As a hemp farmer, you’re in for an uphill battle when it comes to keeping your crops safe from pests and diseases.
In fact, a recent UC Cooperative Extension Survey identifies the 9 vertebrate pests, 14 insect pests, and 13 diseases that cannabis growers contend with each season.
Of course, the most common pests and disease vary by region . . .
But make no mistake about it: if you’re in the hemp game, you need to learn how to identify the very things threatening to destroy your hard work.
By the end of this article, you should have a good understanding of these pests and diseases, so you can . . .
- Plot the best path forward for pest prevention
- Decide if you need to move an outdoor grow undercover
- Discern when to sacrifice of a few of your hemp plants
- Share your knowledge with other hemp farmers
Alright, let’s dive in.
Worms & Caterpillars
These creatures are wildly attracted to your hemp crop, cozying up inside the buds so they can, erm, do their business. They’re difficult to control if you don’t take swift action, and are ruthless when it comes to attacking your acreage. Different species prefer different parts of the plant; corn earworms may move into the flower, while wireworms attack at that root and can destroy the whole plant.
The Solution: You can apply a biological insecticide like DiPelâl while the larvae is still small and manageable. Or, if you live in mild weather conditions, get parasitic wasps to act as your pest control.
Sticky buds bristling with CBD are great.
Sticky buds coated in aphids? Not so good.
You see, these tiny aphids suck the sap out of your plants, creating a milky coating that leads to mold. And even if you use an organic pesticide to kill them, their dead carcasses will create mold too.
The Solution: Do not remove plants infested with aphids, as they can just drop off that plant and onto others. Instead, turn a plumber’s torch on low and burn the plants where they are.
Everyone gets thirsty when it’s hot and dry outside, including those pesky leafhoppers dying to suck the sap out of your plants. And when they do, your hemp crops will endure clusters of leaf damage in the form of white spots. With larger infestations, those spots can lead to yellow, dying leaves.
The Solution: You can control an infestation of leafhoppers with Spinosadâ, a certified organic substance whose soil microbes effectively treat pests in the larval stage. Note that this substance presents potential harm to honey bees for the first 3 hours after application.
Tiny but ruthless, thrips are barely perceptible pests that threaten to pierce the cells of your hemp leaves and suck out all of their contents. Most common for growers with indoor hemp crops, thrips become a problem when they present in large quantities. You’ll also be more likely to attract them if you’re growing hemp nearby other crops.
The Solution: Because thrips flock to water-stressed hemp plants, the best way to prevent them is through sound irrigation practices.
Hemp plants can successfully withstand a small population of mites. But as soon as that number grows, these pests will pierce through leaves and suck the color out of them from the bottom leaves all the to the top. And as a hemp farmer, that means contending with weak, brittle foliage, damaged buds, and ultimately, a ruined profit.
The Solution: Interestingly enough, you can fight these sucking mites with other predatory mites.
Of all the things that went wrong in the 2019 hemp season, mold was at the top of the list.
Because moldy hemp plants lead to bud rot . . .
Which is an inevitable death sentence for your end product (and your profit).
“In certain regions, mold and mildew can become a serious issue for some farmers,” says Advanced Hemp expert Justin Pullin.
“Although an outdoor environment is in the hands of mother nature, we can still take preventative measures to help alleviate any issues that can arise. If you have the right system in place to accommodate for things like airflow, it can make a huge difference in health of your crop.”
The Solution: Some hemp farmers suggest rotating your crops to protect against mold buildup. However, the most proven method of prevention is purchasing mold-resistant hemp seeds from a vetted seller. And when you notice powdery mildew developing on your plants, prune them. If they’re already showing severe damage, you’ll want to part ways with them for the greater good of the rest of your crop.
Now, there are a number of reasons why some hemp farmers aren’t returning to the industry in 2020.
Chief among them, however, is the troubling reality of cross-pollination so many farmers contended with last year.
You see, when pollen spreads from surrounding hemp farms that aren’t relying on feminized seed, it can wreak havoc on your crop’s value. When male plants pollinate your female plants, they can longer focus on maximizing their genetic potential to produce high volumes of CBD and other chemical compounds. Instead, they’re busy focusing their energy on creating seed.
The last thing you need is a seeded-out hemp crop distracting your plants from developing big yields filled with sticky buds and valuable compounds.
The Solution: You can’t control prevailing winds that carry pollen from farm to farm, or hot and dry weather that encourages pollen to drop. You can, however, advocate for other hemp growers to use feminized seeds.
Talk to your neighbors so you can come up with a game plan for finding and culling male plants, as well as staggering acreage so each of your crops remains isolated enough to prevent cross-pollination.
When it comes to prevents mold, pest, and cross-pollination, preparation is the biggest to success.