JenREES 8-2-20


York and Seward County Fairs: Here’s wishing the best to all the youth competing in the York and Seward County Fairs this week!

IMG_20200802_142707

One group of youth competing at the York Co. 4-H Trap Shooting competition today.

Crop Update: It’s unfortunately not hard to find southern rust in fields anymore as I’m finding it in every field I walk into. Incidence is mostly confined to lower canopies with the highest I’ve seen so far on the ear leaf. What’s concerning to me is the amount of rust I’m seeing (ear leaf and below) in canopies of fields that have already been sprayed. Some fields sprayed in mid-July will be out of residual soon, which is also concerning to me. Physoderma brown spot, which moves with water and isn’t a significant pest, can be confused with southern rust. While it can look bad, a major difference with Physoderma is that there’s no raised pustules (bumps) on the leaves. I haven’t seen gray leaf spot at ear leaves or above yet. I’ve added pictures of what I’m seeing on my blog at jenreesources.com. There’s been some questions about ‘late season’ Nitrogen applications. I’ve had to ask how late is ‘late season’; brown silk has always been the latest I recommended. Most University research considered ‘late season’ as by tassel time. I haven’t found any University research that has said applications should be made later than brown silk or would be beneficial past this time.

In soybeans, there’s a disease called Phyllostichta leaf spot that I had never before seen.

25697

Phyllostichta leaf spot. Photo courtesy John Mick, Pioneer.

It’s one caused by a fungus that begins often as brown lesions on leaf margins and can move between leaf veins. In learning more about it, it can be residue born or seed transmitted. It doesn’t sound like anything to be too concerned about, just something different that’s been seen in some fields this year.

Painted lady butterflies are the orange and brown butterflies that are flying now that are often confused for monarchs. A painted lady female can lay up to 500 pale green eggs on plants individually instead of in egg masses. The larvae (called thistle caterpillars) hatch in around a week and can feed from 2-6 weeks depending on weather conditions. They feed on around 100 different host species including thistles, soybeans, asters, zinnias, etc. These butterflies are often used in schools to teach students about complete metamorphosis using the life cycle of a butterfly.

00100lrPORTRAIT_00100_BURST20200731101446071_COVER

Painted lady butterfly (underside) on soybean leaf.

Soybean Defoliators: In addition to thistle caterpillars, other defoliators including various worms, grasshoppers, Japanese beetles are also present. Thresholds for damage for all soybean defoliators is 20% defoliation of plants during the reproductive stages. If you’re unsure what 20% defoliation in soybean looks like, check out the graphic in CropWatch at: https://go.unl.edu/7qjg. It’s actually a good graphic to keep on one’s phone as it’s very easy to over-estimate 20% defoliation.

Unsolicited Seeds from China: I haven’t heard of anyone in this area officially receiving a packet yet. USDA is aware that people across the country have received suspicious, unsolicited packages of seed that appear to be coming from China. USDA’s Animal and Plant Health Inspection Service (APHIS) is working closely with the Department of Homeland Security’s Customs and Border Protection, other federal agencies, and State departments of agriculture to investigate the situation. Anyone in Nebraska who receives an unsolicited package of seeds should immediately contact Julie C. Van Meter at 402-471-6847) or Shayne Galford at 402-434-2346. Please hold onto the seeds and packaging, including the mailing label, until someone from your State department of agriculture or APHIS contacts you with further instructions. Do not plant seeds from unknown origins. At this time, there’s no evidence indicating this is something other than a “brushing scam” where people receive unsolicited items from a seller who then posts false customer reviews to boost sales.

Squash Vine Borers tend to be a problem at some point every year. If you’re seeing zuchinni, squash, or pumpkin plants looking wilted and suddenly dying, check the stems at the base of the plant. If you see insect frass (like sawdust), squash vine borers are most likely the culprit. You can remove the plants and discard if you’re done with them. Otherwise, you can also slit the stems and kill the larvae. Then cover the stem base with soil to encourage new root growth. There’s only one generation a year and it’s too late to apply insecticides (should be applied to plant base beginning in late June-mid-July). Some master gardeners also say wrapping the base of stems with aluminum foil discourages moths from laying eggs.


IMG_20200731_094214

Southern rust: Small, orange to tan clustered pustules primarily on the upper sides of leaves.

IMG_20200731_094750 (1)

Physoderma brown spot: the tiny clustered tan spots (below mid-rib) and purple blotches on mid-rib that also occur around leaf axils and on outer stalk tissue. Upper left-hand corner of this picture is bacterial leaf streak.

Physoderma brown spot on outer stalk tissue. It looks bad but not penetrating beyond the outer stalk tissue.

About jenreesources

I'm the Crops and Water Extension Educator for York and Seward counties in Nebraska with a focus in irrigated crop production and plant pathology.

Posted on August 2, 2020, in Crop Updates, JenREES Columns and tagged , , , , . Bookmark the permalink. Leave a comment.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: