Category Archives: Uncategorized

We are not there yet, but getting close!

Today, Aug 26 2021, we pod blasted a few peanut cultivars grown at the Tidewater AREC in large plots to observe pod maturity at this time. While the peanuts planted in the first week of May might be ready in 20-25 days from now, those planted in late May are approximately 30 days from the optimum maturity. Keep in mind that weather is also a decisive factor; therefore, sampling for maturity again in 10-14 days from now will allow to pinpoint more accurately the day when peanuts are ready for digging.

Wynne planted on May 25.
Walton planted on May 3.
Sullivan planted on May 25.
Bailey II planted on May 5.
Bailey planted on May 25.

Introducing the New & Improved Soybean Yield Contest

In an effort to better recognize Virginia’s soybean producers, Virginia Soybean Association is completely revamping the 2021 Soybean Yield Contest! Through a combination of checkoff dollars and sponsorship support, we’re happy to announce the  a new and improved soybean yield contest.

There will be two categories: full-season and double-crop. There is no restrictions on irrigation (irrigated fields are accepted). Most of all the awards for the top 3 winners in each category has increased substantially due to our sponsors (see below).

1st Place – $2,500

2nd Place – $1,000

3rd Place – $500

This has already garnered a lot of interest. We look forward to receiving your entries.

For more information and entry forms, visit the Virginia Soybean Association website or contact me.

Pickleworm/Melonworm Monitoring Update

Both melonworms and pickleworms have been detected in squash plantings yesterday in Cape Charles and Machipongo farms. Approximately, 80% of the plants showed at least one flower bud/fruit with borrowing injuries. Most of the squash fruit and flower buds contained 1-2 melonworms in the latest stages of their larval development (4th-5th instar, Fig. 1). Pickleworms on the other hand, have just started to show up in the area and only 1st to 3rd larval instars were found, most of them on top of flower buds and growing fruit (Fig. 2). Both pests were also detected in one cucumber planting on approximately 30% of the plants sampled. These pests have been detected in squash plantings in Blacksburg this week at a lower infestation rate compared to the Eastern Shore.

Well-timed insecticide applications are crucial for the management of these pests and recently hatched caterpillars that haven’t borrowed into the plant tissue are more susceptible to insecticides. However, once they borrow inside fruits and flower buds, contact insecticides are usually not enough to suppress these pests. The use of systemic insecticides is preferred.

Useful tip: Pickleworms and melonworms are NOT the same as squash vine borers. Squash vine borers borrow into the stems causing severe damage and eventually plant death (Fig. 3), unlike pickleworms and melonworms that feed mostly on the reproductive parts of the plant and occasionally the leaves.

If you find borrowing damage in cucurbit crops on your respective farm or gardens, please contact me at lorelopezq257@vt.edu

Stay tuned for the next update!

Lorena Lopez, Ph.D., Department of Entomology, Eastern Shore AREC, Painter, VA
Photos by Lorena Lopez.

Pickleworm and Melonworm Monitoring Program

We at Virginia Tech are starting a pickleworm and melonworm monitoring program. This program involves information exchange between cucurbit growers and extension agents across the state that look for these pests’ damage to blossoms or fruit and report it back to me, Lorena Lopez, a vegetable entomologist at the Eastern Shore AREC. I will send out a weekly alert of the incidence of these pests in the state, based on this information chain and monitoring efforts in cucurbit crops located in Blackburg and the Eastern Shore AREC. The goal is to keep growers updated and help them manage these sporadic late-season pests.

A quick overview of these pests:

Both pickleworms and melonworms feed on wild and cultivated cucurbit species. Pickleworm adults are not active during the day, only at night when females lay their eggs close to flowers or flower buds. The larvae burrow into the fruit where it feeds and develops. Larva color varies from light green to translucent with multiple dark spots and varies in size from 0.05 to 0.6 inches long. Melonworm adults are usually found during the day on the plants but they can be active during day and night. Females lay their eggs on the underside of the leaves. Larva feeds mostly on leaves and can cause damage by skeletonizing them. However, melonworm larvae can also feed on the fruit and on some occasions can borrow into the fruit like pickleworms. Melonworm larvae are usually light green with two white lines in the back and have a similar size to the pickleworm larvae. Adults of both pests are very hard to differentiate.

Pickleworm larva (J. L. Capinera, UF/IFAS)
Melonworm larva (L. Buss, UF/IFAS)
Fruit damage caused by pickleworm and melonworm larvae (L. Lopez, Virginia Tech)

Early this week we found melonworms in our yellow summer squash at the Eastern Shore AREC. Yellow summer squash is one of the preferred hosts of these pests. All melonworm larvae were found feeding inside the fruit which is uncommon for this pest. We haven’t found any pickleworms yet.

The help and communication network between extension agents, cucurbit growers, and entomologists like myself is vital for the monitoring program. Thus, if you find borrowing damage in the cucurbit flowers or fruit in your respective farm or gardens, please contact me at lorelopezq257@vt.edu

Stay tuned for next week’s update!

Lorena Lopez, Ph.D., Department of Entomology, Eastern Shore AREC, Painter, VA

Corn earworm update for August 5, 2021

Corn earworm (=bollworm) moth catches increased this week in our black light traps. The average number of moths caught per night was: Greensville = 7; Hanover = 11; Prince George-Templeton = 6; Prince George-Disputanta = 3; Suffolk = 22. Here is the Table. Thanks to our trap operators Sara Rutherford, Laura Maxey-Nay, Scott Reiter, Josh Holland, and Sally Taylor’s entomology crew.

In our adult vial tests this week (July 29-August 3), 43% of moths survived the 24-hour exposure to cypermethrin (a pyrethroid insecticide) at 5 micrograms per vial (n = 169 moths tested). The season average is 25% survival (446 moths tested).

Wet weather Brings Disease Pressure for Peanuts

Recent rains and cooler temperatures have maxed out out the risk for leaf spot and Sclerotinia blight of peanuts. In fungicide trials at the Tidewater AREC in Suffolk, VA I counted 9 hits of Sclerotinia blight in 70 row-ft in one untreated plot. Late leaf spot was evident at low levels in the lower canopy as well. Hopefully 2 preventive sprays have been made for leaf spot, but many growers may not have made an application for Sclerotinia blight at this time.

I know my above comments sound like doom and gloom, but growers typically have less disease pressure than we do at our experiment station as they use longer crop rotations. Most of our plots are on a 2-3 year rotation where most growers in Virginia rotate land to peanuts every 4 or more years. Crop rotation remains our best tool to reduce risk of disease losses in peanuts in the Commonwealth.

Peanut leaf spot can occur in all peanut fields, but soilborne diseases such as stem rot and Sclerotinia blight are problems in less than half of production fields, which is a good thing. Most growers know which fields they have problems with these diseases which allows them to treat them differently than most fields. With Sclerotinia blight risk high and already observed, growers need to make preventive fungicide applications of fungicides specific to this disease. if an application of Miravis/Elatus has been made in the last 10-14 days you should be good for another 10-14 days depending on weather conditions. If you haven’t applied a fungicide that effectively controls Sclerotinia blight, I recommend Omega 500 at 1 – 1.5 pts tank-mixed with a leaf spot fungicide in fields with histories of the disease. I also advise growers to scout these fields to determine if disease is present and to assess the effectiveness of fungicides already applied. The best place to look for Sclerotinia blight is in the largest, deepest vines in the field and in low areas that tend to hold moisture longer. The disease may cause leaves to wilt on individual stems (flagging) and tan, necrotic tissue that has white, fully fungal growth can be observed on these stems near the stem base beneath the canopy. See picture of typical Sclerotinia blight on peanut stems in the image below.

Tan lesions and white fungal growth on peanut vines affected by Sclerotinia blight. At the top of the picture just left of center you can see the small, black sclerotia on one of the stems.

You may see flagging from Tomato Spotted Wilt Virus (TSWV) but no lesions on stems or fungal growth is present. I have had to take a closer look at several plants that had flagging leaves only to find that it was TSWV causing symptoms.

Typically a follow-up spray for Sclerotinia blight is warranted 21 days after the initial application of Omega 500. If you are using the 2-spray program of Miravis/Elatus there is no need to make an application of Omega 500 unless you are more than 30 days prior to harvest and disease pressure and weather conditions pose a high risk of severe damage.

If you have questions related to peanut disease management please feel free to contact me.

David Langston – e-mail dblangston@vt.edu, cell (757) 870-8498, office (757)807-3536

Making decisions for the first peanut leaf spot spray

Right now most peanut growers are deciding when to apply the first leaf spot fungicide and which fungicide to use. The recommendation the past few years has been to start spraying peanut fungicides at R3 (beginning pod) but no later than July 10th. I recommend using a chlorothalonil product (Bravo, Echo, Equus and others) at the 1.5 pt/A rate. I also recommend using Alto at 5.5 fl oz/A + 1.0 pint/A of chlorothalonil as an alternative. Tebuconazole (Folicur) is often tank-mixed with chlorothalonil at 7.2 fl oz/A but I wouldn’t expect a lot of leaf spot activity with tebuconazole as resistance to that fungicide by the leaf spot pathogens is widespread. Tebuconazole may still provide some activity against southern stem rot (A.K.A. “white mold”). Subsequent fungicide applications for leaf spot can be made according to the last effective spray date (LESD) using the Virginia Leaf Spot Advisory on the Peanut-Cotton Infonet https://webipm.ento.vt.edu/cgi-bin/infonet1.cgi or using a 14-day calendar-based approach.

In some fields growers may see early spotting that could be from herbicide injury or irregular or “funky” leaf spot. Irregular leaf spot can look an awful lot like early leaf spot but generally occurs earlier in peanut development regardless whether environmental conditions are favorable or not for early leaf spot. According to the Virginia Leaf Spot Advisory the risk of developing leaf spot has been low to moderate across all location thus far, but with current rain conditions that may change. No known cause has been attributed for irregular leaf spot and it has not been shown to cause economic losses. My main concern is that irregular leaf spot may cause growers to react to what they think is the beginning of an early leaf spot epidemic and spray needlessly or use more expensive products to control leaf spot. With irregular leaf spot, brown spots may be surrounded by yellow halos or large yellowed areas, defoliation may or may not occur, and spores are never present on spots. Anytime you suspect irregular or actual fungal leaf spot you can bring or have samples sent to the Plant Diagnostic Clinic at the Tidewater AREC for identification. If you have question or concerns please don’t hesitate to contact me.

David Langston, Plant Pathologist, Virginia Tech Tidewater AREC 6321 Holland Rd., Suffolk, VA 23437 cell phone (757) 870-8498 office phone (757) 807-6536 e-mail dblangston@vt.edu

Plant bug pre-bloom surveys and insecticide recommendations

The entomology program at the Tidewater AREC has spent this week scouting cotton fields across Virginia growing regions. First, I want to thank our technicians, graduate students, ANR Agents, Johnny Parker, and especially, our cooperating farmers. Cotton surveys are made possible through funding by Cotton Inc. and the Virginia Cotton Board.

I want to emphasize that overall plant bug numbers are very low, square retention very high, and the majority of fields will not be blooming by next week. Fields above threshold at this time are rare and sporadic. Use restraint when making pesticide applications without scouting first because we have many weeks left to manage insect pests. The most important time to manage plant bugs is during the first two weeks of bloom (see below graph from Seth Dorman’s work) and late-planted cotton is at higher risk of yield loss. Spraying at threshold (pre-bloom = 8/100 sweeps and <80% square retention) is as good as spraying every week (which is a pretty bad idea for secondary pest infestations, logistics, and costs).

Until the 2nd week of bloom, scout fields using a sweep net. Pay attention to areas of the field where cotton is rank and or borders other crops, but do not make decisions based on hot-spots alone.

Several insecticides are effective for plant bugs in cotton pre-bloom including neonicotinoids (imidacloprid, thiamethoxam), acephate with or without novaluron (Diamond), flonicamid (Carbine), and sulfoxaflor (Transform). Rotating insecticides, opposed to spraying a broad-spectrum like acephate season-long, will save you trips across the field. See the below table from our 2020 experiments demonstrating that using sulfoxaflor (Transform) alone, flonicamid (Carbine) alone, rotating a neonicotinoid (Centric) with sulfoxaflor (Transform), and using acephate with novaluron (Diamond) resulted in fewer trips across the field when compared to acephate alone. Also note that acephate with novaluron (Diamond) resulted in a second spray only at the end of August when it is debatable whether we have time to make a harvestable boll (i.e., it is likely that yield protection was based on a single spray). ALL INSECTICIDE APPLICATIONS YIELDED THE SAME. I do not recommend pyrethroids because of documented resistance in Virginia. They may or may not work on your farm. Pyrethroid resistance increases as the season progresses. Please make the decision that is right for your farm based on your experience and knowledge.

Please let me know if you have questions and or concerns. Email, call, or text. I hope everyone has a safe and happy 4th!

Fungicide Use in Corn and Soybeans

Corn
Some corn may have been sprayed as early as V5 but now we are approaching tasseling and some fields have already begun to tassel. With the corn prices being what they are more growers are inclined to apply a fungicide. Multiple studies have shown that a single application of a DMI (FRAC Group 3) + QoI (FRAC Group 11) fungicide at VT-R1 provide the best chance of return on investment. The Corn Disease Working Group of the Crop Protection Network updates the corn fungicide efficacy table in the following link.

https://crop-protection-network.s3.amazonaws.com/publications/fungicide-efficacy-for-control-of-corn-diseases-filename-2021-03-09-163332.pdf

The last few years we’ve seen more Gray leaf spot on corn in Virginia than other foliar disease. Be aware that if you used Xyway in-furrow you may not be protected against Southern corn rust that comes in later in the season some years. Typically, by the time Southern corn rust is observed in Virginia it will not impact yield greatly. However, for late-planted corn fungicide application must be made by R3 (milk stage) to limit yield loss due to Southern corn rust.

Soybeans
In Virginia, our primary foliar disease of soybean are frogeye leaf spot, Cercospora leaf blight and Septoria brown spot. Scouting for these diseases at or prior to beginning flower (R1) will give an estimation on the amount of disease pressure in a given field if diseases are present. Fields with disease pressure early are more likely to benefit from a fungicide application. Fungicides have the best chance of potentially reducing yield loss to foliar pathogens when sprayed beginning at pod initiation (R3) through seed initiation (R5). If dry conditions are prevalent during this spray window a fungicide spray is not advised. Be aware that foliar fungicides do not offer much protection against seed decay organisms or soilborne pathogens of soybeans. Below is the link for the Crop Protection Network’s soybean fungicide efficacy table.

https://crop-protection-network.s3.amazonaws.com/publications/fungicide-efficacy-for-control-of-soybean-foliar-diseases-filename-2021-03-12-182833.pdf

It is not advisable to spray QoI (FRAC Group 11) fungicides alone as fungicide resistance to this group has been observed in the fungal pathogen that causes frogeye leaf spot.

If you have questions or concerns please don’t hesitate to contact me.

David B. Langston, Jr.
Professor and Extension Plant Pathologist
Tidewater Agricultural Research and Extension Center
6321 Holland Rd., Suffolk, VA 23437
Office (757) 807-6536
Cell (757) 870-8498
FAX (757) 657-9333
e-mail dblangston@vt.edu

Do I plant soybean or wait for rain?

Until these big high-pressure systems sitting in the eastern part of the country move east, it looks as if we are in for another week or so of dry weather. This is not good for soybean planting, any way you look at it.  So, what should we do?

There are basically three options:

Plant shallow in dry soil and hope for enough rain to get the seed out of the ground. If you decide to take this approach, you want to ensure you achieve uniform seed depth and that you are not allowing the seed access to moisture below the seed that could lead to variable emergence. This approach would be less risky in clean-tilled situation where you are more confident that you have dried the soil out at shallow depths. Soybean seed will sit in the ground for several weeks and still emerge well when rainfall occurs. Some worry about “cooking” the seed during this period.  Although it is true that the seed will continue to respire and its ability to germinate will decline, the bigger risk is that you catch a small rain that allows the soybean seed to imbibe water but not enough to get it out of the ground.

Caution must be exercised in no-till systems.  With no-till the soil has not been uniformly dried out with tillage; therefore, there is non-uniform moisture distribution across the field.  This leads to uneven access to moisture and ultimately emergence variability. Parts of the field will have adequate moisture to get the soybeans out of the ground, other parts will be completely dry as in tilled conditions, and much of the field will be in between.  Those in-between areas are likely to have enough moisture to swell the seed and/or initiate germination but not have enough moisture to allow the seedling to emerge.  This is my least favorite option.

Plant deep to the moisture. Under most conditions, soybeans may be planted 0.75 to 1.5 inches deep. But I don’t usually like to go much over 1 inch deep, especially in May.  I want soybean to come out of the ground as fast as possible. With that said, we planted some at 1.5 inches last week. Soil temperatures are generally high enough right now for the seed to germinate and plants emerge relatively quickly. Soybeans should not be planted deeper than 2 inches. Many are not finding soil moisture at less than 2 inches. Even if there is moisture 1.5 inches down, exercise caution using this approach, especially your soils are prone to crusting, because a heavy rainfall could seal the soil before the soybeans emerge. In tilled conditions, the planter can push the soil down a little, creating a ridge of fluffy soil on each side.  A heavy rain will cause this soil to move into that furrow and possibly add another ½ to 1 inches of soil to your depth.  If you are going to go this route, check the emergence score on the variety.

Keep the seed in the bag until the next time we catch rain. This is the safest approach and the one that I am leaning to now. Based on historical data, we have another couple of weeks before we start seeing yield declines from delayed planting. Data from recent research throughout the Mid-Atlantic shows that each day delay in planting past mid-June can result in a ½ bu/A or more yield loss and in general these yield declines begin in the second or third week of June. We still have some time before we get to that point. The optimum planting date range for soybeans is late-April through mid-June, although it will vary from year-to-year and field-to-field based on rainfall, soil water holding capacity, and soybean maturity, but the goal is to get the soybean plants to lap the middles before reproductive growth begins. We still have still have time to do this in most cases. 

Waiting to plant is more of a concern for those who still have early-maturing varieties to plant (MG 3 and early-4), as these varieties will have less time for vegetative growth. I do suggest planting your earliest maturity groups first, whichever strategy you choose to employ.  Later maturity groups have more time for adequate growth when planting is delayed.

What about fungicide seed treatments? You have likely already decided on this and cannot change.  But fungicidal seed treatments are less likely needed in this situation where soils are warm. It looks as if temperatures will be warming all week, so I don’t see cold soils as a problem.

Whatever decision a grower makes, uniform seed placement in critical to achieve uniform emergence and ensure each seed has as equal of access to water as possible. I don’t get too concerned if some plants emerge just a few days apart, but we don’t need them emerging a week apart. Dr. Rachel Vann of N.C. State discussed the importance of uneven and delayed emergence in soybeans – How Important Is Uniform Emergence in Soybeans?  Still, keep in mind that although earlier emerging plants will usually yield more, the late emerging plant will still contribute to yield.  Due to soybean’s compensatory ability, the yield on the whole will differ little from only a few days difference in soybean emergence within the row.  If you know me, you know that I’m not a fan of planting with drills due to lack of equal spacing within the row.  This lack of even spacing will become increasingly important if plant emergence is not good. 

In conclusion, there are advantages and disadvantages to each planting option discussed, but we still have time to plant soybeans in our region before we see drastic yield declines. All options discussed will likely result in delayed emergence due to environmental conditions.