Category Archives: Peanuts

Timing N, Ca, and Boron On Peanuts

Peanuts are looking really good now. We are between pegging and developing seeds at this time. We are on our second and third fungicide applications across the county. We are starting to see evidence of caterpillars. I saw some three corner alfalfa hoppers yesterday as well.

UGA Extension Fertility Scientist Dr. Glen Harris wrote a good piece of information on timing nutrients in peanuts. (Since I already wrote about applying landplaster, I moved the calcium to the bottom since it is a lot to read.)

Timing is everything right? Well, that’s not exactly true when it comes to applying these fertilizer nutrients on peanuts. Rate, source and placement, to round out the “4Rs” of fertilizer management, are important too. When it comes to timing though, if you are too early or too late you could come up short on providing these key nutrients to peanut.

Nitrogen – If peanuts are inoculated or in a short rotation, they should not need any nitrogen fertilizer. This includes putting nitrogen in a starter fertilizer or spraying foliar nitrogen. However, in the case of an inoculation or nodulation failure, nitrogen fertilizer will be recommended as a “rescue” treatment. The timing for fixing this problem is critical and should be detected and fixed around 30 days after planting or soon thereafter. It only takes 60 lb. N/A to fix the problem. Yes, peanuts normally fix more N than that, but recent research as shown that 60 lb. N/A is enough. Split applications and rates up to 180 lb. N/A yielded no more peanuts than the 60 lb. N/A treatment. Ammonium sulfate also seems to be the product of choice in this situation.

Developing seed (R5 Reproductive Growth Stage)

Boron – Since boron is important for pollination and fruiting, the recommended timing for B applications on peanuts is early bloom. And since it is a micronutrient that foliar feeds well, the recommended practice is to include boron with early fungicide sprays. Can you apply boron to the soil at planting? Yes, but this timing may be considered too early since like nitrogen, boron can be highly mobile in soils, i.e. leach out and not be available later when needed. And how late is too late to apply boron? Again, since peak pod fill for peanuts occurs 60 to 90 days after planting, once peanuts are 80 days old or older, the chances of applying boron and getting a yield increase decrease dramatically. And what about rate? The UGA recommendation for B on peanuts is 0.5 lb. B/A. This can be applied in one application or split into 2, 0.25 lb. B/A applications. Rates higher than 0. 5 lb. B/A in a single application can cause burn to the foliage. Rates less than 0.25 lb. B/A, for example 6 ounces of a 5 % liquid B that only provides 0.025 lb. B/A, are considered ineffective and not economical.

Boron burn on peanuts

Calcium – The two most common ways of supplying calcium to the pegging zone of peanut are lime at planting and gypsum (calcium sulfate) at early bloom. Again, timing of applying these two is critical and is linked to the solubility of calcium in these materials. The calcium in lime is not as soluble as the calcium in gypsum so it must be applied earlier to give it time to get in the pegging zone. Applying lime at early bloom is too late.

What about applying gypsum at planting? I get this question all the time. While in some years you could probably get away with this, in other years, like this year for example, applying gypsum at planting would have been too early and not a good idea. Heavy rains on sandy soils can actually “leach” (dissolve and move downward) the calcium right past the pegging zone (top 4 inches). If you applied gypsum too early or if you got 4 to 6 inches of a “leaching rain” soon after application, then you may consider reapplying the gypsum.

Of course, you may want to take a hard look at if you needed gypsum in the first place by looking at your calcium levels and the calcium to potassium ratio in a soil sample from the pegging zone. And what if you are about 60 days after planting and don’t want to run over lapped vines and discover you need some calcium? The period from 60 to 90 days after planting is considered “peak pod fill” and research has shown that applying 10 gal/A of calcium chloride thru the pivot with irrigation water can provide some much needed calcium to developing pods. This treatment will not raise the soil test calcium levels like lime or gypsum will but can be effective.

And what about foliar feeding calcium? The answer for timing of that one is easy…never! Calcium simply does not translocate form leaves to developing pods plus you could never get enough calcium to the pods from a quart per acre foliar calcium even if it did work.

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Weather & Disease Update

It’s hard to say we don’t want more rain, but more and more we’re saying just that. We’re having showers nearly every day or every other day, sometimes as much as an inch and a half. It’s starting to show up in the field where cotton is getting ‘wet feet.’ Some of our rain has come with strong winds. Our largest field of tobacco took a hit from these winds knocking plants to the ground in some places. The only hope is to stand it back up as best as possible. It is still causing issues with topping since the flowers on the ground began growing straight up.

We have a good crop of tobacco this year, but it was hit hard from strong winds and rain. Some areas completely blown to the ground.

Flowers turned from wind affects topping

From UGA weather station in Cairo, here are the rain numbers since the beginning of May.

Disease Update

Here is our latest disease update from UGA Extension Pathologist Dr. Bob Kemerait:

Southern Corn Rust: I was stunned when agents in our disease diagnosis class visiting a field in Morgan County found a very active spot of southern rust. Unbelievable because until yesterday, it had ONLY been found lightly in Seminole and Marion Counties. Obviously, as we expected, southern rust could be present anywhere in Georgia now.  Why it has not “exploded” yet is a mystery to me given the conditions we have had, but CLEARLY the spores have spread across the state.

The corn in that field as at hard-dough/early dent, so it does not need to be treated; however growers with later planted corn not yet at R6/dough stages should be aware there is at least some threat.

Target spot of Cotton: Perfect weather but I am NOT calling for an automatic fungicide application at first or at third bloom.  BUT I am saying that every cotton grower SHOULD be aware that these can be important and critical timings. As cotton approaches bloom, I hope growers can put some eyes and boots in the field and begin looking for it, lower leaves first. Weather is very favorable- growers with a history of disease in the field and those with high-input, strong yield potential should be the growers with the greatest chance for benefit. Target spot will not steal the entire crop, but it will take away a valuable portion of the crop.

Consider:  Growth stage (blooming yet?)  history of disease, reports from scouting, (have early symptoms been found?), what’s the weather like now and what is the forecast?  What is the value to the growing in a preemptive application “to be done with it”?

White mold and leaf spot in Peanut: We are seeing some of both.  Growers, don’t get behind!

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Filed under Corn, Cotton, Disease, Peanuts, Tobacco, Weather

Peanuts And Valor Injury

We plant a lot of peanuts on plantations here in Thomas County. As we were finishing up peanut planting, manager at Wild Ridge Plantation Jason Sanders made a great video of them planting near the Florida line. They filmed it with a drone camera. Jason did a great job making this video. I think I need to get my ‘video band’ down to Wild Ridge and get a band shot from this drone camera.

Our peanut crop is looking good since we’ve had a few weekly rains. Fungicide programs are starting up now, and we’re still needing some rain. We had a few showers this week, but not much to count. UGA Extension Weed Scientist Dr. Erick Prostko has this update on valor that I want to share:

Peanuts that were planted approximately the last two weeks in May were in a great place to get hammered from Valor because of the Sporadic heavy rainfall events (below).  If you received one of these heavy rainfall events on Valor treated peanuts when they are cracking and small (~2 weeks after cracking), injury will occur.

Georgia Rainfall Totals from May 20 – May 24, 2017

 Peanuts typically recover from this injury without a yield penalty.  In a 2009 research trial, more than 5″ of rainfall occurred in the 30 day period after peanut planting.  Peanut injury was significant but yields were not reduced even at a 2X rate.

 

Valor injury to peanut. Photo by Dr. Erick Prostko

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Peanuts Cracking

Dryland peanuts are coming up in the northwest part of the county. This is where we have had more rain. We’re talking about thrips, herbicides and some disease issues now. Below is a graph from UGA Extension Peanut Entomologist Dr. Mark Abney on latest thrips counts:

Thrips numbers on our traps have remained relatively steady for the last 3 weeks, though we did see a spike last week in Colquitt County. My first thrips trials are just now emerging from the ground, and I have not heard any reports of thrips control problems on early planted peanut as of today.

I have had questions this week about rates of imidacloprid for in-furrow applications. I recommend the upper end of the rate range for whichever formulation a grower is using….We should NOT be doubling the rate or cutting the rate in half. Be sure to check the label of the product you are using as rates vary by formulation.

Weed Control

We may not have as much Valor as preemerge out there since we are dry and concern of no activation. Where we have Valor on the ground with good activation (0.5 – 0.75″ within 7 days), it usually gets us through our “at cracking ” treatments until we use Cadre. If we don’t have Valor, we will need to be gearing up for our cracking spray 15 – 25 days after planting. But we only need to apply ‘cracking’ sprays if weeds have come up.

Disease Control

The only note to make is this week’s rainfall this week could help to cool soils, at least in the short term, and reduce risk to Aspergillus crown rot of peanut.

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Disease & Nematode Management Considerations For 2017 Peanut Planting

Peanut growers can use a different products at planting time for the management of diseases and nematodes. Decisions as too what product to use over another, or to use a product at all, can be very confusing. Fighting seedling disease used to be simple- all growers used a fungicide seed treatment, and if they wanted some “stand insurance” they could also spray Abound in-furrow. Today, in-furrow applications are important considerations for the management of tomato spotted wilt, seedling diseases, Cylindrocladium black rot, white mold, and nematodes, not to mention thrips! Below are management options for the growers put together by UGA Extension Pathologists Dr. Bob Kemerait, Dr. Tim Brenneman and Dr. Albert Culbreath:

Note: The rates provided here are on a “per/A” basis. Typically, the full rate can be placed in single rows; the rate is typically halved per twin row. For example, Abound, 6.0 fl oz/A in-furrow for single rows becomes Abound, 3.0 fl oz/A in each of the twin rows:

Management of Tomato Spotted Wilt

Tomato Spotted Wilt Virus

A number of products can be used to manage thrips on peanuts. However, only one product, Thimet (ai: phorate) is effective in reducing the risk to this disease. The reduction in risk to tomato spotted wilt is not related to the thrips control that it provides, rather is seems to be associated with the response of the plant to Thimet. Thimet likely activates defense-response genes in the peanut plant that help to protect the plant from the virus. Growers who want to plant early (before May 1), or who want to use cultivars with spotted wilt risk points greater than those of Georgia-06G, might especially want to consider to using Thimet for management of tomato spotted wilt.

Management of Seedling Diseases

Peanut seed and young seedlings are susceptible to attack from a number of fungal pathogens. The two most important fungal pathogens causing death of peanut seedings in Georgia are Rhizoctonia solani and Aspergillus niger. Fungicide seed treatments are a critical tool to manage seed rots and seedling diseases; currently nearly all seed is treated with Dynasty PD. Dynasy PD is composed of azoxystrobin, fludioxonil, and mefenoxam. However, growers can also protect the developing plants from seedling diseases with in-furrow fungicide applications of fungicides like Abound (5.7-11.4 fl oz/A), Proline (5.7 fl oz/A), and Evito (2.3-3.5 fl oz/A). These fungicides are typically used to compliment seed already treated with a fungicide seed treatment.

Aspergillus Crown Rot

The most effective in furrow spray for stand establishment has been Abound, although Proline also has activity on these pathogens and Evito is labeled for this use as well. The benefits of these products have not been as consistent in recent years, and research is underway to determine the factors involved.

Management of Cylindrocladium black rot (CBR) and early-season white mold

Proline (5.7 fl oz/A) applied in-furrow has been an important treatment for the management of CBR. Though this disease has been less widespread in recent years, an application of Proline in-furrow is still useful where there is a threat of CBR. When favorable conditions, such as very warm weather, occur early in the season, in-furrow applications of Proline also offer some protection from early-season white mold. The extent of the protection is likely less than that provided by banded applications of Proline 3-5 weeks after planting. Decisions to use Proline in-furrow should be made based upon a) risk to CBR, and b) risk to early-season white mold (although there are effective alternatives for white mold).

Mycelium and sclerotia (yellow bee bee’s) from white mold

Management of Nematodes

Nematode-resistant cultivars continue to hold up well against even high populations of root knot nematodes. However, growers electing to plant a susceptible cultivar like Georgia-06G in fields infested with the peanut root-knot nematode should consider the use of a nematicide. Popular nematicides for peanut production in Georgia include Telone II (4.5-6 gal/A), Velum Total (18 fl oz/A) and AgLogic 15G (7 lb/A). To prevent injury to seed and seedlings, fumigation with Telone II should occur 10-14 days prior to planting and when soil conditions are not too dry (powder) nor too wet (mud). Fumigation with Telone II can provide excellent control of nematodes but DOES NOT control thrips. Growers who use Telone II must still apply something for management of thrips.

Velum Total is a combination of fluopyram for management of nematodes and also imidicloprid for management of thrips. Growers who use Velum Total do not need to add any additional thrips control product in the open furrow. (Note that imidicloprid does not reduce the risk to tomato spotted wilt.) Also, use of Velum Total does provide additional early-season management of leaf spot diseases. The extent of this protection from leaf spot is such that growers should be able to skip the 30-day after planting fungicide application for leaf spot, unless they have planted a very susceptible cultivar like ‘Georgia-13M’ or TUFRunnerTM’511’.

A question that often arises is, “If I use Velum Total, do I get any protection against seedling diseases as well?” The “bottom line” to this question is that use of Velum Total should complement a seed treatment and be good “stand insurance” and we would not add anything else. The biggest factor by far to reduce the impact of seedling disease is the quality of the seed and putting that seed in the right soil conditions at the right time.

AgLogic 15G (7 lb/A) is for management of thrips and nematodes. AgLogic does not reduce the risk to tomato spotted wilt. The rate is lower than what was historically used for Temik 15G (10 lb/A). Additional research is needed to assess the efficacy of the 7 lb/A rate on management of nematodes. In high risk field it may be advisable to use a combination of these nematicide options.

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Planting Peanuts

A few growers have started planting peanuts late this week as subsoil moisture comes more of an issue. Most growers will want to pull the trigger next week. We’re planting right now with some fungicide and inoculant in furrow. Here is a few pointers from UGA Extension Agronomist, Dr. Scott Monfort and Dr. Scott Tubbs:

Soil Temperature

It is recommended that the average daily soil temperature remain above 68 degrees for 3 consecutive days and without cold temperatures in the forecast for the next week before making the decision to start planting peanut. With a warm winter so far, the temperatures had been in the “acceptable” range of conditions … during the last week of March.

armer temperatures are expected to return during the week of April 10-16, and I anticipate the 4-inch soil temperature will warm quickly to a point acceptable for planting by the middle of that week. There are no other cool spells showing in the extended weather forecast through April 21, so I anticipate peanut planting should be in favorable conditions sometime next week including adequate soil moisture because of this past week’s rainfall.

It is important to watch for additional rainfall in the forecast, especially under non-irrigated conditions, in order to activate herbicides after planting. Even with soil temperatures above 68 degrees, it will often take peanuts 7-14 days to emerge from the ground in these conditions (with cooler night temperatures still causing some fluctuations in soil temperatures). In ideal conditions, growers would want to plant with adequate moisture, sustained 68 degrees at the 4-inch soil depth, no cool temperatures expected in the 10 day forecast, but some rain expected within one week of planting in order to ensure optimal peanut emergence and herbicide activation to give the best possible growing conditions from the beginning. Hopefully we can get some peanuts in the ground a few days on either side of Easter this year and catch a rain the following week to get this season off to a great start.

Inoculants

Last year was a very hot and dry year. In those conditions, the survivability of the living Bradyrhizobia bacteria needed to inoculate peanuts is generally reduced. Thus, there may less than adequate nodulation of peanut in some fields or some parts of fields if relying solely on native soil Bradyrhizobia to infect the roots of peanut for N-fixation this season. This is true even if planting in short rotation where peanut was planted within the last few years.

I would recommend growers strongly consider the investment in a peanut inoculant at-planting this year, especially in fields that did not have any cover crop residue on them last year to minimize direct heat impact and reduce evaporation of soil moisture in the upper portion of the soil profile. It has been stated before by my predecessors and colleagues, an inoculant application is one of the most cost-effective “insurance policies” at a grower’s disposal.

Depending on the product used and contract price received for peanuts, it usually takes in the neighborhood of 100 lb/ac yield increase to cover the cost of the product. It is common in my research trials and in reviewing research from colleagues to get greater than 100 lb/ac yield increase on average over multiple years of trials even in a standard rotation. More importantly is to consider the cost of NOT applying an inoculant and having a nodulation failure where there is not adequate N-fixation. The cost of applying the amount of N needed by peanut would greatly exceed the cost of applying an inoculant over the course of many, many years. The risk of not getting a return on investment for an inoculant compared to the risk of potentially losing a large proportion of yield potential one year is not an equal level of risk in my opinion.

Keep in mind that the product is listed on the label to be delivered at around 1.0 fl oz per 1,000 linear row feet (may differ slightly depending on which product is selected). This is developed for single row application! Inoculant application is not like adjusting seeding rate, where you are pulling half of the amount out and moving it over to the adjacent twin furrow. With an inoculant, the applied amount needs to be per furrow according to label instructions. Therefore, a twin row planting inoculant application will double the amount of inoculant applied compared to a single row planting. I have no data at this time to support using a half-rate of inoculant per furrow to keep the total application rate per acre the same as a single row planting.

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December Row Crop Disease Update

A few things to think about with regards to disease and nematode management in preparation for the 2017 field season.

La Nina:  Our UGA Extension climatologist Pam Knox has good information available on our current conditions, but here are my thoughts:

We are currently in a “weak” La Nina situation, “weak” because the equatorial waters of the cost of Ecuador are more than a half degree COOLER than normal.  As best I can tell, the waters have been about 7/10 of a degree cooler which barely qualifies as a La Nina (as opposed to last year where we had a robust and sure-enough El Nino).  So what does this mean? During La Nina years, the Southeast tends to (“tends to” means more often than not, but not always..) experience warmer and drier winters. Because we have a weak La Nina, this forecast could change.

Pigweed seedhead in broccoli before Thanksgiving. We are yet to have frost to knock back pigweed growth.

Pigweed seedhead in broccoli before Thanksgiving. We are yet to have frost to knock back pigweed growth.

How does our current “La Nina” impact our recommendations?

  1.  Drier is not a good thing as it may mean we don’t fill up irrigation ponds for next year.  It my mean we have a lot of trouble establishing cover crops this fall.
  2.  Warmer temperatures may mean that kudzu, volunteer peanuts, corn, cotton-regrowth, etc. pathogens (like those that cause soybean rust and southern corn rust) may survive and increase longer than they would with an earlier “killing” frost.  Also, as long as the crops and volunteers are active in the field, nematode populations can continue to increase and build.  This will lead to larger populations for next season. Once the plants are killed, the nematodes can no longer feed. Once soil temps drop below 65F, the activity of the todes drops off as well.
  3.  We may get some very cold weather soon, so we may not need to worry that much; however the general prediction is that we will have a warmer winter.
  4.  The weather this winter will have some effect on TSWV and insects for next year.  It remains to be seen what and how… but it will impact them.

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Filed under Corn, Cotton, Disease, Peanuts, Soybeans, Weather