Honey dew” can cause sooty mold to grow. 

Root Rot

Brown, slimy smelly roots…If you are experiencing this, it is a common problem in hydroponic systems or container pots that are often oversaturated or if unhealthy.

Slugs / Snails
If every morning you see new holes eaten out of your leaves with slime trails leading to the damage you probably have some form of slug or snails in your grow environment. These pests can cause damage to leaves and leave unsightly messes on your plants. 

Spider Mites

Spider mites care a common problem for growers their small size and wide range of habitats can make their transmission into your grow a common occurrence.  The damage left by these guys looks like small spotting that eventually turning hazy and pale will kill your leaves. When populations outgrow their food source, they will start to create webs, and travel up your plant to as high as possible a point to hopefully launch onto another plant.

​Thrips are a fast-moving beetle like insect that lives off your plants sugars and look very small not unlike a tiny grain of rice. They can be many colors but most commonly are white/translucent and black. These bugs live on your plants and breed in your soil where their larvae grow. The damage they leave is that of many little scratches that kill that part of the leaf and become necrotic and yellow/brown.

Tobacco Mosaic Virus
TMV is a virus that can destroy all your fan leaves leaving you plant without optimal photosynthesis or nutrient storage. Its unknown how many cases have been reported in Cannabis but its well documented in Tobacco and theoretically can infect any leafy plant.

Whiteflies/ White fly
Whiteflies often mistaken for silverfish will cause damage to your older leaves and if left unchecked will kill your plants. Their leavings will cause mold and bacteria to develop. There are a few types of common whiteflies only differentiated by birthing process and development in nymph stages of life. Controlling either type is a different process so identification is key. 

White Powdery Mildew or Powdery Mildew
WPM is a specialized fungus known as an obligate biotroph, its infection grows in your plants tissue only to bloom and infect other plants. Mostly seen on leaves a white powdery substance will form, these are spores ready to be released in infect other living plant tissue. Control/prevention depend on your environmental conditions and keeping an environment not suitable for its transmission. 

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