Vol. 96.2
April 5, 1996
Change in reporting CEU hours: We are in the process of revising the CEU reporting procedure. There is an old saying that goes something like this; "if you stay around long enough things will come to a complete circle". The CCA program is not very old but we are making a complete circle in the way we report CEUs. The national office has adopted a procedure very similar to the way we originally (until January 1, 1996) used in Pennsylvania, signing a roster sheet which is used to record your attendance at a particular meeting. This means we will dispense with the green CEU recording form and the hassle of mailing that to Madison. In the future the meeting organizer will provide a roster for you to sign. You will be provided a five digit number to keep for your records. This is called a tracking number and will be used if there is a question about CEUs at a later date. When you sign the roster, you will need your certification number otherwise you will have to use your social security number.
As in the past, if you attend a meeting that has not been state board approved and you feel it warrants credit, mail me a copy of the program and verification that you attended the meeting. The program will be evaluated and if appropriate, CEUs will be assigned.
Individuals or organizations wanting to obtain CEUs for a program they are organizing should continue to send me the information as in the past. CEU credits will be assigned, the tracking number and a roster sheet will be mailed to you from Madison. The roster will be returned to Madison once the meeting is complete.
If you have any questions about the change, do not hesitate to contact me.
Elwood Hatley
The following are some thoughts on the spring management of winter grains.
1. Determining An Adequate Stand. Satisfactory yields depend on having approximately 40 heads per linear foot of row when planted in seven inch rows. To achieve this, we need a stand of 18 to 20 plants per foot of row. Winter grains plants have the ability to increase tiller production as the population is reduced. This reduces the effect of low populations on yield. However, populations can be reduced to the point that the land area should be replanted into another crop later in the spring. This occurs when we have about a 50% stand remaining or 9 to 10 plants per linear foot of row.Elwood Hatley, CCA & John Ayers
Resistance is the most important defense farmers have against the majority of alfalfa diseases. Alfalfa varieties are available with moderate to high resistance to verticillium wilt, fusarium wilt, bacterial wilt, phytophthora root rot, and anthracnose. Consult your county agent for information on the diseases prevalent in your geographic area and plant varieties that have the necessary resistance. Be aware that some susceptible plants will be present in moderately and highly resistant varieties, due to normal genetic variation. The susceptible plants will develop symptoms and probably die if they become infected. This is not a cause for concern because, over time, the resistant plants will fill in and compensate for the loss of the susceptible plants and yields will be satisfactory.
Resistant varieties are not available for controlling either sclerotinia stem rot, or crown and root rot. Only moderately resistant varieties are available for controlling the various foliar diseases of alfalfa. Farmers must rely primarily on sound cultural practices to manage these disease so as to minimize their economic impact. Sclerotinia crown and stem rot has become more prevalent over the last few years and has the potential to devastate fall seedings of alfalfa when the weather is cool and wet. Sclerotinia, the fungus causing sclerotinia crown and stem rot, survives as sclerotia on the soil surface and in plant debris. Sclerotia are black, hard, irregularly shaped fungal structures that resemble rat droppings. They vary in size, ranging between 0.25-0.50 inches. The sclerotia germinate in late summer and produce small mushroom-like structures that release the spores of the fungus. These spores will infect young seedings and cause rot when weather is wet and cool. Sclerotinia is responsible for some of the stand decline attributed to winter injury. Conventional tillage buries the sclerotia, which prevents many of them from germinating and producing spores. Conventional tillage is recommended for establishment of fall seedings of alfalfa. Conservation or no-till methods may be used for spring establishment because the sclerotia do not germinate in the spring and by the time they germinate in the fall, the plants will be large enough to have some resistance.
Foliar diseases of alfalfa include phoma, lepto, common, and stemphyllium leaf spots. Although some resistance is available, cutting management is the best method of coping with the leaf spot diseases. These diseases cause premature leaf drop, and have the potential to reduce yield and hay quality. Alfalfa stands with moderate to high levels of foliar disease should be cut early before the leaves are lost. Early harvesting increases hay quality and removes inoculum from the field. The removal of diseased leaves from the field should reduce the amount of foliar disease in the next regrowth.
Do not cut alfalfa when the leaves are wet with dew or rain. Water on the leaves and stems helps the various pathogens to spread. Mowing, itself is a very efficient way to spread diseases through stands of alfalfa, because the pathogens are carried from diseased plants to healthy plants on the mower blades and cutter bars. For this reason, farmers should mow the newest fields first and the older, more pathogen-infested fields last. Pathogens such as those causing anthracnose and verticillium wilt don't survive well in the soil, but can survive in plant debris and hay that sticks to harvesting equipment. Good sanitation, namely cleaning hay and other debris from mowers, rakes, balers and wagons will reduce the spread of these pathogens into new plantings in the spring.
Fungicides generally are not used on alfalfa because of the cost and concerns about fungicide residue. Fungicides, however, may be used at planting to help control phytophthora root rot. Phytophthora root rot can kill young plants quickly when the soil is poorly drained or when fields are wet for several days after a heavy rain. Control of phytophthora root rot primarily relies on the use of resistant varieties and these are very important in areas that are prone to wetness. In addition, seed treated with the fungicide metalaxyl (Apron) should be used when planting known problem areas. This fungicide, formulated for use as a soil drench under the name Ridomil, is available for soil application at planting.
Good crop management is critical for controlling root and crown rot of alfalfa. This disease is caused by several pathogens and no resistant alfalfa varieties are available. Plants that are healthy and growing well will withstand the onslaught of root rot much better than plants that are under stress because of poor nutrition, too frequent cutting, and insect pressure. Plants that are under stress from these and other causes do not have the food resources needed to fight the various pathogens. Care should be taken during establishment to ensure the correct levels of phosphorus and potassium and soil pH, and these nutrient levels should be maintained throughout the life of the stand.
Rotation is an important disease management tool. Rotations should be for 2-3 years with cereals, and corn being good crops because they are not susceptible to alfalfa diseases. Weed control in the rotational crops is important. Several alfalfa pathogens, including Verticillium and Sclerotinia, can survive in weeds, therefore, good weed control is essential to reduce the potential for disease when alfalfa is replanted. Good crop management coupled with the use of resistant varieties will prolong the life of an alfalfa stand and reduce the impact of disease on yield.
Barb Pennypacker, Research Associate in Agronomy
Below are selected corn and soybean herbicides that are relatively new or have the potential to cause problems in rotational crops. Though the majority of these are "new" chemistry products, keep in mind that older herbicides such as the triazines (e.g., atrazine, Bladex, Princep, Sencor) and chloroacetamides (e.g., Dual, Micro-Tech, Frontier, Harness, Surpass) still have certain rotation restrictions as well. The information listed in this table is our interpretation of label statements or a "best-guess" estimate. Consult the product labels if two or more herbicides are applied during the same season. Before applying any herbicide, consult the most recent label.
| Herbicide | Alfalfa | Clover | Field corn | Sorghum | Soybeans | Swt. corn | W.barley | W.rye | W.wheat | Spr. oats |
|---|---|---|---|---|---|---|---|---|---|---|
| a AH = after harvest; NY = next year; NR = no restrictions. bPlus successful field bioassay. |
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| Accent | 12 | 10 | NR | 10 | 10 | 10 | 4 | 4 | 4 | 8 |
| Basis | 10 | 18 | NR | 18 | 0.5 | 10 | 18 | 18 | 4 | 8 |
| Beacon | 8 | 18 | 0.5 | 8 | 8 | 8 | 3 | 3 | 3 | 8 |
| Broadstrike + Dual | 4 | 26b | NR | 18 | NR | 10.5 | 4.5 | 4.5 | 4.5 | 4.5 |
| Broadstrike Plus | 10.5 | 26b | NR | 12 | 10.5 | 10.5 | 4 | 4 | 4 | 4 |
| Exceed | 15 | 15 | 1 | 10 | 10 | 3 | 10 | 10 | 10 | 10 |
| Permit | 18 | 18 | NR | NR | 10 | NY | AH | AH | 3 | AH |
| Scorpion III | 10.5 | 26b | NR | 12 | 10.5 | 10.5 | 4 | 4 | 4 | 4 |
| Herbicide | Alfalfa | Clover | Field corn | Sorghum | Soybeans | Swt. corn | W.barley | W.rye | W.wheat | Spr. oats |
|---|---|---|---|---|---|---|---|---|---|---|
| Key: NR = No Restriction; AH = After Harvest; B = Bioassay a Read the label for additional restrictions due to rate, rainfall, soil, pH, and application rate. b Corn hybrids, which are classified IMI-corn or as tolerant (IT) or resistant (IR) to Scepter and/or other imidazolinone herbicides (for example, Pursuit), may be planted the spring of the year following Scepter or Pursuit application regardless of rainfall or time interval from chemical treatment to corn planting. c Plus successful field |
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| Broadstrike+ Dual | 4 | 26c | NR | 18 | NR | 10.5 | 4.5 | 4.5 | 4.5 | 4.5 |
| Canopya | 10 | 12 | 10 | 10 | NR | 18 | 4 | 4 | 4 | 18 |
| Classica | 9-15 | 9-15 | 9 | 9-15 | NR | B | 3 | 3 | 3 | 3 |
| Command | 12 | 12 | 9 | 9 | NR | 9 | 12 | 12 | 12 | 12 |
| Concerta | 9 | 9 | 9 | 9 | NR | 9-B | 3 | 3 | 3 | 3 |
| Pursuita | 18 | 26 | 8.5b | 18 | NR | 18 | 9.5 | 4 | 4 | 18 |
| Pursuit Plusa | 18 | 26 | 8.5b | 18 | NR | 18 | 4 | 9.5 | 4 | 18 |
| Reflex | 10 | 18 | 10 | 18 | NR | 10 | 4 | 4 | 4 | 4 |
| Resource | NR | NR | NR | NR | NR | NR | NR | NR | NR | NR |
| Scepter | 18 | 18 | 9.5b | 11 | NR | 18 | 11 | 18 | 4 | 11 |
| Squadrona | 18 | 18 | 11b | 11 | NR | 18 | 11 | 18 | 4 | 11 |
| Synchrony STSa | 12 | 12 | 9 | 9 | NR | 18 | 3 | 3 | 3 | 3 |
Dwight Lingenfelter
Roundup and Roundup Ultra received U.S.EPA approval for preharvest application in alfalfa. This application timing is aimed at the control of certain perennials such as quackgrass prior to rotation away from alfalfa. Treated alfalfa may be harvested 36 hours to 7 days after application. According to Monsanto, harvesting before 5 days after treatment will minimize forage deterioration. Monsanto states that dairy cow feeding studies show that a preharvest application of Roundup to alfalfa will not influence forage quality, palatability, protein, or fiber content. Cow feeding studies show that ingestion of treated forage results in non-detectable Roundup residues in muscle tissue and fat (less than 0.05 ppm), and in milk (less than 0.025 ppm).
Application of Roundup can be made in the fall or spring when weeds are actively growing (quackgrass with at least 6 inches of growth). Apply Roundup or Roundup Ultra at 1 quart per acre (maximum rate allowed). Use low rate technology (maximum of 10 GPA carrier with appropriate adjuvants) for improved activity. Deep tillage after harvest will increase control results. In numerous university research trials, Roundup has not been an effective herbicide for the control of alfalfa, especially during spring application. Therefore, plowing the treated forage following harvest or an additional herbicide application will probably be necessary for complete control of the alfalfa. In addition, adequate spray coverage of the target species within the alfalfa forage may be a concern.
Where this label may have some utility for Pennsylvania forage producers is in the control of certain cool-season perennial grasses such as quackgrass and orchardgrass prior to rotation. Application in the fall is most effective on these grasses. Additional alfalfa control measures will probably be needed the following spring. Although application in late spring has traditionally been less effective in controlling most perennial species including alfalfa, this strategy could help those producers that frequently try to capture both that first cutting hay and timely no-till corn planting (have their cake and eat it too). Although a mid-May to late-May application should help control quackgrass and suppress orchardgrass, bromegrass, and canary grass, alfalfa regrowth will continue to require preplant tillage or a "timely" postemergence systemic herbicide application.
Bill Curran
There area several species of slugs. Slug feeding can occur on the leaf surface (the type we are most familiar with), but slugs can also sever sprout slightly below the leaf surface as well as feed on the seed. Therefore, these latter two types of damage can occur when slits do not completely close at planting. Generally, when the plants grow beyond the 5-leaf stage, less damage occurs, although there are reports of damage occurring later than this. Slugs are moisture-loving invertebrates, and consequently drought can cause high mortality, resulting in lower plant damage in dry conditions. Because of their association with moist conditions, slugs are more likely to be associated with reduced tillage, where moisture levels are higher, and hiding places are more abundant. Heavy manure applications, particularly where clumps of manure exist, are also favorable slug habitat. And, similar to other early-season invertebrates, slugs may do more damage where slow-growing conditions occur, such as prolonged wet, cold weather. Scouting for slugs is difficult. Reports from Maryland indicate that scouting at night can be done, and damaging populations may occur if there are greater than 5 slugs per square foot. Other research at Penn State indicates that damage less than 20 to 30% of leaf area eaten typically is not serious when growing conditions are good. Another scouting technique is to look for eggs at the base of the plant.
It is best to keep in mind cultural practices when thinking of how to manage slugs. Research from Maryland indicates that switching to tillage for one year will dramatically reduce populations. Other techniques, aimed at promoting rapid plant growth, are to delay planting (to allow higher temperatures) and avoiding wet seedbeds. Trash wheels or row cleaners on the planter may also reduce populations because they decrease slug habitat near the seed zone, as well as promote faster plant growth. Finally, lack of slit closure can increase slug damage because it allow them to feed on the seed and makes it easier to sever the sprout.
Progress in chemical control has been slow. In the last several years, metaldehyde baits (Deadline Bullets) were made available. They are registered at 10 to 40 lbs. per acre, which even at the low rate can be expensive. Some research has indicated that the low rate (10 lbs./acre) banded over the row is as effective as the higher rates. Research from Ohio has even indicated that perhaps 5 lbs./acre (banded) may be effective in soybeans. If slits exist, the chemical will be less effective. Valent, manufacturer of Deadline Bullets, is also working on a pellet formulation which can be applied through the planted box, as well as another formulation of a broadcast treatment. There is also a company in the midwest who is looking at a slug and snail bait. Some growers have had some success with using 30% urea applied at night. Currently, however, the only registered chemical option available is Deadline Bullets.
Results from corn rootworm trials in Pennsylvania and Iowa are shown in tables 1 and 2. Entomologists use the common "Iowa" root rating system to determine damage to roots: a rating of 1 is an undamaged root system, a rating of 6 is the most severely damaged (all three nodes are chewed completely back), and ratings of 2 to 5 are intermediate. Economic damage begins to occur when the root rating exceeds 3 to 3.5. From the root ratings shown, the best treatments (lowest root ratings: 2.6 to 3.2) in the Rock Springs 1995 trials occurred with Counter 15G T-band, Fortress 2.5G T-band and in-furrow, all Force treatments, Furadan 4F broadcast+cultivation, and Lorsban 15G T-band. Less effective were the Dyfonate II T-band and Furadan 4F broadcast treatments (root ratings of 3.9 to 4.4). All these treatments were significantly better than the untreated plots (root rating of 5.4). Because of the extreme drought in Pennsylvania in 1996, yield data were nor reliable, and are not reported. Table 2 shows a 4-year summary of soil insecticides in Iowa. It summarizes the average root ratings achieved with various materials, and the consistency of materials in terms of how often they achieved a root rating of 3.0 or less, over many trials in Iowa. The results seem to agree with our results from Rock Springs. Counter treatments, Fortress 2.5G in-furrow, Force 1.5G, Aztec 2.1 G, and Lorsban 15G seemed to be better treatments.
There will be two new rootworm insecticides registered for the 1996 growing season: Aztec and Fortress. Aztec is from Bayer, and is a combination of an organophosphate (2.0 % tebuprimiphos) and a pyrethroid (0.1% cyfluthrin). Fortress, from DuPont, is an organophosphate (chlorethoxyfos), and will be available in either a 2.5G or 5G formulation. Both these compounds will be applied at much lower rates (2.5 oz active ingredient/acre for Aztec and 2.6 for Fortress), compared to other granulars (typically 21 oz active ingredient/acre). Trials in Pennsylvania (Table 1) and Iowa (Table 2) indicate that these new compounds compare favorably with others presently registered. As with other organophosphates, there is concern with insecticide/herbicide interaction in regards to plant injury. Typically, the greatest concern of insecticide/herbicide interactions is with using Counter, which has systemic activity in the plant, and ALS herbicides (sulfonylureas, imidazolinones, sulfonomids). Neither Aztec or Fortress are systemic, and reports from Iowa have not found herbicide interactions with them. Nonetheless, it is something to keep in mind.
Fortress 2.5 G and Aztec are available in typical bags, and are applied as any other granular. These new granular materials are labeled for field corn, popcorn, sweet corn, silage corn, and seedcorn, and are also labeled for control of wireworms, white grub, and seedcorn maggot. They are also labeled for cutworms, but this remains to be effectively evaluated. Please read the label of these products carefully, as there are special precautions relative to application near water, wildlife and fish. During 1996, Fortress 5G will be sold and applied only through the SmartboxTM, a closed handling system from DuPont that mounts on the planter. If you need more details, contact your local DuPont representative.
| Treatment | Formulation | Ratea | Application methodb | Root Rating |
|---|---|---|---|---|
| a Rates are expressed as oz. AI/1000 ft of row. b T-band and In-furrow granular applications were made at planting (May 16). BRD/CLT = Furadan broadcast on June 16, followed immediately with cultivation; BRD = broadcast with Furadan 4F only. |
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| Fortress | 2.5G | 0.15 | T-Band | 2.6 |
| Furadan | 4F | 1.20 | BRD/CLT | 2.6 |
| Counter | 15G | 1.20 | T-Band | 2.7 |
| Force | 3G | 0.12 | In-furrow | 2.8 |
| Force | 1.5G | 0.12 | T-Band | 2.8 |
| Force | 1.5G | 0.12 | In-furrow | 3.0 |
| Lorsban | 15G | 1.20 | T-Band | 3.0 |
| Fortress | 2.5G | 0.15 | In-furrow | 3.1 |
| Force | 3G | 0.12 | T-Band | 3.2 |
| Regent | 1.5G | 0.12 | T-Band | 3.2 |
| Furadan | 4F | 1.20 | BRD | 3.7 |
| Regent | 1.5G | 0.12 | In-furrow | 3.9 |
| Dyfonate II | 15G | 1.20 | T-Band | 4.4 |
| Untreated | - | - | - | 5.4 |
| Product | Application Method | Percent Consistencyb | Root Rating |
|---|---|---|---|
| a from M. Rice, Integrated Crop Newsletter, Iowa State University, November 10, 1995. b percent of trials in which a root rating of 3.0 or less was achieved. |
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| Counter 20CR | T-band | 100 | 1.9 |
| Counter 15G | T-band | 100 | 1.9 |
| Counter 15G | In-furrow | 100 | 2.0 |
| Counter 20CR | In-furrow | 100 | 2.0 |
| Fortress 2.5G | In-furrow | 97 | 2.2 |
| Force 1.5G | In-furrow | 97 | 2.4 |
| Aztec 2.1G | In-furrow | 94 | 2.4 |
| Aztec 2.1G | T-band | 92 | 2.3 |
| Force 1.5G | T-band | 92 | 2.3 |
| Lorsban 15G | T-band | 89 | 2.4 |
| Dyfonate 15G | T-band | 81 | 2.6 |
| Thimet 20G | T-band | 81 | 2.8 |
| Fortress 2.5G | T-band | 72 | 2.8 |
| Untreated | - | 0 | 4.8 |
Steve Spangler and Dennis Calvin
Lebanon County is starting to become busy with field activity. Most spring alfalfa and grain seeding is complete and winter small grains have been topdressed with (N) to promote tillering. With winter came winter annuals like henbit and chickweed and some alfalfa received a herbicide treatment to reduce the weed competition.
Alfalfa has about 2 inches of regrowth (April 3) so the timing of the herbicide was critical. Small grains also have some winter annual weeds, but several producers are hoping to hit the Canada thistle at the same time.
Snow mold took a toll on early seeded rye and wheat where the top growth formed a mat under the snow. Some fields were severely affected but most are hurt only where the drill crossed in the head lands creating a double seeding.
Producers are gearing up for planting corn and beans in a couple weeks. To assist in the effort, we are conducting a manure spreader, sprayer and planter maintenance workshop on April 16, 1996 at the Lebanon Fair Grounds. All are welcome to attend. Call the Lebanon Co. Ext. office for more information
Del Voight
Lebanon Co. Ext. Agent
William S. Curran
Associate Professor Weed Science
email: wsc2@psu.edu
Website Address: http://fcn.agronomy.psu.edu/