York and Seward County Fairs: Here’s wishing the best to all the youth competing in the York and Seward County Fairs this week!
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.
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.
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.
Physoderma brown spot on outer stalk tissue. It looks bad but not penetrating beyond the outer stalk tissue.
Crop Update: By the time you read this I truly hope and pray we’ve received some rain for the entire area who receive this! Al Dutcher and I have been somewhat frustrated regarding the drought monitor reacting to short-term precipitation events over long-term trends. We both spoke at a meeting this week where he shared parts of this area have 6-8″ deficits dating back to the beginning of our water year (October 1). The soil moisture sensor ground-truthing I’ve been doing with area farmers shows that the larger rains only helped the top two feet of the profile and rains have been spotty since. I think the driest portion of the area seems to be from Lawrence to Bladen south. Drought monitor did put a portion of our area back into ‘abnormally dry’ again and you can see the updated soil moisture readings for the region at http://jenreesources.com.
We were blessed with cooler temperatures which helped slow the crop progression. The heat was pushing crops along quickly which can negatively impact yields as we discussed in a recent CropWatch article. The cooler temps with humidity and leaf wetness also favored gray leaf spot, though, and I’ve seen it move up to a leaf below the ear in several fields in several counties this past week. Every field situation may differ so it’s important to check your specific fields.
Soybean Management Field Days: It’s hard to believe but this is the 20th year of Soybean Management Field Days! They will be held August 7-10 at four locations across the State beginning with 9 a.m. registration and concluding at 2:30 p.m.:
Kenesaw — Tuesday, Aug. 7, Dean Jacobitz Farm
Albion — Wednesday, Aug. 8, John and Mike Frey Farm
Hartington — Thursday, Aug. 9, Ed Lammers Farm
Cedar Bluffs — Friday, Aug. 10, Ray Jr. and Kevin Kucera
- Marketing, Risk Management and Farm Policy
- Weed Management: Cover Crops and Weed Control, Conventional vs. Traited, Soybean Variety Production
- Cover Crops: Managing Soybean Insects and Pathogens
- Cover Crops and Soybean Production Irrigation Management, Soil Fertility, and Cover Crop Research
Horticulture Update: It’s been a tough year for garden produce! The heat has affected flower set, pollination, and fruit production on many types of plants. I’ve also received many questions about tomato leaves curling. Leaf curling can be due to many things such as water stress, virus, and herbicides. Much of what I’m seeing now is water stress-related where uneven watering is occurring or because of the amount of leaves present (especially on heirloom plants) and the plant’s inability to keep up with transpiration. Have also received questions on bumpy tomato stems. The ‘bumps’ are actually adventitious roots (also known as tomato stem primordia) where if they touch the soil they’d form roots. Above ground, they are just these bumps and are present when we have high humidity or overwatering. These conditions are also being favored by the heavier one-time rain events that have been received during the growing season this year.
Squash vine borers causing tunneling in crown and vines of zucchini plants.
Also lots of questions this week regarding cucumber, squash, and melon vines dying! There’s a number of potential culprits. Most affected zucchini (including mine) and pumpkins contain squash vine borers. The female moth lays eggs at the base of plants where the eggs will hatch and the caterpillars will bore into the stem. The borer is white or cream colored with a brown head and can get to be 1″ long. They tend to prefer squash over melons and cucumbers. So what can you do now? Kathleen Cue, Extension Educator in Dodge County shares “If plants look good but holes in the stem indicate infestation, a knife can be used to cut with the grain of the stalk to find the borers. Use the point of the knife to pierce them and don’t be surprised if more than one borer is found in a stem. Once the borers are removed, cover the cut area with soil to encourage new roots higher up on the stem. Champion pumpkin growers will place soil over many nodes (the place where leaves emerge from the stem) along the length of vines to encourage lots of rooting. This gives plants greater resiliency if the squash vine borer has destroyed the crown of the plant.” So, if you’re still desiring more squash and pumpkins, that’s one option for you. If your plants are completely destroyed, you can just remove all the dead material to remove any actively feeding caterpillars as well. For next year, make sure to rotate the area where you plant your vine crops. Area master gardeners have shared they put aluminum foil around the stem base of vine crops to keep the borer larvae from penetrating the vines. Another option is to apply insecticides like carbaryl or permethrin around the base of stems. Trapping the adults in June by using yellow-colored containers filled with water can provide an indication when the moths are flying. You can then use floating row covers over the plants to prevent egg laying and remove them once flowering begins to allow pollination to occur. I will discuss other vine crop problems next week.
Reminder of York County Fair this week!