Once enough of the root system has been chomped away, symptoms such as problems in the leaves and slow and abnormal growth can occur. The worst outcome from a fungus gnats infestation is the death of one or all of your cannabis plants.
If you are growing marijuana outdoors, you have much less control over the conditions when compared to an artificial indoor environment. However there are numerous ways to prevent fungus gnats from munching on your crop. One option is to sterilize your potting soil to make sure no pesky eggs are laying in wait. Some growers go so far as to employ predatory insects to annihilate those that are preying on your weed. Planting garlic and onions in close proximity to your plants can form a defensive shield that wards off predators also. For more tips on protecting your outdoor cannabis crops, see The Basics of Cannabis Outdoor Growing.
Secondly, as discussed, analyze your watering methods. Cease watering your plants until the top soil has dried out. This will bring down the amount of fungus in your soil and starve the larvae. To speed up the drying process direct a light fan at the topsoil.
Applying neem oil to your soil is a good way to tackle the problem. It has been shown to be very effective at clearing fungus gnats and other pests that might be lingering. Sprinkling food grade diatomaceous earth onto your soil will help too, as it is a natural and organic insect killer derived from fossilized shells.
Every grower desires optimal yields of massive buds from their marijuana plants. Fungus gnats are a factor that can damage this outcome. However there are numerous ways to protect your weed from this pest.
Prevention is better than a cure. This is because such measures can protect your marijuana plants from ever having an infestation to begin with, saving you the time and money of dealing with fungus gnats once they are in place.
Growing cannabis is an incredibly rewarding and therapeutic activity; it could even be called an art form. However, like everything in life, it does not come without its trials and tribulations. One of these challenges is the pesky fungus gnat. These minute critters are no bigger than two millimeters in length, but don’t let their size deceive you. They are capable of pumping out two hundred eggs per week, and their primary target is the bottom of your marijuana plants. This location also happens to be home to one of the most important aspects of weed anatomy, the root system responsible for mineral extraction and water absorption. Therefore it is easy to see how this mischievous invader could trigger some pretty big problems.
Inspect your weed plants daily. As well as taking time to witness their beautiful aesthetics and aromas, take a quick check to identify any possible fungus gnats symptoms. The sooner you find out they are there, the faster you can remedy the problem.
An obvious sign of an infestation is seeing fungus gnats buzzing around your precious weed plants or crawling through the soil in which they live. However, due to their tiny size this can be easy to miss until it is too late and problems start to take effect. Other signs to seriously look out for are pale leaves, brown edges on leaves and dark spots that occur on leaves. Other signs include leaf drooping, twisting and yellowing. Whole plant symptoms include stunted bud growth, slowed root growth and overall wilting.
Protect your weed plants by learning how to prevented and treat fungus gnat infestations
If we choose chemical insecticides – and we always suggest their responsible use as a last, desperate choice because of possible negative effects on other living beings and the environment – we can try Diazinon, sold by various brands, or some imidacloprid-based insecticides for cannabis (use half the dosage indicated by the manufacturer and check results). Usually, a single application – or two at most – will be enough to eradicate the pest.
Adult specimen of a black fly
Neem flour is an effective control method of this pest. This product is ideal to combat pests in the substrate, whether flies, larvae or any other insect are feeding upon the roots. After watering the plants, pour neem powder on the substrate until forming a thin layer. This layer “seals” the substrate so no adults can lay eggs on it, and no larvae can emerge from it.
The typical symptoms of this pest are a slowdown of the plant’s growth, sometimes followed by fungal infections as the aforementioned Pythium or others such as Phytophtora, Fusarium, Verticilium or Botrytis.
The scent of mint repels fungus gnats
As happens in many cases, this plague can cause direct or indirect damage to the plants. Larvae mainly cause direct damage: they feed by chewing the fine root-hairs, thus affecting nutrient uptake and increasing the chances of fungal infections in the roots like the feared Pythium. Indirect damage is caused both by larvae and adults, leading to diseases, virus infections, or fungal growth.
With regard to biological control, we have several alternatives. We can use Steinernema feltiae, a microscopic entomoparasitic nematode that feeds on insects without affecting plants, animals or the environment. Another option is the predatory mite Hypoapsis Miles or the beetle Atheta Coriaria, both efficient weapons against this pest, especially larvae.
As we have said, sciarid flies require poor lighting and humid, warm conditions for proper development and reproduction. After the pairing between male and female, they lay around 50-200 eggs in the substrate, which hatch after 48-72 hours under favorable conditions. Then, and during the next 2-3 weeks, the larvae pass through four different development stages before reaching the adult stage. In its last stage, larvae are white with black head, and measure approximately 5mm in length.
On this article you’ll learn about fungus gnats, a very common pest in greenhouses and indoor grow rooms. We tell you how to identify, manage and erad