Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Question of the Week – Austrian Winter Pea

Posted by romeethredge on May 16, 2015

Last week I had a photo of some seeds. They are Austrian Winter Peas. The plants look kind of  like English peas. Stan Deal is growing them here for seed. They make an excellent cover crop, they are leguminous. Last week we took a sample of them and sent it to the UGA lab to be tested for N value for the next crop.

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This week’s question concerns potatoes. This was brought in to me. What caused this on the home grown potatoes?

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NCLB 2015

Posted by romeethredge on May 14, 2015

We are finding some Northern Corn leaf Blight (NCLB) in field corn now at low levels. I had not found any until today, myself but crop consultant, Jim Griffin sent me some this photo yesterday of some he found in Baker county. Some of the lesions we are seeing may be Northern Corn Leaf spot which isn’t a big problem, but there is some NCLB at low levels in some fields.

He said it was in tall corn with a close rotation, every other year corn, not quite to tassel stage.

I found some at low levels in tasseling corn in Seminole county today.  I also saw some stinkbugs in corn at low levels. There are more of them near small grains fields that are drying down.

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Corn Tasseling

Posted by romeethredge on May 13, 2015

Lots of field corn is now tasseling in deep southwest Georgia. Some fields have ears that are silking now, too. All the photos below were taken this week.

Heat units are moving it along and lots of irrigation water is being put on it. Water use is at about 0.30 inch per day at this point. Here’s an excerpt from UGA Grain Scientist, Dewey Lee’s blog post about Corn.

“For those that are irrigating, you have every opportunity to prevent water stress if you have the capacity to meet the water demands.  It is extremely important that nitrogen and water not be limiting particularly as the crop advances towards silking.  The number of potential kernels per row is completed about one week prior to silk emergence. The most common stress at this point is usually from drought or some nitrogen deficiency.”

 

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You can count the rows of kernels on this ear, it had 18, which is very promising as the grower has 32,000 plants per acre.

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Wheat Harvest 2015

Posted by romeethredge on May 13, 2015

We have begun wheat harvest in deep south Georgia. Moisture is running about 10% in some fields, depending on the variety as well.  I’ve heard some 60 to 70 bushel estimated yields. Some test weights are low, but some at 60 or so reported. We are seeing shriveled kernels from disease problems, mainly Fusarium head blight.  Look for the pink on them and it’s likely fusarium. This can cause deductions so if you are seeing pink on shriveled kernels then make sure to turn up the fans to blow most of that out.  I have photos of some below.

UGA Grains Scientist, Dewey Lee, has more observations at his Georgia Grain Crops.

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Fusarium Head blighted kernels on right side, notice pinkish appearance.

 

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Posted in Plant Pathology, Wheat | Tagged: , | 1 Comment »

Perennial Peanut Field Day 6-6-15

Posted by romeethredge on May 11, 2015

There is a good Perennial Peanut Field day coming up in Marianna, Florida. For the details go to the Panhandle Ag News.

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Mayhaws Being Picked

Posted by romeethredge on May 8, 2015

Here we see some mayhaws that are growing on the Braswell Farm near Iron City. They have the best crop I’ve seen out there and they are good. I ate several of the mayhaws and they seem sweeter to me than usual. They will make some great coral colored jelly that will taste so good on a hot buttered biscuit.

Some varieties haven’t ripened yet but will soon.

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Sugarcane Aphid Management 2015

Posted by romeethredge on May 7, 2015

Dr. David Buntin, Grain Entomologist, University of Georgia, has prepared this concerning this aphid pest.

In late August 2014 a new aphid was found attacking grain sorghum in Georgia.  This aphid is the sugarcane aphid (Melanaphis sacchari).    I was contacted by Roger Sinyard county agent in Marion County, GA and by the end of the season the aphid infested most sorghum in central and southern parts of the state.  Infestations reached very large levels in many fields and most sorghum fields were treated one or more times to control the aphid.   I anticipate that sugarcane aphid will be a serious pest of sorghum in 2015 and most likely will require active management in near all sorghum fields in the state.

Background:  The sugarcane aphid (SCA) has occurred in Florida since 1977 and Louisiana since 1989 feeding on sugarcane.  About 2 years ago the aphid shifted hosts and a strain with a preference for grain and forage sorghums appeared.  First found in eastern Texas near Beaumont, this new strain has rapidly spread eastward across the southern United States in 2014.  It is now widespread across the southern U.S. and occurs from Texas, Oklahoma and southern Kansas to central Florida, most of Georgia and as far east as Florence, SC.  It most likely will continue to spread to new areas in 2015.  The aphid infests all types of sorghum including Johnsongrass, Sorghum halepense.  Indeed Johnsongrass supports populations in areas were grain sorghum is absent.  The aphid must overwinter on green sorghum plants in areas where volunteer sorghum and Johnsongrass do not go completely dormant.

Xinzhi Ni, USDA-ARS

Identification: It is important to scout sorghum fields in your area for its presence.   It is fairly easy to identify.  Wingless forms are a uniform pale cream to yellow with black feet and black cornicles (the small tubes present on the end of the abdomen).

Damage: Where it has been found in Georgia, it is present at very high numbers of several thousand aphids per plant across entire fields.  Large populations of fluid sucking aphids cause serious injury to the plants including death of leaves and sometimes plants. Feeding injury causes reddish lesions on the stems and leaves.   Studies in MS in 2014 showed that the greatest yield losses occurred during pre-boot, boot and early panicle emergence stages with yield losses of 52 – 100%.  Pre-boot infestations at this time can prevent heading and infestations during boot and early panicle emergence can cause sterile heads.   Infestations during soft dough also reduced yield by about 20%. The aphid can remain present in large numbers in the field until harvest.  It produces large quantities of honeydew, a sticky sugary substance that adheres to the plants, which may interfere with harvest and could damage combine harvest equipment.

Photo by Pat Porter, Texas A&M, AgriLife Extension

Management Practices for SCA Aphid

1) Plant early – Although the aphid was not in Georgia at planting time last year, experience in the Delta region found that aphids did not usually infest sorghum until later in the season and early planting may avoid very large infestations.   In other words, late double-crop plantings are at greater risk of severe infestations.

2) Use an insecticide seed treatment.   Trials in the Delta region last year found that insecticide seed treatment would limit seedling infestations for 30 – 40 days after planting.   All registered neonicotinoid insecticides are effective including thiamethoxam (Cruiser), clothianidin (NIpsIt Inside, Poncho) and imidacloprid (Gaucho others).

3) Scout early and often.   Fields can quickly be inspected for the presence of aphids by looking are on the underside of leaves.  Once aphids are detected, scout at least once, preferably 2 times per week, because aphid numbers build very quickly.  Shinny lower leaves with honeydew are a clear sign of infestation.

4) Beneficial insects usually do not control infestations.   SCA and their honeydew attract large number of beneficial insect predators such as lady beetles, syrphid fly larvae and lacewings.   No aphid parasites were observed in Georgia last year but a parasitic wasp is present in TX and LA and could move eastward.  No aphid fungal disease has been observed either.  Generally the rapid rate of increase in aphid populations overwhelms the beneficial insects and severe plant damage usually occurs.

5) Treat when aphids reach threshold levels.  Several threshold levels are being used in the Delta region for 2015.  One conservative threshold is 25% infested leaves with 50+ aphids per leaf at whorl from preboot stage through dough stage.  In MS, the threshold at pre-boot and boot stages is 20% infested plants with large aphid colonies (100+) and localized areas of heavy honeydew present.  From bloom through dough stage the threshold is 30% infested plants.  I think either of these sets of thresholds will prevent serious yield losses and would suggest using whichever threshold is easiest for you to use.   Once threshold is reach do not delay application because infestations can very quickly go from the threshold level to 100% infested plants and hundreds of aphids per leaf.

6) Use an effective insecticide.  PYRETHROID INSECTICIDES ARE NOT EFFECTIVE and may flare infestations by killing all the aphid predators.  Regardless of the insecticide, rapidly expanding populations are difficult to control.  Foliar insecticide options for SCA are:

  • Transform WG (Dow AgroSciences). Transform WG is not fully registered yet, but Georgia, Alabama and several other states haves a section 18 emergency exception approved for 2015 until Nov. 20, 2015. In my insecticide trails last season, rates of 1.0 and 1.5 oz per acre were effective.  Use the 1.5 oz rate if aphid populations are increasing rapidly.  The label allows for 2 applications per season and not more than 3 oz per acre per crop and has a 14 day PHI.
  • Sivanto (Bayer Crop Protection). Sivanto has a full section 3 label and a supplemental 2ee label for lower rates on sorghum and other grain crops. The 2ee rates are 4 – 7 fl. oz per acre.  Sivanto was very effective in my trials at rates of 3, 5, and 7 fl. oz. per acre, so the 4 fl. oz. rate should be effective.  At the 4 oz rate it can be applied up to 7 times during the season but has a 21 day PHI.
  • Chlopyrifos (Lorsban Advanced, Nufos, other). Lorsban is labeled at 1 to 2 pints per acre.  The 2 pint rate has a 60 day harvest interval and 1 pint a 30 day harvest interval.   The 2 pint rate was 80-90% effective in my trial last year but could not be used after the boot stage due the 60 day PHI.  The 1 pint rate was variable and only partly effective.  DO NOT USE CHLORPYRIFOS ON SWEET SORGHUM.
  • Dimethoate ( Dimethoate, Cygon). Is labeled up to 1 pint per acre with a 28 day PHI.  Most dimethoate products cannot be used after head emergence. Dimethoate was variable in my trials and not recommended without further testing.

7) Good coverage is key to effective control.  Use tips and GPA for maximum coverage especially lower in the canopy. A minimum of 10 gpa by ground and 5 gpa by air is highly recommended.

8)  Avoid pyrethroid insecticides for other sorghum pests.   For sorghum midge try to avoid routine pyrethroid sprays for sorghum midge.  Instead scout and treat at 1 adult per panicle.   Chlorpyrifos (1 pint per are) for low to moderate infestations.   Early plantings often avoid serious midge infestations.  For fall armyworm in the whorl, the threshold is 50% infested whorls.  Use Belt, Prevathon or Lannate which are specific to caterpillars.  For headworms, corn earworms fall armyworm, sorghum webworm, the threshold is 1 worm per head and use Belt, Prevathon, Beseige or Lannate.

9) Check fields 2-3 weeks before harvest for infestations.   A treatment may be needed if large numbers are in the head to prevent damage to combines.  Hybrids with taller stalks and more space between the grain and upper leaves may make harvest easier by reducing the amount of leaf material going through the combine.  Large infestation producing large amounts of honeydew and sooty mold may interfere with harvest desiccants.  Transform WG can be applied up to 14 days before harvest.

Summary.   Most likely SCA will infest sorghum statewide in Georgia and occur much earlier than in 2014. SCA will be difficult to manage cost effectively.   Planning and scouting will be keys to successfully managing this new invasive pest and prevent serious losses to sorghum in Georgia in 2015.

For additional information and photos see:

http://www.amsac.org.mx/docs/PUB0272_Sugarcane%20Aphid%20as%20a%20Pest%20of%20Sorghum%20-%20David%20Kerns.pdf

http://www.mississippi-crops.com/2015/02/24/management-guidelines-for-sugarcane-aphids-in-ms-grain-sorghum-2015/

http://news.utcrops.com/2015/03/sorghum-thinking-sugarcane-aphid-control-2015/

http://bug.tamu.edu/cdn/Villanueva%20New%20Aphid%20Pest%20of%20Sorghum%20AgriLife%20Extension.pdf

https://sites.aces.edu/group/crops/blog/Lists/Posts/Post.aspx?ID=73

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Question of the Week – Sensitive Briar

Posted by romeethredge on May 7, 2015

Last week I had a photo I took in a wooded area of Sensitive Briar, one of my favorite plants. It is sensitive to the touch and will fold the leaves together, as this has where I just touched the leaf.  The flower reminds me of Horton Hears a Who.

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This week I have some seeds for you to identify. This is a crop that will soon be harvested. What is it and what is it good for?

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Posted in Wildlife | 2 Comments »

Corn Progressing at a Rapid Rate

Posted by romeethredge on May 7, 2015

Here you can see where I painted the 6th leaf a while back and now its way down and we have corn now 6 to 7  feet tall in our oldest fields. In this field planted on March 11th we are now in the V11 stage. That’s about right when looking at the Degree day chart as we have accumulated about a thousand hours. See chart below showing the hours accumulated since this was planted , about 300 more than the last 2 years.

The tassel is now about to my chin when I cut into the stalk, see second photo, so we will be tasseling before too long. Corn is growing fast but it still has a long way to go, it has only accumulated about 10% of the total dry matter. It’s critical to keep it wet now with these dry sunny conditions.

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Seeing Some Burn on Corn

Posted by romeethredge on May 7, 2015

We are seeing some burn on corn leaves, mostly due to fertilizer applications. In the leaves below you can see the evidence of an application of dry fertilizer that burned the leaves. You can see that the problem occurred at a certain point in time in the past. The leaf my thumb is on was just emerging from the whorl so it just was burned  mostly on the leaf tip. The next leaf down was still in the whorl, not fully unfurled. You can see it was likely half way unfurled and the fertilizer caught in it and burned it some.  Sometimes this can be mistaken for disease or insect problems, but you can see the damage is across the leaf due to the leaf area below that not being out of the whorl yet.

I’ve also seen leaf burn due to herbicide drift this week. We can stand some drift or fertilizer injury on corn when its small without much effect on it but when we get bigger corn we can cause some yield reduction.

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