The roots of your marijuana plant play one of the most critical roles of the plant's success. Healthy roots are incredibly important in order to have a happy plant and can have large impact on the final outcome of your grow.
Root pests can be overlooked because they are much harder to spot then leaf pests. Sometimes these underground nuisances are only diagnosed during a transplant or when the infestation is severe enough that the vitality of the plant is diminished.
Fungus gnats, for example, are small black flies that lay their eggs in damp soil. When the eggs hatch, the white writhering larvae can be found near the base of the plant stem and they also dig down amongst the plants roots and eat the small root hairs. It is not until the infestation becomes severe, that the plant will start to show signs of nutrient deficiency as it is unable to uptake as it should. However even a small infestation can have an impact on final yields, though the plant may show no signs of distress. Fungus gnats are also known for spreading plant disease.
Another soil dwelling pest to be on the look out for is the root aphid. Aptly named, the root aphid is a cousin of its canopy dwelling look alike. These round bodied underground pests eat the roots and multiply quickly making them a formidable foe. They can be hard to detect as they will tend to blend into their surroundings. The health of the plants will decline slowly and can mimic other plant issues.
Here are some of the signs and symptoms that may indicate you have a problem with a root pest.
- Sudden wilting or yellowing, especially if it is just single branch and the others look healthy.
- A chalky, powdery substance at the top of your root zone.
- Black, sooty mold on stalks or stems, or at ground level where your plant’s main stalk emerges from the ground.
- Small winged adult flies that are stirred up when the plant is moved.
- Plants appear to have nutrient deficiencies even though the feeding program has no issues.
- Down in the soil small wiggling worm-like insects may be found.
- Root rot, or discolored roots.
A hydrogen peroxide (H2O2) flush done in small amounts can help treat root pests. While this treatment can be successful, using too much can damage your plants. There are premixed products available such as ZeroTol that can help take the guess work out of dosage amounts. Keep in mind that any hydrogen peroxide based product will also kill any beneficial microbes that are in your soil.
Beauveria Bassiana is a fungal contact insecticide and living organism that acts like a parasite infecting different types of pest bugs. Some common brands are: Velifer, Botanigard MAXX, and Mycotrol. There has been some preliminary research that shows Beauveria Bassiana will also help the beneficial insects as it will weaken the pests allowing the beneficials to more easily kill and consume them.
Benefical insects that can help with root aphid prevention are: Nematode Steinernema feltiae and Hypoaspis Miles. Chrysopa Carnea will clean up any adult fliers. For fungus gnat prevention/treatment we recommend: Nematode Steinernema feltiae, Atheta Coriara, and Hypoaspis Miles.
As with all cannabis pests, prevention of root pests is very important. A small amount of beneficial bugs before there is an outbreak is more cost effective than treating an infestation in the later stages of your plant's life cycle.
Biobloomed offers simple recommendations to full blown integrated pest management programs for free. Contact us for more information.