Current Situation: Rain over the past week has been a blessing. Lesser corn stalk borers have been to topic in peanuts. Cotton is being side-dressed with nitrogen. The corn crop ranges from blister stage to ½ milk line. The illustration below shows rainfall amounts for last Saturday. Rainfall amounts ranged from under an inch to around 4 inches.
The drought monitor map was released last Thursday. It is illistrated below. Sixty eight percent of Colquitt County was classified as abnormally dry, and 31 percent was classified as in moderate drought.
In this episode, Dr. Scott Monfort talked peanuts with Dr. Mark Abney, Dr. Eric Prostko, Dr. Scott Tubbs, Dr. Wes Porter, and Dr. Glen Harris. In this episode, the peanut team talked about the dry conditions that have persisted for 3-5 weeks, lesser corn stalk borer, weed escapes, and irrigation. You can listen to the podcast here.
Below is a link to the eighth episode of the Talkin’ Cotton Podcast, which is a discussion surrounding the current situation faced around most of our state including irrigation considerations, fertility, insect management, and pesticide stewardship.
Episode 8 –https://www.buzzsprout.com/2350262/15322783
Strongarm/Cadre/Cobra – Prostko
A few quick comments based upon texts, e-mails, and phone calls this week:
- Clethodim + Strongarm + Crop Oil + AMS Tank-Mixes???? Nothing better than good data. See chart below. Anywhere from 0% to 17% less grass control when Strongarm was mixed with Select. You may recall that grass control is often reduced when POST grass herbicides are tank-mixed with certain fungicides and herbicides (i.e. antagonism). Antagonism can be avoided by applying the POST grass herbicide first then applying the other agri-chemicals ~3 days later.
Cadre Programs? Check out this picture from my peanut plots earlier this morning. Further proof of the need for Cobra (or Ultra Blazer) + any Group 15 herbicide (Dual Magnum, Outlook, Warrant, Zidua) applied in combination with Cadre + 2,4-DB. Most or all of the Palmer amaranth populations in Georgia have some level of resistance to the ALS-inhibiting herbicides.
I have received a question or two about Cobra (lactofen)? According to the UGA Pest Management handbook the rate is 12.5 oz per acre and a PHI or 45 days. Apply after peanuts reach 6 true leaf stage of growth. Use a crop oil concentrate at 1% v/v (1 gal/100 gals). Provides good control of pigweeds, morning glories, ragweed, copperleaf, wild poinsettia, and eclipta. Cobra can be tank-mixed with Anthem Flex, Basagran, Cadre, Outlook, Pursuit, Select, Warrant, Zidua, and 2,4-DB. Rain-free period is 30 minutes.
What about rain fast on peanut herbicides? Again, according to the UGA Pest Management handbook Ultra Blazer, Basagran, Storm, has a rain free period of 4 hours. Cadre has a rain free period of 3 hours, and Strongarm is 2 hours. Clethodim, Classic, Poast, 2,4DB, Pursuit is 1 hour. Paraquat is rain fast in 30 minutes.
I have been seeing some larger pigweed in peanuts due to the crazy weather we have been experiencing. According to Dr. Eric Prostko, what are my thoughts about controlling large pigweed in peanuts with Cobra or Ultra Blazer?
1) I do not have a preference between Cobra or Ultra Blazer if the pigweed plants are 2″-4″ tall.
2) I do prefer Cobra over Ultra Blazer when plants get bigger than that. But I would not expect any miracles when plants get larger than 4″. For the record, labeled maximum heights for Ultra Blazer (24 oz/A) and Cobra (12.5 oz/A) are 4″ tall/6 leaf and 3″ tall/6 leaf, respectively.
3) If plants are too big, growers are wasting his time and money on a revenge spray.
Lesser corn stalk borers. Lesser corn stalk borers have been a topic of debate over the last week. The rain over the weekend has been answered prayer. Rain does not kill lesser cornstalk borers. The rain did wash away silk tubes and make scouting more difficult for a few days, but the insects are still here. If we experience lower temperatures and regular rainfall over the next three weeks, we will see lesser numbers dwindle. We can pray for that.
We cannot irrigate LCB away prior to canopy closure. Once peanut vines lap the row middles, irrigated fields that are watered adequately will rarely experience LCB populations above threshold.
I have been finding a few cutworms in area peanut fields. Cutworms rarely warrant treatment in peanuts, but when populations are high, they can cause significant injury. Cutworms can be found on foliage in the daytime, but it is more common for them to feed at night and retreat to the soil once the sun comes up. Scratching around in the top inch of soil at the base of plants is the best way to find cutworm larvae in peanuts during the day. Dr. Abney has discussed cutworms in the past.
Cotton: Aphids and spider mites have been on the rise this past week in area cotton fields. Plant bugs have been spotty around the county. Hopefully after the rain this week, the aphid fungus will be found.
A dynamic threshold which varies by the number of stink bug susceptible bolls present is recommended for determining when insecticide applications should be applied for boll feeding bugs. The boll injury threshold for stink bugs should be adjusted up or down based on the number of susceptible bolls present. Use a 10-15% boll injury threshold during weeks 3-5 of bloom (numerous susceptible bolls present), 20% during weeks 2 and 6, and 30% (+) during weeks 7(+) of bloom (fewer susceptible bolls present).
When selecting insecticides for stink bug control it is important to consider other pests such as whiteflies, corn earworms, aphids, or mites which may be present in the field. The objective is to control stink bugs but also to minimize the risk of flaring another pest which are present. A couple of bullet points below to consider when selecting a stink bug insecticide:
• Consider week of bloom and use the dynamic threshold.
• Pyrethroids provide good control of southern green stink bug but only fair control of brown stink bug (increased pyrethroid rates improve control of brown stink bug and bifenthrin generally provides greater control of brown stink bug compared with other pyrethroids).
• Determine ratio of southern green to brown stink bugs, organophosphates provide better control of brown stink bugs compared with pyrethroids.
• If whiteflies are present, use bifenthrin and avoid dicrotophos during weeks 2-5 of bloom.
• If aphids are present, include dicrotophos and avoid acephate if an organophosphate is needed.
• If mites are present, avoid acephate if an organophosphate is needed.
A few words from Dr. Don Shurley in relation to the cotton market.
Cotton Marketing News: Cotton Price Taking Baby Steps Forward | Panhandle Agriculture (ufl.edu)
Forages: I received a call or two about armyworms in hay fields. Economic treatment thresholds are three armyworm larvae per square foot in hayfields and pastures.Young larvae are much easier to kill than adult armyworm larvae. Several insecticides are available to control armyworms and please consult your local county Extension agent for options. Please pay careful attention to grazing or pre-harvest intervals of the product used for armyworm control.
Can I use a sweep net to scout for bermudagrass stem maggot in my hay field? I am glad you asked. Alternatively, you can easily use a sweep net to collect and identify the adult BSM fly in the field. The adult flies tend to stay down in the forage canopy and rarely fly higher than 18 inches above the canopy. Sweep net estimates have been found to be relatively accurate predictors of actual fly populations in the field. It is not uncommon to find 50-80 flies in a sample of ten sweeps during July and August (peak BSM damage season). This translates to ~300-500,000 flies per acre! Be sure to sweep deep into the canopy, as the flies do not fly very high. While the flies are more active in the morning hours, it is difficult to sweep if dew is present. Plan to scout your fields just after the dew dries off the grass, around 11 am to noon. Transfer your sample (about 10-15 sweeps) to “insect cube” or a plastic bag and place in a freezer for 5-10 minutes. Remove from the freezer and count the number of flies. If you have observed a significant (30%) level of damage in your field and find at least 40-50 flies in your sample, then it’s time to employ the appropriate control strategy.
Control strategies are contingent upon timing of damage If the BSM damage occurs near the end of a regrowth cycle (~3 weeks after the previous cutting or grazing), the yield loss is estimated to be less than 10% so you can harvest as normal. However, if the hay crop damaged at an early stage of regrowth (e.g., 6-8 inches) is unlikely to further develop. If the crop is damaged at this point, it is crucial to remove (mow and harvest, if possible) the damaged grass to enable new growth to occur.
Strategically-timed pyrethroid insecticide applications can significantly reduce the adult BSM fly population and protect the bermudagrass during the most sensitive regrowth phase. The BSM flies tend to remain deep in the canopy, so apply the insecticide in a volume of water in excess of 12-15 gallons/acre to ensure adequate canopy penetration. Suppressing the BSM can be effective when a recommended rate of an insecticide is applied after the bermudagrass has begun to regrow (7-10 days after cutting) following an affected harvest. A second application can be made 7-10 days later to suppress any flies that have emerged or arrived since the last application.
If you would like more information on this subject, then go to this link.
I have received numerous calls about nitrates in summer annual forages this past week. Growers need to identify and test all forages that may have accumulated nitrates. Below are a few points to consider about nitrates in forages.
- Nitrogen fertilization increases the risk of nitrate accumulation.
- Some plants accumulate nitrates at a greater rate.
- Split applications of nitrogen fertilizer (organic or inorganic) within the growing season.
- Do not harvest or graze forage within seven days following a drought-ending rain.
- Do not feed green chop until the whole plant has been tested for elevated nitrate concentrations.
- Harvest the crop as silage when possible.
- Nitrates tend to be highest in the lower stem and leaves.
- Increase the harvest height to minimize the inclusion of lower plant parts and low growing weeds.
- Do not graze crops closely.
- Use field test kits to rule out samples low in nitrates but confirm field results with a laboratory analysis when results indicate moderate or higher levels of nitrate (>2,500 parts per million–ppm).
- Dilute high nitrate forages with feedstuffs that are high in energy.
- Provide plenty of clean water and supplement with sufficient vitamins and minerals.
- Avoid or minimize feeding forages that are high in nitrates to lactating, pregnant, or sick animals.
- Limit animals to 3 or 4 hours of access to high-nitrate hay per day so that intake is limited to approximately 50 percent of normal. Supplement the lower hay intake by feeding a grain or by-product feed (6 to 10 pounds per day depending on lactation status and forage quality) BEFORE allowing the animals to access the high-nitrate hay.
If you are testing forages for nitrates, the slide below contains information on nitrate levels and how to manage during times of drought.
Also, more information on nitrates can be obtained here.
A few words from Dr. Lawton Stewart, UGA Beef Cattle Specialist, on the drought situation and beef cattle.
As you all know, many parts of Georgia are suffering through some degree of drought conditions. This can be a double, maybe triple, whammy effect on producers because not only do they not have pastures to graze this summer, but they also may not be able to harvest enough hay to get through the winter, and they are currently having to feed what little hay they have. Hopefully, by the time you read this, you’ve received plenty of rain and drought isn’t an issue, but for many, this will not be the case.
Deciding what to feed can be tricky. Do you buy more hay or consider a hay replacement ration? It is important to maintain the nutrient requirements of the herd through a drought so that animal performance is not compromised in the current and upcoming seasons. Here are a couple of questions you may be asking and some considerations.
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.
- Also consider culling cows that or open, old, or are producing smaller calves.
- Utilize a roughage source such as wheat straw, cotton seed hulls, crop residue, grazing drought stressed crops, or 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.
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.
- If you need to purchase the hay quickly, then pull samples and analyze as soon as possible.
- 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 in 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. The amount fed per head is held constant at 25 lb., but this may change for both feeds, depending on how it is fed. The prices used are not constant across locations. Producers should price feed resources locally to make the comparison.
- Note that if hay is being wasted, it is more economical to buy a replacement ration. This point is not necessarily to steer you towards the feed, more so, to show the value of proper handling of purchased hay.
Have a safe and great July 4th,
Jeremy M. Kichler
Colquitt County Extension Coordinator
The University of Georgia Cooperative Extension does not endorse or guarantee the performance of any products mentioned in this update.
