Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Archive for May, 2012

Question of the Week – Little Blue Heron

Posted by romeethredge on May 31, 2012

Last week I had a bird identification question.  It was a Little Blue Heron.  It stands 24 inches tall and is fairly common. It feeds by wading slowly and getting small fish. Its young is white colored. The bill is pale blue with a darker tip.

This week I saw this large spider in a corn field with it’s web between 2 stalks of corn. It already had one insect beside it and I hope it will provide us with some biological control of the stinkbugs out there.  What spider is this?

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Peanut Burn

Posted by romeethredge on May 31, 2012

Peanut burn is common on older peanut leaves due to the in furrow insecticide, usually phorate aka thimet, that is moving through the plant.  After a rain or irrigation the chemical moves into the plant and in doing its job to control thrips it causes some burn to the plant and can even cause some leaf drop. The burn is usually on the leaf edges and can be confused with leafspot. It will grow out of this injury soon.

 In the botton photo, Philmore Higginbotham is in his peanut field checking for thrips injury earlier this week.  He was in good shape as his in furrow insecticide was working well.  Thrips need to feed on the plant to ingest the chemical to control them so even with good control you will still see a little feeding damage.

Also, down there near Desser they have received pretty good rains recently.

Posted in Entomology, irrigation, Peanuts, Plant Pathology | Tagged: , , , | 1 Comment »

Plant Disease in Georgia

Posted by romeethredge on May 31, 2012

Considerations for Disease Management for Row Crop Diseases

Here’s a great plant disease update from Dr. Bob Kemerait, UGA Plant Pathology.

 

This Memorial Day Week is an EXCELLENT time to both assess disease management strategies in your row crops and to assess the risk for the diseases themselves.  The importance of this week is based on two critically important factors- crop development and the passage of Tropical Storm Beryl.  Even those growers who did not receive a drop of rain from Beryl should still consider disease management now- if for no other reason than winds from the storm may have moved fungal spores over long distances and dropped them literally in their laps.

 

Whether you have corn, cotton, peanuts, or soybeans in the field now and received some rainfall and cloudy conditions from Beryl, then the risk of fungal diseases in your field increases.  One factor is that the rain and subsequent cloudy weather, coupled with high humidity, have created near-perfect conditions for the formation of spores on existing spots and lesions.  Also, raindrops hitting last year’s crop debris could also send spores to infect lower leaves of the crop.  A second factor is, obviously, that the spores that detach from the spots and lesions and land on other leaves also have near-perfect conditions for infection to occur.  Extended periods of leaf wetness significantly increase the chance that a spore that lands on a leaf (or other suitable tissue) will infect.  A third factor has been the wind.  On the level of a field, the mechanical action of leaves brushing up against one another coupled with the mechanical dispersal of rain drops hitting the leaves will send spores from one leaf to another and perhaps beyond. Even if you didn’t receive a single drop of rain from Beryl (wow….) your crop is still at risk from long spread dispersal of spores like southern corn rust and Asian soybean rust.  For example, rust spores could be carried in upper air currents from Florida and deposited on the crop; cloudy weather reduces UV radiation and further increases the potential of the spores to survive over long distances.  Bottom line: I believe that it is very likely that many fungal infections developed in our crop over the past 48 hours; a week from now we may very well begin to find outbreaks of diseases that would have been much delayed had Beryl not blown our way.

 

So what to do?  The first thing I will recommend is for every row crop grower in the path of Beryl to consider what benefit a fungicide could provide at this time.  NOTE- I DO NOT SAY that every corn, cotton, peanut or soybean grower should spray!  Simply, conditions are now favorable for the spread of important diseases of each crop.  Below are some examples:

 

Peanut- If your crop has not reached 28 days after planting, I would not be too worried about leaf spot diseases, unless you are planting peanuts behind peanuts.  A short peanut rotation will increase the risk for early outbreaks of all diseases.  White mold?  Yes- that could be a problem early this year.  Warm temperatures early in the season coupled by an extended period of moisture could further ignite a white mold epidemic.  Bottom line for peanuts?  I probably would not change much in an already sound peanut fungicide program, other than to perhaps initiate the program a bit earlier.  And where leaf spot disease is already in a field, consider use of a fungicide with curative activity (Headline, Tilt/Bravo, Stratego, etc.) over a pure protectant like chlorothalonil alone.  Last couple of notes on peanut:  A) so far, tomato spotted wilt has not seemed to be a bad as I thought it might be- growers are doing an EXCELLENT management job!  B) Cooler, wetter weather will certainly help to reduce the threat of Aspergillus crown rot on young seedlings.

 

Corn- Much of the commercial corn crop has reached tasseling or will do so quickly.  I believe that “tasseling” is an important growth stage where growers need to consider the need for a fungicide; tasseling is NOT the time for an “automatic” application for each and every grower!  For example, I believe that some small amount of northern corn leaf blight can be found in the majority of fields in the state but this alone does not necessitate a fungicide application.  Short corn rotations, a more susceptible hybrid, and wet, windy weather will increase risk to the disease and the grower should be prepared to make an important decision.  It has been my experience that unless a hybrid is especially susceptible to NCLB, this disease does not “explode” in a field like rust does.  Still, after a passing storm and extended leaf wetness periods, the disease could develop quickly in fields at risk.  In such cases, TIMELY applications of a fungicide with curative activity (triazole fungicides) will be more beneficial than a protectant fungicide alone.  Benefits of a triazole/strobilurin mix?  Extended protective window and curative activity.  Bottom line:  with Beryl, conditions for diseases in corn are enhanced in south-central and southeastern Georgia.  This simply further increases risk; an increase that growers should consider in their decision to spray (or not).  If a grower has sprayed a fungicide and is considering an additional spray, he or she should assess the level of disease in the field prior to the storm and the time since the last application.  FINALLY- With the passing of Beryl, we will continue to closely monitor the potential for introduction of southern rust with the winds.

 

Cotton- Where rainfall was abundant (it wasn’t in Tifton) growers could see some temporary increase in seedling disease.  Also, the same wet weather could produce outbreaks of Ascochyta “wet weather” blight which also should be of only temporary importance.  I am most curious about the impact of the weather on Corynespora/target spot.  In fields where the disease has occurred in the recent past, the falling rain could splash the fungal spores from the soil to the leaves of even young plants.  Will this happen in 2012?  I don’t know but I strongly advise growers who find spots on their cotton at any growth stage approaching first square (and beyond) to have it diagnosed quickly.  As always- the best way to manage a disease like Corynespora/target spot is to protect the crop early before it becomes established.

 

Soybeans- Asian soybean rust is known to be active on kudzu just across the Georgia-Florida line in Leon and Gadsden Counties.  It has not yet been found in Georgia; however I expect it will be sooner rather than later.  Once the disease is found, soybean producers in surrounding areas should protect their crop by the late bloom stage.  As in southern corn rust, UGA Cooperative Extension is monitoring the introduction and spread of soybean rust closely and results can be found at www.sbrusa.net.

 

Posted in Corn, Cotton, Peanuts, Plant Pathology, Soybeans | Tagged: , , , , | Leave a Comment »

Corn Scald

Posted by romeethredge on May 30, 2012

Lots of Corn Scald is showing up this week. Mike Johnson of Agri AFC here is looking at some scald at the edge of the field. It’s often seen at field edges. This is where corn is stressed and where heat and wind and dry conditions can affect it worse. Often the irrigation end gun just barely wets some of these areas. I think under very hot conditions the little bit of water some end guns put out cause it to be worse, almost like a magnification of the sun. Definitely the water on the overheated, stressed leaf is a problem.

Posted in Corn | Tagged: | 1 Comment »

Stink Bug Alert

Posted by romeethredge on May 30, 2012

I took off for Memorial Day but the stink bugs decided to really go to work early this week.  Yesterday a lot of stink bugs were found in many fields.  Most of what I saw were brown stink bugs but other types were present as well.  See the stink bug here near the young ear that is very susceptible to damage at this point.  Further down you can see Payson Trawick checking out some of their corn.  He’s helping his father and grandfather with their corn fields.

 

 

 

 

 

 

 

 

 

 

 

 

 

Posted in Corn, Entomology | Tagged: , | Leave a Comment »

Wheat Harvest – Test Weights

Posted by romeethredge on May 27, 2012

Wheat harvest is finishing up on most farms. Here’s some wheat being combined on North American Farms near the Donalsonville Airport. Yields have been pretty good but Test weights have been variable. Dr Dewey Lee, UGA Scientist has a good discussion concerning this on his blog at this link  http://georgiagraincrops.com/disease/wheat-yield-and-test-weights-vary-in-2012   Some causes he points out are: Rain wetting mature grain before we could get it out, vernalization (getting enough cold), stress during grain fill, disease presure, and winter temperatures.

Posted in Agriculture, Wheat | Tagged: | Leave a Comment »

Cotton Planting Nears End

Posted by romeethredge on May 25, 2012

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Some folks are through planting cotton and many are almost done. Stephen Houston Jr is here planting some cotton after wheat and canola has been harvested. Stands of cotton look good mostly with a few problems around. Some replanting going on as usual but it’s a much better situation than last year.

Thrips have been bad and here’s some information concerning thrips and emerging cotton from the 2012 UGA Cotton Production Guide.

With good soil moisture and warm temperatures at planting, seedlings usually begin to emerge in

5 to 7 days with full stand in 8 to 11 days, but can be delayed or complicated by seedling diseases

or rapid moisture depletion. Physical hazards to establishing stands that occasionally occur

during this period include hard soil crusts and blowing sand. The adverse effects of both can be

greatly reduced with rotary hoe or rolling cultivator operations. These implements should be

operated just deep enough to break the crust. An irrigation of 0.3 to 0.5 inches can be used to

soften or weaken a crust and accomplish the same objective. Timing this operation is critical. If

a hard crust is evident when the seed root is 0.6 to 0.75 inches long, it should be broken

immediately, being careful not to completely uproot more than 20 to 25 percent of the seedlings.

Soil crust strength can be measured with a small pocket penetrometer. Emergence decreases

rapidly at soil strengths above 10 psi when cotton is planted deeper than 1 inch.

Thrips Management

Thrips are consistent and predictable pests of seedling cotton that infest cotton at emergence.

Thrips initially feed on the lower surface of cotyledons and then in the terminal bud of developing

seedlings. Excessive feeding results in crinkled malformed true leaves, stunted plants, delayed

maturity, reduced yield potential, and in severe cases reduced stands.

At-plant systemic insecticides provide consistent yield responses and are used by most

growers for early season thrips control. In-furrow applications or seed applied systemic

insecticides are taken up by the plant as it germinates and develops providing protection during

early growth stages.

Supplemental foliar sprays may be needed if environmental conditions are not conducive for

uptake of at-planting systemic insecticides or if heavy thrips infestations occur. Systemic foliar

insecticides should be applied to cotton which had an at-plant systemic insecticide when 2-3

thrips per plant are counted and immatures are present. The presence of numerous immatures

suggests that the at-plant systemic insecticide is no longer active. If no at-plant thrips insecticide

is used, multiple well timed foliar applications will be needed.

The following factors related to thrips biology and ecology should be considered when planning

thrips management programs:

• Thrips infestations are generally higher on April and early May planted cotton compared

with later planting dates.

• Thrips infestations are lower in reduced tillage systems compared with conventionally

tilled systems (winter cover crops should be killed at least 3 weeks prior to planting and

no green vegetation should be present at planting).

• Seedling injury and potential yield impacts from thrips feeding are compounded by slow

seedling growth due to cool temperatures or other plant stresses.

• A rapidly growing seedling can better tolerate thrips feeding.

• Seedlings become more tolerant of thrips feeding as they develop; small seedlings (<2-

leaf) are more sensitive to thrips injury in terms of yield loss compared with 3-4 leaf

seedlings.

• Slow growing seedlings will remain in the thrips “susceptible window” for a more

extended time compared with a rapidly growing seedling; it is unlikely that seedlings

which have reached the 4-leaf stage and are growing rapidly will benefit from

supplemental foliar sprays.

Posted in Cotton, Entomology | Tagged: , | Leave a Comment »

Corn Progressing

Posted by romeethredge on May 25, 2012

Corn is really progressing and looking very good. It’s silking and silks are drying in some fields, where pollination is done. It’s been a real job to keep the water on it.

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Question of the Week – Raccoon

Posted by romeethredge on May 25, 2012

Raccoons love corn. Last week I had a photo of raccoon tracks coming out of a corn field. I’ve seen many raccoons come out of  corn fields.  They love to eat it in the milk stage, and will actually often shuck it before eating it.

This week we saw this bird in a pond next to a corn field. My son Jesse took this photo. What is it?

Posted in Corn, Wildlife | Tagged: , | Leave a Comment »

Northern Corn Leaf Blight (NCLB) Update

Posted by romeethredge on May 25, 2012

NCLB is getting worse in some fields but is moderate to low in others. See photo below that shows a bad field.  Here’s a link to a TV  news story we did concerning NCLB http://youtu.be/TgREN1WLF7Y

It’s going to be on a field by field basis that control decisions should be made. A factor that enters into the mix is stink bug pressure since both problems can be treated with a spray. We have not seen a lot of stink bugs this week ,  however yesterday I saw 2 sets of hatchouts so we need to be on the lookout.  No Southern rust has been found here but we are getting reports of it in Louisiana.

Here’s some more NCLB info from Dr Bob Kemerait. UGA Extension Scientist.

Northern Corn Leaf Blight (NCLB):  It CAN be a very damaging disease, especially when conditions are favorable- rainfall, short rotation, good corn growth, early infestation, susceptible variety.  HOWEVER, to complicate things, just because NCLB occurs in a field does NOT mean it will be a problem- drier conditions will cause it to stall.

I believe that it is most important to protect the crop with fungicides if top-yields are expected, rainfall has been favorable, the disease appears early, and the grower UNDERSTANDS THAT FUNGICIDES ARE AN IMPORTANT TOOL, BUT NOT GURANTEED TO IMPROVE YIELD WITH NCLB EVERY TIME (early infestation with southern corn rust ALWAYS warrants a fungicide where yields are to be protected.

Posted in Agriculture, Corn, Entomology, Plant Pathology | Tagged: , , | Leave a Comment »

 
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