This summer is going by so fast and started so early, it feels like July and not June. Many insect pests are ahead of normal this year. Corn rootworm larvae were hatching earlier than previously recorded, Japanese beetles are here and it is not yet July. I caught 110 male western bean cutworm moths on the 24 th of June and usually I do not capture any before July 1 st. Western bean cutworm This insect has been in Wisconsin for almost 10 years. From a historical perspective, this insect has been a pest of corn and dry beans (not soybeans) in western Nebraska to southern Idaho for many years. However, since the early 2000 s it has been moving eastward and now extends its range as far East as Ontario and New York. Populations of this pest have reached rather high levels, increasing 77% in Wisconsin alone from 2009 to 2010. Last year the population was not as high as it was in 2010. The central part of the state, the Central Sands, is still the hot spot though it seems like its range is increasing in the state. Descriptions Eggs The eggs are deposited in rather tight clusters ranging from 20 to over 100 eggs, with an average size of about 50 per cluster. The eggs are barrel-shaped with small ridges running from the top of egg to the bottom. When first laid by the female, they are bright white and gradually turn purple when the larvae are ready to emerge. The eggs hatch in about 5 to 7 days. Egg masses are usually found on the upper side of the upper leaves. Larvae Newly deposited eggs (Marlin Rice photographer) Hatching eggs (Marlin Rice photographer) The body of the caterpillar is a dull orange with a black head when they first hatch. The collar immediately behind the head is also black. The fully developed caterpillar is about 1 to 1 ½ inches long and the collar has two broad brown stripes-- it is the only caterpillar found in corn that has this characteristic. The larvae have 6, sometimes 7, growth stages or instars.
Western bean cutworm caterpillar, note brown bars behind head. Adult The adult moth can be distinguished from other common miller moths by a cream-colored bar on the leading edge on the forewing. It is about ¾ of an inch long and will be brown, gray, and cream. Biology-life history Generally in Illinois and Wisconsin, the moths begin to emerge and fly in July, peaking in late-july and continuing until mid- August. The degree day accumulations, at a base temperature of 50 F, that coincide with moth flight are 1319 for 25%, 1422 for 50%, and 1536 for 75% moth emergence. Females are attracted to corn that is just prior to the tassel emerging (V16-V17). Females spend the day in the whorl and deposit eggs on the leaves that have yet to emerge, hence when the leaf emerges, the eggs are on the upper surface. Moth trapping with sex pheromone baited traps Upon hatching, the caterpillars feed on the egg shells and will feed to some extent on leaf tissue. They will move to the tassel and feed on tassel tissue and pollen. Although, they tend to hatch in mass and will disperse to adjoining plants. Eventually they will move to feed on silks and kernels. Larvae require about 25 to 30 days completing development through the 5 th growth stage or instar, with an additional 6 to 7 days to complete development through the 6 th stage. If a 7 th growth stage is required, it will take 6 to 7 additional days. Western bean cutworm caterpillars are not cannibalistic, unlike the corn earworm, so it is not
uncommon to find several feeding together on the same ear. After the caterpillar completes development, it will exit through the husk and drop to the soil. It will burrow into the soil to a depth of 3 to 6 inches, depending on soil types. In sandy soils they will burrow deeper than in heavier soils. The caterpillar constructs an overwintering chamber and spends the winter in the chamber, with pupation occurring the following spring. Weather impacts Weather can have an impact on western bean cutworms. Hard-driving rains during egg hatch and before the caterpillars enter the husk can dislodge larvae and reduce populations. The smaller the caterpillar is, the greater the impact on mortality. Moisture also is important during moth emergence from the soil -- if the soil is dry, emergence of the moths from the soil will be reduced, especially in heavier soil types. Crop injury The caterpillars cause direct injury when they enter the husk and feed on kernels. Though the western bean cutworm will feed on kernels at the ear tip, like corn earworm, they also will feed down the ear and can cause extensive injury to the middle of ear and to the kernels at the base of the ear. Injury is often associated with fungal infections which may become more of an issue in the higher humidity regions of the central Corn Belt than in the drier areas of western Nebraska. Research has shown that an average of 1 caterpillar per plant at the dent stage can result in a 3.7 bushel yield loss. Management Western bean cutworm injury to corn ear Insecticides are recommended if 5% of 100 plants (5 plants) are infested. It is recommended to sample 20 consecutive plants at 5 locations for egg masses or small larvae. For more information, contact your local Syngenta representative. Benefits beyond yield with Quadris and Quilt Xcel fungicides on corn It wasn t so very long ago that fungicides were applied only on high-value specialty corn, seed corn, and the like. However, many more corn growers today are using fungicides as part of their routine production practices than they have in the past. What has changed? Is there a new super fungal pathogen that has come in from another country? The answer to that question is no. Today approximately 22% of the U.S. corn acres are treated with fungicides because growers have come to recognize the economic benefits from fungicides like Quadris and Quilt Xcel. The immediate value to these growers is yield, but if one looks closer they might realize that they are gaining much more. Physiological benefits from Quadris and Quilt Xcel fungicides Syngenta has heavily invested in research focused on the physiological benefits that Quadris and Quilt Xcel fungicides provide to crops like corn. In general, these effects include improving water use efficiency, improving plants efficiency to utilize the sun s energy in the process of photosynthesis, and allowing the plants to stay greener longer, therefore allowing plants to put more energy into yield. What this all means to the grower is that they tend to realize greater yields (Table 1), better disease control and stalk integrity (Figure 1) and therefore less lodging, better harvest efficiency, and reduction of volunteer corn in the crop to follow.
Each one of these attributes is valuable to the grower s bottom line. Figure 1. Quilt Xcel protects leaves from fungal diseases and maintains Table 1. Yield benefits from Quadris and Quilts Xcel fungicides on corn. stalk strength for more efficient harvest and reduced lodging. To get a better picture of what this all means, think of it this way: say a grower gets a 10 bu/a increase in yield from his/her Quilt Xcel application on corn at R1. At $5.85 per bushel, this represents a benefit of $58.50 per acre. However, due to reduced lodging, that grower also can get the combine through 1.7 miles per hour faster. According to economic models, that represents another saving of $10 per acre (fuel, labor, equipment wear and tear, etc.). Now consider the value of reduced volunteer corn in the soybean (or corn) crop the next season. Data from recent trials illustrates that one or two volunteer corn plants, or one or two volunteer hands (multiple plants) per five feet of row can decrease soybean yields by 9.6%, 27.0%, 43.5%, and 56.8%, respectively (Figure 2). So do the math with beans at $11.30 per acre and add it to the tally. Yes, product and application costs also need to be taken out, but you should begin to get the bigger picture of overall grower value. We are nearsighted if our value meter stops with just the yield benefits that growers get from Syngenta fungicides. Figure 2. Effects of volunteer corn (population and density) on soybean yield. When should growers apply fungicides on corn? Growers have several options. They can apply Quadris at 6 oz/a or Quilt Xcel at 10.5 oz/a by ground rig during the V4-V8 growth
stages, or they can apply Quilt Xcel at 10.5 oz/a at R1. In some cases, growers have recognized additional value from both an early and late application. Yield benefits from these applications in large plot commercial field trials in 2010 and 2011 were similar (Table 1). You also can gain additional cost benefits by applying your early fungicide application with your herbicide. Since most growers will be putting out a herbicide application in the early growth window of V4-V8, they can also minimize the cost of a repeat trip across the field by mixing Quadris or Quilt Xcel in with their herbicide. However, you do not want to do this with just any herbicide combination. Syngenta scientists have conducted numerous field and greenhouse trials over the past two years to determine which mixtures are crop safe and which are not. Quadris or Quilt Xcel fungicides can be applied with Touchdown brands, Callisto, Callisto Xtra and Halex GT herbicides. Where allowed, atrazine should be added to the tank for best weed control in corn up to 12 inches tall. Additionally, NIS (non-ionic surfactant), AMS (ammonium sulfate), foliar fertilizers and nutritional products can be added, as appropriate. For additional information, contact your local Syngenta representative. 2012 Syngenta. Important: Always read and follow all bag tag and label instructions before buying or using Syngenta products. The instructions contain important conditions of sale, including limitations of warranty and remedy. Some crop protection products and seed treatments may not be registered for sale or use in all states or counties. Please check with your state or local extension service before buying or using Syngenta products. AAtrex 4L, AAtrex Nine-O, Agri-Flex, Agri-Mek 0.15EC, Agri-Mek SC, Avicta 500FS, Avicta Duo Corn, Avicta Duo 250, Avicta Duo Cotton, Besiege, Bicep II Magnum, Bicep II Magnum FC, Bicep Lite II Magnum, Callisto Xtra, Denim, Endigo ZC, Epi-Mek 0.15EC, Expert, Force 3G, Force CS, Gramoxone Inteon, Gramoxone SL, Gramoxone SL 2.0, Karate with Zeon Technology, Karate EC, Lexar, Lumax, Proclaim, Voliam Xpress, Warrior II with Zeon Technology and Warrior with Zeon Technology are Restricted Use Pesticides. Not all traits or trait stacks listed are approved for sale or use in the United States. These traits and trait stacks are not being offered for sale. Plant Performance assumes the presence of disease pressure. Crops or other materials produced from Agrisure Corn Traits products can only be exported to, used, processed and/or sold in countries where all necessary regulatory approvals have been granted. Actara, Agri-Mek, Agri-Mek 0.15EC, Besiege, Centric, Centric 40WG, Curacron, Curacron 8E, Denim, Durivo, Endigo ZC, Karate with Zeon Technology, Karate EC, Platinum, Platinum 75SG, Proclaim, Voliam Flexi, Voliam Xpress, Warrior with Zeon Technology, and Warrior II with Zeon Technology are highly toxic to bees exposed to direct treatment or to residues on blooming crops and weeds. Do not apply these products or allow them to drift onto blooming plants if bees are foraging in the treated area. Some seed treatment offers are separately registered products applied to the seed as a combined slurry. Always read individual product labels and treater instructions before combining and applying component products. Performance evaluations vs. competitive products are based solely upon interpretation of publicly available information, including public presentations, regulatory submissions, and observations made in commercial fields. The trademarks displayed or otherwise used herein ("the Trademarks") are registered and unregistered Trademarks of a Syngenta Group Company or third parties. CLASSIFICATION: PUBLIC