Growers Network’s Disease Profile: Powdery Mildew

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In this series of articles, Growers Network talks about a few of the most common Cannabis diseases you need to watch out for. Today’s topic: Powdery Mildew

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Plant diseases are a major headache in any grow operation and Cannabis has no shortage of diseases. So for today’s disease profile we’re going to discuss Powdery Mildew, a disease you may find yourself dealing with in your grow.


Quick Look:

  1. Common Name: Powdery Mildew
  2. Scientific Name: Various
  3. Symptoms: White dusty coating on leaves, stems, and flowers
  4. Caused by: Fungus
  5. Timing: Spring onward


Powdery Mildew


PM
This is powdery mildew (photo courtesy of marijuanatimes.org)

What is it?

Powdery Mildew is a fungus that reproduces rapidly and eats plant matter. Powdery mildew thrives when the ambient humidity is high and there is little to no airflow. It is relatively easy to treat if swift action is taken, but inaction will lead to crop loss.

What to look for

Unlike some Cannabis ailments, powdery mildew is relatively easy to spot. What you’ll notice are white patches of fungal growth on your leaves, stems, and buds. Some species can be harder to detect as the fungus primarily affects the underside of leaves.

How to Treat/Prevent

Non-Chemical Control

To combat powdery mildew without chemicals, growers should make sure to control humidity wherever possible. Additionally, keeping your plants stress-free can reduce susceptibility to Powdery Mildew. Growers should destroy all infected plant material to help prevent reinfestation. Lastly, early pruning of infected sites can greatly reduce the chance of an infestation.

Related Article: Dehumidification: It’s All About the Dewpoint

Chemical Control

There are a variety fungicides available for treatment of powdery mildew. However, caution should be taken in both product selection as well as application since Cannabis is a consumable crop. That said, there are a variety of products that combat fungal growth and spores with little to no chemical residue when used appropriately.

Disclaimer: The previously mentioned chemical methods of control are suggestions only and not endorsements. Make sure you are aware of the laws regarding pesticide use in your jurisdiction. Growers Network DOES NOT advocate breaking any laws.


One Other Thing

Any buds or flower that were infected by powdery mildew should not be sold for consumption or consumed. They should be disposed of immediately. Smoking contaminated product can lead to very serious health risks, so DON’T DO IT.


So now you know a bit about Powdery Mildew and what you can do to prevent it from ruining your grow. Have additional questions about powdery mildew? You should join our forum where you can post pics and ask our expert community about this topic or any other!

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Cannabis is legal! (In Canada)

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In this article, Growers Network discusses the change in legal status of recreational Cannabis in Canada.

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Legal Canadian Cannabis


Canadian Cannabis enthusiasts have reason to celebrate as today marks the official legalization of recreational Cannabis in our neighbor to the north. While medical Cannabis has been legal in Canada since 2001, purchase and use of recreational Cannabis has still been prohibited.

Though Cannabis legalization is still a national experiment in Canada, Prime Minister Justin Trudeau has vocally touted the benefits of legalization, which include reducing criminal activity related to Cannabis use, as well as reducing the amount of black market Cannabis that is easily obtained by minors. Additionally, a portion of the tax revenue generated has already been pledged to combat Canada's opioid crisis.

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Are there any other potential benefits? Well, since Uruguay legalized Cannabis in 2013, related crime has dropped significantly, and in US jurisdictions with legalized or decriminalized Cannabis, police have benefited by being able to focus resources on more serious crimes than possession and consumption of Cannabis. Additionally, since legalized and medical Cannabis have provided a boon of tax revenue elsewhere, it seems that Canada will enjoy this additional economic boost as resident Cannabis enthusiasts pony up their money to enjoy their legal weed. Last year alone, Canadians spent over four billion dollars on medical Cannabis, and recreational sales are expected to approach five billion, though some think it will take time to reach that mark.


So now you know how Canada hopes to benefit from legalization, but what does legalization look like in Canada? Here’s the gist:

Who Can Buy Recreational Cannabis in Canada?

  1. Adults nineteen and over may publicly carry up to 30 grams (about one ounce) of Cannabis.
  2. Adults nineteen and over may grow up to four plants in their home for personal consumption.
  3. Sale of Cannabis products to minors is strictly prohibited.

Where Can Canadians Buy Cannabis?

  1. Cannabis is sold in all provinces and territories by licensed retailers. Information on specific regulations by province are available here.
  2. Cannabis will not be sold in tobacco shops or liquor stores.

Can People Cross the Canadian/US border with Cannabis?

The answer to this question is a definitive “no.” Crossing the Canadian/US border with Cannabis is prohibited, even if traveling to/from US states where recreational use is legal.

What about previous Cannabis convictions?

An additional piece of good news resulting from legalization is that the Canadian government plans to pardon individuals convicted of possessing thirty grams of Cannabis or fewer.


Canadian legalization is an exciting development for Cannabis advocates everywhere as other jurisdictions look for signs of its success or failure. So how will this “national experiment” work out? Only time will tell, but if analogous trends are any indication, it’s high time Cannabis go legal.


What do you think? Which country will be the next to go legal with Cannabis? Leave a comment in the survey below, or better yet, join our forum and start a discussion!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Growers Network’s Pest Profile: Whiteflies

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Whiteflies.

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Garden pests are a pain and Cannabis certainly has no shortage of them. So for today’s pest profile we’re going to discuss whiteflies, a common pest you may find yourself dealing with in a Cannabis grow.


Whiteflies


whiteflies
Meet the Beatles whiteflies

What are they?

Whiteflies look like their name suggest, are little white flies. They have also been described as looking like small white moths, though in truth they are more closely related to aphids and cicadas. They attack plants in much the same way as the spider mites we mentioned last time. They hide on the underside of leaves and use their piercing mo to suck nutrients, water, and sugar from the plant.

What to Look For

Whiteflies will typically be detected before you see any damage to the plant. Just giving the plant a slight shake can create of cloud of scattering whiteflies. Affected leaves will become spotted as a result of the whitefly feeding. Additional effects on the plant include leaf yellowing, leaf drying, and slowed growth.

How to Treat/Prevent

Like all of the pests we mentioned there are a variety of effective treatments. Your first line of defense is always vigilant monitoring. Additionally, whiteflies have developed a resistance to many synthetic pesticides which makes prevention even more important. Companion planting is recommended, specifically marigolds or zinnias which will attract natural whitefly predators such as hummingbirds and parasitic wasps.


Now you’re whitefly wise! Make sure to check out the rest of the articles in our Pest Spotlight series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Growers Network’s Pest Profile: Spider Mites

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Spider Mites.

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Garden pests are a pain and Cannabis certainly has no shortage of pests. So for today’s pest spotlight we’re going to discuss spider mites, a common pest you may find yourself dealing with in a Cannabis grow.


Spider Mites


mites
If your buds look like this, I'm sorry. Monitoring for these critters is crucial.


What are they?

Spider mites refer to several species of arachnids that live on the underside of leaves, feeding on the foliage and damaging the plants. In cannabis, spider mites can result in low yields and and in extreme cases, total plant death.

Editor’s Note: All mites are arachnids. That does not mean that you can see them with your naked eyes!

What to Look For

Spider mites are most often detected on the underside of leaves. Affected leaves can appear spotted or striped due to mite feeding with heavily impacted leaves turning yellow and dying completely. An additional sign is their eponymous webbing, a silk secretion left on the underside of leaves.

How to Treat/Prevent

The first line of defense against mites is diligent monitoring. If you find spider mites early, they can be removed before any real damage has occurred to your plant, or at least minimal damage. Additional controls include introducing predatory species such as the ladybug, the minute pirate bug, or even Phytoseiulus persimilis, another mite species that will kill the spider mites and leave your plants alone. There are many safe, organic pesticides available, as well as miticides, however, these miticides are often toxic, and we typically don’t recommend them for a consumable product such as Cannabis.

Editor’s Note: If you are able to see the webbing with your naked eye, you are too late in addressing the problem. By that point, the infestation will likely be so bad that the only way to correct the problem is to slash and burn any plant that appears infested.


Now you know your spider mite basics. Make sure to check out the rest of the articles in our Pest Spotlight series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Growers Network’s Pest Profile: Slugs and Snails

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Slugs and Snails.

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Garden pests are a pain and Cannabis certainly has no shortage of pests. So for today’s pest profile we’re going to discuss slugs and snails, common pests you may find yourself dealing with in a Cannabis grow.


Slugs/Snails


slug snail
Aren't they adorable? Don't be fooled. They'll eat your plants and everyone you care about.


What are they?

Slugs and snails are invertebrate organisms with the major distinction between them being the snail’s shell. Both of these organisms love to eat leaves, and Cannabis leaves are no exception. While a few of these creatures won’t devastate a crop, an infestation of them can, and that’s why vigilant monitoring is important.

What to Look For

In addition to spotting the organisms themselves among your plants, they can be detected by the chiseled holes they leave in the foliage (which are sometimes mistaken for caterpillar damage) as well as the slimy trails they leave behind.

How to Treat/Prevent

There are a variety of methods for controlling slugs and snails. You can pick them off by hand and kill them, or you can use natural predators such as frogs and toads. These pests are also fond of beer so you can set up an easy pitfall trap by burying a can up to the lip and partially filling it with beer. Some growers also recommend laying out eggshells, lime, or diatomaceous earth around the plants to stop slugs and snails.


So that’s the skinny on slugs and snails. Make sure to check out the rest of the articles in our Pest Profile series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Growers Network’s Pest Profile: Leaf Miners

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Leaf Miners.

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Garden pests are a pain and Cannabis certainly has no shortage of pests. So for today’s pest profile we’re going to discuss leaf miners, a common pest you may find yourself dealing with in a cannabis grow.


Leaf Miners


leafminer
A larval leaf miner next to a damaged leaf. Note the tunneling.


What are they?

Leaf miner is a general term for a variety of insects whose larval stage is characterized by their “mining” or “boring” behavior as they tunnel inside leaves. Adults leaf miners lay their eggs in soil and when the larvae emerge, they feed on the interior of leaves. They impact cannabis grows by reducing yields and their tunnels can make the plants susceptible to fungal and viral infection.

Editor’s Note: These insects are sometimes called “boring insects” not because they are dull or uninteresting, but because they “bore” through plant material.

What to Look For

Leaf miners look like small worms or caterpillars. The tell-tale sign of a leaf miner attack is a winding, lightly colored trail that shows on the surface of the leaves.

How to Treat/Prevent

A localized outbreak of leaf miners can be controlled through removal of the pests by hand or by pruning the affected leaves from the plant. Sticky traps are often used both to catch adults in the process of depositing eggs in the soil, and around the base of the plant to catch the larva before they can reach it. Beneficial predators such as parasitic wasps can also be employed to control and kill larval leaf miners.


That’s it for the our intro to leaf miner maladies. Make sure to check out the rest of the articles in our Pest Profile series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Growers Network’s Pest Profile: Grasshoppers

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Grasshoppers.

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Garden pests are a pain and Cannabis certainly has no shortage of pests. So for today’s pest profile we’re going to discuss grasshoppers, a common pest you may find yourself dealing with in a cannabis grow.


Grasshoppers


grasshopper
Swarms of grasshoppers have been known to devastate crops.


What are they?

Grasshoppers are insects with a voracious appetite for plant material and have been known to devastate crops in large swarms. They are sometimes referred to as locusts, but there is no taxonomic distinction between these and grasshoppers. Locust is a name applied to the various species when they travel in large swarms, but it doesn’t take a locust swarm to damage your Cannabis. Grasshoppers are closely related to crickets in the order Orthoptera.

What to Look For

Grasshoppers are relatively large insects, and are easy to spot among your crop. They love Cannabis seedlings, so it’s particularly important to monitor for grasshoppers during this stage. Most species of grasshoppers have cylindrical bodies, long hind legs, and wings.

How to Treat/Prevent

There are a variety of methods to control and prevent grasshopper infestations in addition to traditional pesticide treatments. Grasshoppers lay their eggs in the soil, so tilling is a good way to expose and kill grasshopper eggs. You can also add targeted beneficials to your soil such as targeted fungi spores that can kill grasshoppers. Also, planting companion crops such as peas or cilantro are a great natural deterrent as grasshoppers avoid these. You may also consider adding bird perches to attract the grasshoppers’ natural predators.


Now you’ve got the goods on grasshoppers. Make sure to check out the rest of the articles in our Pest Profile series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Growers Network’s Pest Profile: Fungus Gnats

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Fungus Gnats.

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Garden pests are a pain and Cannabis certainly has no shortage of pests. So for today’s pest profile we’re going to discuss fungus gnats, a common pest you may find yourself dealing with in a cannabis grow.


Fungus Gnats


gnat
Gnats are tiny members of the fly order Diptera. Like this one.

What are they?

Fungus gnats are tiny (3-5mm) members of the insect order Diptera (the flies) which lay their eggs in soil and whose larvae feed on decomposing plant and root material. Fungus gnats prefer dark conditions and thrive in high humidity, making indoor and hydroponic grow operations particularly susceptible. However, moist soil is also a draw for these pests. In addition to direct damage caused by the larvae, a fungus gnat infestation can also increase the odds of a fungal or viral infection since these gnats also carry diseases with them.

What to Look For

Due to their small size and the fact that most of the damage occurs beneath the soil, an outbreak of fungus gnats can be hard to detect, depending on your media. Generally, you need to be vigilant in your monitoring and watering schedule. A major sign of infestation is slowed plant growth due to the destruction of root material. Additionally, fungal infections may be a sign of fungus gnat infestation. If soil or media never seems to dry out, you may be at increased risk of fungus gnats as well.

How to Treat/Prevent

If you want to prevent fungus gnats, there are a number of products available, but the best thing you can do is avoid overwatering your plants and control the humidity. By keeping the top layer of the soil dry, you will prevent the adult fungus gnats from laying their eggs. Another option is laying down a layer of mulch to prevent the fungus gnat females from laying their eggs in the soil. There are also biological controls available in the form of predatory mites and nematodes that will eat the gnat larvae while leaving the plant in peace.


Now you’re full of fungus gnat facts! Make sure to check out the rest of the articles in our Pest Profile series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Grower’s Network’s Pest Profile: Aphids

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Aphids.

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Garden pests can really bug you and Cannabis certainly has no shortage of pests. While the old saying goes that an ounce of prevention is worth a pound of cure, that adage doesn’t do much when you’re dealing with an infestation.

So for today’s pest profile, we’re going to talk about aphids, a pest you may find yourself dealing with in a cannabis grow. We’ll include info on treatment, and yes, we’ll throw in that ounce of prevention.


Aphids


aphids
These are Aphids. Notice the ant that was attracted by the honeydew.


What are they?

Aphids are the small, sap-sucking insects that you can see in the image above. In addition to damaging the plant by sucking nutrients, water, and sugar from the leaves and stems, they leave behind a sticky secretion called "honeydew" that can facilitate growth of mold. They can also spread disease as they feed on new plants.

What to Look For

Aphids prefer to be out of the light so they are most prevalent on the undersides of leaves and on stems and stalks. Honeydew can also attract ants, which can be another sign of aphid infestation. Additionally, aphid leaf damage shows as yellowing or curling.

How to Treat/Prevent

There are a variety of treatments available for aphids including predatory organisms such as ladybugs and predatory mites, organic pesticides, and oils. Commercial pesticides are also available but many growers prefer an organic approach before resorting to using these chemicals. If the infestation is not too widespread, pruning the plant and removing the aphids by hand is another effective option.


Now you know your aphid basics. Make sure to check out the rest of the articles in our Pest Profile series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.


Growers Networks Pest Profile: Caterpillars

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In this series of articles, Growers Network talks about a few of the most common Cannabis pests you need to look out for. Today’s topic: Caterpillars.

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Garden pests are a pain and Cannabis certainly has no shortage of pests. So for today’s pest profile we’re going to discuss caterpillars, a common pest you may find yourself dealing with in a cannabis grow.


Caterpillars


caterpillar
These hungry critters make short work of leaves.


What are they?

Caterpillars are the larval form of moths and butterflies. Caterpillars are voracious eaters. They eat the soft tissues of plants, and the damage they cause is often visible as they chew through leaves and flowers. Additionally, a caterpillar infestation can lead to fungal infections such as bud rot (Botrytis) when they defecate on the flowers or injure stems with their bite.

What to Look For

There are several things to look for with caterpillars. Since some caterpillars are relatively large, they can be spotted visually. However, adult butterflies will lay eggs on the higher leaves of the plant, so seeing this occur is your first clue. The eggs are small and it’s useful to have a magnifying device handy if you’re looking for them. Another sign of infestation is the obvious foliage damage.

How to Treat/Prevent

There are a number of effective treatments available to stop a caterpillar infestation, with many of them being biological remedies. These products are specifically made for larval pests and contain bacillus bacteria that occur naturally in soil. Additionally, plants can be inspected regularly and any eggs or larvae can be removed by hand.


Now you know your caterpillar basics. Make sure to check out the rest of the articles in our Pest Profile series.

Happy Growing!


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About the Author

Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network.