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During the period 9/6 – 9/12 moth trap catch numbers for cotton bollworm were lower in comparison to the previous week with the highest catch reported in Baldwin county (59 moths). The tobacco budworm moth trap catch was also low.with the highest catch in Autauga county. (31 moths). The soybean looper moth trap catch was significant at 4 of the 5 trapping sites with the highest number recorded in Limestone county (475 moths).
Inspecting soybean fields in extreme western Alabama on September 12 and 13 revealed that the red banded stink bug (=RBSB) has become well established in the region from Baldwin county to Pickens county. Soybeans were sampled in Baldwin, Marengo, Dallas Perry, Sumter, Pickens and Tuscaloosa counties and RBSB's were easily found in all these counties except Tuscaloosa. Fields sampled in Tuscaloosa had been treated with bifenthrin 10 days earlier and this significantly reduced stink bug numbers. The greatest density of RBSB's was found in unsprayed test plots at the Fairhope Research Station in Baldwin county. The average density per 3 row foot of adults plus immatures in test plots in which a total of 50 three-row-feet drop cloth samples were taken was 1.4 RBSB's (26% adults), 0.69 southern green stink bugs (15% adults), and 0.4 brown stink bugs (20% adults). Inspection of soybean pods in these 6 counties showed low levels of stink bug- damaged beans within pods in the upper portion of the canopy. All these soybean fields that were surveyed for stink bugs were in the R6 to R7stage. The southern green stink bug was the most abundant stink bug in the other counties and it comprised at least 90% of all stink bugs present in these 5 counties. No brown marmorated stink bugs were found in any of the surveyed fields. If winter temperatures do not significantly reduce numbers of these stink bugs ,which could potentially overwinter, then growers could see worrisome numbers of stink bugs, including RBSB's in next year's crops. Foliage-feeding caterpillars were also abundant in some of the fields. The soybean looper was the most common worm observed in all counties except Sumter where velvetbean caterpillars were very abundant (greater than 3/sweep) in R2 stage soybeans.
Some 6- to 10-day-old escaped bollworms were found in top cotton bolls in one DPL variety in Monroe County on 9/12 providing more evidence that we are seeing reduced effectiveness in the ability of dual-gene cotton to prevent bollworm damage in cotton. During the last 3 years there appears to have been a gradual loss in efficacy of dual-gene cotton in preventing boll damage by bollworms..Sampling of cotton test plots at the Wiregrass Research station and field reports indicated that the wind and rain from Hurricane Irma reduced the number of silverleaf white fly (SLWF) adults by 90% and washed away much of the honey dew on the leaves. Immatures are still present and could still impact lint quality but the level to which this will occur appears to have been reduced. This may be the only positive effect from Irma which has reduced lint weight and grade index plus has made cotton harder to defoliate and harvest.
For referring to the data table, please click here.
Tim Reed, Extension Entomologist
Ron Smith, Extension Entomologist
Alana Jacobson, Research Entomologist
With all of that being said, the above numbers are for May-August. The first half of this month hasn't done us any favors. Through the first 14 days of September, we are now 471 DD60s behind for this year compared to 2016 and 233 DD60s off from the five year average (2012-2016) (graphs below). It's not all doom and gloom though. The 10 day forecast is projected to be mostly sunny with highs in the mid-80s to low 90s. This should be excellent for cotton maturation and should go a long way in doing so. If the forecast holds true, I would expect things to look very and different in the next two weeks.
Note: All readings taken from the TN Valley Research & Ext. Center in Belle Mina, AL.
Tyler Sandlin, Extension Agronomist
Since mid-July, I have received several grower inquiries regarding mid-late season weed control in peanut. Most of them were related to large morningglory, sicklepod, coffeeweed, pigweed, FL pusley, etc. Growers wanted to know what options they can spray to control those weeds when their peanut is around 90 days old. I hate to tell them use a bushhog to mow weeds down, but at this point, herbicide options are limited due to pre-harvest interval (PHI) restrictions on herbicide labels. For example, a PHI of 90 days means that growers cannot apply this herbicide within 90 days before harvest.
It is understandable that growers may have a few patches of weeds in mid-late season that they want to clean up. However, if someone is in deep trouble with weeds when his peanut is at 90 days after planting, I believe that he did not use proper postemergence treatments early on in his crop. Lack of residual herbicides in early postemergence treatments is a major cause for this problem. Chloroacetamide herbicides such as Dual Magnum, Zidua, Outlook and Warrant applied at full label rate can usually provide 20-30 days of residual weed control and they are critical components to a successful season-long weed control program in peanut.
As a conclusion, for those who struggle with mid-late season weed problems in peanut:
Extension Weed Scientist, Assistant Professor
SEPTEMBER 1, 2017
During the period August 22-28 the cotton bollworm (CBW) trap catch numbers were steady to higher in comparison to the previous week at 3 of the 6 trapping sites with the highest number captured in Baldwin county.(See Table on page 2) The tobacco budworm (TBW) moth trap catch was significantly lower at 3 of the 4 trapping sites with Henry county having the highest number of TBW moths. Soybean looper (SBL) moth trap catch numbers were down by 24% to 49% at 3 sites but increased significantly in Elmore and Limestone counties.
There are still scattered fields of late-planted cotton that are at risk to losses caused by CBW, but most of the cotton is now at cut-out and is no longer being checked for insects. We have had one report this week of pod worms (=CBW) exceeding the economic threshold in double-cropped soybeans in Colbert county. Last year we had a few scattered soybean fields in Lawrence county with pod worms that required treatment during the first week of August. Populations of pod worms that exceed the economic threshold in soybeans tend to be very spotty. Soybean loopers are the main insect of concern this week for double-cropped soybeans in parts of North Alabama. The need to get the corn crop harvested and rains since August 30 have hindered looper applications. The velvetbean caterpillar (VBC) is now the predominant caterpillar pest of soybeans in central and south Alabama. The density of extremely small VBC larvae ranged from 50 to 70 per 3 row feet on untreated soybeans in test plots at the Fairhope research station in Baldwin county on 8/29. Up until this week a mixed population of SBL's and VBC 's have consumed 40% of the foliage in non-sprayed plots but now the looper numbers have declined significantly and VBC's are increasing. If these small VBC larvae survive the result could be complete defoliation. Based on our test plot results last year, if soybeans were sprayed with bifenthrin, Dimilin, Intrepid/Intrepid edge or Prevathon/Besiege on August 15th the VBC population probably will not cause much defoliation through mid-September.
The stink bug complex on soybeans is a major concern for late-planted soybeans in central and south Alabama. This week at the Prattville station when 8 unsprayed R7 stage soybean plots were sampled taking 10 sweepnet sweeps per plot (swept low and hard across 2 rows) the mean number of stink bugs collected per sweep was 1.65. The population consisted of brown marmorated stink bugs (70%, mostly immatures), red banded stink bugs (16.7% mostly adults) and southern green stink bugs (13.6% mostly immatures). Near this soybean test cotton bolls in unsprayed plots on the edge of the station and bordering a road had 93% punctured bolls. The brown marmorated stink bug was commonly observed in these cotton plots. The red banded stink bug is spreading across central and south Alabama. This pest has been reported this year in Pickens, Greene, Monroe, Escambia, Baldwin and Henry counties. It may be present in most counties from Tuscaloosa to the coast. Another mild winter could set the stage for serious problems with red banded stink bugs in 2018. The silverleaf whitefly is the major concern for cotton growers in the southeast portion of the state. One practice that has been shown to improve whitefly control is to add an oil or soap product to the insecticide and use higher volumes of water per acre to improve coverage.
Tim Reed, Extension Specialist, Entomology & Plant Pathology
Ron Smith, Visiting Professor (retired), ACES
Alana Jacobson, Assistant Professor,Entomology and Plant Pathology
Barry Freeman, ACES
This report is based on continuous insect monitoring information (May to August) using sticky wing pheromone traps. In this article we have also compared insect counts from 2016 (a drought year) and 2017 (a wet year) to provide some interesting trends to readers.
Ayanava Majumdar, Extension Entomologist
Kris Balkcom, Extension Agronomist
Cotton bollworm moth numbers increased significantly during the second week of August at the Limestone and Elmore county sites. Tobacco budworm moth numbers nearly doubled at the Henry county site, but held fairly steady at the Elmore, Autauga and Limestone county sites. There was a noticeable increase in soybean looper moths trapped during the second week of August at the Autauga and Elmore county sites while numbers remained significant at the Escambia and Limestone county sites. Infestation levels of cotton bollworms in Bollgard 2 and regular Widestrike varieties triggered treatments this week in some cotton fields in the Huntsville area. There have been few reports of bollworms reaching treatable infestation levels in the rest of the state this week. Clouded plant bugs were reported to be the predominant plant bug pest in some Blackbelt cotton fields. Tarnished plant bugs , stink bugs and leaf-footed bugs were the most common pests of cotton fields in Mobile county. Bollworms (=pod worms) have been reported to be present in soybeans but the numbers we have heard about this week are relatively low. Soybean looper (SBL) numbers are increasing in some areas of the state. Loopers numbered 6 per row foot with 5% defoliation in soybeans planted the last week of July at the Gulf Coast station at Fairhope on 8/15 with 60% of the loopers still small. Ground cloth samples yielded just above 4 SBL's per row foot in an insecticide trial at Brewton on 8/15 and today (8/18) the defoliation level has reached 15% in untreated plots. Similar looper numbers and defoliation levels were observed at the Headland station today. SBL numbers are also increasing at the Prattville Ag Research unit and defoliation is starting to increase toward 5% in some later-planted soybeans. A report from the Blackbelt region stated that there were mixed populations of caterpillars in soybeans in the Dallas/Marengo county area that included SBL, green cloverworms and velvetbean caterpillars. Fungal disease has significantly reduced the kudzu bug population at Brewton and Prattville.
The silverleaf white fly continues to move westward in the Wiregrass region infesting both cotton and soybeans. Later-planted cotton is especially at risk and the chemicals recommended to control this pest are in very short supply. Cotton that is cutting out now may not be damaged if no immatures are present. A Timely Information newsletter with detailed information about this pest will be provided next week.
Click here for a table showing moth trap catches.
Extension Specialist, Agronomic Crops
August 21, 2017
Soybean rust (SBR) has now been detected in 33 of the 67 counties in the state. The disease has been found in both commercial soybeans and in kudzu patches as far north as Cullman and Morgan counties. If you would like an update on the occurrence of SBR in Alabama or across the U.S. check out http://sbr.ipmpipe.org .
Soybean fields that received a fungicide application with an appropriate product at the R3-R4 growth stage that have reached R5 (pod fill) or beyond likely DO NOT need a second fungicide application. Fungicides should not be applied for SBR control after the R5 growth stage.
Soybean fields at the R3-R4 growth stage may benefit from a fungicide application with a product that contains a triazole product as either a pre-mix fungicide or tank mix combination if the disease has been observed in your region of the state. Triazole fungicides have curative activity and will reduce severity of the disease in fields where SBR is already present. A combination fungicide (strobilurin/triazole) should give you 3 to 4 weeks of residual protection against SBR and other foliar, pod, or stem diseases.
Soybean fields in vegetative growth stages are at high risk to the disease this year. Fields should be monitored closely for development of SBR. A fungicide application with a product that contains a triazole should be strongly considered at the R2-R3 growth stage if the disease has been observed in the field or if conditions favor SBR development.
Plant Pathologist, ACES
The Alabama Peanut IPM program conducts routine pest monitoring using sticky wing traps from various locations statewide. Based on trap catches from May to August 2017 (see illustration on the left), it is evident that the above-normal rains in June and July disrupted moth activity for many species; this resulted in a 'quiet' time when we didn't see very many caterpillars on peanut foliage. The only insect that appeared to maintain a high activity in crops during the rains is the beet armyworm, which appeared very early on the foliage also. Cool temperature and wet weather is also good for beneficial insects that are able to catchup with low caterpillar populations. Overall, moth activity is rapidly increasing for loopers and armyworms. Our peanut research plots in Headland are now riddled with holes with caterpillar numbers between 2 to 3 caterpillars per foot of row. In other words, peanut producers should be on high alert for defoliation and intervene before the threshold is reached. Some of the new peanut varieties with vigorous growth seem to tolerate a high caterpillar number but don't risk a late season outbreak of foliage feeders. Also, wet weather causes three-cornered alfalfa hoppers and leaf hoppers to increase rapidly – we do not want them to go deep into the canopy and feed on pegging branches.
Caterpillar control in commercial fields should include a variety of materials. See illustration on the right to understand some of the selective insecticides available for peanut producers. Note the 'spider mite risk zone' on the illustration – that is when caterpillar feeding is at peak on the peanut and we get the most complains of spider mite flare up due to excessive use of synthetic pyrethroids. Therefore, synthetic pyrethroids are mentioned outside the 'spider mite risk zone' as a way to slow down or stop caterpillars with minimum applications. Chemicals belonging to Class 5 (spinetoram), 15 (diflubenzuron, novaluron), and 18 (methoxyfenozide) have long residual and are selective materials for small caterpillars. Those insecticides are great for drought year when plants may be stressed and we need to protect natural enemies. Premix insecticides such as Beseige can be helpful to manage caterpillars and leaf hoppers, such as in rainy years. Xentari (a microbial insecticide) does very well for caterpillar control in early season; repeated applications are necessary to manage armyworms and other species.
To know more about the various caterpillar species in peanuts (insect identification), please see this blog article. For more details, please call an agronomic crops regional extension agent or go online for downloading the 2017 Peanut IPM Guide. The Alabama Peanut IPM program also has a mobile-friendly website and sends additional pest alerts via Facebook.
Soybean rust was detected in Houston, Dale, Autauga, Elmore, Butler, Conecuh, Escambia, Clarke and Marengo counties this week. The disease was found in soybean research plots in Autauga and Elmore counties and on kudzu in the other locations. Soybean rust has likely spread throughout much of the southern third of the state. The continuous wet weather and relatively moderate temperatures have favored the pathogens development this year, and with the late soybean planting many acres maybe at risk in the state.
Growers should be advised to consider a fungicide application this year, preferably a product with both protectant and curative activity.
Images of Soybean Rust on Kudzu in Butler County are below.
See the Soybean Fungicide Guide for 2017 that a group of Extension Plant pathologists update each year.
Also the link to the National Soybean Rust website.
Extension Plant Pathologist
With summer comes hot and dry weather in the southeast. Many insect pests and mite species thrive in the hot weather. In many parts of the south east, spider mites can be a major nuisance throughout the crop production season whether it is open field crop or under high tunnels. Spider mites can cause direct crop injury and produce contamination, so timely detection and reduction are critical for producers. Here is some critical basic information about spider mites.
Mites are not insects. The most common species of mites in Alabama and adjoining states is the twospotted spider mite that is easily identifiable from the two spots on their oval body. Mites look like dust particles that move - use a magnifying lens when scouting for mites! Typically, producers will find spider mites along with numerous eggs under the webbing on lower surface of leaves. Twospotted spider mites have a very wide host range from row crops to horticultural plants. Russet mites are smaller than the twospotted spider mites and have elongate bodies. Infestations seem to start from lower leaves and these mites have a restricted host range.
Extension Entomologist, ACES
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