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nanaimo,B.C,Canada

What are most growers doing with there leaves that have powderey mildew on them? Are you composting them,tilling them into the garden,or discarding them all together.

Dave

9/15/2003 5:52:50 PM

Bobcaygeon Ontario

Burn them and put the ashes in your garden if you can. Otherwise get rid of them. Doug

9/15/2003 7:18:13 PM

nanaimo,B.C,Canada

What about the vines,will they also be infected with the mildew?

DAVE

9/15/2003 8:18:13 PM

churchville, ny

I have been using the same plot of land for 15 years. I hand pull every vine and leaves off the ground and either burn or dispose of everything. Why take a chance of leaving any disease in the soil Tom

9/15/2003 8:22:40 PM

[email protected]

There is little or no threat of reinfecting the patch with PM infected leaves. The more aggressive warm weather version of PM (Sphaerotheca fuliginea, the one the troubles AG's the most) is spread primarily by airborne conidia that come only from actively growing infected plants. The causal fungi are obligate parasites and cannot survive in the absence of living host plants. Conidia that lands on the ground dies there. So most of the infection we see up north is thought to originate from actively growing plants growing to our south that are infected & bearing the live conidia.

It is currently thought that since there is always an infected plant in active respiration somewhere in the world, all new infection is coming from these plants in a never ending cycle.

In other words, we have already spread our conidia long before our leaves have shriveled. Turn about is fair play!!

Don't waste time burning unless you enjoy it. Till the debris under if PM is all you're concerned with.

Steve

9/16/2003 6:39:11 AM

Oz

does pm live on any other type of plant?

9/16/2003 9:18:18 AM

Garden State Pumpkins

should see my Lilacs!!

9/16/2003 9:45:05 AM

Sequim, WA

Feed the to the cattle. Pastures still really dry, not much green there.

9/16/2003 10:50:48 AM

[email protected]

This PM infects all forms of cucurits. Melons, Canteloups, Pumpkins & Squash. I do not believe it is the same causal pathogen as infects Lilac. So don't cut them down yet Chuck. I'll snoop around & make sure. Just looking for a good excuse to cut ours down. LOL.

Steve

9/16/2003 6:55:17 PM

Itzetown City

Tremor, is the soil in CT so contaminate so that spores of fungi died when tuch the ground?

Spore of fungi keep alive for a long term everywhere also in the seeds of a plant. They germinate if the basics are right for them.

As we talk about false PM the most hostplant is lilac and elderberry. Take care of these plants and grow these plants not to near to pumpkin plants.

Our agriculture university and the old people say: "Remove the leaves of potatos, tomatos and curcubita from the soil and dont bring it in to the compostheap so the pathogens can not passed on to the next generation of plants. Better is to change the patch all year if growing these veggies."

You have right, the most spores came from hostplants with the wind in the right weathercondition. But if we can reduce the infectionrate by burning the leaves or give them to the garbage dump, why not?
It will save copper, in both way. ;-)
My 2 (copper)cents.

9/17/2003 3:27:28 AM

[email protected]

No the soil here isn't contaminated. Not too far from here it is but that's another story. LOL

Spores do not live anywhere they want. The fungal disease triangle include the following 3 requirements or disease doesn't happen.

1.) Causal Pathogen
2.) Suitable Environment
3.) Succeptible Host

Take even one of the three away & we have no disease. Period.

*SOME* foliar diseases can be from soilborne pathogens. But Powdery Mildew isn't one of them. As I stated previously, PM is transmitted to uninfected plants by *airborn conidia only*. And the conidia can only survive on *living* green tissue of a succeptible host plant. Not soil. No green plant material of the required host & the PM conidia dies.

Now of course there are plenty of other diseases that can & are spread by sclerotia, pycnidia, or other dormant resting spore types that can reside in soils. When a disease of this sort is what you're dealing with, then proper field sanitation is a must. Burning plant debris is helpful in these cases. But to suggest that all diseased debris will be collected & burned is not realistic. Helpful yes. But not 100%. Some diseased parts will always be missed.

continued________________

9/17/2003 8:15:24 AM

[email protected]

This is why Basamid is becoming so popular among growers who have trouble with soilborne diseases. It is not usually practical for us "hobbyist growers" to let fields lay fallow for the time required to discourage soilborne disease. Some also live too long for this approach to be practical. And crop rotation would lead to taking the year or years off from growing AG's. So...........

At any rate, Powdery Mildew infected leaves can be tilled under with no impact on the following year other than the return of organic & mineral elements that were taken by the plant (a good thing). Assuming there are no other disease present that would give rise to other strategies of course.

The key is to know the diseases we're dealing with & acknowlege that a control strategy for one might be completely unreliable for another.

Steve

9/17/2003 8:15:37 AM

Cologne / Germany

My only soilborne desease returning each year is called "weeds".

9/17/2003 8:39:34 AM

Itzetown City

Weeds in our patch are come in airborne, the little parachuters from the neighborgarden as there are dandelion and thistle.

9/17/2003 9:03:45 AM

Southern WI

This brings us back to floh's question, while the plant is still alive, do we remove the infected leaves, will the plant continue to grow?

9/17/2003 9:20:32 AM

[email protected]

I stopped in to my son's school today. We have 3 such diseased marvels there. The Powdery Mildew is so bad (I can't spray them there) that we haven't even 10 full leaves left out of 3 plants. I have never in my life seen pumpkins with this much PM. And there are NO leaves before the fruit at all. I've either grown or been around growing pumpkins since 1970 & have never seen anything like those poor diseased wreched specimens. LOL In this case, there has been no measurable growth in OTT for the past 3 weeks.

Steve

9/17/2003 9:56:54 PM