Powerdy Mildew

[Daily Vitamins]

And outdoor growing season comes to a quick end . I noticed powerdy mildew and I like clean buds so it’s going to compost or a fire I guess . Things were looking good . Sucks . See you all indoor I guess

 

[FellaAndrene]

Look into wollastonite and other sources of silica (rice hulls, vermiculite) you can use in your soil mixes.

W-10 grade wollastonite - the same as used in these studies - can be bought from ceramics shops.

Suppression of Hemp Powdery Mildew Using Root-Applied Silicon

Powdery mildew (Golovinomyces spadiceus) is the most common disease of greenhouse cannabis. Most hemp grown for cannabinoid production is propagated by cuttings or started from feminized seed in greenhouses and then moved outdoors, while most marijuana and some hemp are grown entirely indoors. To determine the effects of silicon on powdery mildew in the greenhouse, silicon was applied to hemp roots in a peat-based soilless mix and evaluated for plant uptake and disease suppression over a 6-week period. This study confirmed that there was a negative linear relationship between percent silicon accumulation in leaf tissue and the percent powdery mildew per leaf area. Mildew severity in the upper canopy was significantly reduced at 300 kg/ha of silicon, while 600 kg/ha was needed for the mid canopy. Results confirmed that silicon may be a useful tool for the integrated management of powdery mildew. As the cannabis market expands, silicon can serve as a viable option for greenhouse growers, especially for plants grown in soils or soilless mixes low or limiting in soluble silicon.

Approaches to Supplementing Silicon in Soilless Media and the Value of Silicon in the Mitigation of Drought Stress

Silicon (Si) is not considered an essential element for plants to complete their lifecycle, but is known to be beneficial for plants under environmental stress such as drought. Unlike natural soils, Si is minimally bioavailable in soilless media. With indoor agriculture and greenhouse production increasing, the benefits of Si have been seen and Si should be supplemented. This work aimed to characterize and quantify the dissolution of Si from media substrates and additives to achieve a steady-state release of Si in soilless media. Typical media components such as coconut coir, peat moss, perlite, rock wool, sand, and vermiculite minimally released Si and depleted within 60 days. Wollastonite, a calcium silicate mineral, and rice hulls steadily released Si in water. The dissolution of wollastonite rapidly released bioavailable Si in peat-based media, but decreased over 120 days while rice hulls gradually released. Both amendments increased coconut coir and peat-based media pH. Either would provide bioavailable Si over the lifecycle of many crop species. To test the dissolution of Si, wollastonite was used to amend peat-based media to grow Cannabis sativa L. under precision drought stress. Precision drought stress can be a useful method for growers to maintain plant size and photosynthetic rates, but it is a sensitive system to balance. We hypothesized that Si would increase the resiliency of Cannabis in this system under drought stress. Although Si supplementation did not increase tolerance of Cannabis to drought stress, Si supplementation inhibited powdery mildew (Golovinomyces sp.), a common fungal disease in outdoor and indoor production, in all three trials compared to Si non-supplemented treatments. Silicon is a beneficial nutrient for crops that should be supplemented in soilless media to increase tolerance to environmental stress such as drought stress and biotic stress such as fungal disease, but requires further study.