Wilcox County Ag

Row Crop Disease Update

Older silks may turn red, but some varieties are red also

Here is our corn in the field. It is silking now and may have less issues than any other crop right now. Sunshine is helping with pollination. Silks come out of the husks over 3 to 5 days. These individual silks continue to grow for about 7 days or until it finds a pollen grain. Once a pollen grain from the tassel lands on a silk (pollination), a pollen tube forms and it takes about 24 hours to grow down the silk to the ovule (fertilization). Then the ovule becomes a kernel.

Here is a good image Kevin Phillips with Pioneer showed me where the silks are not pollinated if they hang on to the kernel.

Silks hanging on to kernel are not yet pollinated. Photo by Kevin Phillips

This time is also very important for kernel development and yield. We don’t need additional stress at this time and during the next 2 weeks. It can reduce the number of kernels per ear.

Below is an update from UGA Extension Pathologist Dr. Bob Kemerait on diseases in current row crops:

CORN No southern rust has been found in Georgia to date.  Apparently, there is not a lot in Florida either.  Spores from Florida are typically a threat to our corn crop.  Little disease there means lower risk here in Georgia.  Jason Brock and I are seeing a fair amount of Northern Corn Leaf SPOT, Southern Corn Leaf Blight and some Northern Corn Leaf BLIGHT on samples that have been submitted.  To date, most of the disease has been confined to the lower, older leaves and little seems to be aggressively spreading.  I am seeing a fair amount of CORN SMUT (Ustilago maydis).  This can cause some loss on a susceptible variety, but is often cosmetic.

MANAGEMENT for CORNStill not southern rust, but conditions are perfect.  Still not sounding the alarm for fungicide application; however many growers are spraying because 1) conditions are perfect, 2) they are worried about missing it, 3) corn is at tassel or beyond and 4) if we do need to spray quickly it may be tough to line up a plane.  Again, I am not calling for general sprays because the rust disease has not been found here and it not rampant in Florida.  However, caution is the better part of valor in some situations.

Early Leaf Spot found Tuesday above Pitts

PEANUTSStill getting reports of Aspergillus Crown Rot in some fields.  Often times linked to farmer-saved-seed.  Tomato spotted wilt is showing up; it remains to be seen just how bad (or good) it will be this year. Conditions are now PERFECT for white mold. Soils are moist and heating up and many are getting afternoon rains.  TIMELINESS IS CRITICAL.  DO NOT GET BEHIND ON WHITE MOLD OR LEAF SPOT THIS YEAR!

Conditions are very favorable for development of peanut leaf spot diseases; reports of leaf spot being found are starting to come in- yesterday from Andrew Sawyer in Wilcox County.

COTTONBacterial blight was found on NG 5007 in Macon County.  Bacterial blight has been reported on DP 1747NR from Irwin County and also Colquitt County.  Bacterial blight is reported on PHY 444, DP 1646 and NG 5007 from SW Georgia, thanks Andrew.  BOTTOM LINE: Conditions have been PERFECT for bacterial blight this year and outbreaks this early are of serious concern.  All outbreaks have been on varieties we know to be at least somewhat susceptible.  Noting can be done now about bacterial blight. Growers should avoid moving tractors and equipment through those fields when plants are wet.

COTTONSignificant Fusarium wilt is being reported from Colquitt County.

Fusarium Wilt in Cotton

SOYBEANS: No soybean rust found to date in Georgia.