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Owensboro, Ky.

About 2 weeks ago one of my plants, 529 Brinkley, started a major wilting cycle. Every day about noon...very hot...the entire plant would wilt severely, and then recover at night. The wilting has now stopped on that plant and some slow growth has resumed...lots of yellow leaves left in the aftermath. Yesterday the next plant up the hill, 740 Simmons, did the major wilt and recovered yesterday evening. This pattern seems very bizarre to me. Any ideas or suggestions. Peace Wayne

7/9/2005 6:10:52 AM

Ctpumpkin@optonline.net

Wilting could be definded as the above ground parts transpiring moisture faster than the roots & vascular system can recover to the point the leaves & stems have lost turgor. The possible causes are many. Let's look them over.

We start with Abiotic influences.

> A soil moisture deficit is the easiest thing to diagnose. Too dry? Water.

> Soil moisture deficits can be mimicked by excess soil salts (sodic soils for too much fertilizer) that cause reverse osmotic pressure on the soil solution. This can reverse pull water from the roots & back into the saltier soil. Soil salts tests are cheap enough if this is suspected. If this is not the case, the next thing to look at is genetics.

> Genetic background influences some plants to handle heat/moisture stress better (ex: 845 Bobier) or worse (ex: 898 Knauss) than others. Knowing the parentage of the seed you're growing helps. Some areas of the "orange belt" benefit from misting &/or shading of plants during midday regardless of genetics though careful seed selection can make the best of stressful times. If no issue here, look to insects.

> Insect & Mite activity can either breach the vascular system (ex: Squash Vine Borer, Maggots, etc.) or remove vascular fluids to excess also causing cellular destruction (aphids, mites, cuke beetles, soil dwelling grubs, etc). If all insects can be rules out as influencing "wilt", the next are to look is fungal diseases.

continued

7/9/2005 9:14:05 AM

Ctpumpkin@optonline.net

> Biotic Diseases are the toughest wilts to diagnose. Bacterial Wilt is (mostly) insect vectored (Cucumber Beetles). Remove & pull a vine to breaking. Look for strands or threads that have clogged the vascular system.

> Fungal Root & stems rots are very difficult to field diagnose until long after the opportunity of treatment options is lost. Fusarium & Rhizoctonia can infect roots, stems, & fruit. Timing, plant parts infected, severity, weather, etc all impact how the disease is visually expressed. Lab diagnosis by a Plant Pathologist post-mortem might be the only option in some cases. Exhume some roots & observe their condition. Brownish spots, sunken areas, or steaks are bad. Firm, white & fleshy is good.

> Phyophthora is another soil-borne root disease that may demonstrate wilt symptoms. Exhume some roots & observe their condition. Brownish is bad, white & fleshy is good.

> Lastly, Root Knot & other Nematodes interfere with the productivity of a root system. Examine roots for unusual branching/knotting.

The farther down this bullet list one has to go before discovering the cause of their wilt symptoms, the more difficult the diagnosis & managemnet stradegy becomes.

Print this out & get in the patch. Hands & knees sluething is the only way. Tools needed are a growers diary, small trowel, magnifying glass, hands, eyes, etc. If all else fails, seek out your local cooperative extension agent.

I probably forgot something but this should get you started towards a solution. Keep this thread posted as to what is discovered as there are treatment options for every one of these issues *IF* the cause is discovered in time.

Steve

7/9/2005 9:14:10 AM

Macomb County

Another possible cause if you've ruled out disease and insects is are you watering only at the crown. If you're doing that and especially hit a hot spell, water often won't make it out into the vines far because it's being used and transpired by the leaves closet to the main root. Hence, you'll get wilting leaves until the day cools down.

7/11/2005 2:45:57 AM

Owensboro, Ky.

If I was watering at crown only wouldn't the first few leaves stay non-wilted? This is a total plant wilt. The strange thing about this problem is that it is affecting only one plant out of 6 in my patch at a time. The first plant affected is no longer wilting, although the 10 days or so of wilting has left 70% or so of the leaves badly yellowing. I will post what I found when investigation is done. Thanks to all. Peace Wayne

7/11/2005 6:37:27 AM