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Looking Ahead
Volume 52 Number 1 Date 04/13/2007 
Periodical cicada - Emergence of Brood XIII has been confirmed in portions of Rock and Walworth counties. Staff of the Janesville Gazette spotted thousands of periodical cicadas on the afternoon of May 31 at Camp Indian Trails on the Rock River north of Janesville. Additional sightings have been reported in the Lake Geneva area. DATCP and DNR records from 1973 and 1990 indicate localized emergences may also occur within areas in Crawford, Dane, Iowa, Grant, Kenosha, Racine, Richland, and Sauk counties this year. Orchard and nursery growers with susceptible stock, including young trees or shrubs with branches ¼ to ½ inch in diameter, should take measures to protect plants from cicada oviposition and feeding in the next week. Brood XIII cicada sightings are being compiled and mapped by DATCP Entomologist, Krista Hamilton. Readers are encouraged to report observations to her by calling 1-866-440-7523 oremailing krista.hamilton@datcp.state.wi.us. Insect Migration Risk Forecast - The University of Illinois Insect Migration Risk Forecast indicated a MODERATE risk of insect migration across much of the Midwest from noon on Thursday, June 7 through noon on Friday, June 8. During this 24-hour period, weather patterns were favorable for insect migration, particularly corn earworm flight activity. According to the IMRF, the greatest risk area was south of I-94 between I-35 and I-29/US 71 east to I-71, including parts of southern and west central Wisconsin. Corn earworm traps placed in these areas could register a ?drop out? of significant numbers of early-season corn earworm moths over the weekend (June 8-10) or a minor increase in moth activity. To view the risk map, please visit http://www.maplecity.com/~sand/cew/imrf.html. European corn borer - Slight increases in European corn borer moth counts were documented at several black light trapping sites and first instar larvae were detected in the tallest Iowa County corn fields surveyed this week. Black light trap counts for the reporting period of June 1 to 8 were: Arlington 18 moths, Chippewa Falls 1 moth, East Troy 32 moths, Janesville 3 moths, Lancaster 6 moths, Marshfield 12 moths, Manitowoc 2 moths, Sparta 63 moths, and Wausau 1 moth. According to the European corn borer degree day model, accumulations are such that peak flight should have occurred as far north as Port Edwards in Wood County where 631 GDD were surpassed on June 7. Corn earworm - Seventeen migratory moths were captured in a pheromone trap near Lancaster in Grant County during the past week, marking the first capture of corn earworm in Wisconsin this season. Recent weather patterns across the upper Midwest may have contributed to the south-north migration that directed these moths into the state. Based on the Insect Migration Risk forecast, additional moths could arrive or ?drop out? over the weekend or in the week ahead. Pheromone lures should be replaced at this time and every two weeks through mid-July. Potato leafhopper - Reproduction was noted for the first time this season on June 2 in eastern Dane County. Some of the second and third instar nymphs spotted on the undersides of rhubarb leaves are likely to have reached adulthood by now. With nymph production underway, populations could begin to build rapidly in the next few weeks. Growers should scout second crop regrowth alfalfa carefully for increasing populations. True armyworm - A full-grown armyworm larva was observed ?wandering? across a Dane County roadway on June 7. This sighting suggests some percentage of the larval population in Dane County has entered the pupal stage. In a matter of days, an increase in true armyworm moth counts may be registered at some southern black light trap locations. Look for moth numbers to escalate in the week ahead. Common stalk borer - In areas where 1,400 GDD will be surpassed next week, including Dubuque and La Crosse, corn fields should be scouted closely for stalk borer activity. The characteristic series of ragged holes caused by larval stalk borers first becomes evident in the border rows. For the past few weeks larvae from overwintered eggs have been feeding in various grasses and weeds, but in advanced parts of southern Wisconsin migration to larger host plants such as corn has begun. Stalk borer larvae are expected to move into corn fields between 1,400 GDD (base 41F) and 1,700 GDD. Since insecticides are no longer effective once larvae have tunneled into corn plants, it is critical to detect infestations early, while the larvae are still feeding in the whorl. Fields with heavy injury may benefit from spot treating infested border rows. Once corn plants grow beyond V7, stalk borer feeding is unlikely to kill affected plants. Mosquitoes - Ades vexans has been the dominant biting species in the past week and is becoming increasingly numerous. Annoyance to humans and cattle may intensify in certain areas of the state during the next two to three weeks now that recent rains have refilled breeding pools. Foreword - This is the first in a series of bulletins which will be published each Friday during the 2007 growing season. With this issue, the Wisconsin Pest Survey Bulletin begins its 52nd year of service to Wisconsin Agriculture, reaching approximately 2,000 readers. The bulletin will again contain a compilation of timely plant pest information supported by the survey efforts of our entomologists, weed specialists, and plant pathologists. This publication is made possible by the many individuals who contribute information, including county extension specialists, orchardists, vegetable growers, agronomists, horticulturalists, DNR specialists, Agricultural Experiment Station staff, crop consultants, and farmers. Subscribers who access the web version of the bulletin have almost certainly noticed its new look. The transition from paper to pixels has been a bumpy one for us. This latest version is our attempt to strike a balance between progress and the precedent set by State Entomologist E. L. Chambers in 1955 when the first bulletin was issued. One of our objectives when designing the new site was to provide fast web access to weekly pest articles; another was to preserve the purpose and simplicity of the paper publication once delivered to doorsteps statewide. Although the homepage has changed, the content has not. We urge bulletin readers to add the new website, http:www.pestbulletin.gov, to their list of favorites and log on once a week for the latest pest findings and forecasts. -- Krista Hamilton, Clarissa Hammond and Liz Meils Black cutworm - Overwintered moths from source populations as far away as southern Texas and eastern Mexico embarked on an annual northward migration into Wisconsin last month. The first moths of 2007 arrived on March 29, slightly more than week earlier than in 2006. DATCP survey specialists are watching for a concentrated pheromone trap catch of 8-9 moths in a 1-2 night period. This event is used to predict when the progeny of the migratory cutworm moths have reached the 4th instar, the developmental stage at which they become capable of cutting corn seedlings. Captures at 48 trapping sites ranged from 0- 2 moths between March 29 and April 2, but no activity has been registered since then. Household pests - Beginning during the last week of March, homeowners in various localities began inquiring about western conifer seed bugs (Leptoglossus occidentalis), boxelder bugs (Leptocoris trivittatus), and multicolored Asian ladybeetles (Harmonia axyridis) they have observed inside their dwellings. Early spring sightings of these nuisance insects are common as the overwintered adults resume activity on warm spring days (>50F). Expect to see survivors over the next few weeks as they move outdoors for the summer. Bear in mind these insects have not fed or reproduced indoors during the winter months. Besides being an annoyance, they pose no threat to homeowners. Seventeen-year cicada - The year 1990 was marked by several historic events. East and West Germany were reunited, the Hubble space telescope was launched, Nelson Mandela was released after 27 years in prison, smoking was banned on all domestic flights, and the award for Record of the Year was presented to Bette Midler for "Wind Beneath My Wings" (a momentary lapse in our collective judgment). More importantly, in 1990 periodical cicadas of the genus Magicicada mated and laid a brood of eggs that has, until this very summer, lived two feet underground as nymphs feeding on the sap of tree roots. Seventeen years have passed since Bette sang her way to the top and the eggs of Magicicada Brood XIII were laid. In a matter of weeks, the plump, subterranean nymphs will claw their way to the soil surface and transform into clear-winged crooners whose sole purpose is to mate, reproduce, and die. In addition to southern Wisconsin, cicadas of Brood XIII are expected to emerge in parts of Iowa, Illinois, Indiana and Michigan. During the 2007 event, densities of thousands of cicadas per acre could emerge and cause physical damage to small trees or shrubs (from feeding and egg laying). Periodical cicada densities exceeding one million per acre have been documented. Orchard and nursery owners with young trees or shrubs should take measures to prevent damage. The simplest way to protect small trees and shrubs is to cover them with screening or cheesecloth when the cicadas begin to emerge. Plants should be kept covered for at least four weeks or until most of the cicadas have died off. Pesticide applications are impractical given the sheer number of emerging cicadas. Besides, this once-every-seventeen-years event aerates the soil, provides food to thousands of predators, and acts as a natural pruning mechanism. Look for week to week coverage of the cicada extravaganza in late May and June issues of the bulletin. -- Krista Hamilton Use CAUTION when handling treated seed - Growers planning to use pesticide-treated seed this season are urged to take all necessary precautions to prevent contamination of grain destined for animal or human food. Seed treated with an insecticide or fungicide pesticide protects seedlings from insects and disease threats, but can be harmful to animals or farmers' bank accounts if mishandled. According to DATCP Seed Specialist Greg Helmbrecht, "even one pesticide treated seed can be enough to contaminate an entire truck load or storage bin and cause the load to be rejected." Clean-up efforts after hauling treated seed are critical to preventing contamination at harvest. Check gravity boxes, truck beds, wagons and all equipment that handled treated seed, particularly if that piece of equipment will be used to haul harvested grain, animal feed or forage. A simple visual inspection of the wagons or other farm equipment is not enough. Any piece of equipment that contacts treated seed must be thoroughly cleaned by pressure washing and then thoroughly inspected. If pressure washing is not an option, avoid using that piece of equipment to handle untreated seed or grain later on. Farmers should also take these steps to keep pesticide-treated seed separate from untreated seed and grain and to prevent exposure to animals and animal feed: 1) Avoid leaving treated seed out in the open where it can be eaten by birds or other animals, 2) Store any unused seed securely and separately away from grain storage areas, and 3) Return unused seed to your seed supplier or to a sanitary landfill. -- Greg Helmbrecht, Seed Specialist 
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