Category Archives: Cotton

Irma’s Aftermath

We were very fortunate in Thomas County since the eye passed east of us. Our winds were in the 40s with gusts in the 70s. There is still obvious damage to our field crops. Here are some pictures of what we have now:

Peanuts

The only negative effect will be altering our digging time, if the field needed to be dug in that time period. We had some peanuts already inverted, but they are drying and will be picked this week. The soil is drying with a few days of sunny weather.

Cotton

It’s about 50/50 with wind damaged fields. Where wind hit hard, cotton is all tangled up. And any bolls/lint that fell off the plant is for sure lost. This is going to affect us on our picking efficiency and spraying. UGA Extension Cotton Agronomist Dr. Jared Whitaker says, “One thing to consider is that cotton that is just beginning to open is the heaviest it will be throughout its life and when opening proceeds, it will allow the plant to stand up.  However, one thing that I’ve seen that I haven’t in the past with blown over cotton is the “rooting out” around the stem at the ground level due to winds from several different directions. This could complicate the issue of cotton standing up and exacerbate the issue of standing up.”

There is more damage to younger cotton that will not be known at this time. Right now, you see a lot of reddening of the plant at the top. This is from stress, but multiple factors can cause this stress. We looked a blown over field today where it was obvious whiteflies were not treated. You will also notice stemphyllium leaf spot this time of year with loss of potassium. But the wind can also cause this symptom, and will hurt cotton in providing energy to those bolls.

Pecans

UGA Extension Horticulturalist Dr. Lenny Wells’ preliminary estimate is that about 30% of the state’s total pecan crop has been lost. This has become the most damaging wind event ever seen by the Georgia pecan industry. Again, most of the damage east and north of us. In Thomas County, we are a little under that 30% based on what I am seeing.

We mostly have limbs / nuts lost, but also some trees down. These are similar trees we lost with Hurricane Hermine – mostly in that 5 – 15 age range. Here is some more information from Dr. Wells:

Growers should take photos of their damage and report it to their local FSA office in order to receive financial assistance with cleanup. Cleanup funds normally pay 75% of the USDA-set cost of a mature tree ($300) up to a maximum of $200,000 per entity. Younger trees will be valued at varying levels depending upon age. In addition, the Tree Assistance Program (TAP) will pay for tree loss when 15% or more of the orchard is destroyed. This pays 65% of the cost of the tree up to a maximum of $120,000 per entity.

This money is not available immediately but your FSA office will gather your report. Requests for cleanup funds are made to Congress and they will then appropriate the funds so it may take a while.

Growers have many questions regarding how to handle fallen trees and the mass of green nuts blown from the trees. The success of righting blown down trees varies considerably with age of the tree. Trees less than 8-10 years old (trunk diameter < about 10 inches) can generally be righted with pretty good success, if leaning less than 45 degrees. Success rate is highly variable when leaning more than 45 degrees.  Success of righting these trees will be much greater when trees are pruned back as if they were to be transplanted with a tree spade because the newly-limited root system must be able to support the tree that remains. The larger the tree, the more you should prune off when righting.

Uprooted trees or those lying flat on the ground should be removed, especially large, mature trees. Such trees often never perform as they should and will be likely to be blown down again at a later date. Uprooted trees usually exhibit visible broken roots on the side opposite of the direction of fall. The major roots on the opposite side of the tree are also generally broken as well. Such trees usually have much more root damage than is apparent.

I’ve had many questions about salvaging the green nuts blown onto the ground and having them de-shucked. In most cases, the expense involved in this will outweigh  the benefit. While there are a significant number of nuts on the ground, in most cases, the volume will be less than most growers think. Pawnee shucks were splitting or open and many of these nuts came out of the shuck and are on the ground. Many would have been ready for harvest this week so these nuts can be salvaged once the debris is cleaned up. Early October harvest nuts like Caddo, Oconee, Elliott, Moneymaker etc. may be far enough along to attempt de-shucking if growers are inclined to do so. However, they need to bear in mind the cost of an additional harvest, transport, cleaning, and de-shucking when making this decision. Later varieties like Desirable, Stuart, Cape Fear, Sumner,. etc. are likely not mature enough for de-shucking even though the kernels may be filled out. If the nut does not pop out of the shuck when stepped on or rolled with your foot or if the shell is still white and the markings have not developed growers should not attempt de-shucking.

There is potential for further damage to appear at a later date from nuts getting knocked around in the storm. This often bruises or damages the shuck and affects development or maturity of the nut and may lead to stick-tights. However, my early observations are that this bruising is minimal. I do not see a lot of bruising as of yet on the shucks so I am hopeful  but it is still a bit early to tell whether or not we will escape this type of damage.

All in all, the Georgia pecan industry has suffered a significant blow but it could have been much worse than it is given the severity of the storm.

Advertisements

Leave a comment

Filed under Cotton, Peanuts, Pecans, Weather

Row Crop Disease Update

In cotton this week checking whiteflies, we are reaching treatable thresholds by the way… I am also seeing some target spot in RANK cotton. Also, it is very low on the plant and is not moving up. Cotton I’ve looked at is 4th and 5th week of bloom. Below is a current disease update from UGA Extension Pathologist Dr. Bob Kemerait:

Cotton

The current weather is very favorable for development of target spot and also spread of bacterial blight.  To date, bacterial blight is only a problem in susceptible varieties…The season is not over yet, and things could change.

Target Spot seen in ‘rank’, irrigated cotton, but on the very lower leaves.

TARGET SPOT:  In some, but not all, of your trials  target spot is a significant issue. From your trials, some varieties are CLEARLY for susceptible. Conditions we have now are perfect for it.  Should every grower spray every field for target spot?  NO!  But growers SHOULD BE AWARE. In one field, target spot was becoming established, and I told him I would likely treat the field with a fungicide. In another field, no target spot was found and I told him I would not treat that field.

Peanuts

We are at a critical point in the peanut season. Reports of white mold in fields are coming in every day and I am receiving some reports of leaf spot. I don’t know of any fields where leaf spot is “out of control” and only one field where white mold is “breaking loose”.  However, both diseases can be explosive given the right environment and time to become established. Growers should stay on an appropriate fungicide program for these diseases and also Rhizoctonia limb rot. Timeliness and coverage are CRITICAL.

Soybeans

Asian soybean rust has been puzzling this year. We found it in kudzu very early in the season, yet to date it remains confined to kudzu in our southern tier of counties. I still expect soybean rust to “break out” as southern corn rust has done, but I can’t understand what it is doing now. Fortunately, our Sentinel Plots are being monitored, so we can keep you up-to-date. Even though the disease has been slow to develop, I still believe that there is merit, especially in southern Georgia, to protect the soybeans during late-bloom/early pod set, especially when applying something like dimilin and boron. There are other diseases, such as frogeye leaf spot, which can be problematic and that can be managed with the same fungicides at the same time.

Leave a comment

Filed under Corn, Cotton, Disease

Scout Cotton For Corn Earworms

UGA Entomologists Dr. Phillip Roberts and Dr. Mike Toews put this information together on corn earworms in cotton.

During the past week we have received a few reports of escaped corn earworm CEW) larvae in Bt cottons which exceed recommended thresholds. Bt cottons are not immune to CEW and never have been. All Bt cottons should be scouted for CEW and growers should be prepared to react in a timely manner if thresholds are exceeded. We have planted Bt cottons for over 20 years.  The technology has moved from a single Bt gene to two gene and now three Bt genes. The addition of Bt genes was for two reasons primarily; 1) to improve efficacy and increase the spectrum of activity and 2) for resistance management. The slide below is a general rating for Bt cottons for various caterpillar pests.

Activity on CEW varies by technology, however all technologies should be scouted. Entomologists in Georgia and other areas of the cotton belt believe we are seeing changes in the susceptibility of CEW to some Bt genes. We have been fortunate in Georgia in that only a small percentage of Bt cottons have required treatment for escaped CEW in recent years. However we have observed changes in performance of Bt corn in recent years, i.e. seeing more damage to corn ears. We are also seeing more feeding on squares in Bt cotton which was very rare 5 years ago. One aspect of Bt cotton that we must not forget is that all Bt cottons continue to provide excellent control of tobacco budworm.

When scouting Bt for CEW cotton scouts should examine the top 12 inches of the plant for eggs and larvae and also examine one bloom, one bloom tagged boll (be sure to look under bloom tag), and an additional boll lower in the canopy. If any damage is observed on the plant the entire plant should be searched. It is important to size larvae as small (< ¼ inch) or large (> ¼ inch). Once larvae reach ¼ inch in length it is likely those larvae will survive on the Bt plant and continue to feed. When we observe escaped CEW larvae they are often associated with fruiting structures near the uppermost white bloom.  So make sure you check blooms, bloom tagged bolls, and small bolls closely. The slide below shows various images of CEW in cotton.

The threshold for CEW larvae in Bt cotton is when 8 larvae ¼ inch or greater in length are found per 100 plants. When treating escaped CEW in Bt cotton coverage and penetration of the canopy with sprays will be important.  We must get the insecticide to the target as larvae will likely be down in the plant canopy. Control of larvae in bolls and under bloom tags will be difficult.

Pyrethroids have been the standard treatment for CEW for many years.  In parts of the cotton belt pyrethroid activity on CEW has deteriorated. For example some states in the Mid-South do not recommend pyrethroids for control of CEW due to pyrethroid resistance and field control failures. We annually monitor CEW susceptibility to pyrethroids in Georgia using adult vial tests. Basically we capture adult CEW moths in pheromone traps and place those in pyrethroid treated vials and monitor survival. During recent years and especially during 2016 we observed increased survival of CEW in these tests which suggests susceptibility is changing. However, we have not observed or been made aware of any field control issues when pyrethroids have been used for CEW control. With that said, we have made few field applications of pyrethroids for control of CEW in any crop during recent years. Bottom line is it will be important for us to check behind pyrethroid applications targeting CEW. There are non-pyrethroid alternatives that will provide very good control of CEW.  The slide below illustrates CEW survival in pyrethroid treated vials.

 

Leave a comment

Filed under Cotton, Entomology

Spider Mites In Cotton

With this heat, it gets dry quick. I found a few plants with evidence of spider mites yesterday. This of course is not good since it is early. When we are scouting fields, look for spider mites. Look for the reddening on the “V” part of the leaf. UGA Extension Entomologist Dr. Phillip Roberts says early detection is critical.

**The best management practice is to NOT flare spidermites with unnecessary insect sprays. If our retention is good (plant bugs), stink bug threshold is low, and aphids have crashed, we need to hold back. It’s about to get hotter, and dry weather makes them worse too.

Leave a comment

Filed under Cotton, Entomology

Cotton Blooming: Insect Update

Some of our earliest planted cotton is now blooming. I thought it would be good to go through an insect update.

Aphids / Beneficial Insects

As reported last week, we found the aphid fungus in Thomas County. UGA Extension Entomologist Dr. Phillip Roberts located the fungus in Tift County last week. Once it’s found in a field, it takes about a week to ‘crash’ the aphids. There are still reports of aphids this week, and I’ve had a question or two. Remember, UGA has not found any yield difference in treating aphids. We’ve had more aphid populations this year, but I would hesitate on treating, especially when they are in ‘hot spots.’ We need to watch beneficials.

In one field this week, I saw many, many lady beetles. On one plant, I saw almost all of its life stages, confirming how many beneficials are in our fields now. The lady beetles can’t eat all these aphids, but the aphids are bringing them to the field. I’ve seen some parasitic wasps too.

Lady beetle puapae

Lady beetle larvae – “Baby alligator”

Plant Bugs

I haven’t talked about plant bugs this year. In fields I go in, retention has been good. 80% retention is our goal. I have seen a plant bug here and there. Dr. Roberts says that in the state, they have been spotty, and only a small acreage has been treated to date.

Sting Bugs

It is now time to scout for stink bugs in blooming fields. Scouts need to crack bolls and look for warts and calloused walls. Treatment decision is based on % of bolls damaged.

Silverleaf Whiteflies

Dr. Roberts says whiteflies are a month early. This is usually an indication of a rough year. We need to look for adults. The precense of adult whiteflies influence deicisions of other pests. Treatment for whiteflies must be timely as well. For more on thresholds and insecticides, visit this previous post on Silverleaf Whitefly Management.

Leave a comment

Filed under Cotton, Entomology

Managing Silverleaf Whiteflies In Cotton

Probably the biggest agriculture pest topic last year, whiteflies became a problem very fast. Because of our warm winter, white are already present, likely meaning another bad year. The goal in silverleaf whitefly (SLWF) management is to initiate control measures just prior to the period of most rapid pest population development. UGA Extension Entomologists Dr. Phillip Roberts and Dr. Mike Toews put together some info on SLWF:

Risk for SLWF

  • Hairy leaf > smooth leaf cotton.
  • Late planted > early planted cotton.
  • Hot and dry > rainy conditions.

Scouting

SLWF adults (solid white wings) and immatures will be found on the underside of leaves. SLWF populations are best estimated from the 5th main stem leaf below the terminal. Main stem leaves are attached directly to the main stem by their petioles. The top or first main stem leaf is defined as the uppermost leaf which is 1 inch or larger in diameter. Adults and nymphs should be counted on the 5th main stem leaf below the terminal.

Adult whitefly in our UGA On-farm Variety Trial on June 29th. Leaves are considered infested when 3 adults are observed. (This counts adults that fly off when leaf is turned over.

SLWF Threshold

Treat when 50 percent of sampled leaves (sample 5th expanded leaf below the terminal) are infested with multiple immatures (≥5 per leaf).

Leaves are considered infested if 5 immatures are observes.

Insecticides

Insect Growth Regulators (Knack and Courier): use of IGRs are the backbone of SLWF management programs in cotton. Effects on SLWF populations are generally slow due to the life stages targeted by IGRs, however these products have long residual activity and perform very well when applied on a timely basis.

Use of other insecticide options which are active on all life stages have quicker effects on SLWF infestations but lack the residual of IGRs.

SLWF is an areawide cross commodity problem. When all parties use sound SLWF management programs all will benefit.

Steps for Efficient Sampling of SLWF

  1. Familiarize yourself with the general location of the 5th main stem leaf in each field.
  2. Select plants at random at least 25 paces into the field and at least 10 paces apart, being careful to keep your shadow from passing over the plant you plan to sample.
  3. Turn the 5th leaf over slowly by its tip or petiole and count the leaf as infested with adults if it has 3 or more adults on it. Include in your counts any adults that fly up from the leaf as you turn it over.
  4. Detach the leaf by the petiole from the main stem. If it fails to snap off easily, you have likely sampled a leaf that is too high on the plant. Recheck your leaf position to make sure you are sampling the 5th leaf.
  5. Examine the bottom of the leaf for the presence of immature SLWFs. Count the leaf as infested if it has 5 or more immatures on the underside of the leaf. Sample at least 30 plants (leaves) per field.
  6. Calculate the percentage of leaves infested with adults and the percentage of leaves infested with immatures.
  7. Treatment is recommended when 50 percent of sampled leaves are infested with immature SLWFs.

1 Comment

Filed under Cotton, Entomology

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!

Leave a comment

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