Monthly Archives: May 2015

Planting Browntop Millet

BrownTopMillet (3)

Here a picture of planting browntop millet. Browntop millet (or dixie signalgrass)  is grown for several different things, here for wildlife attraction (dove fields) with many plantations in Thomas County. It is also used in erosion control, straw production, and forage production. It is occasionally used for grazing or hay production. Browntop typically grows only to two to five feet tall and produces only 60 to 70 percent of the dry matter of pearl millet or sorghum x sudan hybrids.

BrownTopMillet (2)

Browntop millet can be planted from mid-April until mid-August in most locations, though later plantings will result in lower yields. To establish browntop millet, broadcast 20 to 25 lbs of seed per acre on a prepared seedbed in spring. Seed should be covered to a depth of 1/2-inch in a firm seed bed.

BrownTopMillet (6)

Here is a link to more info on warm season forages: Georgia Forages: Grass Species

Leave a comment

Filed under Grain

Scouting For Thrips In Cotton

Cotton 009

Cotton planting started last week and here is some coming up on the east side of the county. Plants are emerging with either cotyledons present or cotyledons + first true leaves emerging. So far, plant stands look good. Both of these fields are irrigated. We are running out of moisture in dryland fields – especially conventional till. In fields were tillage has been minimum or a cover crop exists, we still have some moisture.

I wanted to check for thrips. They will initially feed on the lower surface of cotyledons and then in the terminal bud of each developing seedling. We expect to see higher thrips infestations on early planted cotton in conventional tillage systems.

Foliar Application Threshold

Many at-plant insecticides are used including in-furrow sprays and seed applied systemics. This is good, but we still need to be aware of conditions favoring thrips. For fields planted after May 10 or where reduced tillage is used, the risk of high thrips infestations is lower. Our threshold for thrips to use foliar insecticides – with or without at-plant insecticide – is when 2-3 thrips per plant are counted and/or immatures are present. The immatures (without wings) are yellow. The presence of immatures means at-plant insecticides are no longer active. (The best way I learn to scout thrips is take a small piece of white paper, and hold it under the plant. Flick the plant over the paper, and you will see thrips crawling on the paper.)

Thrips inury is cupping of the leaves

Thrips inury is cupping of the leaves

I counted thrips in a few fields yesterday and found no immature thrips. On average, I observed 1 per seedling. This is nearing threshold, but good to see no immatures present. Something to consider is our warm growing conditions now. Seedlings become more tolerant of thrips feeding as they develop, and a fast growing seeding can better tolerate thrips feeding. A plant that is under stress from cold or herbicide is more likely injyred by thrips since it stays in that young stage.

However, negative impacts of warm weather is our winter crops drying down. I am seeing this in the field now. Once our rye, ryegrass, etc. dries down, thrips will move to something green to reproduce. UGA Extension Entomologist Dr. Phillip Roberts expects it to be a normal year for thrips; therefore, we need to be scouting fields and preparing for foliar applications.

Leave a comment

Filed under Cotton, Entomology

Wheat Closer To Harvest – Fusarium Head Blight A Concern

Wheat 011Here is a field in the northwest part of the county that is getting close to harvest. This field started with a less desirable stand, but you wouldn’t notice now. It is at milk stage progressing towards Feekes 11.3 where the kernel is hardening. There was a fungicide applied at heading, which has helped with disease. Rain in this part of the county is also much less than average, so this helps when disease is present.

Here is a brown stink bug on a head.  Sometimes wheat is infested with stink bugs during grain fill. The brown and southern green stink bugs may reproduce and have a complete generation in wheat before harvest. However, according to UGA Extension Entomologist Dr. David Buntin, they almost never require control. As wheat dries down, stink bug adults disperse to nearby summer crops. We would only treat if 1 or more stink bugs per square foot are present at milk stage. Treatment is not needed in the dough stage.

However, when wheat harvest gets underway, we need to pay close attention to the corn crop as stinkbugs will move to corn. UGA Extension Agronomist Dr. Dewey Lee says this could be a problem particularly around VT/R1 stage.  Corn is very susceptible to stinkbug damage at this stage. Dr. Lee recommends applying an a labeled insecticide by airplane rather than through the pivot.

Brown Stink Bug

Brown Stink Bug

Fusarium Head Blight – Dr. Dewey Lee, UGA Grain Agronomist (5/11/15)

The last four weeks, I have answered lots of questions about fusarium head blight, stagonospora glume blotch, tan spot, rust and even the possibility of cold damage on pollen from frost and loss of pollination.  All of these are potential causes of yield and test weight losses in small grains.  The biggest ‘killer’ though is fusarium head blight (FHB)…It will produce a vomitoxin called deoxynivalenol, more commonly called DON which in high enough concentrations will cause the grain to be rejected from the market. Over the last two + weeks, I’ve received a lot of samples or pictures which have demonstrated widespread infection of FHB.  As I stop and look at fields, it is evident that FHB is the major cause of our problems and the yield loss appears to be substantial.  Additionally, rye, barley and triticale are also affected by the disease.

Fusarium Head Blight

Fusarium Head Blight

The wheat fields that I have visited appear to have a 50+% loss. it is easy to see the shriveled, affected grains. Upon separation, the shriveled grains accounted for 50 to 65 % of the total grain set on the heads.  In most cases, even where growers applied two fungicide applications, yield loss from FHB is still high. I had hoped that we got by without much infection, but rain saturated the fields that flowered earlier as well as those that were still flowering, leading to considerable infection rates. Unfortunately, we can’t spray by air when it’s raining, misty or foggy…..which is the time we see high rates of infection.  You may read that Prosario , Proline , and others listed as preferred fungicides however, they are not 100% effective and by some accounts only 60 to 70%.

Leave a comment

Filed under Entomology, Grain

Corn Needs Water

Corn-001

Our earliest corn is progressing through the V9-V11 growth stage. This is planted in what is usually our driest part of the county, so we must be on top of irrigation. With no rain in more than 10 days, keeping up with irrigation is critical, especially for corn around V6 growth stage where yield potential is being determined. Many growers may be using moisture monitors or other technology to determine when and how much to irrigate.  If you do not use one of these methods, consider using the checkbook method for scheduling their irrigation events. Terrell County Agent Nick McGhee has put together tables from the “checkbook method” from the 2015 UGA Corn Production Guide:

Corn Water Use At Various Growth Stages

EstimatedWaterUseInCorn-Table-10

Water Holding Capacities of Coastal Plain Soils

WaterHoldingCapacities-Table-11

Checkbook Method Example

This example shows how to use the two tables above and the “checkbook method” to determine when and how much to irrigate.

Step 1. The soil type of the corn field is a Tifton soil series. In Table 11, look at the average available water holding capacity in in/ft increments. Assuming a rooting depth of 24 inches (2 ft), the total available water is 2.2 inches (2 ft x 1.1 in/ft)

Step 2. The corn crop is 65 days old. From Table 10, the daily water use is about .31 inches/day

Step 3. Determine the irrigation by setting a lower limit of available water due to soil tension. For this example use 50% of allowable soil water depletion. In other words, only half of the water in the root zone will be allowed to be depleted. Therefore, 1.1 inches of water will be needed to replace the soil water that was either used or lost.

Step 4. Determine the amount of irrigation to apply by dividing the amount replaced by an irrigation efficiency. Assuming 75% as the irrigation efficiency, the amount of irrigation to required is 1.1/.75 = 1.47 or 1.5 inches.

Step 5. Determine the frequency of irrigation by dividing the amount of water replaced by water use per day. An example of frequency of water (either rainfall or irrigation) need: 1.1 in /.31 in per day = 3.5 days.

Step 6. Therefore, it is necessary to apply 1.5 inches of water every 3.5 days to maintain 50% available water for 65 day old corn.

We are also seeing some nitrogen burn and herbicide drift causing these spots on the leaves. Below is drift from herbicide and is common in all corn fields, but nothing to worry about.

Corn-Herbicide 007

Leave a comment

Filed under Corn, Irrigation

Pecan Nut Casebearers: Should We Spray?

NutCasebearer (3)

We’re approaching the time when Pecan Nut Casebearer (PNC) is normally treated in the state. There has recently been a lot of debate regarding just how much damage PNC does to the pecan crop here in Georgia. In Texas, PNC is a terrible pest. It’s a much different situation in Georgia.

UGA Extension Pecan Horticulturalist Dr. Lenny Wells has these comments:

Casebearer Damage, Photo by Dr. Lenny Wells

Casebearer Damage, Photo by Dr. Lenny Wells

I saw a few orchards over in the Blackshear area with multiple generations of PNC last year. But, I have never seen that anywhere else in Georgia. If I were one of these growers with problems last year, yes, I would spray for PNC this year, but otherwise I would give the PNC spray considerable thought before making the application.

Ted Cottrell with USDA in Byron has done extensive work regarding PNC damage and management here in Georgia and all the data points to the fact that PNC is almost never an economic pest of pecan. In other words, you can spray it, but it costs you more to make the spray than you lose in the value of the nuts the PNC damages. Its easy to spray them ‘just in case.’ But, growing pecans is a business and a good businessman recognizes the $10 per acre spent on an unnecessary PNC spray in a 100 acre orchard represents $1000 that could have been better used elsewhere in the operation.

Casebear Egg - Photo by Dr. Lenny Wells

Casebear Egg – Photo by Dr. Lenny Wells

Capturing moths in pheromone traps does not relate to the amount of future nut injury you may or may not have in the orchard. This simply provides an alert that egg laying by female moths will begin 10-14 days after a peak in trap catches. Traps really should have been placed in the orchard in mid April. Detailed information regarding scouting can be found by visiting the Pecan IPM PIPE website.

If no PNC injury is detected after treating, it is wrong to assume the treatment controlled PNC injury if no significant injury occurs anyway. Of course, this can work both ways. The only way to be sure whether or not you need to spray is to scout for eggs on the nut clusters.

In a year with a good crop load, such as we appear to have this year, PNC can even help to thin the crop a little, which may be needed. In addition to costing extra money, unnecessary sprays of some insecticides (chlorpyrifos) can lead to early season aphid problems. This contributes an additional cost to making the PNC spray. If growers choose to spray anyway, avoid broad spectrum materials like Lorsban or pyrethroids. Belt, Intrepid, or Dimilin are better choices for those who will sleep better at night when spraying.

Leave a comment

Filed under Pecans

Thrips Monitoring – April 25 – May 1

Here is an update on thrips monitoring from UGA Extension Peanut Entomologist Dr. Mark Abney:

There were very few tobacco thrips on our traps last week. What does that mean ? It means there was no large migration/dispersal of thrips last week. It does not mean that peanuts that emerged two weeks ago will not have thrips on them, and it definitely does not mean that peanuts going into the ground this week are at reduced risk for thrips damage. We need to keep an eye on our fields as they emerge and especially as they get a few weeks post emergence when at-plant insecticides may begin to run out.

Thrips-Graph-5-1-15

Questions have come in about the use of imidacloprid on twin row peanut. As mentioned in an earlier post, there are two formulations of standalone imidacloprid available (2F and 4.6F) and one premix formulation of imidacloprid and a nematicide (Velum Total); the rates are different for the three formulations. Check the label of the product you are using to be sure the rate is correct. The amount of product that can be applied per acre does not change with single vs. twin row patterns. That means that in twin row patterns, each twin row will have half the amount of product that would go under a single row. I do not have any data from trials where imidacloprid was applied under twin rows. We are currently testing this and other thrips management practices.

Leave a comment

Filed under Entomology, Peanuts

Corn Purpling

Corn-PDefficiency 005

Here is some dryland corn planted in central Thomas County that has shown these purple symptoms for some time. This purple on the outer edges of the leaves is due to a phosphate deficiency. This corn is in the V5 growth stage, and we would normally see these symptoms earlier than now. UGA Extension Fertility Scientist Dr. Glen Harris says symptoms of phosphorus deficiency are different within variety. One variety may show more purpling than another.

Phosphate deficiency in corn

Phosphate deficiency in corn

This field was soil tested and the proper amount of P was put out at planting. Dr. Harris says the cooler temperatures have allowed this to show up. Phosphorus is not soil mobile and is taken up by “root interception.” When soil temperatures drop and roots cease to grow, phosphate deficiency results. If this field had no P at planting, then it would be recommended to apply some 10-34-0. Since P was put out at planting, the corn will grow through this.

Leave a comment

Filed under Corn, Fertility

Pond Weeds – Fanwort

Fanwort (3)

FanwortHere is a pond I looked at yesterday infested with fanwort, also called cabomba. Fanwort is a submerged, perennial weed.  The submerged leaves are opposite, and attached by a single petiole. Above the petiole they form a “fan-shaped” leaf. Fanwort also has a small white to pink flower which forms on the tip of the stem and stands just above the surface. One of my photos shows the flowers across the surface of the water.

UGA Extension Aquatic Scientist Dr. Gary Burtle says diquat has been used successfully on fanwort.  Fluridone can also be used if water flow through the pond is minimal. This pond has dense weed growth, so repeat treatment will be advisable.

Stock grass carp at 10 per infested acre following chemical application in order to obtain long term control.

Here is a link to more information on biology of Fanwort.

Flower of fanwort

Flower of fanwort

Fanwort (5)

Fanwort flowers

 

Leave a comment

Filed under Aquatic Environments

Peanuts Cracking, Weed Control Options

We have some peanuts coming up in the northwest part of the county. Here are some twin row 06G. Thanks to Mitchell County Agent Andy Shirley putting together a few herbicide options from UGA Extension Weed Scientst Dr. Eric Prostko:

PeanutsCracking 010

WeedControl-2015-1 WeedControl-2015-2 WeedControl-2015-WithoutValor

Leave a comment

Filed under Peanuts, Weed Science

April 2015 Crop Enterprise Cost Estimate

UGA Extension Economists have revised the April Crop Comparison Tool which can be found at that link.

April-CropEnterprise

Leave a comment

Filed under Economics