Monthly Archives: June 2011
I’ve received several questions on trees. If you have silver maples or pin oaks that are looking a little yellow, most likely the yellowing
is due to iron chlorosis. Symptoms of iron chlorosis include leaves with green leaf veins while the leaf tissue is yellow-green. Iron chlorosis is common in several of the towns in Clay County due to higher pH soils (more basic soils) which makes the iron unavailable to the plants. Trees can be injected with iron sulfate in the base of the trunk with the amount injected dependent on the diameter of the tree. There’s also another method of soil injection with micronutrients that can also be used. I also have a list of tree care providers for the area for trunk injections; please contact the Extension Office if you’re interested in obtaining this list.
On evergreen trees, spruces losing their new growth or inside needles may be doing so due to two different fungal diseases or spidermites. If you are noticing this problem on your spruces, the time to prevent fungal diseases will be May next year with products such as Bravo, Daconil, or copper-sulfate based products. Spidermites can be managed with insecticidal soap. Ponderosa, Austrian, and Scotch pine trees with brown fungal bands on needles causing the needles to turn brown can be sprayed with a copper-sulfate based product now to help prevent further browning. If large branches of your trees have needles dying, the culprit may actually be the pine wood nematode which causes pine wilt disease in Scotch pines. There is no cure for that disease. To determine if pine wilt is the problem, cut a piece of dead/dying branch that is at least 1 inch in diameter and 4 inches long and send it to the UNL Plant and Pest Diagnostic Lab for diagnosis. Cedar trees are also showing Cercospora blight right now with needles turning brown. We used to think nothing would kill a cedar tree, yet many cedar windbreaks have needles turning brown and this fungal disease is killing needles due to restricted air flow and high humidity within our windbreaks. Restricted air flow is something you’d like with windbreaks but many of the trees in windbreaks were planted too close together many years ago and we’re starting to see more of a problem with various fungal diseases. Another option to spraying fungicides is to consider removing every other tree from the windbreaks to allow for more air circulation to cut back on fungal diseases.
If you’re unsure how to tell what kind of evergreen tree you have, cedar trees have needles like ropes. Spruce needles are single and when you roll them in your fingers, they have edges to them. Fir needles are also single and when you roll them in your fingers, they don’t roll easily like spruce needles because they are flat (flat fir). Pine needles are always in groups-of 2, 3, or 5. Austrian and Ponderosa pines have the very long needles; Austrians will always have long needles in groups of 2 but Ponderosa’s will have long needles in groups of 2 or 3 (If you ever see 3 needles, it’s a Ponderosa pine!). Scotch pines always have short needles in groups of 2. White pines have needles in groups of 5.
White Heads in Wheat
The last week I have received questions about white heads in wheat. An excellent resource from UNL to determine various wheat head disorders can be found here. If the heads are completely bright white and you can easily pull those heads out of the stem, the culprit is the wheat stem maggot. This insect will sever the stem above the top node so that the stem upward to the head are white while the rest of the plant remains green. I usually only see a few of these types of heads scattered around in fields and there’s no recommendations for managing it because damage isn’t considered economical.
If your heads have white or pink colored kernels in them in addition to regular looking kernels, chances are the discolored kernels have Fusarium Head Blight also known as head scab. The kernels eventually may have a brown discoloration to them and the stem just below the head may also turn a brown-purple color. The Fusarium fungus that causes head scab is the same that causes stalk rot in corn. Wheat on corn rotations in no-till systems have a greater potential of scab in wheat, but these situations don’t mean that scab will always occur. Ultimately, rainy, humid conditions for a 2 week period around flowering is the primary factor for allowing scab to occur.
If you are finding scab in your fields, there’s nothing to spray or do now. Set your combine to blow out the lighter, shrunken, scabby kernels to help avoid dockage at the elevator. I would also recommend to avoid saving back scab-infested seed. Plan to purchase certified seed instead for next year and be sure to have a fungicide seed treatment applied to it to avoid problems with smut.
Rootless Corn Syndrome
Heavy rains in previous weeks have washed soil away from developing roots in some fields. Plants now up to 4-5 leaf stages in affected areas are hanging on by the main radical root. Some plants haven’t been able to survive while others have. Looking closely, brace roots are developing at the crowns of affected plants and eventually, they will begin to kink themselves to pull the plants upright again. There’s not much to do in this situation, but if you have the ability to get soil built up around the root base by cultivating, that can help. If not, an irrigation or rainfall may also help.
Often I see rootless corn syndrome as a problem with smaller plants-3 leaves or less-in which the seed was planted shallow to allow for planting in wet soils. Windy conditions and lack of soil moisture near the surface can allow for poor root development leading to rootless corn syndrome. Thus, I recommend planting corn 2″ deep and not planting shallow to avoid this problem later on.
Saturday was a neat day at the Clay County Fairgrounds starting with the 5K and 10K runs in which I heard 65 people ran or walked in! It was exciting to see the crowd that turned out to watch this first year event and hopefully it’s conducted again because it seemed like a success for the first year! After the road race, it was our Regional 4-H Dairy Cow and Goat show. That’s always an enjoyable show as it is laid back and fun-but it’s also a reminder that fair is just around the corner!
Following the dairy show, we tried something new. Some 4-H families adopted some rescue llamas so they were hoping to show them. While livestock isn’t my strong suite, I know nothing about llamas so we opted for an exhibition this year. A 4-H Club from Polk County generously came down and ran the exhibition for us.
It was interesting watching showmanship as the youth held the halters high but not close to the llamas’ mouths and they never changed sides when the judge walked past. Probably the most interesting part was watching the obstacle course. Essentially it’s like a glorified trail’s course for horses, only more interesting! Youth had to pick up a hula hoop and put it around his or herself then have the llama essentially walk through it. The llama had to back between logs, walk over bridges, change pace, and in different spots it had to put two feet in a ring laying on the ground and the youth had to do things like show the judge the llama’s hooves or teeth! Needless to say, it was very interesting and I think everyone watching learned a great deal!
Discussion: Irrigation Scheduling
I’m adding this post as a discussion topic as we get into the growing season for producers to post their irrigation scheduling questions or to share what their sensors and ET gages are reading. With the Nebraska Ag Management Network, we’ve learned that producers often need other producers to check their readings with-kind of like a support group for producers involved with this effort. That’s because it’s hard to not irrigate when neighbors are irrigating and your irrigation scheduling tools are telling you that you don’t need to irrigate! We’ve had some good discussions in the past so I look forward to the discussions this coming year!