Guess the pest – Maryland Agronomy News

Guess the Pest! Week #25 Answer: Brown Stem Rot of Soybean

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

Congratulations to Jacob Urian for correctly identifying the disease as brown stem rot and for being selected to be entered into the end of season raffle for $100 not once but five times. Everyone else who guessed correctly will also have their name entered into the raffle.

Guess the Pest Week #25 Answer: Brown Stem Rot of Soybean
By Nancy Gregory, Plant Diagnostician; ngregory@udel.edu

Brown stem rot of soybean is caused by the fungus Cadophora. Brown stem rot symptoms on stems include a general browning that extends from the soil line up the stem, or starts at a node. Symptoms usually show up in mid-summer/pod fill. When affected stems are split lengthwise, there is a brown discoloration of the vascular tissue. Remnants of the pith made be observed in a ladder like pattern. Foliar symptoms look like sudden death syndrome but Fusarium would be found on basal stems with SDS. Symptoms for both diseases tend to be more severe in fields with soybean cyst nematode.

The BSR fungus survives in soybean residue in the soil, but not on seed, and infects roots early in the season during wet, cool conditions. Univ of Wisconsin researchers have shown that a pH lower than 6.5 favors the development of BSR. Management of brown stem rot includes crop rotation, good residue decomposition and selection of resistant varieties. Some resistance is available to BSR and to SCN. Seed treatments and fungicides do not control brown stem rot.

This was the last Guess the Pest challenge for the 2018 growing season.

Thanks to all that followed along each week and submitted answers. Next week, we will hold the “end of season” raffle for the $100 gift card. Everyone that submitted a correct answer will automatically be entered into the raffle for each correct answer that was submitted. If you were a weekly winner, you will have your name entered not once but five times into the end of season raffle. I will also be contacting you soon to make arrangements to get you a copy of A Farmer’s Guide to Corn Diseases.

Guess the Pest! Week #25

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

Test your pest management knowledge by clicking on the GUESS THE PEST logo and submitting your best guess. For the 2018 season, we will have an “end of season” raffle for a $100.00 gift card. Each week, one lucky winner will also be selected for a prize and have their name entered not once but five times into the end of season raffle.

This week, one lucky participant will also win A Farmer’s Guide To Corn Diseases ($29.95 value).

You can’t win if you don’t play!

Guess the Pest Week 25:

What is this disease?

Guess the Pest! Week #24 Answer: European Corn Borer

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

Congratulations to Grier Stayton for correctly identifying the insect as a European corn borer and for being selected to be entered into the end of season raffle for $100 not once but five times. Everyone else who guessed correctly will also have their name entered into the raffle. Click on the Guess the Pest logo to participate in this week’s Guess the Pest challenge!

Guess the Pest Week #24 Answer: European Corn Borer

It’s hard to believe that a pest that once caused an estimated annual economic loss of $1 billion dollars in the United States is now a rare occurrence. The European corn borer (ECB), as the name implies, is actually native to Europe and was introduced into North American in the early 1900s. In addition to being a pest of corn (field corn and sweet corn), it is also considered a pest of many vegetable and field crops. Since the adoption of transgenic corn hybrids in the mid-1990s, losses due to ECB have been virtually eliminated in Bt crops and significantly reduced in other vegetable and non-Bt field crops. This is one of the pests that the UD Insect Trapping Program monitors with black light traps. The reason we continue to monitor ECB populations throughout the state is because even though generally speaking, populations have been low, there are still local pockets where ECB is causing damage. The photo above of the ECB larva was taken on the Eastern Shore of VA by Helene Doughty from a non-BT sweet corn plot that was 100% infested with ECB.

For information on the benefits of Bt adoption, read this article: Regional pest suppression associated with widespread Bt maize adoption benefits vegetable growershttp://www.pnas.org/content/early/2018/03/06/1720692115

Guess the Pest! Week #24

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

This week, one lucky participant will also win A Farmer’s Guide To Corn Diseases ($29.95 value).

You can’t win if you don’t play!

Guess the Pest Week 24:

What is this insect?

Guess the Pest! Week #23 Answer: Sudden Death Syndrome of Soybean

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

Congratulations to Lamar Witmer for correctly identifying the disease as sudden death syndrome of soybean and for being selected to be entered into the end of season raffle for $100 not once but five times. Everyone else who guessed correctly will also have their name entered into the raffle. Click on the Guess the Pest logo to participate in this week’s Guess the Pest challenge!

Guess the Pest Week #23 Answer: Sudden Death Syndrome of Soybean
by Nancy Gregory, Plant Diagnostician, University of Delaware; ngregory@udel.edu

Sudden death syndrome of soybeans (SDS) is caused by the fungus Fusarium virguliforme. We started seeing this disease in Delaware in 2002 in cool and wet seasons, but have seen it more often in the past few years. SDS can be confused with other stem diseases such as Phomopsis stem canker and charcoal rot. Leaf symptoms of yellowing and browning between the veins are typical, and leaves shrivel and fall off, leaving petioles still on the stems. If stems are pulled up and placed in a plastic bag overnight, blue spore masses of the fungus may be seen at the base of stems. The internal stem tissue (cortex) may show dark discoloration. There is a toxin produced by the fungus that is responsible for the symptom pattern showing up at the top of the plant. The fungus overwinters in debris, and disease is most severe when infection occurs early. Improving drainage, alleviating compaction, and treating seed may help get seedlings established.

Guess the Pest! Week #23

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

This week, one lucky participant will also win A Farmer’s Guide To Corn Diseases ($29.95 value).

You can’t win if you don’t play!

What is this disease?

Guess the Pest! Week #22 Answer: Helicoverpa zea, Corn Earworm

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

Congratulations to Amanda Heilman for correctly identifying the insect as an adult corn earworm and for being selected to be entered into the end of season raffle for $100 not once but five times. Everyone else who guessed correctly will also have their name entered into the raffle. Click on the Guess the Pest logo to participate in this week’s Guess the Pest challenge!

Guess the Pest Week #22 Answer: Helicoverpa zea, commonly known as corn earworm

The moth in the photograph is an adult Helicoverpa zea, commonly referred to as a corn earworm. The adult moth is a nectar feeder and not considered a pest. However, corn earworm larvae are considered by some to be the most economically important crop pest in North America. They are highly polyphagous meaning they feed on many different species of plants. Corn, especially sweet corn, is a preferred host plant. However, they also attack soybean, sorghum, snap bean, tomato, and cotton to name a few. Larvae prefer to feed on reproductive plant structures including blossoms, buds, and fruits. It is because of this large host range, and the fact that Helicoverpa zealarvae are so destructive that they are known by several other common names including tomato fruitworm, cotton bollworm, and podworm.

For the latest trap counts for corn earworm in your region, visit mdmothmap.com.

Guess the Pest! Week #22

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

This week, one lucky participant will also win A Farmer’s Guide To Corn Diseases ($29.95 value).

You can’t win if you don’t play!

What is this insect?

Guess the Pest! Week #20 & 21 Answer: Trissolcus japonicus

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

Congratulations to Greg Hawn (week 20 winner) and to Joseph Streett (week 21 winner) for correctly identifying the insect as Trissolcus japonicus and for being selected to be entered into the end of season raffle for $100 not once but five times. Everyone else who guessed correctly will also have their name entered into the raffle. Click on the Guess the Pest logo to participate in this week’s Guess the Pest challenge!

Guess the Pest Week #20 – 21 Answer: Trissolcus japonicus
Bill Cissel, Extension Agent – Integrated Pest Management, Joe Kaser, Research Associate, USDA-ARS Beneficial Insects Introduction Research, and David Owens, Extension Entomologist

Trissolcus japonicus, a tiny wasp commonly referred to as the Samurai wasp, is an egg parasitoid of the invasive brown marmorated stink bug (BMSB). This particular species is native to Asia and has been in quarantine since 2007 and under evaluation for potential release as a classical biological control agent. In 2014, wild populations of Trissolcus japonicus, slightly different from the ones that were in quarantine, were detected in Beltsville, MD and since, additional discoveries have been made throughout the region, including Washington, D. C., Virginia, West Virginia, Pennsylvania, New Jersey, Ohio, and Delaware. It is believed that Trissolcus japonicus may have hitchhiked a ride in a BMSB egg mass that was on plant cargo shipped from Asia, but it is difficult to say exactly how it got here. In fact, it appears that the samurai wasp has hitchhiked here more than once!

A single Trissolcus japonicus female is capable of parasitizing an entire BMSB egg mass which typically contains ~28 eggs. When the male parasitoids emerge, they wait on the egg mass for the females to emerge so they can mate. They are capable of having up to ten generations per year.

To help with reducing BMSB populations in Delaware, we partnered with some of the folks at the USDA Beneficial Insects Introduction Research Laboratory in Newark, DE to redistribute Trissolcus japonicas throughout the state. When I share that we are releasing a parasitic wasp to help with BMSB control, the first reaction that I typically get is, “Will it sting me?” If you look at the photo with some wasps on the dime, you will understand why this is not a concern. Hopefully, this tiny wasp will live up to its name as the Samurai wasp and do its part in controlling BMSB.

Fun Entomology Fact: A female Trissolcus japonicus will chemically mark the BMSB eggs that she laid eggs in and defend them against other parasitoids.

Here is a link to a very informative fact sheet from UF on Trissolcus japonicus: http://entnemdept.ufl.edu/creatures/beneficial/wasps/Trissolcus_japonicus.htm

Guess the Pest! Week #20 & #21

Bill Cissel, Extension Agent – Integrated Pest Management, University of Delaware; bcissel@udel.edu

This past week’s Guess the Pest was a little challenging so for this week, I added a few more photographs (a few of you accurately identified the insect and the weekly winner for GTP Week 20 will be announced next week).

Hint: If you attended the Carvel Research and Education Center Field Crop Tour on Thursday, August 16 and were on the vegetable tour, I shared the answer during my presentation.

This week, one lucky participant will also win A Farmer’s Guide To Corn Diseases ($29.95 value).

You can’t win if you don’t play!

What is this insect?

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