Originally Posted by Sam_Skunkman
In my experience PM is linked to WLD varieties and their hybrids. (Wide Leaf Drug)
Use NLD varieties as they have lots of natural resistance to PM.
You can attempt to find WLD hybrid varieties that have higher resistance, I suspect it will not be easy. Some terpene expressions seem linked to higher or lower resistance also.
Lots of growers have knocked back PM issues getting their metal levels higher in the soil and the plant, most specifically Mn, Cu and Zn. All of which in sulfate form qualify as organic.
Most composts, worm castings and manures are loaded with Fe, causing massive balance issues against the other metals. Where you have Fe=>Mn, you can add 50 to 200% yield increases.
Without that ratio being close, the plant won't complex simple sugars, meaning that active production is greatly reduced due to a simple balancing problem.
Maui is one of those places where Mn>Fe by the way.
When there is not enough Ca, the cell walls are not as strong as well. Everyone that has gotten their soil analyzed (see the slownickel lounge thread) has had way too much K vs Ca.
Love your posts by the way!