Guess the pest – Page 3 – Maryland Agronomy News

Guess the Pest! Week #15

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!

What caused this damage?

Guess the Pest! Week #14 Answer: Corn Rootworm

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

Congratulations to Kathleen Heldreth for correctly identifying the damage in the photo as corn rootworm damage 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 #14 Answer: Corn Rootworms

The corn plants in the photo are damaged by corn rootworm larvae. As you can see, the larvae feed on the roots and root tissue of the plants causing the plant roots to be “pruned”. Older larvae will tunnel into the roots leaving visible entrance holes and blackened root tips. Plants with excessive root pruning will usually lodge and in reaching for the sun, become “goosenecked”. Corn rootworm infestations are unusual for Delaware and not something we typically have to manage for. Crop rotation is the preferred method of control in regions with sporadic populations. Corn rootworm females prefer to lay eggs in corn fields in August and September. The eggs do not hatch until the following spring. If the field is rotated out of corn, the larvae will starve to death in the absence of a suitable host plant.

Guess the Pest! Week #14

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).

What caused this damage?

Guess the Pest! Week #13 Answer: Ozone Damage

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

Congratulations to Keith McGowan for correctly identifying the damage in the photo as ozone damage 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 #13 Answer: Ozone Damage

Photo and article by Nancy Gregory

Ozone damage on vegetables is observed during hot and humid weather in our region. The most susceptible crops include potato, watermelon, cantaloupe, pumpkin, squash, snap bean, and lima beans. Symptoms occur on the top, younger leaves, and show up as dark spots on potato. On cucurbits, ozone damage shows up as yellowing with spots having a white crusty center. Watermelon is the most susceptible in this group. On beans, spots are small and bleached looking, and leaves may have a bronzed appearance on the top surface. Affected leaves may yellow and drop. Ozone is easily misdiagnosed and hard to accurately confirm, since an episode of air pollution cannot be chemically tested for. Inversion layers in hot humid weather result in trapped air at the field level that has a high level of air pollutants. Air remains at field level until winds pick up and disperse it, and four or five hours at levels of 80 ppb can result in damage. Some cultivars have some tolerance, and keeping plant stress low can help to avoid damage.

Guess the Pest! Week #13

Bill Cissel, Extension Agent – Integrated Pest Management; 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 the damage on the potato leaves?

Guess the Pest! Week #12 Answer: Ground Beetle

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

Congratulations to Chris Williams for correctly identifying the insect in the photo as a ground beetle 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 #12 Answer: Ground Beetle

There are many different species of Carabidae beetles, commonly referred to as ground beetles, which can be found in crop fields that are helping to keep pest populations in check. However, they aren’t all as attractive as this particular species of ground beetle. Ground beetles are considered “generalist predators” meaning they prey on many different kinds of pests. One pest that they are known to prey on is slugs. With very few natural enemies, gaining a better understanding of the predator-prey relationship between ground beetles and slugs can provide valuable insight into how we can take advantage of these natural enemies to help with slug control.

Curious about some of the current Delaware Soybean Board funded research being conducted at the University of Delaware?

Click on the link to watch a short (90 second) Youtube video to learn more about some of our research with ground beetles and slugs: https://youtu.be/fSMX74XhSbI

Fun Entomology Fact: In Europe, there is a species of ground beetle that is commonly referred to as the “Slug Killer”.

Guess the Pest! Week #12

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 #11 Answer: Thrips Injury on Soybean

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

Congratulations to Travis Kinnison for correctly identifying the damage in the photo as thrips injury 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 #11 Answer: Thrips Injury on Soybean

Thrips are small bodied insects that use piercing-sucking mouthparts to feed on plants. The damage in the photo is of thrips feeding injury on soybean. The threshold for thrips is 8 per leaflet and leaf damage. However, we rarely reach populations high enough that the physical feeding injury warrants treatment. In fact, thrips are most known for their ability to vector plant diseases such as soybean vein necrosis disease (SVNd).

Adult Soybean Thrips

There are at least three species of thrips, including soybean thrips, which are capable of vectoring SVNd. From 2015-2017, we conducted a state-wide survey for SVNd, sampling 88 fields for thrips and disease symptoms. Our findings determined that the disease is prevalent in Delaware. We detected SVNd in 11.6% of the full season and 22.8% of the double crop soybean fields included in the survey averaged across all three years.

Here is a link for more information about the SVNd survey results,: https://cdn.extension.udel.edu/wp-content/uploads/2015/10/30120518/SVND-grower-summary-and-report.pdf

Soybean Vein Necrosis disease (SVNd) Symptoms.

Here is a link to a short Youtube Video Discussing SVNd symptoms:https://youtu.be/7gXDLjm5x7Q

Fun Entomology Fact: Thrips is the proper terminology used whether it is singular and plural. So you can have one thrips or many thrips.

Guess the Pest! Week #11

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 caused this damage?

Guess the Pest! Week #10 Answer: Stagonospora nodorum Leaf Blight and Glume Blotch

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

Congratulations to Buzz Lowe for correctly identifying the disease in the photo as Stagonospora nodorum leaf blight and glume blotch 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!

Stagonospora nodorum Leaf Blight and Glume Blotch

By Nancy Gregory

Stagonospora nodorum leaf blight and glume blotch can cause yield loss on wheat, especially if infection occurs before grain fill. Stagonospora overwinters in crop residue and can be spread in infected seed. Disease is favored by environmental conditions of high moisture and wind, resulting in spore movement up through the canopy. Disease spread slows when weather turns dry. Symptoms include oval to round, brown leaf spots with yellow halos. The glume blotch phase is characterized by gray to purple brown discoloration on the outer seed coverings. Closer look with a hand lens may show a dusty cast to the heads when the fungus is producing spores. Management strategies include rotation to soybean, corn, or other on-hosts, as well as proper plant density to avoid over-crowding. Fungicide applications of a labeled triazole or strobilurin product at heading can be a part of a management plan. Resistant varieties are available for fields with a known history of glume blotch.

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