September 30, 2015 · 6:53 PM
We are almost done harvesting milo for grain in Thomas County. This is the first season all of us have dealt with sugarcane aphids from beginning to end. The majority of fields in the county have been treated 4 times for aphids. This does seem like a lot of sprays; however, in these fields, yield reports are good. In these fields, SCA was spotted early and treated at or below threshold.
There was a few fields that were treated late, according to threshold. SCA reached the top of the plant before spraying. A couple of weeks later, the lower leaves completely desiccated due to aphid pressure. These yields are much lower than average. Other reports are were volume is high, 17%-19% moisture, test weight is low. Could this be from SCA?
UGA Extension Entomologist Dr. David Buntin says, yes, this can be the result of SCA. However, test weight be also be related to wet and dry cycles. And this season will certainly be marked by wet and dry cycles. Another issue we have noticed are small heads and large heads. Dr. Buntin says when heads are in two or three different stages of growth, this is result of SCA. SCA don’t have huge phytotoxic effect of feeding, but lots of feeding over time delays heads emerging.
At this stage, we still need to check heads for aphids. Mississippi saw a 20% yield reduction when aphids persisted into the heads.
September 30, 2015 · 6:52 PM
Here are some more slide from UGA Extension Economist Dr. Nathan Smith on PLC Payments.
September 29, 2015 · 2:08 PM
Here are some slides by UGA Extension Economist Dr. Nathan Smith on our current peanut situation. Thanks to Seminole County Agent Rome Ethredge for organizing these slides for use.
September 24, 2015 · 4:21 PM
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September 23, 2015 · 8:59 PM
At the beginning of this month, I started getting lots of turf calls about caterpillars. We are still seeing them rampant now. They are sod webworms and different species of armyworms. I have mostly seen sod webworms, which are less than an inch long and have dark spots over their body. They overwinter as caterpillars in protective webbing. In the spring, they feed and molt into the pupal stae. The adults emerge, fly and mate. They have two or three generations a year.
Sod Webworm damage
It is recommended to treat in the young larval stage; however, its later instars that do damage to the turf. It’s easy to see the chewed grass blades. Sod webworms tend to survive better in higher-cut turf. This season, I’ve noticed them in St. Augustinegrass. I have seen them previously in centipedegrass.
We have been discussing treatment and checking behind turf that has been sprayed. You won’t find the dead worms because the organic matter is very high, unlike row crops, where dead bodies are quickly broken down by microbes and fungus is thatch. UGA Extension Enotmologist Dr. Will Hudson says they have developed an adaptation where if they are sprayed in the latest larval instar, they will go ahead and pupate. In South Georgia, caterpillars can be in issue through the month of September.
What about adult moths? We are still seeing a high amount of moths. It is not recommended to treat moths since most moths do not produce caterpillars that survive to a size that will do noticeable damage. Dr. Hudson says – as of now- it’s pretty late in the season for another generation to do much damage to a healthy lawn.
Another pest I just saw this week is damage from chinch bugs. Chinch bugs infest during dry conditions. Our rain in Thomas County has been very spotty the last 3 weeks. We’ve been over a week in town without rain, and I saw this damage at our courthouse. There was no chewing on the grass blades, so I looked in the grass and found chinch bugs.
Chinch bugs have the piercing/sucking mouthparts like stinkbugs and feed at the base of the grass blade. This damage shows up as discoloring of the leaves and stolons. They tend to associate with St. Augustinegrass. They feed in clusters and damage first appearch as circular patches of yellowing turf that resemble drought. They are very tiny – can fit inside your pinky finger nail. Pull back the grass and look through the thatch. If they are present, you will see the bugs crawling around. They are so small, it is difficult to catch them.
Second Instar Chinch Bug
Here is one I caught and put on the microscope. I could tell he did not have wings and is immature. They have a gradual metamorphosis where immature resemble mature except without wings. The only difference is color. I sent this to Dr. Hudson and he said this is second instar. The first instar is bright red, then this color for the next. Then they turn gray for a couple of molts, then get darker for the last stages. I was asking him about white color ones I was seeing but couldn’t catch. “The whitish looking ones are probably adults, since the wings are reflective and give a white appearance.”
Filed under Entomology, Turf
September 22, 2015 · 9:24 PM
Pecan leaves can start to show symptoms of minor disease in the late season. Most of the time, it’s nothing to worry about. These foliar diseases won’t defoliate the trees in the next few weeks. The leaves are beginning to senesce anyway. UGA Extension Horticulturalist Dr. Lenny Wells has information on one of these issues:
Photo by Dr. Lenny Wells
One of these raising its head (now) is a relatively new disease we began seeing just 4 or 5 years ago. Symptoms are expressed initially as a dying or browning of the terminal leaflets on a compound leaf which progresses backward toward the base of the leaf. Eventually it moves into the leaf rachis (the main stem of the compound leaf) and the entire compound leaf may die. If you stand back and look at a tree infected with this disease the scattered dead compound leaves will look like dead brown patches in the tree. UGA research pathologist Tim Brenneman has identified this as a fungal pathogen called Neofusicoccum. I will be referring to it as “terminal die-back.”
Most minor foliar disease like this infect the leaves a month or two prior to symptom expression. Dr. Brenneman suggests use of a strobilurin or a DMI/strobilurin mix like Absolute or Quadris Top when conditions favor infection (usually prolonged wet conditions). Even if a grower has used these materials, their timing may have been off enough to allow infection. Once you see the symptoms its too late to do anything about it. But, even when terminal die-back occurs earlier in the season we have not seen any long-term damage to the trees and no effect on nut quality so don’t get too alarmed when you see this problem.
September 17, 2015 · 9:28 PM
Here is a Tift 85 pasture that has been cut twice so far and is showing symtpoms down on the leaves and lower down the stem. We are seeing both leaf blight (helminthosproium) and leaf rust. These issues we commonly see in late summer when weather is warm, usually between 75 degrees F and 90 degrees F, and with high relative humidity.
Bermudagrass leaf spot is caused by a fungus from the genus Helminthosporium, and the disease has been informally called Helminthosporium leaf spot, Helminthosporium leaf blotch, or Leaf Blight. Leaf lesions of helminthosporium are irregularly shaped and brownish green to black in color. We may see it in irregular patches. Leaf spots are more numerous near the collar of the leaf blade.
Leaf Rust postules
Leaf rust or Puccinia disease has similar impacts as Helminthosporium. We will also see red to orange lesions can on leaf and stem. Look for a raised area or blister which is the rust postules like we see in wheat and corn. Rubbing your finger over the leaf will leave a rusty color.
Management is strictly avoidance. Coastal, Tift 44, and Tift 85 have some level of resistance while Alicia is extremely susceptible. But even less susceptible varieties are infected with leaf spot when potassium is low. Most reported leaf spot cases are directly related to low soil potash. Nutrients are removed from bermuda hay fields in about a 4-1-3 ratio of N, P2O5, and K2O with harvest. We need 75 percent as much potash as nitrogen applied each season. Split applications of K are better in sandy soils. With helminthosporium, removing the inoculant is also recommended. In addition to tying up nutrients, thatch holds water and reduces air circulation. This is a conducive environment for inoculum. The only practical way to reduce thatch is burning in spring before green-up.
Visit Leafspot Diagnosis and Management in Bermudagrass Forages for more information.
Filed under Disease, Pasture
September 17, 2015 · 1:02 PM
Looking at peanuts in the field and having peanuts checked for maturity, we are seeing more leafspot show up. Some growers have said it literally showed up over night. Most of these peanuts are close to the Florida line. We see late leafspot get on these peanuts many times. Some defoliation has been noted. Here is a picture of late leafspot sporulating on the bottom of the leaf.
Here are some comments on late leafspot from UGA Extension Pathologist Dr. Bob Kemerait from the 2015 Peanut Update:
- Finding some leaf spot in a field at the end of the season is usually not a problem. As long as the diseases are controlled throughout the season, limited defoliation (up to about 30 – 40%) is not likely to affect your yeield. The appearance of leaf spot at the end of the season typically does not mean that your program was ineffective or a failure.
- Some grower in Florida are mixing chlorothalonil with Topson-M or Topsin 4.5F or copper fungicides such as Kocide for their final leaf spot sprays to increase peg strength prior to harvest. What do we recommend in Georgia?
- Combinations of chlorothalonil and Topsin-M currently provide excellent control of leaf spot.
- Combinations of chlorothalonil and copper are also effective in the control of leaf spot.
- Data collected at Clemson University demonstrates that peg strength is not increased with use of Topsin-M, Topsin 4.5F, or copper.
- Failures in leaf spot management in a peanut field are often linked to:
- Unacceptable delays in starting your program.
- Improper calibration of equipment (not enough material applied).
- Unacceptable delays between applications (weather conditions keep growers out of a field).
- Rain events immediately after a fungicide application have washed fungicide away.
Filed under Disease, Peanuts
September 16, 2015 · 1:08 PM
We’ve been digging peanuts for a few weeks in Thomas County now. However, more and more are coming out of the ground each week. We were looking at 130-140 days, and now the same profiles are moving past 140 days. Some fields have been dry and difficult to invert. There’s been some rain on some of the crop since we started digging. Rain has been in spots and is causing some issues with growers now. Other places in the county are having more ideal harvest conditions. Here is a six row digger in Ochlocknee.
At this time, we also need to watch for dryland peanuts getting stressed and turning loose in the hull. I’ve checked many more profiles this week and starting to see a higher percentage of kernels turn loose. Here is Brandon Hickey checking some peanuts just after digging.
I’ve also been asked about any cotton picking starting. East of Coolidge we have some cotton being picked this week. This is some of the first I saw defoliated and is dryland where we cutout sooner.
Some reports of grades coming in from dryland fields are good. Other reports say grades took a small downturn this week. Still have a ways to go.
Filed under Cotton, Peanuts
September 11, 2015 · 5:20 PM
Digging has been going on for a few weeks in Thomas County. Our acreage is mostly dryland and mostly almost all 06G variety. This is our third week scraping peanuts. Until this week, many samples were running 130 – 140 days. That is sooner than last year and the year before. Some fields with less rain are not moving and pushing into the 140s. Peanuts need both heat and moisture to mature. We have seen it drop in temperature since the last week of August and supposed to be cooler this weekend.
I’ve seen much less “split” profiles this season. This happens when the peanut crop goes through a period of no rainfall. This makes the digging decision more difficult – going with the current crop or waiting on the next. Our profiles have been more consistent like this one below.
Another thing we check for is peanuts turning lose in the hull. This is when the funiculus detaches from the peanut kernel breaks away from the pod and thus the plant. Once the peanut has ‘turned loose’, it no longer matures. We need it to stay attached to continue feeding and gain weight. It will detach through normal maturity OR when under stress. Many of our dryland fields have been under stress, and high percentages of peanuts turning loose also makes our digging decision more difficult. Seminole County Agent Rome Ethredge made a good blog post on Funiculus explaining this works.
Here is some more information from UGA Extension Peanut Agronomist Dr. Scott Monfort on current peanut maturity:
Based on our own Hull-Scrape Maturity Profiles on some of our research trials (GA-06G) and feedback from many county agents, the early to middle of April and Early May planted fields are tracking around 140 days after planting (DAP) time frame. This is not surprising but many growers have commented that we are ahead of schedule due to the heat. We are not that much ahead, if any. Most of the other cultivars like GA-12Y, GA-13M, and the TUFRunner Cultivars are looking more in the 145-155 range.
Here are other factors to consider when determining optimum digging time:
- Is the sample representative of the field?
- How many acres does sample represent?
- What is Variety/Planting Date?
- Irrigated/Non-Irrigated. If Non-Irrigated, have you received adequate rain etc.
- What do the vines look like?
- Any disease/TSWV?
- Make sure to open pods and look at the peanuts. How many are coming loose?
Do not forget the Non-Irrigated Acres! Pull samples from the non – irrigated acres in the 110 to 130 day old range. We have seen several non-irrigated fields that received good rains early but no rain in the last 3 to 4 weeks and they are ready to go. Some peanuts are beginning to come loose in the shell in these fields due to the lack of rain.