As August approaches, now is the time to be scouting peanuts for leaf spot and soilborne diseases and making timely fungicide applications. Calendar-based or advisory-based spray programs can be followed, but be sure to make your fungicide applications before rainy weather makes it difficult to get into fields. Many of our leaf spot outbreaks over the past couple of years were due to extended periods of rainfall and delayed fungicide applications. Cooler, wet weather over the past several days has increased the risk for Sclerotinia blight. In our research plots at the Tidewater AREC, we found small amounts of late leaf spot, Sclerotinia blight, and southern stem rot this week. The leaf spot and Sclerotinia blight advisories, which can be found on the Peanut Cotton Infonet website, indicate disease risk is currently high. For fungicide recommendations, contact your county extension agent or Dr. Hillary Mehl (firstname.lastname@example.org).
Early this year, ‘Walton’ peanut was jointly released by Virginia Tech and the University of Florida. Walton is a Virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) cultivar with similar good agronomic performance when compared with Bailey, Emery, and Bailey II under “normal” production (Table 1), but with superior performance than these cultivars under extreme water deficit conditions. Seeds are elongated in shape and seed testa color is light pink to pink. It has dark green foliage; an intermediate growth habit and the main stem is not distinguishable from the lateral branches. Walton is a high-oleic cultivar with maturity similar to Virginia-type cultivars developed for the VC region. Breeder seed is being increased at the University of Florida in 2019, and more will be produced next year at the Tidewater AREC and in Florida. For commercial production, seed will become available at the earliest in 2021.
Table 1. Results of the Peanut Variety and Quality and Evaluation multi-state (VA, NC, SC), multi-location (5), multi-year (4) (2015-2018)
|Variety||Yield (lb/A)||Crop value ($/A)|
|Walton||5334 ab||940.0 a|
|Bailey||5243 abc||920.5 ab|
|Bailey II||5515 a||978.1 a|
|Emery||5048 bc||892.5 abc|
|Sullivan||4876 c||831.6 bc|
|Wynne||4859 c||826.4 c|
More information it can be found here Walton’ a High Oleic Virginia-type Peanut. Walton will be presented at the VA Peanut Tour on July 30th, at Tidewater AREC.
Tidewater AREC will host the 2019 Virginia Peanut Tour on July 30th. The flyer of the event is here July 30_Flyer.
- The new 2019 Virginia Peanut Production Guide is available at this link https://pubs.ext.vt.edu/SPES/SPES-67/SPES-67.html
- This guide describes peanut production practices including cultivars, planting, management, and harvest. Under management, information is provided on the optimum time for nutrient and irrigation applications; describes rotations effect on yield; soil preparation, etc. It also identifies major pests for the region including weeds, insects and disease, and how those to be controlled.
- Archived Peanut Production Guides can be accessed from: http://www.sites.ext.vt.edu/newsletter-archive/peanut-production/index.html
Friday, Sep 7th, a pod-blasting clinic was organized in Windsor, Isle of Wight County in Virginia. Farmers brought samples for maturity evaluation from 40 fields, in majority from the IOW but a few were from Suffolk and Southampton. Samples were taken from fields totaling a minimum of 3100 acres of peanut. Based on the mesocarp color, we identified that one sample was ready to dig, 12 in a week, 15 in a week and a half (10 days), 8 in two weeks, and 4 in three weeks or more. This indicated that two thirds of these fields were ready for digging after this week and after the hurricane Florence has passed.
Peanut varieties planted were in majority Bailey and Sullivan with only very few acres of Wynne and Emery, the last being a new cultivar just released in 2015. On these checked fields, farmers did not irrigate and only one farmer used Apogee, a growth regulator that could have affected maturity. Defoliation due to leaf spot was almost absent in all fields, as it was rootworm damage.
The earliest to be dug, in no more than a week, were fields planted during the first week of May and receiving constant rainfall in June, July, and August. Note that precipitation received in July and August exceeded by far this year the multi-annual average for most fields. Some fields planted in mid-May and constantly rained out, also showed digging approaching in 7-10 days (picture below). The only early May plantings a little behind, 10-14 days from digging, were fields with a dry June, regardless if for the rest of the summer they were wet; and the majority of fields planted in mid-May. Based on the color charts, the fields planted during the last week of May could wait three weeks or more before digging. Meanwhile, several other pod-blasting clinics will be organized to help farmers decide when and what fields to start digging with.
This result came to no surprise. It has been determined that Bailey requires about 2700 °F heat units (or GDD) to reach optimum maturity. The Cotton – Peanut Infonet online service provided by Virginia Tech here https://webipm.ento.vt.edu/cgi-bin/infonet1.cgi shows that by Sep 7th peanut planted on May 1st received 2649 °F in Suffolk, 2637 °F at Capron in Southampton, 2718 °F at Skippers in Greensville, and 2640 °F at Waverly in Sussex. Researchers at the University of Georgia determined that every event of rainfall and irrigation received by a crop at one inch or above has an effect equivalent with 10 °F heat units and can speed up peanut maturity. If so, 100 or 200 heat units are to be added to those measured by the thermometer. Indeed, under the conditions of this year early May planted peanuts are expected to be ready for digging 7 to 10 days sooner than last year.
Peanut Extension activities will continue this Fall. Interested to see what future peanut varieties look like? Then come here Martin Field Day Flyer. Or maybe willing to learn more on peanut production from peanut specialists, and interested in finding when is the optimum time to harvest your peanuts? Then you are welcome here VA PEANUT Upcoming Events – 2018.
Statewide, approximately 18% of ears were infested with corn earworm larvae. Corn is considered a nursery crop for corn earworm, allowing the pest to complete a lifecycle and then move on to other crops such as soybean, cotton, and peanut in August. There is a linear correlation between the infestation level in corn and the amount of soybean acreage that gets treated with insecticide for this pest. Please see the attached pdf for more details: CEW_survey_results_2018
A Peanut Tour will take place at the Tidewater AREC (1045 Hare Road, Suffolk, VA, 23437) on Aug 15. Presentations include precision irrigation and crop stress sensing, weed control and tank mixes, and disease and insect management. Meetings with the new Extension Agents in the Southeastern region will be facilitated. A new rotary peanut harvester by AMADAS will be displayed. The flyer with more details is here. Aug 15_Flyer(5) Please do not forget to call (757-807-6538) or email (email@example.com) if you plan to attend. Hope to see you soon!
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.
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 (firstname.lastname@example.org). 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.
For more information or questions regarding the Peanut iPiPE contact Dr. Hillary Mehl (email@example.com).