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JenREES 10-21-18

Grateful for beautiful weather and harvest progressing again! We got the York Countyimag6606 Corn Grower Plot out on Friday and special thank you to Ron and Brad Makovicka for their work and dedication to that effort! I will share the official plot results next week.  The York County Corn Grower Banquet will be held on Thursday, November 15 at Chances ‘R in York with social time at 6:30 p.m. and meal at 7:00 p.m. Tickets are only $10 per person for a wonderful meal! Tickets can be obtained from any of the local directors or from the York County Extension Office at (402) 362-5508.Nate Blum from Nebraska LEAD Class 36 will give a presentation on his international tour and there will also be updates from Local, State, and National Corn Directors. For those who estimated yields during the plot tour, you need to be present in order to win the Yeti cooler.

Corn Yields: There’s an interesting article in this week’s CropWatch at http://cropwatch.unl.edu regarding final yield forecasts. Interesting to me are the box plots showing the range of ’30 year average’ vegetative and reproductive stages vs. 2018. The high heat in June shortened the vegetative time-frame. However, the silking through grain fill period was relatively typical for most locations and the long grain fill period with lower temperatures allowed for the better yields we’re experiencing (where drought and late-season hail wasn’t a factor).

Soybean Harvest Losses: Four soybeans in one square foot equals 1 bu/ac harvest loss. Various publications show how to determine harvest losses in areas of 10 to 25 sq. feet. For those with the SoyCorn Pocket Field Guide, page 78 shows estimating loss based on combine header width: http://nebraskasoybeans.org/wp-content/uploads/2017/02/SoyCorn-Field-Guide.pdf.

Evergreen Trees: Some evergreen needles are also changing color right now. It is good to look at your trees to determine the cause of the needle color changes. Evergreen trees actually go through a natural needle drop process with some years resulting in more thinning than others. I think this year may be one of those years as stress events can make needle drop heavier. Needle drop appears as needles turning yellow and falling from the tree. Pine trees may keep their needles for 2-3 or more years while spruce keep theirs for 5-7 years before needle drop occurs. Natural needle drop tends to appear along the main trunk and inside needles of the tree.

I also check for the presence of fungal disease. If the pine tree needles have dark spots/bands on them, it may be a fungal disease like dothistroma needle blight (on Ponderosa and Austrian pines) or brown spot (on scotch pines). The fungi actually kill the needles both directions from the location of the infection. With our heavy rains and high periods of humidity, I’m seeing increased fungal disease in evergreen trees this year. Fungicides applied in mid-May and again in mid to late June can help prevent this.

Pine wilt disease occurs in Scotch and Austrian pines. It’s caused by a bark beetle that has nematodes in its gut. The nematodes are native to Nebraska but Scotch and Austrian pines are not. Ponderosa pines aren’t affected because they’re native to Nebraska. The beetle ‘vomits’ the nematodes into the xylem (water-carrying vessels of the tree). The tree senses the presence of the nematodes and shuts down water to various branches as a way to prevent the nematodes from attacking. Thus why one sees a major branch then side of a tree turning gray-green then yellow-brown. Unfortunately, the entire tree will die typically within 3-9 months. Some farmers have tried trunk injections and drenches around their trees in hopes of saving them, to no avail.

On spruce trees, I’m seeing yellow/purple/browning of needles. This often is due to a fungal disease called rhizosphaera needle cast. One way to determine if this is the culprit is to look for tiny black dots on the gray twigs next to affected needles. The black dots are actually fungal structures that allow for infection to occur. Fungicide applied in May and after heavy rains can help. I always intend to spray my spruce tree each May but have failed to get it done the past several years. With recent rains, I’m trying it this fall to see if it can help; will let you know!

There have been several calls about arborvitae rapidly turning brown and I’m seeing evidence of heavy spidermite pressure at one time. Spruce spidermites affect spruce, juniper, arborvitae, etc. The rains and snow washed them off, which is one way to manage them. Evidence can be stippling (tiny yellow-green dots on needles) and also using a magnifying glass, one may see some webbing on undersides of needles. One can also just bang the needles on a white piece of paper to see if any mites are still active. Mites are most active in the cooler times of the season…so August through October in this case. Great resources for additional information include: Diseases of Evergreen Trees and Insect Pests of Evergreen Trees which can be obtained here: https://nfs.unl.edu/publications.

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The dark spots/bands observed on these needles are indicative of fungal disease (dothistroma needle blight on Austrian and Ponderosa pines) and (brown spot on Scotch pines). The fungus kills the needle both directions from where infection occurs creating needles that are often part green to yellow-brown eventually becoming yellow-brown.

JenREES 5-13-18

It was great to see so many fields of corn and even soybean emerging throughout the

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area this past week!  Also grateful for the rain we received in York and for those who received some in other areas.  There are still areas who continue to miss rains and I remain concerned about the soil moisture situation.  I have another soil moisture update this week at http://jenreesources.com if you’re interested in checking that out.

Thursday night/Friday morning’s high winds caused some damage with overturned pivots/corner systems and tree damage.  We also saw newly emerged corn and even soybean cut off or

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Corn plants were buried or cut off by blowing residue/soil.  A few remaining plants in this area of the field can be seen.

buried due to blowing debris/soil, particularly in soybean stubble.  It will be important to watch the plants in these fields the next several days.  By late Friday afternoon, I was already seeing new growth occur, which is good.  Typically, that has been the response in the past-new regrowth in corn as the growing point is still below ground.  However, it will be important to watch the corn plants for any bacterial issues that may kill seedlings.  One can also split open a few plants and look for a healthy growing point.  Regarding the soybean, I have seen soybean lose cotyledons due to hail, crusting, freeze, and wind damage, and still produce a plumule at the top of the soybean stem.  It’s just hard to know for sure what will happen so it’s best to watch the plants in the fields.

Wheat in Nuckolls, Thayer, and Webster counties ranges from elongation to near boot and is turning blue-gray from moisture stress.  Wheat is a crop that I’m always learning about-it can look really bad (or really good) and then end up surprising a person regarding yield either way.  Lower leaves

in fields are turning yellow-brown.  Some of this is due to moisture stress while there’s also powdery mildew pretty thick in lower canopies of wheat that had more tillers.  A few have talked with me about using the wheat for hay or silage and then potentially going in with short season corn, sorghum, or a forage crop.  Our forage specialists would recommend that if the wheat variety has awns, it’s best to either take for hay or silage at the boot stage so the awns don’t cause issues with livestock feeding.  Todd Whitney, Extension Educator in Phelps/Gosper counties, had worked with a feedlot using an awnless wheat variety.  Because of the additional growth that occurs in wheat (and other small grains) from boot to full head elongation, they found biomass production may be increased 25% if the forage was harvested during the later pollination period.

Evergreen Trees:  There’s also been a lot of evergreen tree questions.  For those noticing spruce trees looking kind of yellow with early morning sunlight, spruce spidermites have been working hard with the cooler, dry weather.  They tend to build populations in spring and fall.  You can check for spidermites by taking a white piece of paper and banging the needles on it.  Then look for the presence of tiny dark green to nearly black spidermites crawling on it.  Rainfall is a great way to wash them off of trees as are strong streams of water (easier done with smaller trees).  There are also a number of miticides available that homeowners can purchase from lawn and garden stores (look for products that say they can be applied to trees for control of spidermites).  A great brochure on insect pests of evergreen trees can be found at: https://nfs.unl.edu/documents/foresthealth/insectevergreen.pdf.

Many of us also noticed our spruce trees turning red/brown/purple/yellow in color last fall.  This is most likely a disease called needle cast of spruce and can be prevented by spraying trees now (mid-May) with a product containing copper sulfate.  Regarding Ponderosa or Austrian pines, if you look closely at the needles and observe dark bands or rings on them followed by death of the needle either direction from the band, the tree problem is most likely due to a fungal needle blight like dothistroma or brown spot in Scotch pines.  They can all be prevented by spraying a fungicide containing copper sulfate now.  The following brochure on diseases of evergreen trees is really helpful:  https://nfs.unl.edu/documents/foresthealth/diseasesevergreen.pdf.  Sometimes the problem is finding the products listed on these brochures in our smaller towns as these brochures were developed in Lincoln.  If these specific products aren’t available from your local lawn/garden store, box store, or coop, I would recommend looking at the products available and look for a product that says it is effective against needle blights on trees.  Not all the products I’m seeing have copper as an active ingredient, but other fungicides are listed and the key would be the fact that the site (trees) and even better, the site with problem (trees with needle blights), is listed on the label.

We also continue to see pine wilt affecting our Scotch (short needles in groups of 2) and Austrian pines (long needles in groups of 2).  Pine wilt disease is caused by the pinewood nematode that is carried within the gut of a long-horned beetle.  The beetle is what creates the ‘shotholes’ often seen in bark of infected trees.  The nematode is native to Nebraska, as are Ponderosa pines (long needles in groups of 2 and 3).  This is why we don’t see the problem in Ponderosa pines but do in Scotch and Austrian, which are non-native to Nebraska.  A tip, if you’re trying to distinguish Ponderosa vs. Austrian pines, anytime you see needles with a group of 3 it’s a Ponderosa.  Pine wilt is caused by beetles carrying pinewood nematodes vomiting them into the water-carrying vessels of the tree (xylem).  The tree senses the nematodes and essentially blocks water to those branches.  Often you will observe a branch then perhaps a side of the tree and eventually complete death of the tree within 6-9 months.  While I have diagnosed many samples of pine wilt, more often when I visit homeowners the tree problems are due to fungal diseases which occur on the needles.

Lawns:  Please remember the importance of sweeping or blowing fertilizer and pesticide products back into the lawn instead of leaving them on sidewalks.  Leaving them on the sidewalks puts them in contact with people and pets walking on sidewalks and moves them into storm water systems via rain that can eventually end up in streams.  I’m also seeing a number of 2,4-D/dicamba products being sprayed around tree bases to kill weeds which is affecting the new growth emerging on trees.  Consider applying a wood mulch layer around the base of trees to help avoid this situation in the future and be sure to read and follow all pesticide labels.

Bagworms in Evergreens

I’ve been receiving questions regarding when to spray for bagworms. Bagworms overwinter as eggs in these up to 2″ bags which are formed throughout the summer with silk and evergreen needles by larvae. Larvae feed until late August or early September. Males then emerge and mate with females through the bag opening in September. 500-1000 eggs are deposited by female moths within their own bags.  After depositing eggs, the females drop to the soil and die.  Bagworms overwinter as eggs within bags fastened to twigs such as these shown in this photo.

Bagworms

Eggs hatch in mid-May to early June. Some caterpillar larvae remain on the same trees containing the bags from which they hatched.  Others are blown by the wind to area trees allowing for new infestations to occur.  This photo shows new bags (1/8-1/4″) being formed on trees as they create these bags around themselves.  Look closely for these tiny bags on trees right now.  The video below shows how to look for bagworms on evergreen trees right now.  Study your trees and look for small movements on small bags being formed.  If you are seeing this, consider treating your trees for bagworms.  Products containing bifenthrin or permethrin irritate caterpillar larvae causing them to come out of the bags and be exposed to the pesticide.  There are a number of other management options available.  Please see the following publication for more information.   

Nebraska Extension Publication:  Bagworms

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