Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Caterpillars eating more than Cattle

Posted by romeethredge on August 28, 2014

Cattle price is too good to let the caterpillars eat up the grazing. Armyworms are doing a number on area pastures and hayfields. A Deacon at church called me on Saturday to come see what was eating up the churchyard and yes it was fall armyworms. They were on the sidewalk by the dozens as we exited the church on Sunday, we were afraid someone might slip down because of them.

2 growers recently told me they checked hayfields on a Friday about noon and by Sunday afternoon there were just stems left. These caterpillars can do a lot in 2 to 3 days. Call your county Extension Agent for control recommendations.

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Posted in Cattle, Entomology | Leave a Comment »

White Sugarcane Aphid now in Georgia

Posted by romeethredge on August 28, 2014

NEW APHID PEST OF SORGHUM

We are finding a new pest in Georgia grain sorghum. I first heard about it in our area on Saturday from consultant Jim Griffin, and County agents reported finding some on last Friday in Marion County, Georgia. Then I found it in 3 grain sorghum fields at moderate levels this week here in Seminole County.  The new aphid is the white sugarcane aphid (Melanaphis sacchari).  It has now been reported in several counties in Georgia and reports are some have been found in Florida and was  found in at least 12 counties in Alabama https://sites.aces.edu/group/crops/blog/Lists/Posts/Post.aspx?ID=48 and seems to be widespread in Mississippi, Louisiana, and eastern Texas.

Here’s a  couple of photos I took of  winged adults and the immature aphids feeding on grain sorghum that is not yet heading.

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The aphid is light in color with no obvious markings other than black legs and “tailpipes” (cornicles).  Other aphids usually have spots, a green stripe or a black head.

 David Buntin, UGA Grain Crop Entomologist says,”

A new aphid, the white sugarcane aphid (Melanaphis sacchari), has been found attacking sorghum in Georgia.   I was contacted by Roger Sinyard county agent in Marion County last week about a very large infestation of aphids in grain sorghum.   The aphid was the white sugarcane aphid.  Subsequent reports find the aphid in 9 total counties in the southwest quadrant of the state (Marion, Decatur, Early, Seminole, Colquitt, Taylor, Terrell, Randolph, and Tift counties).   More counties most likely will be added to this list in the next few weeks.

The white sugarcane aphid (WSCA) has occurred in Florida since 1977 and Louisiana since 1989 feeding on sugarcane.  About 2 years ago the aphid shifted its host preference to grain and forage sorghums.  First found in Texas, this new strain has rapidly spread eastward across the southern United States in 2014 and is now widespread in Mississippi, Louisiana, and eastern Texas, and Arkansas.  It is expected that WSCA will continue to spread rapidly throughout Georgia over the next few months.   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 back).

Where it has been found in Georgia, it is present in many fields at very high numbers of several thousand aphids per plant across entire fields.  The aphid sucks plant fluid and these large populations are causing serious injury to the plants including death of leaves and sometimes plants. The aphid remains present in field until harvest.  It produces large quantities of honeydew, a sticky sugary substance that adheres to the plants, which may interfere with harvest and may damage combine harvest equipment. Entomologist in Texas, Louisiana and Mississippi report 20 to 50 % yield loss and sometime the total loss of the crop from harvest damage.   A tentative threshold is:  treat if more than 30% of plants are infested AND there is an average of 100 – 250 aphids per sorghum leaf.   This publication from Texas AgriLife Extension shows the different aphids on sorghum and information about white sugarcane aphid biology and damage. http://nueces.agrilife.org/files/2014/05/Sugarcane-Aphid-Publication.pdf   Interestingly a study by Kathy Flanders at Auburn University suggests this new strain prefers sweet, grain and forage sorghum over sugarcane and it does not attack millets.  Johnsongrass is also listed as a host for WSCA.

WSCA is difficult to control and populations may bounce back quickly following an application. Currently labeled insecticides in grain sorghum are not adequate.  High rates of Lorsban (24-32 oz) appear to provide decent control but cannot be used for late-season infestations because of the 60 day preharvest application restriction.  Dimethoate, malathion and the 1-pint rate of chlorpyrifos provide only about 50% control.  Pyrethroid insecticides are not effective and may flare aphids.  If headworms occur, consider using Belt or Prevathon for control.  The states of Texas, Louisiana, Mississippi, Arkansas and Oklahoma have a Section 18 (emergency use exception) exception approval to use Transform WG (sulfoxaflor, Dow AgroSciences).    Studies in these states show an application of 1.0 – 1.5 oz per acre is about 90% effective, although aphids can build back in a few weeks.   We are working on a section 18 emergency use exception request for Georgia, but Transform WG is currently not allowed in Georgia.”

Some related articles from other states include:

http://news.utcrops.com/2014/08/white-sugarcane-aphids-found-in-tennessee-sorghum/

http://www.arkansas-crops.com/2014/07/14/sugarcane-grain-sorghummilo/

http://www.mississippi-crops.com/2014/06/26/white-sugarcane-aphid-a-potentially-devastating-pest-of-grain-sorghum/

http://www.mississippi-crops.com/2014/07/11/white-sugarcane-aphid-update-and-impact-on-midge-applications/

http://www.mississippi-crops.com/2014/07/15/treating-white-sugarcane-aphid-decision-aid/

http://www.mississippi-crops.com/2014/07/25/white-sugarcane-aphid-update-7252014/

http://www.mississippi-crops.com/2014/08/01/white-suagarcane-aphid-update-812014/

http://louisianacrops.com/2014/07/17/sorghum-midge-and-white-sugarcane-aphid-concerns/

http://louisianacrops.com/2014/06/20/white-sugarcane-aphid-considerations-and-status-in-louisiana-grain-sorghum/

http://louisianacrops.com/2014/06/16/sugarcane-aphid-numbers-increasing-in-grain-sorghum/

This publication from Texas AgriLife Extension shows the different aphids on sorghum and information about white sugarcane aphid biology and damage. http://nueces.agrilife.org/files/2014/05/Sugarcane-Aphid-Publication.pdf

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Question of the Week – Pine Devil

Posted by romeethredge on August 27, 2014

Last week I had a photo of the Pine Devil Caterpillar (Citheronia sepulcralis). They are large and grow up to 3 and a half inches long. They feed on pines but usually you’ll just find one at a time, thank goodness.

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They are similar to the Hickory Horned Devil which is green and we see them sometimes as well, in pecan trees.

 

 

This week I have another insect ID question. What is this we found flying around and will it sting?

 

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Posted in Entomology | Tagged: | 2 Comments »

“One Hungry Planet”

Posted by romeethredge on August 27, 2014

I like this Ag Awareness Video.

 

 

Here are some screenshots from the video.

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Downy in Soybean

Posted by romeethredge on August 27, 2014

Downy mildew of soybean is being found now in most all the fields I go into at low levels.  Downy mildew is easily identified as yellow spots on leaves with a characteristic tuft of fungal growth on the underside of each spot.  One may need to look carefully to see the fungal growth, which is typically a grey color.

 Dr. Bob Kemerait, UGA Extension Scientist says, “The University of Georgia typically does not recommend spraying fungicides for control of downy mildew because a) the disease is not believed to cause significant yield losses, and b) our fungicides for control of soybean diseases less effective against that type of fungus.”

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

Dry Peanuts

Posted by romeethredge on August 27, 2014

Dryland peanuts have had it rough this year. There have been very spotty rains and some areas have been very dry.  We have some fields that will likely yield quite low due to the weather and what it brings on. When we have weather like this we tend to have more problems with Lesser Cornstalk borers (LCB) and spidermites.  We’ve also seen some pod splitting in fields where it was dry for a long time and then a big 2 inch rain comes and some of the pods split open.

 

Here’s some of the dry… then wet pod splitting.

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Lessers have been the worst I’ve seen in a long time this year. They will bore into peanut pods like in photo, and will kill stems as well.

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Posted in Peanuts | Tagged: | 1 Comment »

Deep Turning Reduces Annual Ryegrass Populations

Posted by romeethredge on August 26, 2014

Georgia wheat production is in jeopardy due to herbicide resistant ryegrass which is a weed problem in wheat.  Ryegrass resistant to all currently labeled postemergence controlling herbicides has been documented and is becoming very common.  Heavy ryegrass infestations, if uncontrolled by poor management or herbicide resistance, can eliminate production. Drs. Culpepper and Webster, UGA Scientists, have done some research concerning this weed and have some good news.

Ryegrass has proven that it is capable of rapidly developing resistance to any and all herbicides used for management; even more so than Palmer amaranth.  A systems approach to management is the only sustainable option and may include rotating herbicide chemistries, rotating crops, and maybe even implementing deep tillage in the more severely infested fields.

Current research is being conducted to determine the potential benefits for deep turning to reduce annual ryegrass emergence.  In our first experiment, we planted ryegrass at 0.5 inch deep and followed with no tillage (our control) or deep tillage.

Our objectives were to determine the following:

1) Could deep turning effectively invert seed on the soil surface?

2) Could inverted seed placed 10-12 inches deep in the soil profile germinate?

Results showed a reduction in ryegrass emergence by over 99% with deep turning (figure/picture below).  Although this experiment does not address ryegrass seed spread throughout the soil profile as is the case in grower fields, it does suggest ryegrass emergence is greatly reduced when it is placed deep in the soil profile.  The next step is to better understand how long the seed will live when buried in our soils under our environmental conditions.

Rarely will any cultural or mechanical practice effectively control ryegrass by itself.  Thus, an herbicide program will usually be needed.  See the wheat production guide or pest control handbook for herbicidal options.

 

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

Peanut Meeting – Donalsonville

Posted by romeethredge on August 23, 2014

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Seminole Extension and Seminole Young Farmers will have a joint Peanut Meeting this coming Monday, Aug 25th at 7:30 PM at Ag Center or High School cafeteria if paving is not yet finished.  Come out to hear Dr. Scott Montfort, our new UGA Peanut Scientist give us a crop update.

Here’s grower Jeff Braswell, with some Ga 06G peanuts he is growing near Iron City.

 

 

Posted in Peanuts | Tagged: | 1 Comment »

Peanut Maturity

Posted by romeethredge on August 23, 2014

Some irrigated peanuts are approaching maturity, but not many. We didn’t have many fields planted in early April this year due to it being very wet and cool. I had samples from a few fields brought in this week from some of these early to mid April planted fields.

There’s really no reason to sample fields to test for maturity until they are 125 days old or so with the current varieties we have. Here’s a chart showing a lot of our varieties, which will mostly be ready to dig around the 135 to 145 day range. There’s a lot of variability in this and that is why we do the peanut maturity checks or “Hull scrapes”

Remember if you are collecting peanuts for a sample to get a good representative sample of the field, plants from several spots, but no bottoms or diseased or skippy areas. We need about 200 nuts, and all the nuts need to be pulled from the vines except the tiny ones.

The “Days between Dates” App is a good way to check the age of peanuts on your smart phone when you have the planting dates.

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We have very limited experience with this year’s crop but most of what I saw this week, only 7 samples, shows the maturity of these earliest peanuts to be projected to be around 150 days of age or so. I looked at Ga 06G’s and Florun 107’s.

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Question of the Week – Purple Nutsedge

Posted by romeethredge on August 23, 2014

Last week I asked about a peanut field weed and what it is and why wasn’t it controlled. Well the weed is purple nutsedge. It is similar to the more common Yellow nutsedge but it often is a darker green and is a stockier plant. It also has the purple seedhead and there’s a difference in the leaf tips. Also if you dig up the nuts they produce, the yellow nutsedge tubers are good but the purple ones taste terrible.

The second part of the question was why wasn’t it controlled when a good sedge herbicide was sprayed in this field? Well the herbicide Basagran works very well on Yellow nutsedge but it’s not good on this particular  purple type sedge, so it survived when all its cousins were taken out. The same goes for Dual preemergence herbicide, it works well on yellow, preemergence, but not on purple.

 

OK, this week I have an insect ID question for you.

What is this caterpillar I was asked to identify this week? It’s big and 2 inches long.

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Posted in Entomology, Weeds | Leave a Comment »

 
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