Monthly Archives: July 2016

Feeding Cattle During Drought

All of GA has seen some level of drought this summer. Down here, we have been fortunate to get recent rains from afternoon thunderstorms recently. In any case, drought affects hay producers by not having pastures to graze and also not being able to harvest hay. With the ebbs and flows of cattle industry, UGA Extension Animal Scientist Dr. Lawton Stewart has some information on managing to minimize effects of drought on farm’s finances. It is important to maintain the nutrient requirements of the herd through a drought so animal performance is not compromised in upcoming seasons.

What if hay is not available? The key is to develop a ration that meets the nutrient requirements of the cows. 

  • The stage of production of your herd is critical to knowing exactly what to feed.  Table 1 lists some example rations to use for different stages of production.
  • Consider early weaning to reduce the nutrient requirements of the brood cows.
  • Utilize a roughage source such as wheat straw, conttonseed hulls, crop residue, grazing drought stressed crops, gin trash.
  • Examples of energy and/or byproduct feed include: grains such as corn, oats, etc., soybean hulls, citrus pulp, wheat midds, hominy.
  • Examples of protein feed include: soybean meal, cottonseed meal, corn gluten feed, dried distillers grains, whole cottonseed.

FeedingCattleDuringDrought-Table1

Is buying hay the economic choice?

  • ALWAYS, ALWAYS, ALWAYS ask for a forage analysis and/or test the hay before purchasing it.  If not, you may be paying a premium for something that will not meet the requirements of your cows.
  • Take into consideration the cost of the supplement AND hay.
  • Also, take into consideration the method of feeding hay.  If hay is not fed in a ring or other way to minimize lost, hay losses can be as high as 30%, or more.
  • Table 2 compares the cost of buying hay versus feeding a hay replacement diet
  • Note that if hay is being wasted, it is more economical to buy a replacement ration.  This is point is not necessarily to steer you towards the feed, more so, to show the value of proper handling of purchased hay.

FeedingCattleDuringDrought-Table2

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Pecan Leaf Sampling

Pecans 002

It is time for us to take leaf tissue samples in pecans.  UGA Extension Pecan Specialist Dr. Lenny Wells has this information:

The general recommended period for leaf sampling is July 7-August 7.

Why does it matter when you sample?

Concentrations of N, P, and Zn on a leaf dry weight basis start off relatively high early in the season, decline rapidly, reach a fairly steady state after mid-June, and then decline near leaf fall.  K tends to start high, then decreases and plateaus at about the same time as N, P, and Zn. Most of the P and Zn that accumulates in the leaves have done so by the time the leaves reach full size. Calcium (Ca) accumulates in the leaves as the season progresses, peaking in August-September. Magnesium (Mg) Manganese (Mn), and Boron (B) also tend to increase as the season progresses, but to a lesser extent than Ca.

PecanLeafSampling

Collect middle-pair leafleats

How do we sample?

  1. Collect 50- 100 middle-pair of leaflets from the middle leaf of this year’s growth (right). Use terminal shoots exposed to the sun. Avoid twigs from the interior of the tree. Collect leaflets from all sides of the tree. Avoid leaflets damaged by insects and diseases.
  2. Abnormal trees or trees not representative of the area should be sampled separately. A complete and accurate description of abnormalities should accompany these samples.
  3. Sample trees of the predominant variety in a given block. If Schley is the main variety, sample Schley; etc.
  4. Immediately upon collection, wipe leaves (entire surface, both top and bottom) with a damp cellulose sponge or cheese cloth to remove dust and spray residue.  Do not allow the leaves to come into contact with rubber or galvanized containers. Partially air dry and place in the large envelope of the mailing kit.
  5. If recent soil test data is not available, it would be advisable to collect a soil sample and have it sent to a soil testing laboratory.  By sampling the same trees each year, growers can more readily see the results of any changes to their nutritional programs.

**Some growers have taken leaf samples throughout the growing season to determine the fertility needs of the tree. This is really unnecessary. Leaf analysis does not necessarily reflect the actual use pattern of mineral nutrients, but instead indicates concentrations of those elements in the leaf at the time of sampling. The tree knows what it needs and when it needs it.

Concentrations of mineral nutrients in the leaves change as leaves emerge, expand, and finally senesce in the fall. For many elements, the least change in concentration occurs from early July-early August.

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Grain Sorghum Dough Stage: Terminating Insect Sprays?

SorghumFlowering,Dough 004Our grain sorghum is past flowering and moving through the soft dough stage. Grain fill is rapid with about half the total dry weight of the grain accumulating during this time. We may see nutrient stress and leaf loss since mobile nutrients are transolocated from the lower to the upper leaves. Between soft dough and hard dough stage, irrigation increases yield by improving grain fill test weight. We don’t see much if any response from water once grain reaches hard dough stage.

Sugarcane Aphids

Once we get to hard dough stage, color, we no longer have to worry about sugarcane aphids. Also, keep in mind should try to avoid using pyrethroids for other insects and aphids. We need to check fields 2 – 3 weeks before harvest. We had issues with honeydew from SCA messing up the combines. 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.

The best way to tell hard dough is by pinching the kernel. The hard dough color is still similar to soft dough. MSU Grain Scientist Dr. Erick Larson says, “Grain Sorghum kernels change color and accumulate hard starch much the same as corn kernels mature. Kernels will mature first at the top of the head, so focus scouting on the kernels at the base of the heads. If you can quickly see a considerable amount of green kernels, rather than the burnt orange / brown color of mature kernels, you need to give the crop some more time to fully mature.”

Like corn, grain sorghum also forms ‘black layer’ from crown of the kernel to the base. Here is a photo by Dr. Erick Larson showing the progression from hard dough to ‘black layer.’

Sorghum Kernel Maturity - Dr. Erick Larson

Sorghum Kernel Maturity from hard dough (left) to physiological maturity or ‘black layer’ (right) – Dr. Erick Larson

Here is information from UGA Extension Grain Entomologist Dr. David Buntin on pre-harvest intervals, rates, and efficacies:

  • Sivanto Prime (Bayer Crop Protection).  Sivanto prime has a full section 3 label and a supplemental 2ee label for lower rates on sorghum and other grain crops. The rates are 4 – 7 fl. oz per acre. Sivanto was very effective in my trials at rates of 4 to 7 fl. oz. per acre with Control usually lasting 21 days or more. At the 4 oz rate it can be applied up to 7 times during the season but has a 21 day PHI.
  • Transform WG (Dow AgroSciences). Transform WG federal label was vacated last winter and a new federal label has not been approved yet. But Transform WG has an approved Section 18 emergency exception for use on sorghum in Georgia in 2016 through April 8, 2017. The big label change for 2016 is Transform cannot be used during bloom to protect pollinators. The label allows for 2 applications per season and not more than 3 oz per acre per crop and has a 14 day PHI. 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.
  • 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. The 1 pint has a 30 day harvest interval, but is usually not effective. The 2 pint rate was 60-90% control for up to 2 weeks. At the 2 pint rate it cannot be used after the boot stage due the 60 day PHI. DO NOT USE CHLORPYRIFOS ON SWEET SORGHUM.
  • Dimethoate ( Dimethoate, Cygon). Not recommended. In my trials dimethoate is variable in control and control if it occurs is only for a week or so.

Sorghum Midge

The susceptible damage period for midge is bloom. Treatment after bloom is too late. The adults are hard to find. We either put a plastic Ziploc bag over the head. The midge will fly to the top of the bag. You can also use a white paper plate, but the midge can fly off. If it’s wings are wet in the morning, it may not fly as well. In either case, we only treat when an average of 1 adult per head is observed after 25 – 30% of heads are blooming. We can treat again 5 – 10 days later if midge is present. The eggs and larvae cannot be killed inside the glumes with insecticide.

NOTE: For midge, try not to use a prethroid because it may flare sugarcane aphids. If SCA are present and pyrethroid is used, we would have to tank mix with Transform or Sivanto.

Sorghum Midge - Photo by Ben Thrash

Sorghum Midge – Photo by Ben Thrash

SorghumFlowering,Dough 005

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Filed under Entomology, Grain Sorghum

Peanut Insects

July is the month when our most serious insect problems in peanuts show up. We need to watch for threecornered alfalfa hoppers, foliage feeding caterpillars, lesser cornstalk borers, two spotted spider mites, and potato leaf hoppers and just anything else that may hang out in a peanut field.

UGA Extension Extension Entomologist Dr. Mark Abney shared some things that we do know about these pests right now:

1. We tend to spray caterpillar infestations when they are below threshold. This may help us sleep better at night, but it does not provide economic benefit to the grower. There are a lot of factors that go into making insecticide applications in peanut, and not the least of these is when is the next scheduled fungicide application.

Our threshold is 4 – 8 caterpillars per row foot. We use the upper threshold when peanuts are not stressed, and lower threshold if peanuts do not look good.

Two-spotted spider mites with webbing

Two-spotted spider mites with webbing

2. Spider mites have been hanging around on cotton this year, and they can devastate non-irrigated peanuts in hot dry years. We need to be diligent about checking peanuts for the first signs of spider mite infestations. Once mites are identified in a field, we should avoid the use of pyrethroids in that field and watch to see if the mites begin to spread. If mites are moving, and the forecast calls for continued hot dry weather it is time to treat. Coverage will be critical to achieving control. A miticide application in 10 gallons of water per acre is most likely a waste of time and money; increase the water, increase the pressure, kill the mites.

Adult Three Cornered Alfalfa Leaf Hopper

Adult Three-Cornered Alfalfa Leaf Hopper – Photo by Dr. Mark Abney

3. Threecornered alfalfa hoppers (TCAH) are going to be in fields. Our threshold (research) does suggest that this insect can cause yield reduction in peanut, but I have seen some very high yielding peanuts with a lot of TCAH stem girdles. If spider mites and TCAH are in the same field, let the TCAHs eat. Anything we spray on TCAH will almost certainly make the mites worse, and that is not what we want to do. Otherwise, pyrethroids are still the first choice for TCAH in peanut.

4. I have received plenty of calls about lesser cornstalk borers in the last two weeks. The weather will be the biggest factor determining what happens from here. If it is hot and dry we could be in for problems; if we get some timely rain, populations are not likely to explode.

Lesser Cornstalk Borer - Photo by Andy Shirley

Lesser Cornstalk Borer – Photo by Andy Shirley

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Filed under Entomology, Peanuts

Sunbelt Ag Expo Field Day – July 14

SunbestExpoFieldDay

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July 7, 2016 · 7:50 PM