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Warwood

Most of us growers who are south of 40 degrees latitude have to contend with this issue. Some, although more minimally, north of this latitude also. I thought I'd call it "Mr. Gummy" (take-off from Wallace's "Mr. Foamy"..lol..(funny name but not a funny issue), anyway....
I've been expecting like most years after we have a few hot, humid days with heavy dew and/or rain to see a little oily dark-brown spot on the outer edge of one or two leaves. I hope to have caught it early enough and have been doing the weekly sprays with Daconil..this week (Mancozeb & Kocide) seems to have halted it. Before spraying, I took out my Mr. Gummy kit (surgical scissors, plastic disposable gloves, Hydrogen Peroxide in spray bottle and Captan in a puffer bottle) out into the patch. I cut around the blackish lesion about an inch back around from the perimeter of the lesion. quickly sprayed the H2O2 then puffed with captan. I don't know if that will help but I thought it can't hurt. So far after this procedure and the spray no more Mr. Gummy. I will have to be diligent when the above conditions exist especially and preventive other than that. I believe the important point is to spray before heavy dews and before or during rainfall especially when hot and humid. I verified the disease by borrowing my grandson's microscope, researching some pics on the net. Yes,there were the conidiaspores looking like sprinkled specs of pepper within the lesion area/s. I then cleaned all tools, microscope and all with rubbing alcohol to sterilize everything. (cont'd)

6/5/2010 2:50:46 AM

Warwood

The interesting thing is that this is new ground. I understand after some research that the microspores (conidia) are transported in from especially southern winds and storms blowing in from the already hot and humid south. The spores land or come in from the rains/dews and connect to plant parts and start reproducing making black/gummy areas on leaves and stems. Also, it's important to keep your patch real clean of debris, weeds and anything the spores can ride in on or multiply on.
I bring this up of course to help any and all concerned and of course for any experts to chime in and give me/and all advice or direction. This is one of my major predicaments as well as preventing Fusarium and keeping groundhogs away. Any of which can quickly end a season of growing.
Questions:
1) Can anyone help further or add anything that would help all of us rid this problem?
2)I understand that Thiophanate methyl can assist with this problem as well. Does anyone know where I could purchase Topsin-M or a marketable substitute?
3) Anyone else troubled by Mr. Gummy?
Thank You, Don

6/5/2010 2:52:02 AM

[email protected]

Agrifos plus Mancozeb for prevention. Curative might not be possible.

6/5/2010 4:12:45 PM

Las Cruces NM

Actually, depeding on the effect/stage, I believe gummy stem blight is a common name ... but is perhaps more commonly called downey mildew. Anyway nice writeup ... cucurbits are heavily prone to various fungal diseases, so with that, see tremor short succinct response!

6/6/2010 8:52:16 PM