In this article:
- Grasshoppers in general
- How to recognize a grashopper infestation?
- How to treat grasshoppers on your cannabis?
When growing outdoors, grasshoppers can be very dangerous for cannabis plants. They love to eat them and are able to destroy them very quickly. When they eat, it’s often at night time which increases the chance for them to destroy a complete yield without you noticing it.
Grasshoppers do not only eat the leaves of a plant, they also like the branches which makes it possible for them to destroy a whole plant in just one dining session (by eating the main-stem). Next to that they are able to infect a bigger area but could also travel a big distance by themselves.
Just like most pests it’s important to act quickly once you have spotted them, or even better: Avoid them from coming to your plants!
Grasshoppers will almost never be alone. On a hot summer day you can hear hundreds of them making their famous chirping sound. Together, they are known to destroy farmers crops very quickly and in some countries they are a true plague. Just one female grasshopper is able to lay up to 400 eggs which will hatch in late spring.
Because they like to eat at night, have a good camouflage and are able to move quickly, it’s sometimes hard to catch them red handed. However, there are enough signs to know your plants are under threat by them. The most important one is the damage they leave on your plant. Recognizing it on time is the key to avoid that your plants are being eaten.
The damage that grasshoppers leave is pretty similair as the damage many other pests leave, so sometimes it’s hard to know which type of bug is eating your plant. However, the combination of the leaf damage with other factors can tell you what bug is exactly eating your plants:
- Very dry conditions + leaf damage is a sign of grasshoppers
- Leaf damage in the start of the season (when most bugs aren’t active yet)
- Only punctured damage on leafs is a sign of grasshoppers (They like to start eating in the middel of the leaf, lot’s of other bugs start from a side)
- Their famous chirping sounds around your growing area + leaf damage
- Leaf damage turning up quickly. (Grasshopper are big and quick eaters. So if lot’s of damage is being done overnight, there is a big chance of grasshoppers)
- Grasshoppers prefer to feast on cannabis seedlings. So if there are seedlings among your plants, and only they get eaten first. You are probably dealing with grasshoppers.
Grasshoppers do like to hang out at the branches/stems after they have been eating. So if you spot any leaf damage, make sure you also check these areas.
There are many methods on how to treat an grasshopper infestation on, and around your plants. However, it’s always better to prevent grasshopper coming to your plants, then it is to start treating them after some damage has occured.
So avoiding them from reaching your plants is the first thing to look at:
1. Keep an eye out for them
When growing outdoors, you should always watch your plants very closely! (daily). Not only for grasshoppers, but for every pest, bug and possibly fungus. The best way to treat a pest, is to recognize it on time!
In the case of grasshoppers, you should pay attention to the weather conditions, noise they make and checking the plants yourself. Grasshoppers become active once the weather get’s hot and the air dry, so thats when you need to check your plants more often then normally.
Next to that, the sound they make is very remarkable. Grasshoppers often come in big groups. So if you hear them all chirp when you are at your plants, it means they can easily reach your plant. If they do and you find them, take them off as quickly as possible!
2. Using “row covers” to keep them away
Row covers might not be the #1 choice for some cannabis growers, because it could interfere with humidity levels and other climate factors. However, to keep harmfull bugs (like grasshoppers) away, it works great! Next to that they that they are pretty cheap.
Row covers are often made out of very small netting that doesn’t way much. That is why you could just draw it over your plant without bothering it. However make sure this doesn’t leave any “wet-spots” on your plant as this might cause mold to grow. In that case, build an simple “greenhouse” out of sticks and the row cover.
Once your plants get too big/high, it becomes harder to fully cover them with the netting and you should look for other methods.
1- Spinosad products
Spinosad is an 100% natural and organic pesticide that will effect the grashoppers nervous system and eventually kills it. Only contact or ingestation with Spinosad is enough for an grashooper (or other bug) to die. You should spray this product all over the plant and anywhere a grasshopper is able to come. Spinosad products often only work for 24 hours, so respraying the plant is necessary.
Spinosad is made from a special fermentation of soil bacteria called: actinomycete Saccharopolyspora spinosa. This organic product might not work as aggresive as other pesticides but is still very effective for grasshoppers and extremely safe for humans, pets and plants.
Another great thing for outdoor/organic growers is that this product is specifically harmfull for certain bugs like Aphids and Grasshoppers and less for other insects. So you can combine this spray with ladybugs without harming them.
2- Insecticidal soaps
An often used product for grashoppers is Insecticidal soap. This special spray is safe and weakens the outer shell of a bug, eventually drying them out. These soaps won’t leavy any residue on the plant and wash off easily. Thats why you need to make sure to apply it properly and multiple times on the plant (always avoid the buds, even when it’s safe).
3- Neem oil
Neem oil is a 100% natural and effective remedy to treat many different pests so you can use this for more then only grasshoppers. However, it also has some downsides to it:
Neem-oil often leaves a very unpleasent smell that eventually could affect your cannabis. So make sore NONE of it reaches your buds. This could really ruin them! Next to that, there is some evidence that Neem-oil could be harmfull to people. Another reason to keep it away from your buds!