CMEG Crop Management Extension Group

Field Crop News

Website Address: http://fcn.agronomy.psu.edu/

May 7, 2008    Vol. 08:09

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

Warm conditions will persist through Thursday as there is a steady increase in the moisture content of the lower atmosphere. As a result, showers will become more likely each afternoon and by later Thursday, most sections will notice some rain. A cold front will push across the region and stall after dark on Thursday allowing a small disturbance to pass just south of the state on Friday morning. Periods of rain will accompany a cooling trend, especially in the southern half of Pennsylvania. Rainfall amounts will generally be less than an inch.

Cooler and dry conditions are expected on Saturday before another, more potent disturbance brings clouds and rain into the state during Sunday.

Rainfall should be about double the amount that will fall late Thursday or Friday. Much cooler air will sweep into the region on blustery winds later Sunday and Monday. Temperatures will average 10 to 15 degrees below normal and winds will gust over 25 miles an hour in many places.

The chilly weather may produce a couple of frosty mornings in the south and central parts of the state either Tuesday or Wednesday morning.

Another quick warm-up is expected later in the week with readings rising well above average by that weekend (May 16–18).

While odds still favor May's temperatures averaging a bit below seasonal levels for the month, there are signs that rainfall should be average to well above normal in most sections, especially in the southern half of the state.

Check out the predicted Growing Degree Days (base 55) for Pennsylvania for the next two weeks at: http://climate.met.psu.edu/data/regional_gdd.php

Spring Scouting Update — Del Voight, Acting Grain Crop Specialist

This week is a critical time to begin observing fields and determine management tactics. Here are some items I observed during my field visits.

Corn has emerged in many parts of Pennsylvania, emergence appears to be ideal. I observed some frost damage to the first leaf out of the soil in some low lying areas. Be on the watch for cutworms. Joanne Whalen in Delaware is reporting high numbers of cutworms this year. I was in one field of cutworms and they are small but the tell tale sign of damage is evident so from now until V4 growers need to be looking for damage. Also in some no till fields I found some slug activity while it is dry enough to keep them in check forecasted rains could create an environment for them to remove significant leaf area. Also consider conducting some stand assessments, count populations to see how it measured up to what was dropped from the planter. This site is useful for replanting decisions and stand assessment http://lebanon.extension.psu.edu/Agriculture/FarmMgt/soybeans.htm. In several fields I was getting about 90% of the drop indicating excellent emergence.

Soybeans have also emerged in the State and these fields will be the magnet for overwintering Bean leaf beetles(BLB) to attack first. I identified four fields in Pa with bean pod mottle virus last season and have activities in place to determine the spread in Pa. This disease is spread from BLB feeding in the spring. In areas known to harbor this disease many states have these treatment options of Cruiser seed treatment, or scout and treat with an insecticide at first sign of feeding damage. For Pa conditions I think we need to keep to thresholds as listed in this publication http://lebanon.extension.psu.edu/Agriculture/Soybeans.htm. However, Dr. John Tooker and I will be involved in assessing the spread of this disease and the need to change management tactics. The beetles are relatively easy to see and the damage is pronounced with shot holes in the leaves.

Small grains are moving quickly toward harvest. I have concentrated on wheat fields and reports from educators from across the state are variable depending on recent rainfall. In areas with little rain there is no sign of disease infection. In others there are low levels of septoria and powdery mildew. Heads are emerging in some areas and now is the time to check the scab reporting website over the next two weeks to assess the need to treat to prevent infection. I reported this last week but here is the link again http://www.wheatscab.psu.edu/. In the Penn State Variety test tremendous differences exist in disease resistance. Dr. Greg Roth reported some with no sign of Powdery mildew and others with a tremendous amount of infection. Ratings for Powdery mildew from Penn State are available at http://smallgrains.psu.edu/pdf/2006-7_small_grains_performance_report.pdf. I also observed corn leaf aphids in high numbers and received reports of cereal leaf beetles attacking the wheat. The Agronomy Guide details management and control for these pests. http://agguide.agronomy.psu.edu/pm/sec5/sec52a.cfm

Chilling Injury Potential in Corn — Greg Roth, Grain Crop Specialist

The warm spell in mid April resulted in a significant amount of corn planted in some areas. Locally, this has been followed by several cool weather fronts and frosty mornings. There may be some potential for chilling injury in some of these early fields. Often chilling injury is not widespread, but can be severe in individual fields and may require replanting.

The most stressful condition for germinating corn seeds is exposure to cold (<50ยบ F) wet conditions immediately following planting when the seed imbibes cold water that reduces the elasticity of the cellular membranes of the developing seedling. This can cause cell rupture and leakage, which can release sugars and promote fungal and insect damage to the seed. This chilling injury can result in reduced vigor of the seedlings and in lasting effects on the growth of the plants.

Once the shoot emerges from the soil, considerable cold tolerance develops in the seedling. When scouting these early planted fields, be on the lookout for some of the typical problems observed under these conditions in the past. Most problems will occur in wetter areas of fields. Chilling injury can resulting in cork screwed seedlings in some cases. In other cases, rotten seeds, some with a developed and yellowed coleoptile can be observed. Some insect feeding on seeds can be observed and contribute seed death— this will likely be reduced with the widespread use of the new insecticide seed treatments. Deep planting on this early planted corn (over 2 inches) can also contribute to reduced emergence. Emergence rates can drop below 90%. Click link to see image http://fcn.agronomy.psu.edu/images/roth0809image1.jpg

When possible, compare performance of varieties or seedlots in problem situations. In some cases, extended exposure to herbicides during germination can increase the potential for herbicide injury. Early detection of stand problems can lead to an early replant decision with minimal yield loss. Assessing replanting of stands with seedlings that are questionable is tricky. I would consider using the Purdue replanting fact sheet in this situation (http://www.agry.purdue.edu/ext/pubs/AY-264-W.pdf ). Once plants emerge, they may take on a yellowish appearance for a few weeks until warm weather resumes. Usually this has no ill effects.

I expect most of our early planted fields will emerge fine and do well. But some may encounter problems, which can be addressed with early scouting, careful diagnosis, and a timely resolution of the problem.

First Cutting 2008 — Paul H. Craig, Dauphin County Educator

In the South Central region of PA the 2008 Spring Season is in full swing. In many areas graziers reaping the bounty of the spring flush of grasses. The weather is always the fly in the ointment but cattle and other livestock never seem to mind the fact that their forage doesn’t need to dry down for harvest. Haylage and hay harvest are another matter.

With the high commodity feed costs the production of the highest quality first cutting becomes more of an economical incentive for timely harvest than ever before. It has been said many times before but will be especially critical this year but high quality forage production means timely harvest often during narrow windows of opportunity. Avoid any delay in harvesting first cutting! It’s been said before but always worth repeating. When it is time to make forage — Stop planting corn and make hay!!

Forage producers know that the first cutting of alfalfa and grasses is the largest yielding cutting each year. Some estimates show first cutting can be 40% of total yields. Because of this, first cutting has the potential to provide forage feeders with either some outstanding forage quality or unfortunately, large amounts of poor quality forage for the entire feeding season.

First cutting also sets the stage for all preceding forage harvests. A delay in first cutting will significantly reduce quality and reduce maximum forage yields for the season. Are you ready for forage harvest?

Many of the top quality producers don’t get caught behind on first cutting. If weather conditions in early to mid—May are suitable for cutting forage grasses and alfalfa they don’t delay. Many growers harvest alfalfa stands as early as late pre—bud or at sign of first bud to maximize forage quality if there is a window of harvest opportunity. Weather may turn wet and keep you out of the fields for 10 days or more and the resulting forage will be disaster for a feeding program. When taking an early harvest (pre or early bud) allow at least 3rd or 4th cutting to reach early bloom, top—dress (K2O) and stay ahead of potato leafhoppers this summer to allow the stand to build up root reserves.

Because of the importance of getting forage harvested on time and quickly and the fact that a heavy first cutting will slow harvest speed, haylage or baleage should be the harvest method of choice.

Here are a few production pointers for making quality haylage and baleage. Optimum moisture levels for grass crops are 45 to 63%. Because alfalfa is high in calcium, which buffers haylage fermentation, moisture levels for alfalfa haylage should be slightly less, 40 to 55% moisture. If making baleage, be sure to wrap bales with at least 6, preferably 8 mils. of plastic to ensure an airtight seal. Wrapping should take place within 24 hours, preferably sooner.

Limit bale diameter to 4 feet to minimize handling extremely heavy bales and ensure safety. Store bales on the ends, which have significantly more layers of plastic wrap, for protection. Mark and store by cuttings. Baleage made with optimum moisture conditions, at earlier stages of maturity and wrapped properly has the potential for 12 months or longer storage. Bales made under less optimum conditions will not have the storability and may need to be fed out in 3 to 6 months.

Direct Cut Barley — Paul H. Craig, Dauphin County Educator

Direct cut barley is barley that is harvested with a small grain head mounted on a forage chopper and then ensiled. In recent years with the increasing adaption of cutting harvester this practice has gained in popularity for production of a high energy good forage feed at times when silos many be getting emptied. Cutting height of direct cut barley is about 6 inches and there is no wilting of the crop. Harvest is at the proper moisture level for different silo types. Farmers with trenches shoot for 65 to 70%, upright silos at 63 – 68% and sealed silos at 55 – 60%. This is usually around the soft dough stage, when milky kernels can be easily crushed in your finger tips. Moisture monitoring and determination is critical. Yields range from 3 to 4 tons/acre of dry matter.

Unlike rye which rapidly increases its level of indigestible fiber, lignin, after heading, wheat, oats and barley actually produce more energy and protein per acre after the crop is headed. In studies at Kansas and Mississippi State, barley was rated the best choice due to higher grain yields and good fiber digestibility. In general, barley silage quality is good, with energy levels slightly lower than corn silage (TDN 64% vs. 69% for corn silage) and a protein level slightly higher (9 – 11% vs. 8% for corn silage). Stage of maturity, variety, fertility, and harvest management can greatly affect forage quality. Everyone recommends using forage testing to ensure its proper substitution in a ration.

Small grains mature much faster than corn silage. The proper harvest window will be very narrow, at most 3 to 6 days, depending on weather. This requires close monitoring of the crop, coordination with harvesters and large capacity equipment. Due to hollow stems a shorter cut, often 3/8 inch, is recommended. However, to optimize fiber in the silage do not over chop. Good packing, rapid fill and preventing air exchange are especially important at that time of year, due to warmer summer temperatures.

Producers with larger acreage may choose to start harvesting earlier but too wet silage looses plant nutrients and produces undesirable, unpalatable, high butyric acid silage. Like corn silage raising the cutting height will result in a drier silage crop. Too dry conditions cause poor oxygen elimination and results in a poorly fermented product. Some have suggested mixing higher moisture alfalfa haylage with too dry barley silage. Either way, monitoring moisture is critical.

Harvesting barley as silage also provides an opportunity for earlier double cropping. This usually leads to higher corn silage yields. Using a computer simulation, Dr. Greg Roth at Penn State found that planting corn silage following barley silage harvest would yield 83% compared to full season corn silage. Waiting until grain harvest, yields were only 65%.

Precut Rye Straw — Andrew Frankenfield, Montgomery County Extension

Rye that was not cut for balage or silage is heading in most of PA at this time and is no longer useful for forage. If you were planting corn when you should have been cutting rye and then the rains returned. Now you have five foot tall rye in your fields. Now what? Cut it with a discbine or haybine and make straw out of it. Unlike hay, rye needs a rain shower or two to bleach it from green to yellow or almost white in color.

Since the straw market has increased in recent years more farmers are looking for ways to bale more straw and have it earlier in the season, rye does both of those things and more. Rye is relatively easy to establish and can be planted later than wheat and yields more straw. A 1½ – 2 ton yield would be average, but it can yield over 3 tons per acre. It is an excellent nutrient scavenger and a good cover crop to protect the soil over winter after soybeans or other low residue crops like vegetables are harvested.

Rye is mowed after heading but before the seed develops, around flowering is ideal. It is tet once or twice while it dries and needs a couple tenths of an inch of rain to bleach, then it is raked and baled. Rye straw makes good bedding for livestock or mulch for construction sites.

For more information on precut rye straw see the article in Hay and Forage Grower “Nothing But The Best”. http://hayandforage.com/mag/farming_nothing_best/index.html

Time to watch for Black Cutworms — John Tooker, PSU Entomology Specialist

With corn planting delayed in many parts of Pennsylvania, growers should be aware that late—planted corn can be severely damaged by black cutworm. Damaging populations of this caterpillar species develop from eggs laid on cool—season grasses and weeds near crop fields. Egg—laying female moths typically migrate into our area on storm fronts during April and May. States to the south and west of Pennsylvania, such as Indiana, Kentucky, Missouri, and Illinois, have reported trapping large numbers of adult females in the past week; therefore, Pennsylvania growers will need to scout in the coming weeks for cutworms and their damage.

Newly hatched caterpillars are about one—quarter—inch long and fully grown larvae approach two inches. Their color can range from gray to nearly black with a pale band or stripe along the center of the back. The skin can appear greasy and has larger bumps interspaced with smaller ones. Many good images are available online.

Black cutworms exhibit two types of “cutting” behavior depending upon the amount of moisture in the soil and size of plants. Where soil moisture is adequate and plants are small, conditions that currently apply to many parts of the state, larvae hide in the soil during the day and move to the surface at night where they cut off plants just above the soil surface. In situations of dry soil conditions, the larvae do not move to the surface to feed, but instead chew into the plant just below the soil surface. This causes the corn plants to wilt and usually die. One larva will cut off an average of five corn plants during its development. Older cutworm caterpillars can also damage larger corn plants by boring into the stalk.

Because cutworms do not tend to be perennial problems, scouting for injury is usually the best tactic. Insecticidal rescue treatments are available and may be applied to damaged portions of fields. Widely accepted thresholds are 2, 3, 5, and 7 cut plants per 100 for seedling, V2, V3, and V4 stage plants, respectively. For fields that are infested year after year, some cultural controls are available. In particular, removal of cool season weeds along field edges can starve young caterpillars and growers should avoid planting corn following pasture, alfalfa or red clover. Alternatively, soil insecticides can be incorporated at planting or Herculex lines of transgenic corn have cutworm activity.

Contributors:County Educators: Paul Craig (Dauphin), Joel Hunter (Crawford), Mark Madden (Sullivan), Mena Hautau (Berks), Kevin Fry (Armstrong), John Rowehl (York), Grant Troop (Lebanon), Delbert Voight (Lebanon). Department of Crop and Soil Sciences, Greg Roth, Sjoerd Duiker and John Tooker.

Editor:Andrew Frankenfield, (Montgomery)

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