Frank Bryant pod blasting the peanut pods (left) and growers commenting on the pod samples (right).
Monday, Sep 14 2020, Extension Agent Livvy Preisser organized a pod blasting clinic in Windsor, VA, at the Indika Farms Inc.
As every year my technician, Frank
Bryant, assisted the Agent with this activity. Keeping the distance, several
growers brought over 25 peanut samples from almost 2000 acres from the
neighboring fields.
In average, peanut still needs 3
weeks or longer to complete physiological maturity, regardless if the fields
were or not irrigated. From all, only one sample of non-irrigated Sullivan was
2 weeks closer to digging. This agrees
with what we have observed in the research plots this week.
Maturity of peanut in Isle of Wight County, VA, on Sep 14, 2020. Samples are from different fields, Bailey (upper left and center), Bailey II (upper right), and Sullivan (below).
Additional pod blasting clinics will
take place on Sep 16 at Carolina Easter, Courtland, VA; Sep 18 at Meherrin Ag.
& Chemical, Capron, VA; Sep 22 at TAREC, Suffolk, VA; Sep 23 at Carolina
Eastern, Courtland, VA; Sep 25 at Meherrin Ag. & Chemical, Newsoms, VA; and
Sep 28, at Indika Farms Inc, Windsor, VA. They are organized by Extension
Agents Livvy Preisser, Elisabeth Pittman, and Josh Holland.
Because temperatures of the past 3
weeks seem to decrease in the next 3 weeks and into the Fall by 15 to 20 F
daily, from high 80s and on some days mid-90s to only mid-70s, the rate of pod
development from immature (white mesocarp color) to mature (brown and black
color) will decrease as well. Therefore, patience is needed with peanut crop this
Fall for harvesting high yields and SMK in Virginia.
Average nightly corn earworm/bollworm moth black light trap captures for this week were: Greensville=28; Prince George-Templeton=5.5; Prince George-Disputanta=7; Southampton=17; Suffolk=76. Here is the Table
For soybean, here is the tool that calculates the corn earworm larval threshold number based on user input values for sampling techinque (sweep net or beat cloth), cost of insecticide application, price of beans, and row width: threshold calculator
We have done 391 vial tests so far this season, with 35% of moths surviving the 24-hour exposure to the pyrethroid cypermethrin at the rate of 5 micrograms per vial.
In the past two weeks, peanut progressed nicely towards harvest maturity. The pictures below show maturity of Bailey on Aug 25 and Sep 8, 2020; and maturity of Sullivan and Emery on Sep 8, in fields at the Tidewater AREC, Suffolk, VA. Recent good soil moisture and high temperatures, not many exceeding 95 F, seem to close the gap between last and this year’s harvest time. It is, still, very improbable to have an early digging, like we have had in the past two years when peanut was complete dug by end of Sep in Virginia. Maybe by the end of Sep, 2020, we will start digging some early planted fields. I will provide weekly updates.
Bailey planted May 14, 2020 and pod blasted on Aug 25 (left) and Sep 8 (right), 2020.
Emery (left) and Sullivan (right) planted on May 14 and pod blasted on Sep 8, 2020.
Damaged kernels probably from earlier noticed pods with Southern Corn Rootworm and other damage.
Average nightly corn earworm/bollworm moth black light trap captures for this week were: Dinwiddie=54; Greensville=15; Prince George-Templeton=13; Prince George-Disputanta=11; Southampton=22; Suffolk=92. Here is the Table
We have 37% survival in our cypermethrin vial tests (338 corn earworm moths tested from Suffolk, VA).
This week, my PhD student, Sean Boyle, observed pickleworm holes in our zucchini and squash in Whitethorne, VA near Blacksburg. This is the first that we’ve seen this pest in 2020. If you have noticed this pest in your area, please let me know – email tkuhar@vt.edu. The pickleworm, Diaphania nitidalis (Stoll) is a tropical moth pest of cucurbit crops including pumpkins, squash, and cucumbers (Fig. 1). It is typically a pest in the southern U.S. and does not overwinter in Virginia. The past few years, the pest has made its way northward in late summer on wind and storm fronts. Several pumpkins growers in Virginia have suffered damage from this pest in since 2017 usually following some August summer storms.
Fig. 1. Pickleworm moth.Fig. 2. Pickleworm larva and entrance hole on pumpkin.
Moths fly to flowering pumpkins, squash, or cucumbers and deposit their eggs. A single female moth can lay up to 400 eggs usually on cucurbit flowers. Larvae feed on flowers (Fig. 2) and bore into fruit leaving a characteristic perfectly round hole often with sawdust-like fecal material around it as well.
Management. Pickleworm is very difficult to predict or monitor for as eggs are very tiny, moths fly at night, but are not attracted to lights, and there is no commercially-available pheromone lure. As a result, cucurbit growers in the South often apply insecticides weekly during the fruiting stages until final harvest. Pyrethroid insecticides can be effective at controlling this pest if sprayed in a timely manner (i.e., lambda-cyhalothrin, permethrin, bifenthrin, Baythroid XL, Mustang Max, etc.). Pyrethroids are often used because of their low cost and because they also control squash bugs and cucumber beetles, but they are not IPM compatible and can result in outbreaks of secondary pests such as aphids. Usually two or more sprays of pyrethroids in late summer can cause severe aphid problems leading to honey dew build up on plants. Other insecticides that control pickleworm include: the spinosyn productss, Radiant and Entrust, the diamide insecticides, Coragen and Harvanta, the insect growth regulator (IGR) Intrepid, and the lepidopteran-targeting insecticide Avaunt eVo. All of these products will have less nontarget impacts than pyrethroids and will also control pickleworm.
Average nightly corn earworm/bollworm moth black light trap captures for this week were: Dinwiddie=48; Greensville=47; Hanover=2.5; Prince George-Templeton=18; Prince George-Disputanta=5; Southampton=13; Suffolk=41. Here is the Table
This year, peanut is nowhere near where it was last year, from the pod maturity point of view. The pictures below show 100% white (immature) pods from Bailey planted on May 14, 2020, and collected on Aug 25. Last year, on Aug 27, pods of Bailey planted on May 3, 2019, ranged from 10% white to 25% brown and black (fully mature), with the majority in yellow and orange mesocarp color denoting substantial progress towards physiological maturity. Indeed, in 2019, peanut was planted earlier than this year, but this only explains part of the reason why this year peanuts are maturing later than in 2019. The other part comes from the dry and hot July, when pollination, and growth of pegs and pods were slowed down. Tropical storm and other rain events at the end of July benefitted pod development, but maturity is still delayed from the last season. I am showing pictures only from Bailey, as the main cultivar grown on 50% of the peanut acreage this year; but we looked at Sullivan, Emery and Wynne as well and they look similar with Bailey. This year, we also noticed on all these cultivars a fair amount of Southern corn rootworm and other pod damage, regardless the soil where pod samples were collected at the Tidewater AREC. I will continue updates on peanut maturity every other week.
Bailey planted May 14, 2020 and pod blasted on Aug 25, 2020Bailey planted May 3, 2019 and pod blasted Aug 27, 2019Bailey pegs and pods on July 20, 2020.Bailey pods with Southern Corn Rootworm and other damage
This article was co-authored by Virginia Tech Entomology Ph.D. student, Kadie Britt.
Here are the corn earworm moth catch numbers from a handful of pheromone traps that we have set up in hemp fields and one sweet corn field around Blacksburg, VA. Trap catch appeared to peak around mid-August with moths emerging from cornfields and has subsided a little toward the end of August. Crops such as soybeans, hemp, tomatoes, and sweet corn are still at risk to this important pest.
Corn earworm moth catch in Heliothis traps baited with corn earworm Hercon sex pheromone lures.
We have already started to see worms feeding on hemp throughout Virginia. CEW feeding on hemp causes mechanical damage to buds, allowing environmental pathogens to enter crop material, ultimately leading to bud rot. Bud rot is visible and present in hemp crops right now but is not prevalent just yet. Managing populations early on will be key to reducing crop injury this season.
Corn earworm larva on hemp plant in Virginia. Photo by Kadie Britt.
Strict regulations on pesticide applications to hemp prevent
the use of many available insecticides. We have conducted a laboratory
experiment to evaluate the efficacy of some products that are currently allowed
for use in hemp in Virginia as well as Pyganic, which is not labeled on hemp,
but is a widely used organic insecticide.
Treatments included in the August 19, 2020 bioassay
included:
To conduct this bioassay, corn earworm larvae (3rd to 5th instars) were collected from untreated sweet corn grown at Kentland Research Farm in Whitethorne, VA. Untreated hemp seed heads were collected from grain hemp, variety ‘Joey’, grown at the Urban Horticulture Center farm in Blacksburg, VA. Seed heads were dipped in spray tank concentrations of each insecticide at the high labeled rate and placed into 1 oz. diet cups. Larval corn earworms were placed directly on top of treated material. Mortality was evaluated at 1, 2, 3, and 4 days after the experiment was set up (Figure 3). PyGanic + PBO provided significantly greater efficacy against CEW than all other products tested with only 6.5% of worms surviving after 4 days. The addition of the synergist is needed for effective control with Pyganic due to pyrethroid resistance development in this pest. Unfortunately, Pyganic is not currently labeled for use on hemp in Virginia. Agree, XenTari, and PyGanic without PBO all performed similarly with 50.3%, 53.5%, and 59.9% of worms surviving after 4 days, respectively.
Survival after 4 days of field-collected corn earworm larvae placed on hemp seed heads that were dipped in spray tank concentrations of various organic insecticides. All products except Pyganic are permitted for use on hemp in Virginia.
Looking ahead this season, insecticide research trials in
CBD hemp will be conducted in Blackstone with all of the aforementioned
products plus many more. We will continue doing lab bioassays with CEW and
other insecticides that are allowed for use in hemp at this time. Results will
be shared as they become available.
Although it’s hard to accurately
estimate soybean yields until maturity, doing so can give you an idea of your
crops potential this year or differences between fields or soil types.
Maybe you’re considering entering the soybean yield contest or maybe you
just want some peace of mind.
Here are some general guidelines
for estimating soybean yield. Again,
estimating soybean yield is inaccurate unless detailed sampling is done late in
the growing season. Estimates are
usually not very good until the soybean approaches physiological maturity (R7).
Only about 50% of the total seed dry
matter has accumulated by the R6 development stage. Stresses during the R6 to R6.5 stages can
result in large yield losses mostly by reduced seed size, but also by reduced
pods or beans per pod. After R6.5,
stresses will cause a much smaller loss.
To estimate yields, follow the steps below. Be sure to sample in 5 to 7 different areas of the field.
1. Determine the number of row feet needed to make 1/1000th of an acre from the table below. In narrow rows, one may use 3 or 4 side-by-side rows instead of one long row
2.
Determine the plant population per acre.
Count the
number of plants for the row feet determined above in 5 to 10 randomly chosen
area of the field. Multiply this number
by 1000. Average the number of sampling
areas. Note that the more areas of the
field that you sample, the more accurate are your estimates.
3.
Determine the number of pods per plant. As you
are making your stand counts, pull up 5 consecutive plants in the row you
counting. These 5 plants should be
growing next to each other. This will
insure that you don’t just pull the best looking plants in the row. Also, try to avoid gaps in the row as the
plant next to the gap will have more pods than the average plant. Count the number of pods on these
plants within the sample area and average.
4.
Determine the pods per acre. Multiply the plant population (step
2) by the pod average (step 3).
5.
Determine the number of seeds per acre. Multiply the number of pods (step
4) by 2.5 seed per pod. This is an
average number of seed per pod for most varieties. Some varieties may have more, some less.
6.
Determine pounds of seed per acre. Divide the seeds per acre (step 5) by 3000
seeds per pound. This number can vary
from 2500 to 3500. Higher numbers
represent smaller seed that are more likely during late-season drought. Smaller numbers represent seed that form with
abundant August/September rainfall. You
may want to obtain a low, medium, and high estimate.
7. Determine the yield estimate. Divide the pounds per acre (step 6) by 60 pounds per bushel.
As an alternative to calculating your numbers, you can use the chart below to determine how many pods or seed per pod you would need at three different plant populations to obtain a certain yield.
Each year, the Virginia Soybean Association in cooperation with Virginia Cooperative Extension sponsors a soybean yield contest.
The purpose of the Virginia Soybean Yield Contest is to emphasize and demonstrate the practices necessary to produce maximum economic yields, to recognize those producers who grow high-yielding soybeans, and to gather data on the practices utilized by these outstanding producers.
There are three Soybean Yield Contest categories: 1) Full-Season, Non-irrigated; 2) Double-Crop, Non-irrigated; and 3) Irrigated (Full-Season or Double-Crop).
Any grower (owner-operator, tenant, or tenant-landlord team) who is a member of the Virginia Soybean Association and produces 10 acres or more of soybeans within Virginia’s boundaries is eligible. Participants may enter one, two, or all contests.
Details of the contest can be found at the Soybean Extension & Research webpage. Please contact your local Virginia Cooperative Extension office if you wish to enter the contest, preferably at least 5 days before harvest.
