Field Crop News at Penn State

Field Crop News

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

May 14, 2004    Vol. 04:03

IN THIS ISSUE:

Mark Your Calendar

Announcements

Weather Outlook

Production

Pest Management

Agents Corner

Announcements

CROP MANAGEMENT GROUP CALENDAR ONLINE

We have developed a new online calendar to keep you abreast of dates planned for our Crop Management Extension Team. The calendar is located at: http://www.events.psu.edu/cgi-bin/cal/webevent.cgi?cmd=opencal&cal=cal209& and can also be accessed from our Crop and Soil Sciences Extension website. Our hope is everyone will use this to help coordinate meetings to avoid conflicts. If you have appropriate dates to consider adding, please contact Lisa Crytser (lac8@psu.edu) or one of our faculty.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

WEATHER OUTLOOK

The first half of May has been very warm not only in Pennsylvania, but across much of the nation. Precipitation is averaging above normal in north-central and eastern parts of the state, but showers have missed large parts of western Pennsylvania. The amount of sunshine is a bit above normal so that drying conditions have been generally good. Winds are averaging near normal, though it has been windier than average in western sections of the state

Warmer than normal conditions are likely for at least another week. Temperatures should be near a maximum in eastern Pennsylvania on May 15. Showers and several strong thunderstorms on May 15-16 will mark a transition to more seasonable readings for May 17. However, warm and somewhat humid air will return from May 18-21. Much of the period will see scattered thunderstorms with the most widespread rain expected around May 21-22. There are indications that noticeably cooler, drier air will push into the region between May 24-27 with even a late frost possible in the northern cold spots. Much of the last week of the month will be dry. The early outlook for the summer still indicates near normal temperatures and somewhat above normal rainfall, though June should see above normal temperatures.

Paul Knight, WeatherWorld@psu.edu
Pennsylvania State Climatologist

PRODUCTION

MID-LATE SEASON CORN PLANTING CONSIDERATIONS

Our full season corn planting is progressing rapidly except on the wet soils in some regions. We are rapidly moving into the planned double crop and later planted corn scenarios. These plantings present several challenges/opportunities that producers and their advisors should consider. First, be careful not to plant this corn in soils that are too wet. While you might get away with this in April, when cool temperatures and moist conditions can help alleviate the effects of sidewall compaction, there is significant risk now for high temperatures to bake the sidewall into an impenetrable zone to the roots of a rapidly growing seedling. Also, consider Bt hybrids for these later plantings- these late planted fields are often where we see the most consistent and severe European corn borer infestations and largest losses to this insect. If you are following corn, where rootworms may be a problem, make sure you have some protection for this pest in place, since the rootworm hatch could coincide with the early development of the young plants and damage could be severe. Also, consider your hybrid maturity. In most places you can still plant all but the fullest season hybrids for your area until May 25 or so. Then you should think about the end use of the crop in regards to your hybrid maturity. These double crop fields can be used to "top off" bunker or tower silos with slightly wetter silage and facilitate better packing- in this case you might not want to use much shorter season hybrids. Our bunker silo survey this year is showing the top of the silo is where we have the most challenges in achieving acceptable silage densities. You might also consider narrow row or twin row corn for the late planted fields. In a two year study in Lancaster we found the benefits from 15 compared to 30 inch rows increased from none in late April to 3 tons silage/acre (65% moisture) on June 15. Consider some of these management tactics as we finish our corn planting around the state.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

WHEAT PROSPECTS AND THE WEATHER

Our wheat plots generally look good, except some of the latest plantings that have poor stands and limited tiller development. The hot weather we are experiencing this week is not a positive factor for wheat yields. The optimum temperature for wheat growth and development is about 77F. When daytime temperatures exceed 86 F, rapid growth and development are encouraged with minimal development of plant parts. Plants grown at lower temperatures during the head development stage would tend to have larger heads, longer stems, large flag leaves, and more fertile florets in each spikelet. The most serious effects of these high temperatures occur in the ear development phase (where most of our wheat is now) rather than in the later grain filling stages. This rapid shift from cool temperatures to hot temperatures is typical of our climate, especially here in central Pa., and limits our ability to manage this crop for high yields obtained in regions with more gradual changes in temperature. Warm temperatures will also limit the crops ability to compensate for thin stands due to winterkill or late planting.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

RYE COVER CROP MANAGEMENT

Rye cover crops have multiple environmental benefits, such as erosion control, reduced nitrate leaching, soil organic matter increases, moisture savings in summer, and supplemental weed control. All these benefits are directly related to the amount of biomass produced by the rye. It is logical to expect greater benefits from a late killed rye cover crop, but that usually means the planting date of corn needs to be delayed. This might cause corn yield reductions, but perhaps the benefits of more rye mulch would outweigh the disadvantages of late planting. To test this, we planted corn 7-10 days after killing a rye cover crop in early and late boot stage, and compared the results with a control (no rye cover crop) in Centre County. Early boot is when the ligule of the last rye leaf is just visible, whereas late boot is when the head is almost emerging (see p. 286 of the 2004 Agronomy Guide). Note that all planting was done no-till. The straw of the previous oat crops was always removed. Early and late planting dates for corn were respectively: May 9th and 22nd 2001, May 1st and 11th 2002, and May 2nd and 22nd 2003.

Rye biomass production differed greatly between years (Table 1). Growth of rye was probably limited in 2001 because of low precipitation in January, February and March. The high biomass production at the late planting date of 2003 was because the kill date was delayed by one week due to extremely wet field conditions.

Table 1. Rye biomass accumulations (lbs/A) at early and late boot stages.
  2001 2002 2003 Average
Early Kill 1020 No data 1399 1209
Late Kill 1635 3336 6311 3761

On average, approximately 1000 lbs/A biomass accumulation can be expected at early boot stage, and 4000 lbs/A at late boot stage. Based on other work we estimate that the C:N ratio for early and late killed rye will be approximately 20 and 40, respectively. The succulent early killed rye will decompose quickly whereas the late killed rye mulch will be present for a prolonged period, possibly until the end of the corn growing season. The results also indicate the challenges of rye cover crop management due to weather conditions. A one week delay in kill date can mean easily a doubling of the rye biomass the producer will have to deal with.

We did not observe a yield decline due to late planting in our study. There was a 10 bu/A yield increase due to no-tilling corn into rye that was killed in the early boot stage. Some other researchers (and farmers) have reported early corn growth inhibition by chemicals leached from rye residue. This so-called allelopathic effect of rye on corn was not observed in the three years of this study. One reason may be that we used Roundup to kill the rye. If Gramoxone is used these chemicals are released more quickly due to cell rupture. Another reason may be that we waited 7-10 days between killing the rye and planting the corn. The allelochemicals are known to lose their effect quite rapidly after rye kill.

Table 2. Corn yields (bu/A) of early and late plantings with or without rye cover crop.
    2001 2002 2003 Average
Early planting Without Rye 183 120 158 154
  With Rye 194 139 159 164
Late platnting Without Rye 182 143 150 155
  With Rye 189 122 154 155

figure 1

Thus we suggest that an early killed rye cover crop will boost yields if corn follows low-residue crops such as oats, soybeans or corn silage. Considering the longer term, however, it may be beneficial to let the rye grow to late boot stage. No yield reduction was associated with that practice compared with not using a rye cover crop. By delaying planting 10 days and letting your rye cover grow to late boot stage organic matter content is likely to increase. Additionally, we observed a slightly lower bulk density in the late-killed rye (Figure 1). Planting corn into late killed rye will hopefully contribute to badly needed increases in the quality of our Pennsylvania soils.

Sjoerd Duiker, swd10@psu.edu, Soil Physics
Bill Curran, wscurran@psu.edu, Weed Management
Crop and Soil Sciences

PEST MANAGEMENT

ADJUVANTS AND COMMON POST HERBICIDE TANK MIXTURES

The use of adjuvants with post herbicides is a critical component for effective weed control. Almost all foliar-applied herbicide labels recommend which kind of adjuvant to include in the tank when a particular product is applied alone. However, when herbicides are tank mixed, the choice of adjuvants (i.e., crop oil concentrate (COC), methylated or modified seed oil (MSO), nonionic surfactant (NIS), or ammonium nitrogen fertilizer (NH4), which includes ammonium sulfate (AMS) or liquid nitrogen (UAN)) is more difficult and sometimes not directly stated on herbicide labels, or worse yet, they conflict with each other. Below is a list of some typical post herbicides and the directions as stated on their labels regarding adjuvants and tank mixtures.

Callisto is used at 3 fl oz/acre but some labels suggest a reduced rate of 1 to 2 oz. Callisto can be tank mixed with Accent, Basis Gold, Steadfast ATZ and others. If used alone or in most combinations, add COC (not MSO) plus NH4.

Celebrity Plus is used at 4.7 oz and can be mixed with Accent, Atrazine, or Distinct. NIS and NH4 must be included whether applied alone or in a mixture.

Distinct is applied at 4 oz, but some labels suggest rates as low as 1 oz when tank mixed with other post herbicides. For best results use NIS plus NH4 under most conditions. MSO may be used instead of NIS when tank mixing Distinct with Option or Equip.

Equip should be applied at 1.5 oz/acre and must include MSO and NH4 if used alone or in combination with atrazine, dicamba (e.g., Banvel, Clarity), or Distinct. (Currently, Callisto is not listed on the Equip tank mix label.) NIS and COC are not recommended for use with Equip or unacceptable weed control will result.

Lumax at 2.5 qt/acre can be applied early post and tank mixed with Accent, Basis, Steadfast, and Steadfast ATZ. NIS is the recommended adjuvant. COC, MSO, and NH4 are not recommended and may cause injury to emerged corn.

NorthStar can be applied alone or in a tank mix at 5 oz/acre. NIS or COC/MSO must be included in the spray mixture, but the addition of NH4 is optional. Atrazine, Accent, dicamba or Marksman are common tank mix partners. Callisto is not listed as a tank mix partner.

Option is applied at 1.5 to 1.75 oz/acre and MSO and NH4 should be included whether it is used alone or in combination with atrazine, Banvel, Clarity, Distinct, or Callisto. (This recommendation differs with the Callisto label.) NIS and COC are not recommended for use with Option or unacceptable weed control will result.

Steadfast ATZ is used at 14 oz/acre and can be tank mixed with atrazine, dicamba, Marksman, Distinct, Callisto, and Hornet. COC plus NH4 are the recommended adjuvants, however, NIS or MSO can be substituted. It does state that MSO should not be used with Callisto tank mixes. Also, NIS is permitted in place of COC in tank mixes that include dicamba (including Distinct), however overall weed control may be reduced.

Yukon is used at 4 oz/acre and should include COC or NIS plus NH4 if applied alone or in tank mixture with Accent or Beacon. However, use only COC if combined with atrazine.

For additional information on postemergence herbicides and their restrictions, please refer to the Penn State Agronomy Guide at http://agguide.agronomy.psu.edu/ or to a recent article from the Univ. of Illinois at http://www.ipm.uiuc.edu/bulletin/article.php?issueNumber=7&issueYear=2004&articleNumber=7

Dwight Lingenfelter , dxl18@psu.edu
Weed Control, Crop and Soil Sciences

NEW EXTENSION PUBLICATION: "REDUCING MOSQUITO BREEDING SITES WHEN USING WASTE TIRES AS ANCHORS FOR BUNK SILO COVERS."

figure 2

After a long winter those full-casing tire used to anchor bunk silo covers are accumulating in piles around the silos. With spring and summer upon us, those tires should not be ignored until they are used again. Mosquito breeding season is here and those tires can be great places for new generations of mosquitoes to develop. With the many wild birds attracted to farms and abundant breeding places, farms can be among the places that contribute to the spread of West Nile Virus (WNV).

A new extension publication describing the potential hazard of WNV, the advantages of anchoring bunk silo covers well, basic tire design features, and options to full casing tires is available from the Penn State Cooperative Extension (UC185). Extension specialists from the departments of Agricultural and Biological Engineering, Crop and Soil Science, Dairy and Animal Science, and Entomology cooperated to cover the many dimensions of the disease, silage preservation, and dealing with waste tires. Sources for additional information about waste tires and West Nile Virus are also listed.

Before the summer rains and warm temperatures arrive, check out this new publication and help to reduce the potential hazards of WNV and maybe improve silage quality in the process.

For more information, contact Dr. Les Lanyon, professor of soil science and management, Department of Crop and Soil Sciences, at (814) 863-1614 or lel@psu.edu.

Les Lanyon, lel@psu.edu
Soil Science and Management, Crop and Soil Sciences

Agents Corner

CAPITAL

Corn and soybean planting and early season development has been progressing rapidly since early May. Rain events are widespread thunderstorms that result in variable soil conditions across the region. There is a wide spread in growing degree data from southern PA to northern Dauphin County. I would estimate that from Harrisburg north there is about a 3 to 5 day difference in conditions.

Early maturing orchardgrass began heading by May 4 and most alfalfa is ¼ budded already. Risk of rain has delayed harvest decisions. Some haylage has been made of excellent quality forages. Manure hauling onto ryelage ground and corn planting are primary activities this week. There is scattered alfalfa weevil pressures, but it is highly unlikely that treatment will be needed at this time. Will need to remind growers to check regrowth for possible treatments.

The wheat is still in the boot stage in the north. Barley is well headed and flowering in most fields. No disease pressure is observed from powdery mildew. There is increasing evidence of winter annual grasses such as cheatgrass in many wheat and barley stands. These weeds are maturing at this time and are seen along roadsides too.

I don't recall every seeing so many dandelions as this year. In crop stubble fields, alfalfa, grasses and CREP lands these seed heads have taken over. Lots of new sources of seeds for coming years. My brother lives in Alaska where dandelions are considered an invasive species. The state has a program to monitor and eradicate any dandelion stands prior to further spread. Hope they do a better job than we have.

Paul Craig, phc8@psu.edu
Dauphin County

CENTRAL

Between daily scattered thunderstorms, corn planting is proceeding on schedule during the second week of May. The earliest that corn was planted in our area was on April 27, and that corn has not yet emerged as of May 11. Alfalfa and orchardgrass are both maturing ahead of schedule, the heat and abundant moisture in the last 7 days helping to make what will be a high yield for first cutting. No soybeans have been planted yet in our area.

Over 7 inches of rain have fallen over the past 5 weeks, and slugs are plentiful. So plentiful in fact, that at one farm, dozens of slugs were resting comfortably on top of an ag bag full of corn silage.

All of the moisture and heat has been good for the new seedings. Both pure alfalfa and alfalfa/grass seedings have had excellent emergence with no setbacks due to soil crusting, drought or frost damage. Due to wet soils, most oat fields were not planted until after April 15. However, the oats have germinated quickly and the fields have excellent stands.

I have heard of no alfalfa weevil concerns; Greg Hostetter theorizes that the wet spring has kept weevil biological control at highly effective levels.

Dave Swartz, dls19@psu.edu
Mifflin/Juniata/Perry

SOUTHWEST

The arrival of normal to above normal temperatures and dryer conditions have put the planting season in high gear. After struggling through the past weeks of challenging conditions farmers are eager to get field work done. Except for a few stray fields, the oats and alfalfa are planted, most of which have emerged. Corn and soybean planting is in full swing, with some of the earlier planted corn beginning to emerge.

The weevils have begun to gain a little ground on the alfalfa, but populations are still below threshold levels. Alfalfa growth has also jumped in the past couple of weeks with the warmer temperatures and is in the bud stage. Orchardgrass is beginning to head and I look for first cutting to begin very soon, weather permitting.

Kevin Fry, ksf107@psu.edu
Armstrong County


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Douglas Beegle, editor,
Professor, Agronomy, dbb@psu.edu

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