Tarnished plant bugs have continued to be a problem in flowering cotton in some Virginia cotton fields. This week, scouts found 10 out of 30 fields above the bloom threshold of 2-3 plant bugs per drop cloth sample across Virginia’s cotton-growing region. Six of these fields averaged above the bloom threshold for the past two weeks (see map below). Dirty blooms may indicate plant bugs are present but should not be used as a threshold for spray decisions. Cracking bolls and observing internal boll injury in small dime and quarter-sized bolls is also a great indicator bugs may be present and causing significant damage. Internal boll injury includes raised warts or outgrowth on the carpel wall, small black punctures that usually match an external lesion, and stained lint. We recommend observing at least 25 bolls per field for internal injury in addition to drop cloth sampling to make informed spray decisions. Plant bug populations have peaked in mid-August over the past few years in Virginia so we recommend continued scouting during the coming weeks. Check out this video if you would like to see a short tutorial on drop cloth sampling.
Plant bug density averaged over two weeks from 24 July to 02 August 2018.
Plant bug internal boll injury symptoms.
Plant bug nymph feeding on a dirty bloom.
Peanut scouts in Suffolk today found fields with above threshold numbers of corn earworm/tobacco budworm (4 per row foot). Fields previously treated recently with chlorpyrifos may be at higher risk because they have fewer beneficial predators.
Black beat cloths can aide in sampling. However, shaking and slapping plants will dislodge worms onto soil for easy counting. Make sure and check around the base of the plant when using either method.
Feeding damage shows up in the form of holes in foliage. Worms may also feed on terminals and flowers so scouting for damage alone is not recommended. Peanuts can lose a lot of leaf material without losing yield, but drought-stressed or herbicide injured plants are at higher risk for yield-loss. Do not spray unless necessary. Recent dry weather in combination with broad-spectrum insecticides can flair spider mites.
Pyrethoids are a common choice for earworm control in Virginia and most products can be tank mixed with a fungicide to save money. Always read and follow label instructions. Pyrethroids are losing efficacy against earworm and we have experienced spray failures in other crops (soybean, cotton, sweet corn). Budworm have been resistant to pyrethroids for some time. You will not be able to distinguish these two species in the field. Refer to NCSU video for details. Do not expect complete control of large worms or high populations. Alternative products labeled in peanut include Prevathon, Besiege, Steward, Radiant, Intrepid Edge, and Blackhawk. A list of products and rates is included in Virginia Tech’s Pest Management Guide.
Tarnished plant bugs continue to be a problem in some Virginia cotton fields. This week, scouts found 14 of 32 fields over the pre-bloom threshold (8 per 100 sweeps) and increasing numbers of nymphs. Drop cloth sampling is recommended for blooming cotton and counting squares is no longer a good indication of feeding. Threshold is 2-3 bugs per sample. Check out this short video (https://www.youtube.com/watch?v=XRnZhLczZJ0) if you have questions on how to use this method or are unsure of what nymphs look like. Dirty blooms indicate feeding, but active populations should be confirmed before a spray is made.
As cotton begins to bloom, neonicotinoids (e.g., Admire Pro, Centric, Belay) lose efficacy and I recommend rotating to a pyrethroid, a pyrethroid/acephate mix, or Bidrin. These products will also control stink bugs if present. Transform is not labeled in Virginia, but our representative in Richmond is working hard to get us a Section 18 and I hope to have one in place by next year at the latest. All of these products will kill beneficial predators in your field. This is a concern as we near bollworm egg lay in cotton.
I encourage you to treat for insect pests only when thresholds are reached. Plant bug control will likely be needed through mid-August when populations peak, even in fields that have been previously sprayed. Spider mites, aphids, and bollworm (in two-gene cotton) risk increases with each broad-spectrum insecticide use, as does the risk for sprayer fatigue.
Special thanks to graduate student Seth Dorman and crew for their continued scouting efforts.
Especially with all the wet weather we have been having in much of the region, it is time to start thinking about peanut diseases. We do not typically see a lot of disease until the canopy closes, but once the vines are touching the environment within the canopy becomes favorable for disease development. Leaf spot programs should be applied beginning at early beginning pod then according to a calendar-based (usually 14 day intervals) or advisory based program. The leaf spot advisory for Virginia can be found at https://webipm.ento.vt.edu/cgi-bin/infonet1.cgi. Some keys to a successful leaf spot fungicide program include:
- Make the first application at the appropriate time (not too late).
- Apply fungicides regularly before leaf spot outbreaks are observed (once disease is present it is difficult to slow down the epidemic).
- Stick to a regular calendar-based program or utilize leaf spot advisories.
- Be mindful of fungicide resistance management (rotate chemistries and/or tank mix with chlorothalonil).
- Scout for soil-borne diseases and utilize fungicides with activity against both leaf spot and other target diseases (e.g. for both late leaf spot and southern stem rot control use a product such as Provost, Elatus, Priaxor, etc.).
Data are currently being collected to improve both leaf spot and Sclerotinia advisories and to develop a southern stem rot fungicide advisory for peanut. This is being conducted through the Peanut iPiPE program. The Integrated Pest Information Platform for Extension and Education (iPiPE) is a program that allows farmers and extension agents to share information with each other through the internet. iPiPE works by allowing users to enter pest data such as presence and severity of diseases or insects. This data will be shared with everyone in an effort to create a more precise system of pest monitoring and management. The Plant Pathology program at the Virginia Tech Tidewater AREC is leading the Peanut iPiPE and using it to improve disease advisories based on observations of disease onset in peanut fields throughout the region. Two undergraduate interns are currently scouting for peanut diseases in the region, and they will enter disease observations into the iPiPE database.
Disease and pest observations can be easily uploaded to the database through a mobile phone app or the online platform. We are encouraging anyone who scouts peanuts to help us collect disease observations. To become a participant, you can request an iPiPE account by visiting the iPiPE platform (http://www.ipipe.org/). Detailed information on the iPiPE platform and a user guide for the mobile app can be downloaded below. Alternatively, you can email disease observations to Dr. Hillary Mehl (email@example.com). In addition, if you are located in southeastern Virginia or northeastern North Carolina and are interested in having your peanut crop scouted for diseases by our iPiPE interns, please contact us.
Peanut iPiPE Stakeholder Card 2018
Peanut iPiPE Users Guide 2018
For more information or questions regarding the Peanut iPiPE contact Dr. Hillary Mehl (firstname.lastname@example.org).
Currently the wheat crop in Virginia is near flag leaf emergence, and flowering will start within a couple of weeks. As flowering begins, be sure to monitor the FHB risk in your area using the Fusarium Head Blight Prediction Center website. Currently, most of Virginia has low risk for FHB infection. The exception is the Eastern Shore where risk is moderate to high in many areas, especially on susceptible varieties such as Shirley. Powdery mildew outbreaks have been observed in some fields this season, and incidence of common rust has been sporadic. Stripe rust has been found in North Carolina, but it has not been reported from Virginia. The 2018 Wheat Fungicide Efficacy Table can be downloaded below. Once wheat approaches the heading stage, keep in mind that strobilurin fungicides should no longer be applied. For specific wheat disease management recommendations or assistance with disease identification, contact Dr. Hillary L. Mehl (email@example.com).
2018 NCERA 184 Wheat Fungicide Table
Currently the wheat crop is in the jointing stages, and we are several weeks away from flowering. Currently the Fusarium head blight (FHB) risk is low for most areas of the state except for the Eastern Shore. These conditions may change as the wheat crop approaches flowering, so be sure to continue monitoring the FHB risk tool (http://www.wheatscab.psu.edu/). Moderate to severe outbreaks of powdery mildew have been reported from several fields in the past week. Be sure to scout wheat fields at this time and apply fungicide when disease is first detected. The updated Wheat Fungicide Efficacy Table can be downloaded below. For specific wheat disease management recommendations or assistance with disease identification, contact Dr. Hillary L. Mehl (firstname.lastname@example.org).
NCERA 184 Wheat fungicide table 2017_Final
The federal labels for XtendiMax® herbicide with VaporGrip® Technology (Monsanto), Dow DuPont ® FeXapan® herbicide Plus VaporGrip® Technology, and Engenia® Herbicide (BASF) now require additional training beyond a Pesticide Applicator’s License prior to use of these products “over the top” of dicamba-tolerant soybean or cotton. Training for 2018 will be provided by the registrants of the products (BASF, Monsanto, and Dow DuPont).
Agents/dealers interested in scheduling a training in their area or having a company representative deliver the training at an already scheduled meeting should contact the following company representatives:
If you schedule a training with either BASF, Dow DuPont, or Monsanto, I would encourage you to make the other companies aware of the training planned in your area. That way, the companies can better coordinate their efforts to reach as many applicators as possible. Also, training by any of the three registrants will cover all dicamba products labeled for in-crop use to dicamba-tolerant soybean or cotton (applicators do not need to take training from the registrant of the specific dicamba product they intend to use).
In lieu of the face-to-face trainings, the companies also plan to have a web-based training that will satisfy applicator training requirements. Michael and I feel the face-to-face training will better prepare the applicators for the off-target challenges of dicamba. Web-based training can be used as a last resort if a grower is unable to attend face-to-face training. The following websites offer more information on web-based training:
There are a few trainings scheduled for the area. See the link below for an announcement from Monsanto for two training sessions in Suffolk, VA on Wednesday January 31st. BASF will be training applicators at the Virginia Grains & Soybean Conference (http://www.virginiagrains.com/annualconference/). The BASF training for this meeting is schedule for Wednesday February 21st at 12:00pm. I anticipate both companies to have other training; Michael and I will keep you updated as we receive word. Please help spread the word on these trainings, as many growers still do not know that training is required. Also,I would encourage you and your applicators to pre-register for the events so folks can plan accordingly.
With that said, feel free to reach out to Michael or me if you have any questions or concerns.
Monsanto Dicamba Training Announcement
Following last week’s rain, the risk for Fusarium head blight (FHB or scab) infections has increased, and the risk is very high even for moderately resistant varieties in certain portions of the state (see FHB Risk Map). Much of the wheat crop is beyond the early flowering stage, but for fields where wheat is currently flowering a fungicide may be needed to protect the crop from FHB infection and DON contamination. Recommended fungicides include Caramba, Prosaro, and Proline. Fungicides are most effective when applied at the start of flowering and up to a week later. The greatest coverage of the heads can be achieved by applying fungicides in 5 gal/A by air and 15 gal/A by ground with a 300-350 um droplet size and nozzles angled forward at least 30 degrees.
FHB risk on May 2, 2017 for moderately resistant wheat varieties. Susceptible wheat varieties that are currently flowering are at high risk for FHB infection throughout Virginia.
Wheat is beginning to flower throughout Virginia, so it is time to make decisions about fungicide applications for both Fusarium head blight (FHB, also known as scab) and to protect the flag leaf as the grains begin to form. Currently, the risk for FHB is low in most parts of Virginia, even for susceptible varieties. The FHB Risk Assessment Tool can be found at http://www.wheatscab.psu.edu. Keep in mind that this is a prediction tool and it will not predict FHB outbreaks 100% of the time. A current screen shot of the website is shown below. Rains are expected over the weekend, but dry weather over the past several weeks has not favored spore production by the FHB fungus, so risk of FHB infection is expected to remain low for wheat that is flowering over the next week. However, now may still be the time to apply fungicides for foliar diseases including stripe rust, powdery mildew, and leaf blotch. The flag leaf must be protected during grain development to maximize yields. Again, due to the dry weather some areas have very little disease, and scouting is still recommended prior to making a fungicide application. However, there have been numerous reports throughout the region of outbreaks of stripe rust (especially on Shirley) and powdery mildew. Do NOT apply a strobilurin or fungicide pre-mix containing a strobilurin after flag leaf emergence (Feekes 9) since this can increase DON contamination in the grain. Prosaro, Caramba, and Proline are the most effective products for reducing scab and DON contamination, and these fungicides will also control foliar diseases such as leaf blotch, stripe and leaf rust, and powdery mildew. A fungicide efficacy table for wheat can be found in a previous post.
Screen shots from the Fusarium Head Blight Risk Assessment Tool (http://www.wheatscab.psu.edu) on April 20, 2017. Currently, risk of FHB infection in wheat that is flowering is low in most parts of Virginia. The exception is along the Eastern Shore where conditions are typically more humid and favorable for spore production by the FHB fungus. For susceptible varieties such as Shirley, FHB risk is moderate to high in some areas. However, for moderately resistant varieties such as Hilliard, the risk is currently low. This illustrates the importance of variety selection in management of FHB and DON contamination in wheat.
Copies of a Wheat Disease Identification Guide from Kansas State are now available and can be requested from Dr. Hillary Mehl at the Tidewater AREC (email@example.com). A PDF version of the guide can be downloaded here. Though not specific to Virginia, many of the diseases included in the guide occur in our region and detailed descriptions of symptoms and management recommendations are included. As always, if confirmation of a disease is needed for wheat or other agronomic crops, plant samples can be submitted to the Virginia Tech Tidewater AREC (6321 Holland Rd. Suffolk, VA 23437). When submitting samples, be sure to fill out the Plant Disease Diagnostic Form with as much information as possible as this will assist us with an accurate diagnosis. The form can be downloaded here: Plant Disease Diagnostic Form