Last week was another exciting week in Colquitt County agriculture. Drier conditions have set in but there is a possibility for rain next week. The cotton crop ranges from just planted to 8 leaf. The local corn crop ranges from v10 to blister stage. The peanut crop ranges from just planted to around 50 days old. Last week, Southern Rust was confirmed in Mitchell County according to Dr. Bob Kemerait on June 7, 2024. The weather (hot with chance of rain) is generally quite favorable for development and spread. Corn growers must be vigilant and prepared. Soybean rust has been found on kudzu collected in Telfair and Tift Counties (June 7, 2024).
Georgia “Storm” for Peanuts. Dr. Eric Prostko, UGA Peanut Weed Specialist
Below are a few comments from Dr. Eric Prostko, UGA Peanut Weed Specialist, on Georgia “Storm” for peanuts.
Since the agent training in Tifton on June 6, I have had numerous questions about the “Georgia” Storm that I talked about in peanuts. The commercial formulation of Storm 4SL from UPL is a pre-mixture (i.e. 1 jug) of acifluorfen (1.33 lbs ai/gal) + bentazon (2.67 lbs ai/gal). The normal recommended use rate (by me) of commercial Storm is 16 oz/A when combined with Gramoxone (paraquat) in an early-post or “cracking” spray. Storm @ 16 oz/A is equivalent to rates of ~11 oz/A of Ultra Blazer 2LC (acifluorfen) + ~11 oz/A of Basagran/Broadloom 4LC (bentazon). In my opinion, 11 oz/A of Basagran/Broadloom is sometimes too much in this mix. At this rate, Basagran/Broadloom will reduce peanut leaf burn but could also reduce efficacy on some weeds in certain scenarios (i.e. larger Florida beggarweed and sicklepod).
I use the term “Georgia” Storm when growers choose to make their own by tank-mixing Ultra Blazer 2LC @ 16 oz/A and Basagran/Broadloom 4LC @ 8 oz/A (i.e. 2 separate jugs). These application rates are more ideal for the general weed complex that growers have in most Georgia peanut fields. Based upon some recent price estimates, “Georgia” Storm is ~$1.75/A cheaper than the commercial Storm. But, many growers prefer the convenience of only having to deal with 1 jug. Both Storm and “Georgia” Storm have performed very well in my 2024 research plots. See below.
I had a question or two last week from peanut growers about Innliven P and how it compares to Priaxor. I asked Dr. Bob Kemerait, UGA Plant Pathologist, about this subject and below are some of his thoughts.
INNLIVEN is pyraclostrobin + propiconazole. That is NOT Priaxor.
PRIAXOR is pyraclostrobin + FLUXAPYROXAD. This is a HUGE difference!
Why??
1. Fluxapyroxad adds additional leaf spot protection; propiconazole (Tilt) not so much.
2. Fluxapyroxad adds some white mold control; propiconazole has no white mold activity.
3. BIG RED FLAG: because of export issues to the European Union, UGA Extension absolutely does not recommend that Georgia peanut farmers apply propiconazole to our peanuts. PERIOD.
Peanut insect situation: I started seeing a worm or two in peanuts last week and no fields approached economic threshold. TBW moths were noted in fields. The threshold for foliage feeding caterpillars in peanut is 4-8 per foot of row depending on crop condition.
Plant bug, plant bug!
It is that time of year when the plant bug questions start coming in. The local cotton crop ranges from just planted to 8 leaf stage of develop. Low populations of plant bugs have been noted in some earlier planted cotton. Below are comments from Dr. Phillip Roberts, UGA Cotton Entomologist, on plant bugs.
Square retention counts should be made once cotton begins fruiting and continuing into the 2nd week of bloom. As we get further into bloom, square retention is a less reliable indicator of possible plant bug feeding due to natural square loss for various reasons. To make a square retention count gently pull the top two main stem leaves apart and look for the presence or absence of a small square. Typically, we teach scouts to monitor a single fruiting site per plant. The threshold is when plants are retaining less than 80% of small squares and plant bugs are observed. It is also a good idea to randomly pull plants in the field to monitor overall square retention. Again, our goal is to maintain 80 percent of all first positions when we enter bloom. Plants with 80 percent first position square retention at first bloom still have maximum yield potential.
Sweep nets (15-inch diameter) are a good toll for monitoring plant bug adults on squaring cotton. Adult plant bugs are elusive, so walk quickly when sweeping. Drop cloths are the preferred sampling tool in blooming cotton and are much more effective in detecting plant bug nymphs Plant Bug Thresholds:
First two weeks of squaring:
| Sweep Net: Drop Cloth: | 8 plant bugs per 100 sweeps 1 plant bug per 6 row feet |
Third week of squaring through bloom:
| Sweep Net: Drop Cloth: | 15 plant bugs per 100 sweeps 3 plant bugs per 6 row feet |
Insecticides recommended for plant bugs include Orthene, Bidrin, Admire Pro, Diamond, Vydate, Transform, and Centric. A few comments on each.
Orthene and Bidrin are organophosphates. Orthene is very active on plant bugs, however it is also is hard on beneficial insects and tends to flare spider mites. Orthene does not have activity on aphids and would likely exacerbate aphid populations if present. Bidrin is also very active on plant bugs and hard on beneficial insects. The Bidrin label only allows higher use rates such as 4-8 ounces per acre from first bloom to 30 days prior to harvest. Bidrin will provide some control of aphids. Delaying use of Orthene and Bidrin until later in the season (after bloom) is advisable.
Transform is very active on plant bugs and provides good control of aphids and is not as hard on beneficials as the OPs. Centric provides good control of plant bugs and decent but sometimes erratic control of aphids. Both of these products would be good choices when targeting plant bugs on squaring cotton. Admire Pro (imidacloprid) has some activity on plant bugs and some activity on aphids and would not be the treatment of choice if plant bug populations were high.
Vydate provides fair control of plant bugs and has little to no activity on aphids.
Diamond is an insect growth regulator and is only active on immature plant bugs. Diamond will not control adults. Diamond is used on many acres in the Mid-South where plant bugs are an annual problem. Diamond performs best when applied before the situation is out of control. If you have fields where high adult populations have been observed and nymphs are starting to be found, Diamond would be a good option. In situations where adults are also being found, a knock down insecticide for adults will also be needed.
Irrigation – I have been seeing irrigation pivots running around the county in corn, cotton and peanut fields. Corn water requirements have increased dramatically since the majority of the crop is approaching or just past VT.
Below is a cotton irrigation schedule from emergence to first bloom.
If you planted your peanuts during late April or early May, most of these earlier planted peanuts will be beginning to bloom, so expect water usage to gradually increase.
Below shows the estimated water use of corn from the UGA Corn Production guide. Water needs increase to around 0.3 inches a day as the crop reaches VT.
Pegging Zone Samples: I’ve gotten a couple of questions this week on doing pegging zone samples in peanuts and “do I really need to put landplaster out on my peanuts?” It’s that time of year to start applying gypsum to peanuts and I’ve already seen a few fields with some being applied. On pegging zone samples and when to apply gypsum, here’s some information from Dr. Glenn Harris:
Growers should pull pegging zone samples just to the side of the existing peanut row about 3-4 inches deep to get an accurate calcium reading from the “pegging zone.” The results from the test will give you a report of the current calcium levels in the soil. The test results need to meet two requirements to skip a calcium application.
1. At least 500 lb/a of soil test calcium AND
2. Calcium to potassium ratio is 3:1 or better
In this case, you don’t need to apply gypsum. If you do not meet EITHER of these requirements, then you need to apply 1000 lb/a gypsum at early bloom. Also, all peanuts grown for seed should automatically receive this gypsum application regardless of soil test calcium levels.
What else happened last week? Drs. Phil Brannen and Bhabest Dutta, UGA Plant Pathologist, brought a group of plant pathology students to tour Southern Valley and Gin Creek. This could not be possible without the help of Southern Valley and Gin Creek.
We planted the an irrigated site of the UGA On Farm Cotton Variety trial last week. This year there are 10 varieties being evaluated in various yield environments across the state. This project could not be possible without grower and industry support. Varieties include DP 2038 B3XF, DP 2127 B3XF, DP 2333 B3XF, ST 6000 AXTP, NexGenNG 5430 B3XF, DG 3615 B3XF, DG H959 B3XF, DG 3799 B3XF, AR 9371 B3XF and AR 9831 B3XF.
We also had the opportunity to attend the annual County Agent Agronomic Field Day training. This gives county agents an opportunity to learn from Extension specialist.
Have a great week,
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.