Small ARMYWORM LARVAE are just beginning to feed now;
CEREAL LEAF BEETLES laying eggs in rye and wheat;
Small BLACK CUTWORM larvae are developing;
HORN FLY AND FACE FLY activity will be increasing on pastured cattle;
CANKERWORMS AND LOOPERS feeding on various trees;
Feeding by BOXWOOD PSYLLIDS causes cupping of terminal leaves;
HOLLY LEAFMINERS will make small punctures in the leaves.
Latest armyworm information - As of 19 April, armyworm larvae have been found in pastures in southern Illinois and large numbers have been found in pastures and corn fields in southeastern Missouri.
Captures of true armyworm moths in UK-IPM's pheromone baited traps at UK-REC in Princeton remain high. During the week ending 15 April there were 359 and 242 moths per trap. The 359 count is up from 290 but the 242 count is slightly down from 252, comparing to captures from the previous week ending 07 Apr 06. The average change for the two weeks is up from 271 to 301 moths per trap week. I doubt that the change in any of these numbers is large enough to indicate any real difference in population size. However, the captures do tell us that the moth flight is still going on in a substantial way. The more or less level trap counts may also indicate that we have reached the peak moth flight. But we will have to wait another week to see if that is true.
IF we have reached peak moth capture, this year's number (301 moths per trap week) is quite a bit smaller than the peak flight (400 moths per trap week) in 2001. That's a good thing!
that the past two weeks' counts are about the same (301 vs 271), that these counts represent the peak flight period, and use 11 Apr 06 as the center of this flight period, then we might estimate the peak larval activity period as follows.
Projecting forward from 11 Apr through today using this year's temperatures, and using historic temperatures for dates in the future the peak larval appearance would be about 27 April.
It appears from the model output that temperatures over the last week or so are much warmer than the historic values. This brings the estimate of major worm activity sooner than previously estimated. All those with crops affected by this insect are urged to begin scouting them soon. However, we are expecting cooler temperatures this week.
Remember that with each passing week we are using more temperature information from the current year and less from the historic data base. So, we should be tailoring the calculations for this year with each week's update. With each week's data we are also closer (time wise) to insects in the field, so there will be less lead time with each update. Start scouting your fields.
Nothing gets attention like blue mold when it comes to diseases of tobacco, and it won't be long before blue mold will become a threat to tobacco in Kentucky and the rest of the United States. Hardin County was in the national headlines briefly this past June when the first reported case of blue mold in the United States was confirmed near Cecilia. Fortunately, we lost very little tobacco to the dreaded disease in 2005. The blue mold epidemic - if that's what you want to call it - was extremely mild compared to previous years thanks to dry conditions throughout most of the growing season. How will blue mold affect the 2006 crop? The truth is we really don't know for sure. The amount of blue mold that we'll see in Kentucky this season is highly dependent upon the amount of inoculum (spores) that is introduced from areas south of us or produced in-state if the pathogen, Peronospora tabacina, survived the mild winter in a protected environment. Weather during the summer months plays an equally important role in the development of blue mold. A wet and cool summer will likely mean a higher risk to our growers from the disease, while hot and dry conditions may equal another year's respite. Given the year-to-year unpredictability of blue mold and its potential to cause serious losses, it's clear why this plague captures our imaginations more than any other disease of tobacco.
Fortunately, there are easy-to-access resources available to help us track the occurrence and movement of blue mold in the tobacco producing regions of the U.S. and to assess the level of risk to tobacco around the country. The Kentucky Blue Mold Warning System is a cooperative effort that involves growers, county agents, and Extension tobacco specialists in Kentucky and other parts of the U.S., as well as the North American Plant Disease Forecast Center (NAPDFC). The status of blue mold in Kentucky and surrounding states is updated weekly and can be found at www.uky.edu/Agriculture/kpn/kyblue/kyblue.htm and in the Kentucky Pest News. Breaking information is made available on the Kentucky Blue Mold Warning System web page and through a mailing list, the KY Blue Mold Alert. Subscribe to the KY Blue Mold Alert mailing list by sending a message to: listserv@lsv.uky.edu. The message body must contain, verbatim, the line subscribe ky-bluem-alert, followed by a blank line. You will receive by return mail a message requiring confirmation of your subscription.
The NAPDFC, located at North Carolina State University, documents the presence of blue mold in locations where inoculum is produced (on cultivated or wild tobacco) that may threaten cultivated tobacco in the U.S. These locations include Cuba, Mexico, and southern Texas. As the season progresses, outbreaks of blue mold across the country are confirmed by local coordinators from each of the tobacco producing states and forwarded to the NAPDFC. This information is used to track the spread of blue mold and is also used, in conjunction with weather models, to predict the future movement of the disease. Local weather forecasts in areas predicted to be in the path of dispersed inoculum are then combined with predicted movement of inoculum to generate a forecast that categorizes risk of infection for a 48-hour period in the threatened region. Status and forecast information are summarized on the NAPDFC Blue Mold page (http://www.ces.ncsu.edu/depts/pp/bluemold/), which is updated on Monday, Wednesday, and Friday from March until the end of August. It is this information that forms the backbone of the Kentucky Blue Mold Warning System, created 27 years ago by Dr. William Nesmith.
The Kentucky Blue Mold Warning System relies heavily, as I mentioned earlier, on input at the local level. In fact, our success depends on it. We can do a great job of tracking blue mold outside the Commonwealth, but need growers and agents to let us know when and where blue mold crops up in Kentucky. Growers should report outbreaks of blue mold as quickly as possible to their local county extension agent so that he or she can pass this information to U.K. extension specialists. We use this information to update the KY Blue Mold Warning System and to develop area-specific advisories. The faster we learn about the occurrence of blue mold, the quicker we can issue an alert, and the sooner our growers can take the necessary steps to protect their crops. Who knows - blue mold may not trouble the region in 2006, but let's be prepared to spread the word should it appear.
Blue Mold Status as of 14 April 2006. Active blue mold has been confirmed in western Cuba, and in western Mexico. The threat to U.S. production areas at this time is low. No active blue mold has been reported in the U.S.
For the latest blue mold status and other tobacco disease information, check the KY Blue Mold Warning System online.
http://www.uky.edu/Agriculture/kpn/kyblue/kyblue.htm
For more information about tobacco pests, visit "Insect Management Recommendations".
The past few years, wireworms have become an increasing occurrence on some central and western Kentucky
farms. Wireworms will attack a wide variety of plant seeds and small seedlings, but most of the
problems we experience are with field corn. Wireworm can keep seeds from germinating or kill the
developing seedling before or after it emerges from the soil. The result is stand loss and less
uniformity in plant vigor which results in less yield potential for the field. Stand loss due to
wireworm damage can occur anytime from seeding through the V3 stage.
While problems with wireworms are on the increase, at least reports of wireworm problems are increasing, it is important to note that there are many other causes of stand reduction. Often it is one or more of these other causes that is resulting in the stand loss. Other causes of stand reduction include planter problems, poor seed viability, damping off or other seedling diseases, and bird/wildlife damage. If you suspect that losses may be due to wireworms, shortly after full seedling emergence should have occurred you will need to dig in the row skips to recover and examine the seed. When digging seedlings or looking for seed, watch for wireworms as well. I've noticed two types of characteristic wireworm damage that occurs before the seedling emerges. The first is to the seedling itself, you should look for one or more holes in the seed and the seed may be tunneled or completely hollowed out. The second type of damage is to the developing coleoptile. Wireworms can damage the growing tip of the coleoptile which will prevent the seedling from emerging.
Another type of damage caused by wireworms is that of seedling deadheart. A deadheart is where the youngest leaves in the developing whorl wilt and die. If the seedling is carefully dug and examined, there will be a ragged hole in the side of the crown. The damage occurs where the wireworm chews into the crown and kills the growing point of the plant. Some plants may begin to develop tillers when the growing point is killed, others will die. Plants that develop a new tiller do not compete well with other plants and contribute little if anything to yield. Unlike with soybeans where undamaged plants can better compensate for lost plants, corn can be greatly affected by stand loss.
The most common wireworm I've seen in these problem wireworm fields is Melanotus depressus. This is a cylindrical, caramel-colored wireworm that doesn't have the pairs of noticeable spots on many of the segments.
Wireworm damage is more common with early planted fields when soil temperatures promote slow germination and seedling growth. Deep planting of the seed and poor seedling vigor (seed genetics) will also keep plants vulnerable to wireworms for a longer period. Once stand loss due to wireworms becomes noticeable, there are no effective rescue treatments. The decision is whether to replant or not. Due to the added expense of new seed, fuel, additional insecticide, potential yield reduction with later planting dates, and the ability of the surviving plants to compensate some for the lost plants, it often takes stand losses of 1/3 or more to justify replanting.
For information about corn pests, visit
"Insect Management Recommendations".
Soybean Cyst Nematode (SCN) is the most serious disease affecting soybean in the United States. Kentucky plants a very high percentage of round-up resistant soybean varieties, and the vast majority of these varieties are also resistant to SCN. Therefore, most Kentucky soybean producers are under the impression that SCN is no longer a production threat. This may or may not be true.
A recent survey conducted by scientists at the University of Missouri indicated:
The above survey results are quite troubling considering that most Kentucky soybean producers, like producers in Missouri, are under the impression that SCN is no longer a concern due to widespread use of SCN-resistant varieties. With funding assistance by the Kentucky Soybean Promotion Board, we will be doing a SCN survey in Kentucky this spring and fall. The main objective of the work will be to generate fresh SCN data for Kentucky so we will know if we are doing the job of managing SCN we think we are doing.
For more information about soybean pests, visit
"Insect Management Recommendations".
Several orchardgrass plantings have moderate to heavy aphid infestations that may be the cause of some
extensive stand loss. The Adair and Pulaski county fields show some extensive brown spots with
dead grass and the surviving grass has colonies of light green aphids. There are oval yellow
lesions on infested leaves that are similar to what might be caused by greenbug feeding.
Specimens have been sent for identification. Please let me know if you see similar events.
Invasion of alfalfa leaves by disease-causing microorganisms (pathogens) can produce dead spots and blight. Leaves with a great number of spots are less effective at photosynthesis, which can result in reduced plant growth. Also, leaves with spot symptoms often drop to the ground, resulting in reduced forage yield and quality. Many of the leaf-infecting fungi and bacteria also infect stems of alfalfa. Often, stem infections prevent water flow to the rest of the shoot, causing sudden wilting and desiccation. Lepto leaf spot, spring black stem, Stemphylium leaf spot, and summer black stem are common alfalfa diseases that cause spotting of leaves. Anthracnose, Rhizoctonia stem canker, Sclerotinia crown and stem rot, and spring black stem cause wilting and blighting of shoots. All alfalfa varieties are more or less susceptible to all of these foliar diseases. Probably the only significant management practice to recommend for leaf-blighting diseases is to take cuttings in a timely manner. Scout fields for premature defoliation for leaf spotting, and be prepared to harvest before much defoliation occurs. If significant disease activity is present, cut sometime between early bud and first flower. Cutting the hay accomplishes several things: it captures the yield from infected leaves before they defoliate; it reduces the buildup of infectious residue on the ground, protecting future cuttings; and it exposes the crowns to the sun and wind, reducing the risk of crown infections from spring black stem. Cut alfalfa when it is ready. Don't wait for a forecast of 3-4 days of sunny, dry conditions. Advancing maturity causes substantial loss in forage quality. Thus, waiting for dry weather can cost as much quality loss as can rain damage.
See Insect Recommendations
for more alfalfa pest recommendations.
Grape diseases are often the limiting factor in successful production of grapes for fresh market use and for wine making. Growers should recognize this general rule: If diseases are controlled well early in the season, there is less need to manage them later in the season. The corollary is that if grape diseases are not well controlled early, then the rest of the season becomes a constant battle against disease. Grape buds have broken and new disease-susceptible growth is emerging from the vines. Disease management in spring between bud break and bloom is critical to growers aspiring to produce a good crop. There are several diseases that are active now even though the symptoms developing from current infections may not be seen for several weeks or months.
Cultural practices to reduce diseases. Keep the foliage dry and less prone to disease by use of intelligent field site selection, training systems that ventilate the leaves and clusters, judicious nitrogen use, and appropriate irrigation practices. Plant disease-free plants and choose cultivars that resist diseases. Although most grape varieties are susceptible to black rot, a few such as Cascade, Cayuga White, Chancellor, Chelois, Cynthiana/Norton, DeChaunac, Elvira, Ives, Vidal 256, and Vignoles are less susceptible. Use good sanitation by removing and destroying diseased and dead wood, and mummies from the vine and on the ground.
Fungicides for disease control. More complete information about varietal susceptibility and timing and materials for grape disease control can be found in ID-94 Kentucky Commercial Small Fruit & Grape Spray Guide 2006, available at County Extension Offices.
Chemical controls need to be integrated because although black rot is usually most important, there are other fungal diseases that need managing. For all four of the early-season diseases, growers can choose protectant fungicides such as mancozeb (Dithane M-45, Manzate 200, Penncozeb), Captan, or Ziram and mix one of these choices with Bayleton, Elite, Endura, JMS Stylet Oil, Nova, Quintec, Potassium Salts, Procure, or Rubigan. Strobilurin fungicides such as Abound, Flint or Sovran can also be used in combination with Endura, Quintec, Potassium Salts, or sulfur. Or, growers may choose Pristine, a combination product, which can be used alone.
Some notes and precautions relating to fungicide use:
Lone star ticks are active with large numbers of the small 6-legged larval stage being found now. Ticks prefer overgrown, brushy areas, especially where small mammals are active. Clearing and regular mowing of these areas allows penetration of sunlight and breezes and removes hiding places for small animals. This is an effective way to provide long term tick reduction.
Ticks are more common along the margins of woods or scrub growth but they can be introduced into lawns by pets or wild animals, particularly field mice and deer. Below are examples of some lawn and garden insecticides that are labeled for tick control in lawns. Other products containing the active ingredients in the column on the left may be used, as well. Follow the label direction for mixing and applying the diluted spray.
Large, black bees have begun hovering around eaves, decks, and wood siding of clients' homes and outbuildings. These are probably carpenter bees searching for mates and nesting sites. Carpenter bees cause cosmetic and structural damage to wood. They can also be intimidating and have the potential to inflict painful stings.
The Problem- Carpenter bees are similar in appearance to bumblebees, but have different nesting habits. Bumblebees generally nest in the ground, whereas carpenter bees tunnel into wood to lay their eggs. Bare, unpainted, weathered softwoods are preferred especially redwood, cedar, cypress and pine. Painted or pressure-treated wood is much less susceptible to attack. Common nesting sites include eaves, fascia boards, siding, wooden shake roofs, decks and outdoor furniture.
Carpenter bees overwinter as adults in old nest tunnels. After mating, the fertilized females excavate galleries in wood, laying their eggs within a series of small cells. The cells are provisioned with a ball of pollen on which the larvae feed, emerging as adults in late summer. The entrance hole and tunnels are perfectly round and about the diameter of your finger. Coarse sawdust, the color of fresh cut wood, is often seen beneath the entry hole, and burrowing sounds may be heard within the wood. Female carpenter bees may excavate new tunnels or enlarge and reuse old ones. Serious damage can result when the same piece of wood is worked year after year.
Males are often aggressive, hovering in front of people who are around the nests. The males are harmless, however, since they lack stingers. Female carpenter bees can inflict a painful sting, but seldom will unless handled or molested.
The Solution- The best time to control carpenter bees is before the tunnels are fully excavated. For homeowners, liquid sprays of Sevin or a pyrethroid (e.g., Bayer Advanced™ Home/Lawn & Garden Insect Killer, Spectracide® Triazicide/Bug Stop, Ortho® Home Defense System/Termite & Carpenter Ant Killer) can be applied directly into nest openings, or broadcast sprayed as a deterrent onto wood surfaces attracting large numbers of bees. The broadcast spray approach is often warranted when carpenter bees are riddling siding on a barn, wood shake roofs, decking or similar large expanses of wood. Broadcast treatment is best accomplished with a pump up or hose end sprayer, targeting wood surfaces that are most favored by the bees (fascia boards, joist ends of redwood decks, etc.). Residual effectiveness of such applications is only about 1-3 weeks, so the treatment may need to be repeated. Individual holes which are already present also can be treated with a wasp and hornet aerosol spray or insecticide dust (e.g., Sevin, DeltaDust), directed into the nest opening. Although carpenter bees are less aggressive than wasps, female bees provisioning their nests will sting. Consider treating at dusk or while wearing protective clothing.
Leave the holes open for a few days after treatment to allow the bees to contact and distribute the insecticide throughout the nest tunnel. Then plug the entrance hole with a piece of wooden dowel coated with carpenter's glue, wood putty, or other suitable sealant. This will protect against future bees using the old tunnels, as well as moisture intrusion and wood decay.
Carpenter bees normally will not tunnel into painted wood. Therefore a more permanent solution is to paint unfinished wood surfaces, especially those with a history of being attacked. Wood stains and preservatives are less reliable than painting, but may provide some degree of repellence versus bare wood. To further discourage nesting, garages and outbuildings should be kept closed when carpenter bees are actively searching for nesting sites. The annoying flying and nesting habit usually subsides by the end of May.
Samples received in the PDDL this past week included Rhizoctonia damping off on tobacco;
Pythium root rot on tomato transplants; Botrytis blight on greenhouse lettuce; Pythium root rot
and high soluble salts on calibrachoa; thrips infestation on impatiens; pine wilt nematode on
Scots pine; and yellow patch on bluegrass.
UKREC-Princeton, KY, April 7 - 14, 2006| True Armyworm
| 271
| Black Cutworm
| 1
| | |
View Princeton trap counts for the entire 2006 season at - http://www.uky.edu/Ag/IPMPrinceton/Counts/2006trapsfp.htm
Fulton County trap counts are available at -http://ces.ca.uky.edu/fulton/anr/Insect%20Counts.htm
For information on trap counts in southern Illinois visit the Hines Report at - http://www.ipm.uiuc.edu/pubs/hines_report/comments.html The Hines Report is posted weekly by Ron Hines, Senior Research Specialist, at the University of Illinois Dixon Springs Agricultural Center.
NOTE: Trade names are used to simplify the information presented in this newsletter. No endorsement by the Cooperative Extension Service is intended, nor is criticism implied of similar products that are not named.
Lee Townsend
Extension Entomologist