MBC Newsletter_04-2017_SINGLE PAGES

April 2017 MANAGEMENT OF WHITE MOLD IN DRY BEAN Dr. Martin Chilvers, Michigan State University Biological control can be part of an integrated white mold management Greg Varner, Michigan Dry Bean Research Board system in both conventional and organic production systems. The most commonly utilized product is Contans® which is a formulation of The disease white mold, caused by the fungus Sclerotinia sclerotiorum the fungus Coniothyrium minitans. The Contans® fungus parasitizes can be a significant problem in dry bean production. The incidence and and degrades white mold sclerotia, resulting in a reduced number of severity of this disease can vary greatly depending on environmental sclerotia in the soil. As with fungicide applications, control is not 100% conditions. Unfortunately, there are no silver bullets for white mold effective. However, the product can be a useful tool to reduce the management. There are no varieties that are completely resistant number of sclerotia in the soil and subsequent disease pressure. and fungicides do not provide 100% control. However, developing a management plan based on a knowledge of field history and best One of the core integrated pest management principles that should not disease management practices can help reduce losses. be overlooked is crop rotation. As sclerotia are capable of surviving in the soil for up to 10 years rotation won’t provide complete control, but Factors that favor white mold development include a history of white mold rotating to a non-host crop such as wheat, small grains, corn and sugar disease in the field, a high yield potential crop with a dense canopy, use beets can help lower the number of viable sclerotia in the soil. of a susceptible variety, narrow rows, high plant populations, and cool moist conditions during flowering. Three factors of the disease triangle In managing white mold consider the following core management must come together for white mold disease; these are 1) presence of the recommendations: pathogen 2) presence of a flowering and susceptible host, and 3) suitable 1. Maintain field records to know where losses are occurring and cool and moist environmental conditions at the time of flowering. identify problematic fields, that may require special management Early signs of the Sclerotinia fungus in the form of small mushrooms 2. Select varieties with the highest level of resistance (http://www. (a.k.a. apothecia) can sometimes be found on the soil surface, but the css.msu.edu/varietytrials/) common birds nest fungus which also produces a mushroom is easily 3. Rotate with non-host crops such as wheat, corn, and sugarbeets and often confused with the white mold mushroom. Spores (fungal seeds) produced by the white mold mushrooms are carried on air currents and must come into contact and grow on senescent (dying) tissue such as flower petals. After growing on these dead tissues they are able to invade adjacent healthy tissue. This often occurs where flower petals have fallen and are stuck in the branch axis or on developing pods. Early disease is evident as water soaked lesions that progress into bleached dry lesions and result in wilting. Identification of disease late in the season is relatively simple. As the name suggests white cottony mycelia (fungal threads) can be found on infected plants. Sclerotia which are the resting body of the fungus and are the approximate size and shape of mouse or rat droppings will be readily produced on and in infected stems and pods, sclerotia have a black outside layer but will appear white when split open. White mold infection can reduce seed quality, and price discounts may occur due to the presence of foreign material such as sclerotia. Fungicides can be used as part of a disease management program, but 100% control is not feasible and results can vary. If fungicides are to be used it is essential to time spray applications to protect flowers, and to ensure fungicide penetration into the canopy for maximum coverage and protection. Once disease symptoms are present in a crop it is too late to save infected plants. Fungicide applications should be thought of as preventative not curative. If fungicides are to be used they should be applied early during flowering prior to symptom development with a possible follow up application a week or 10 days later. Greg Varner conducts fungicide efficacy testing and can provide product information specific to Michigan conditions (www.michiganbean.org). Irrigation should be managed to minimize conditions favorable for disease. Infrequent heavier watering is better than frequent, light watering. Development of disease is dependent on moist soil conditions. SOURCE: IOWA STATE UNIVERSITY Disease can be limited by keeping the soil surface beneath the canopy as dry as possible. Apply only enough water for adequate growth during flowering and increase water application as necessary after flowering. Continued on page 4

CHECKLIST: GROWING DRY BEANS IN MICHIGAN Greg Varner, Michigan Dry Bean Research Board flatten the small bean plants as it is riding on the higher Planting Population: pushed up soil created by the tire tracks. The beans are literally bent over and pop back up. o Planting populations of 110,000-130,000 for navy and black o Reducing tire pressure of 8-10 lbs when rolling helps with beans is adequate. wheel track problems. Narrow tires will sink more than wider o Small reds and pinto bean populations should be 85,000- tires will. Some have used terra-gators to avoid compaction 105,000. problems. o Beware of contamination from seed tenders being used o A pre-plant combination of two or three herbicides of for soybeans. We have seen this kind of contamination the Dual, Outlook, Eptam, Treflan, Prowl, Sonalan and Pursuit past two years in Michigan dry bean fields. Be careful to has given good season long control in clean fields. Most avoid mixing dry bean classes this way. growers have had to rely on additional post herbicides Nutrient Management: of Reflex, Raptor and Basagran to control escaped o A 25 cwt dry bean crop removes about 90, 30 and 40 broadleaf weeds. Remember that Raptor should be used pounds of N-P-K. for lambsquarter control and Reflex should be used for o Research has shown narrow row dry beans will respond to ragweed control. Select Max and Assure II are used for about 60 pounds of applied nitrogen. Our kidney bean (and annual grasses and volunteer corn. large seeded) growers will use closer to 70-85 pounds of Disease Management: nitrogen. A survey conducted in Michigan shows dry bean growers used 56 pounds of nitrogen. o White mold fungicides are used on most narrow row production with some exceptions like drought and poor growing beans. o Phosphorous and Potassium fertilization was much more Endura, Omega and Propulse are the best white mold control geared to soil tests with some growers using no P and K products when used at 100% Bloom. If TopsinM is used, for dry beans. stay with 30 ounces. In some past years, growers applied o About 50% of producer’s band fertilizer at planting and two sprays because of continued wet weather in August. If others spread fertilizer or use liquid nitrogen with their pre- anthracnose disease appears, Priaxor and Headline are very plant herbicides. Some research has shown higher yields good products to control the secondary spread of anthracnose. when fertilizer is broadcast than when banded at planting Priaxor (copack) is better than Headline alone. Zenith black time. Many feel bean roots will grow to the band and not beans are now resistant to anthracnose and should be used by develop a deep, spreading root system in the soil profile. o Very little pop-up fertilizer is used in dry beans. I have growers who have had anthracnose in the past. Anthracnose can last 22 months in the soil which requires a three-year cautioned growers over the years to be very careful with rotation with susceptible varieties. in-furrow placement of fertilizer on dry beans because of potential germination problems. In-furrow fertilizer Insect Management: tolerance also depends on the soil moisture and texture. o Mid to late season insects such as tarnished plant bugs o The micronutrients, Zinc, Manganese and Sulfur should be and spider mites have to be controlled if threshold numbers added if soil tests are lower than adequate. appear. Likewise, the western bean cutworm should be Field Management: trapped to determine numbers in the sandy kidney bean growing areas. o Rolling the field after planting, aids in pushing stones, large dirt clods and root balls in the soil. There are some growers Harvest Management: who do not roll their beans because they want to avoid any o Desiccants used for harvest aid is almost essential for potential of compaction and slow water infiltration. direct-cut quality dry beans. Some bean fields will dry down o Rolling, levels the soil surface for closer cutting and less completely, but in most years, there is enough green growth harvest loss. Rollers being used in Michigan are usually to warrant a desiccant application. Sharpen has become the 30-60 feet. Rolling one to three days after planting will most used desiccant in Michigan. Combinations of Sharpen help reduce surface crusting and soil compaction because and Gramoxone looked very good in the 2016 harvest of dryer soil. Timing of rolling still has to be done weather season. Aim and Gramoxone was rated lower because permitting. There have been cases of dry beans already of inconsistent dry down later into the harvest season. emerged and growers still rolled them with little to no Roundup can be used as a harvest aid to dry down weeds, damage. The seed furrow is lower and the roller cannot but has a slower dry down requiring 10-14 days.

2017 DRY BEAN WEED CONTROL Christy Sprague, Michigan State University weed emergence after the POST herbicides were applied. With the 2017 growing season just around the corner it is important to make Weed control in dry beans in 2016 was a challenge. Dry conditions sure that good weed control plans are in place. While weed-free fields soon after planting through early postemergence herbicide applications are not always a guarantee, there are several key elements that rendered most of the PRE and POST herbicides with less than ideal should be considered before dry bean planting that will make the goal activity against many of the weeds that were in Michigan dry bean of weed-free dry bean fields at harvest closer to reality. fields. Additionally, late-July and early-August rains led to late-season WEED MANAGEMENT CONSIDERATIONS Know your enemy! Understanding the key weeds that you are trying to manage is imperative to designing an effective weed control program in dry beans. This is especially important if you have herbicide-resistant weeds on your farm. Weed populations that are resistant to ALS-inhibiting (Group 2) herbicides are a significant challenge to dry bean growers, since several of the limited number of herbicides that are registered for use in dry beans belong to this group. For example, common ragweed can be a significant weed problem in dry beans. Permit, an ALS-inhibitor, has good activity on non-resistant common ragweed. However, throughout Michigan there are many common ragweed populations that have been identified as ALS-resistant, rendering Permit and other ALS-inhibitors ineffective against these populations. This puts significant selection pressure on other effective herbicides, such as Reflex (Group 14). If herbicide-resistant weeds have been a problem on your farm it is important to take this into consideration when planning your weed control strategy. Check out https://pestid.msu.edu/resistant-weeds-michigan/ for a complete listing of herbicide-resistant weeds in Michigan. Start clean! As with all weed control strategies starting with a weed-free seedbed is essential. Removing weeds with tillage or an effective burndown herbicide treatment prior to crop emergence can give the crop the competitive advantage over new emerging weeds. If you are planning on using a burndown herbicide, it is important to realize that not all burndown herbicides are safe to use prior to planting dry beans. There are several herbicides that growers use in soybean that can either injure or kill dry beans. Therefore, it is important to make sure that the herbicide you use is labeled for use prior to dry beans. Some burndown herbicides that are currently safe to use prior to dry bean planting are glyphosate and Gramoxone. Soil-applied herbicides. Consider using preplant, preplant incorporated or preemergence herbicides with residual activity as a foundation program for hard to control weeds. This is particularly important in dry beans since there are very few herbicide options for POST weed control. Relying on a total POST weed control program can be difficult. Weeds can become too large, affected by the weather (hardened off by hot-day conditions), or may just not be effectively controlled with postemergence herbicide applications. Getting a start on weed control early in the season will insure greater overall success for your weed control program. Also using a weed control program with a soil-applied herbicide that has residual activity limits the use of “rescue” herbicide treatments late in the season that can further stress dry bean growth. Timely POST applications or cultivation. It is important to target POST herbicide applications when weeds are small (ideally 1 to 3 inches tall). Many of the herbicides labeled for dry beans are more effective when weeds are small. Additionally, with some of these herbicides lower use rates (i.e. Reflex) can be used to control smaller weeds ultimately reducing overall weed control costs that can help the bottom line. Applying a soil-applied herbicide will also help extend this window by providing some early-season control of these weeds. Volunteer soybean control. Soybean contamination in dry beans has become a major concern in the marketplace. In fact, processors have rejected entire loads since soybean is considered a Class 1 allergen and also due to GMO concerns raised by importing countries. Volunteer soybean could be a problem in dry bean fields that follow soybean in the rotation due to the milder than normal winter that we experienced this year. It is imperative that volunteer soybean be controlled in these fields. While several passes of tillage prior to dry bean planting can be an effective form of management. It will be important for growers to scout for volunteer soybean. If volunteer soybeans are found in dry bean fields they can be effectively controlled in the vegetative stage with a POST application of Permit (halosulfuron). Recommendations on the use of Permit in dry beans can be found on page 145 in the dry bean section of the 2017 MSU Weed Control Guide for Field Crops (E0434). Rotational crop and pH restrictions. Several herbicides have rotational crop and pH restrictions. For example, all postemergence broadleaf herbicides, except Basagran, have rotation crop restrictions. Major rotation restrictions for each of the soil-applied herbicides will be listed below. Also refer to Table 12 (Herbicide Crop Rotation Restrictions) in the MSU Weed Control Guide for Field Crops (E-434) or the individual herbicide labels. For weed control in dry beans, I strongly recommend a two-pass of several weed species and help protect your dry bean yields. For program that starts with a soil-applied herbicide program. Using a two- more information on weed control in dry beans consult the MSU pass program may add to the overall cost of your weed management Weed Control Guide for Field Crops (E-434) http://msuweeds.com/ program, but this program will result in overall more consistent control publications/weed-control-guide/.

Offer expires June 2017

WESTERN BEAN CUTWORM, BT CORN, AND DRY BEANS Christina Difonzo, Michigan State University numbers of egg-laying females that may eventually move into nearby If you are a corn grower, you may know that the 2016 season was a rough bean fields. year for western bean cutworm damage (and related ear mold infection) But back to Bt corn. A female moth can’t tell if a corn plant is a Bt across the Great Lakes region. The big story was the widespread failure hybrid or not; she keys in on crop stage, hoping to give her larvae an of Bt corn, specifically the Cry1F Bt protein, to control larvae in many advantage by laying eggs on plants with juicy, nutritious tassel tissue. locations. In Michigan for example, I found signs of ear feeding in nearly In the past, if a female laid eggs on Cry1F corn, this was a death every field I visited in August. Field observations as well as research sentence for many of her offspring. Cry1F hybrids had fewer larvae data point to the development of resistance to Cry1F by western bean, and less damage at the end of the season than similar non-Bt hybrids, not a problem with corn plants making Bt toxin. For 2017, entomologists because many newly-hatched larvae were killed by the Bt toxin. As a in the region recommend that growers manage their Bt corn hybrids the dry bean producer, you could view neighboring Cry1F corn as providing same as non-Bt hybrids, i.e. scout and spray fields if needed, regardless some free WBC control—not in a specific bean field, but in the overall of the Bt traits in the plant. numbers of cutworm in your neighborhood, i.e. fewer larvae completing development in neighborhood corn fields meant fewer moths next So what the heck does that have to do with dry beans? I’ll get there eventually. Most dry bean fields in Michigan share the landscape with season). Many hybrids planted in Michigan (Herculex 1 and Xtra, corn within a mile or two, if not adjacent. The western bean cutworm Acremax, Smartstax, and more) contain Cry1F, and I suspect these population is also shared between the crops, as moths are strong thousands of ‘deadly’ acres helped to ‘dampen’ the overall western bean flyers and move around to find mates and egg-laying sites. Females cutworm population level in certain regions, or in certain years when corn are attracted to pretassel corn for egg-laying, so moths initially colonize was well-synchronized with WBC egg-laying. But the recent reduction fields or parts of fields in that prime stage. After pollen shed is done in a in effectiveness of Cry1F against western bean cutworm larvae means particular field, females move to less-mature corn or into neighboring dry that much more of the corn acreage in the state is now susceptible to beans. In fact, scouting pretassel corn can give a good warning of high WBC infestation. This could mean higher overall populations across the state, as more larvae complete development in corn. With that in mind, what should you do for the 2017 season? STEP 1 Bucket trap to determine peak and numbers: I recommend using green bucket traps, available locally from Great Lakes IPM in Vestaburg, Michigan (989-268-5693 or www.greatlakesipm.com, catalog #IPS-G004). Great Lakes IPM also sells the WBC pheromone lures and Hercon Vaportape to attract and kill moths in the buckets. Although bucket traps are $10 each, I prefer them because they do not require a liquid-filled capture area, like the homemade milk jug trap. Milk jugs traps dry out easily or fill up with decaying moths after a single- heavy flight. Unless you check traps daily, they are messy, smelly, and hard to count. The buckets are easier to maintain and they can be reused year after year. Hang buckets by July 1, before flight picks up. The recommendation is for two buckets per field, at opposite ends. Ideal placement is to hang traps on a pole at 5 ft in height, in an unobstructed location (in the open) such as a ditch bank or in low vegetation on the field margin. This placement allows pheromone to disperse and draw in moths from a wide area. Hanging buckets in a treeline is less optimal and limits trap catch. Check traps weekly, on a schedule; this allows you to see a pattern in moth flight over a 7-day period and detect the peak. Based on previous experience, a trap catch over 150 per trap is an indication that local moth populations are high enough to impact dry beans. STEP 2 Check pretassel corn for egg masses as moth capture peaks. This is an early warning that egg-laying females are present. It is relatively easy to find egg masses in corn, but nearly impossible to find them later when females switch to laying eggs in the neighboring dry bean canopy. STEP 3 Check dry bean field for larval pod feeding, given a high trap catch and egg laying in nearby corn. Larvae spend the daytime hours on the ground, so pod feeding is often the only way to detect their presence. In early August, if larvae are present, small round holes will be visible on the surface of pods or chewed through the pod wall. We recommend spraying at this point. In field trials conducted in central Michigan, a strong, positive relationship was found between the percentage of WBC damaged pods and percent pick at the end of the season; ~12% pod damage resulted in 1% pick. Of course, this was the relationship at the end of the season, after larvae completed weeks feeding. In early August, pod feeding is just beginning and will increase until harvest. Spraying when pod feeding is noted prevents damage from increasing to the 10-12% level.

STANDARD U.S. POSTAGE PAID LANSING, MI PERMIT NO. 37 516 South Main St., Suite D Frankenmuth, MI 48734 MANAGEMENT OF WHITE MOLD Continued from page 1 4. Fungicides may form part of a management practice, but they open flower). I have encouraged growers to hold off their first spray will not completely control disease, keep replicated checks (non- if the weather is dry and the soil surface is too dry to allow sclerotia sprayed areas) in the field to monitor disease control germination of the mushroom-like apothecia that produce the white mold spores causing the infection. Most growers cannot spray all their acres 5. Biological control can be used as part of a management strategy to reduce sclerotia load in the soil at once and have good histories of white mold in dry beans the past 4-5 years. These growers should hold up a few days after bloom before 6. If irrigating, reduce irrigation frequency during flowering spraying if weather is dry. North Dakota State University has had a 7. If white mold is a significant issue, consider adjusting cultural very good trial of showing degrees of white mold severity when wet soil practices, such as row width and populations to enhance air flow surfaces occur just before bloom and during the first 7-10 days of bloom. to minimize cool moist microclimates that often develop beneath Basically, this says the later wet weather occurs during bloom, the less the canopy white mold infection the field will have. A question I get every year is which of the three fungicides is the best for controlling white mold. Spray Fungicide Applications in Dry Beans trials conducted in Michigan by myself have showed little difference in yield between these three fungicides. In the past few years of heavy for White Mold Control white mold infection, it is more common to see growers spraying a The three fungicides used and recommended the most in Michigan fungicide for the second time. There is data showing yield increases for for white mold control are Endura®, Omega® and Propulse®. Another these second sprays if the weather remains conducive to white mold older product TopsinM®, does control white mold satisfactory if growers infection. Another thing we have seen with spraying Endura is the dry use the high rate of 30 ounces. The first three products should be beans will not get the secondary molds (gray to black) at harvest as fast used at the 8 ounce rate at 100% bloom (100% of the plants have one as the Omega and the Propulse fungicides. Published by the: The official broadband supplier of the MBC: Michigan Bean Commission Air Advantage, LLC. 516 South Main Street, Suite D, Frankenmuth, MI 48734 465 North Franklin St., Suite C, Frankenmuth, MI 48734 Office: 989-262-8550 Phone: 989-652-9500 Ext 2224 Email: jcramer@michiganbean.com Fax: 989-652-4959 Website: www.michiganbean.org http://airadvantage.net