CURRENT BLUE MOLD STATUS
by William Nesmith

*BLUE MOLD WATCH ISSUED FOR EASTERN AND SOUTHERN KENTUCKY
**BLUE MOLD ACTIVE IN CAROLINAS
***ACROBAT MZ IS NOW LABELED FOR USE IN KENTUCKY

Eastern and Southern Kentucky May Have Been Exposed:
The North American Blue Mold Forecast System has advised that the trajectory of travel of the spores from Reno, Georgia could have reached eastern and southern Kentucky during the Memorial Day Weekend. The Reno, Georgia source is highly resistant to Ridomil. If Infection probably occurred if live spores landed on tobacco in Kentucky between May 24 and 26, because conditions were nearly ideal for infection. Therefore, I am issuing a Blue Mold Watch for portions of southern and eastern Kentucky - all points east of a line from Cumberland County, Ky northeast to Boyd County, Ky. This is a very low-level risk, because the spores are probably being washed out close to the source due to rains. I urge growers along and east of this line to maintain spray programs in all transplant production systems, close your spray intervals to 5 days using Ferbam, Dithane, or Acrobat MZ. Improve air movement by removing bed covers and using fans in greenhouses. County Agents are advised to begin checking closely for early symptoms of blue mold (expected as a yellow spot, probably isolated as one per bed) starting on May 29. Crops set in the field that have any connection with southern transplants should receive at least one application of Acrobat MZ.

Kentucky At-Large:
Blue mold has not been detected from anywhere in Kentucky. A low-level risk from airborne introductions of blue mold into Kentucky from the southeast occurred during the recent holiday weekend (See above). Introduction from Texas probably has not occurred during the past 10 days. Introduction of low levels of blue mold into Kentucky on transplants from the southeast may also have occurred, because transplants from Florida and Georgia continue to be shipped, received, and transplanted in Kentucky. Since metalaxyl-resistant blue mold has been confirmed in Georgia and other outbreaks have been found closer to the transplant production areas, this potential risk should be taken seriously. IF THE KENTUCKY CROP (field or beds) HAS A CONNECTION WITH SOUTHERN TRANSPLANTS, IT SHOULD BE UNDER A SPRAY PROGRAM USING ACROBAT MZ! Until other threats materialize to the state of KY, application of Acrobat MZ should be targeted only against crops with a connection to southern transplants (plugs, finished-plants, or fields set from such).

ACROBAT MZ Status:
The Kentucky Supplemental Label for Acrobat MZ is now registered in Kentucky, as of May 21. The product is labeled for use until September 30 in communities directly threatened by metalaxyl-resistant blue mold. There are several points that need to be given more attention than last year.

• Growers need to follow the label AND have the Supplemental Label in their possession during application. (Note: the supplemental label is NOT on the bag.)
• Dealers and Growers need to keep specific records of sale and use - basically what is normally required for restricted use chemicals.
• The label is very clear as to exactly how this fungicide is to be applied. Several scientists with the Land Grant Colleges worked with American Cyanamid Company to help improve this area of the label. Poor coverage equals poor control!
• Currently, applications are restricted to 4 in the transplants and 4 in the field and not to exceed 10 lbs/Acre/season. EPA officials have indicated they will consider approving additional applications if warranted, so long as the 10 lb-limit per acre is not exceeded. We will be requesting that modification to the label, BUT THAT CHANGE HAS NOT BEEN APPROVED. CURRENTLY WE MUST LIVE WITH THE 4 APPLICATION LIMIT.

Southeastern States With Blue Mold:
Blue mold remains active in the southeastern US (Florida, Georgia, and North Carolina have confirmed cases).

North Carolina: On May 22, Dr. Tom Melton, North Carolina State University reported that blue mold had been found in four (4) old tobacco plant beds in Green Co., NC (eastern North Carolina). Sporulating lesions and systemic symptoms were observed. It appears the blue mold had increased 1 - 2 cycles dating back to spore trajectories forecasts from Florida on 2 May and/or Reno, Georgia on 14 May. Replanting from the infected seedling beds to the field had occurred as recently as 21 May. No Ridomil had been used on the beds. Metalaxyl-sensitivity tests are planned. The plant beds were destroyed.

Georgia: Dr. Paul Bertrand, Extension Plant Pathologists, University of Georgia, reported on May 20 that blue mold had been confirmed in three new locations in Georgia, supporting that some spread has occurred. A field of flue-cured tobacco located in Grady County four to five miles southwest of the outbreak in cigar-shade tobacco; in Echols Co. blue mold is very active in a quarter acre portion of a larger field; and in Ware County a very low-level incidence was found. The blue mold in all these locations has been present for a while and may have begun the same time as that in the shade tobacco at Reno, Georgia. The Cuban source trajectory suspected in the case of the Reno blue mold could account for all these other sites.

Blue mold at the Reno site is not sensitive to Ridomil, confirmed as metalaxyl-resistant by both Novartis and University of Kentucky labs. This outbreaks continues and is actively spreading across the field and up the stalk of infected plants. The shade cloth is providing an ideal environment for blue mold as evidenced by sporulation on the upper surface of many lesions.

Florida: Dr. Tom Kucharek, University of Florida, reported that blue mold remains active with 3 new counties added. Losses of 5% have occurred on some farms due to damage of the lower leaves.

Texas: The levels of blue mold activity in Texas remains about the same as last week. Recent rains have occurred which may have supported local spread, but more importantly, the moisture should help sustain the host (wild tobacco) longer than normal.

Tobacco Information Hotline: The University of Kentucky, in cooperation with Valent Chemical Co., has been operating a Tobacco Information Hotline for two years. Considerable tobacco information is available through this toll-free line, including frequent updates of the Kentucky Blue Mold Warning System. The number is 800-204-7323.

Radio: Radio is one of the major routes used by the Kentucky Blue Mold Warning System to disseminate information. Weekly programs are made available to County Extension Offices and subscribing stations through the Department of Agriculture Communication Service. Regular blue mold updates have been available for years through Jack Crowner and his regular radio programs in the region. A relatively new outlet is now available in central Kentucky with Price Allen's Noon Farm Program at AM 1380, broadcasting from Winchester, Ky.

TRAINING ON ACROBAT MZ FOR DEALERS, COMMERCIAL APPLICATORS, AND COUNTY EXTENSION AGENTS
by William Nesmith

American Cyanamid, Kentucky Department of Agriculture's Division of Pesticides, and the Plant Pathology Department, University of Kentucky will conduct a series of special training sessions related to the correct use of Acrobat MZ under the recently approved Section 18 in Kentucky. These meetings are mainly for pesticide dealers, commercial applicators of tobacco pesticides (e.g. custom applicators), and County Extension Agents. They will also address many of the short comings experienced in 1996 related to improper applications and poor record keeping.

The meetings will be held at the following locations and times:

• June 3, 9:30 to 11:30 Eastern Daylight Saving Time, Shelbyville, Ky at the Shelby County Extension Office
• June 3, 1:30 to 3:30 Eastern Daylight Saving Time, Lexington, Ky at the Fayette County Extension Office
• June 4, 9:30 to 11:30 Central Daylight Saving Time, Columbia, Ky at the Adair County Extension Office
• June 4, 1:30 to 3:30 Central Daylight Saving Time, Cave City, Ky at the Cave City Convention Center
• June 5, 9:30-11:30 Central Daylight Saving Time, Princeton, Ky at the University of Kentucky Research and Education Center

ADMIRE TRANSPLANT WATER APPLICATION
by Lee Townsend

The following Application Guidelines for use of Admire 2F in the transplant water were developed by the Bayer Corporation.

• Determine the number of plants per acre and gallons of transplant water used per acre.
• Calculate the Admire dosage per transplant tank based upon how many plants each tank will treat (at 1 fl oz per 1,000 transplants)
• Partially fill the transplant tank with water before adding Admire
• Pre-mix Admire in water before adding to the transplant tank.
• Keep the Admire solution agitated or mixed regularly to avoid settling in the transplant tank.
• When refilling the transplant tank, add the appropriate amount of Admire for the volume of water being added.

CUTWORM DAMAGE APPARENT IN SEVERAL PLACES
by Lee Townsend

Over the weekend, variegated cutworms destroyed several trays of transplants in at least one outdoor float system. The damage was not seen in time to prevent substantial losses. The adult or moth stage is active as early as mid-March and lays groups of 60 or more eggs on lower leaf stems and leaves. Early feeding signs by small cutworms are easy to overlook. Once they are about half-grown (about 3/4' to 1" long), their feeding rate picks up significantly and widespread injury can appear literally "overnight". Orthene as a foliar spray can be used in these situations but it is vital to catch the problem early.

CORN INSECT UPDATE
by Ric Bessin

As cool temperatures continue to prevail, insect activity, for the most part, has been low. Is this an assurance that fields do not have to be scouted regularly? Absolutely not! The cool temperatures have resulted in slow seedling growth. This means that many corn fields have remained in the vulnerable seedling stage. Growth will provide corn protection and limit damage from cutworms, corn flea beetle, and armyworm. While armyworm can be found attacking waist-high corn, damage to seedlings is often more severe. Cutworms are able to feed and develop at temperatures below which corn can develop. The weather pattern we are experiencing can favor increased cutworm damage.

The slow corn growth will aid in limiting first generation corn borer problems. Most the hybrids grown have a moderate to high level of corn borer resistance while they are less than 18 inches in height. Other than in extreme northern Kentucky, first-generation European corn borer moth flight has begun across the state with the southwestern portion of the state approaching peak flight soon.

Producers in western Kentucky, west of Elizabethtown and south of Owensboro, need to monitor late plantings for southwestern corn borer (SWCB). This destructive insect has been on the increase the last four years. Corn planted after May 1 in this region of the state is at greater risk to SWCB. Unfortunately, most growers do not realize that they have a problem with this insect until harvest, when much of their corn is on the ground. To prevent losses from this insect in late planted corn, producers need to be monitoring for this insect while they are scouting for European corn borer. First-generation SWCB larvae first appear in Early June.

Summer-form SWCB larvae are milky-white with a brown head and have numerous distinct brownish-black spots on the body. The European corn borer is smaller, creamy-white with numerous less-distinct black spots and faint gray stripes running length of body. For the first two weeks, first-generation SWCB larvae feed within the whorl of the plant. After feeding in the whorl, larvae move down the stalk and tunnel into the stalk. Numerous holes in the emerging leaves and leaf breakage due to midrib tunneling are characteristic.

Monitor fields in early June for initial shot-hole feeding to whorl leaves. Similar to management of European corn borer, timing is critical for control. Larvae can only be effectively controlled while they are feeding within the whorl. Once they enter the stalk, they cannot be controlled. Management of the SWCB relies on maintaining the first generation infestations below a 35% economic threshold.

POTENTIAL EARLY SEASON PESTS
by Lee Townsend

Irregular germination or gaps in stands may be caused by seedcorn maggots. The potential for infestation is greatest in early-planted fields with a significant amount of organic matter in or on the soil surface. The long spell of cool weather has slowed germination and favored this insect.

Symptoms include damage to the cotyledons and stem by the tunneling of small white maggots. If maggots are no longer present, small reddish brown pupal cases may be seen in the soil. The adults, similar in appearance to house flies but smaller and thinner, may be seen making short, hopping flights over the soil surface. Usually the damage is relatively evenly scattered over an entire field. There is no rescue treatment but severe stand loss, in the form of large gaps of missing plants, is needed to produce significant yield loss. If stand reduction justifies replanting, use an insecticide seed treatment.

Bean leaf beetles chew small, rounded holes in the leaves. These 1/4" long beetles vary in color from light yellow to bright red. In addition, four black spots and stripes may be present on the wing covers. A black triangle can be seen where the base of the wing covers attaches to the segment behind the head. Overwintering adults are active early and can feed ravenously on emerging seedlings. The numbers of beetles and level of injury should be used to make control decisions.

• Cotyledons slightly injured, less than 30% injury to unifoliate and open trifoliates
  • 4 to 6 beetles per foot of row- Sample again in 7 days.
  • More than 6 beetles per foot of row- Sample again in 3 days.
• At least 1 cotyledon completely destroyed; 30% to 40% injury to unifoliate and trifoliates
  • 4 to 6 beetles per foot of row- Spray immediately, no loss expected. (Sample in again in 3 days if 4 or less beetles)
  • More than 6 beetles per foot of row- Spray immediately, treatment overdue.
• Two cotyledons destroyed; more than 40% defoliation
  • 4 to 6 beetles per foot of row- Spray immediately (Sample in again in 3 days if 4 or less beetles. Some replanting may be needed if plants are dying)
  • More than 6 beetles per foot of row- Spray immediately (Some replanting may be needed if plants are dying)

Very small yellow spots on leaves and cupping or burning of leaf margins may be due to potato leafhoppers. These insects have been abundant early in the season and cutting of alfalfa may drive adults into nearby soybeans. Look for these small, light green insects on the underside of plant leaves.

Thrips injury can produce small silver spots or flecking on soybean leaves. Look for the very small, elongate insects on the underside of the leaves.

RECENT DATA CONFIRM THAT ALFALFA VARIETIES DIFFER LITTLE IN SCLEROTINIA RESISTANCE UNDER OUR CONDITIONS

Paul Vincelli, Extension Plant Pathologist
Jimmy Henning, Extension Forage Agronomist,
David Herbst, Extension Agriculture Agent, Adair County

Sclerotinia crown and stem rot of alfalfa continues to be a significant limiting factor for successful late-summer seeding of alfalfa throughout the state. While alfalfa fields are successfully fall-seeded in many instances, dramatic outbreaks occur frequently enough that many producers avoid fall-seeding entirely. Factors that increase risk of this disease include: known history of the disease; no-till seeding; and late seeding (particularly after Labor Day). See the UK Extension publication, Risk Factors for Sclerotinia Crown & Stem Rot in Fall-Seeded Alfalfa, PPFS-AG-F-2, for a discussion of these and other risk factors.

This disease has been a frustrating one to work on. Essentially everything we at UK have tested in our research program has failed to provide any increment of disease control, except the use of experimental, unlabeled fungicides. Thus, any research data showing some promise for giving even partial control of this disease gets our attention. We'll take any incremental improvement we can get against this disease. After all, such practices as early seeding do just that--give plants more time to develop some degree of partial resistance.

Two currently available alfalfa varieties are reported to have partial resistance to Sclerotinia crown and stem rot: Cimarron VR and WL332. Let us stress the term PARTIAL resistance. No claims are made that this will prevent the disease, nor that it will hold up under severe disease pressure. However, as stated above, we are interested in any possible increase in resistance against this difficult disease. These varieties have indeed performed well in well-conducted tests at Ohio State University.

In 1996, an experiment was conducted under commercial conditions in Adair Co. to evaluate three varieties: Cimarron VR, WL332, and Fortress (the latter was used as a susceptible but otherwise high-yielding variety). The field was in no-till corn in 1995 and a red clover/orchardgrass pasture prior to that. Roundup at 1 qt/A was applied as a burndown. Replicated plots were seeded no-till on 23 Sep 96 at 18 lb seed/A; plots were separated by orchardgrass strips. A uniform, vigorous stand was established in autumn, 1996.

Weather was favorable for Sclerotinia activity for much of last autumn and winter. Based on stand survival, disease pressure was moderately severe to severe throughout the field. On 6 May 97, with about 8-10" of height on surviving alfalfa, percent ground cover was estimated visually at various locations in each plot. The presence of sclerotia on dead plants confirmed the cause of the stand loss. The data were analyzed statistically and are presented in the following table.

Table 1. Ground cover by alfalfa varieties following an outbreak of Sclerotinia crown and stem rot, 6 May 97.

	Percent ground cover
Alfalfa variety	Average	Range
Cimarron VR	22a	2 - 65
WL332	13 a	1 - 30
Fortress	7 a	1 - 20

Means followed by the same letter are not significantly different (P>0.20 for ANOVA variety effect).

The varieties tested did not differ significantly in stand survival following a moderately severe outbreak of Sclerotinia crown and stem rot. Variability in response was extreme, probably a reflection of variation in disease pressure in the field.

These data are consistent with our previous research at UK. The level of available resistance to Sclerotinia crown and stem rot in commercial varieties and breeding lines is inadequate for Kentucky conditions.

Thanks are expressed to Mr. Randy Nelson in Adair County, who was willing to conduct this test on his farm.

NEW PRODUCTS
by Lee Townsend

Cutter 1 Insecticide Cattle Ear Tags, which contain 40% diazinon, can be used on beef cattle or non-lactating dairy cattle. Apply one tag per animal for horn fly control or 2 per animal to aid in the control of face flies. Calves less than 3 months of age should not be tagged because ear damage may occur. Cutter 1 tags are a product of Bayer Corporation. Diazinon, an organophosphate insecticide, has been effective against pyrethroid-resistant horn flies.

Countdown, also a Bayer Corporation product, is a residual insecticide for control of flying and crawling insects in and around livestock premises. Cyfluthrin, a synthetic pyrethroid insecticide is also the active ingredient in Tempo. It is available as a 2 pound per gallon emulsifiable concentrate or a 20% wettable powder.

by Patty Lucas

May 16 - 23

by Julie Beale and Paul Bachi

Diagnoses on tobacco last week consisted predominantly of Sclerotinia collar rot, target spot and angular leaf spot. Blackleg has begun to develop in greenhouse situations; cases of black root rot and Rhizopus soft rot were also seen.

Diagnoses on fruits and ornamentals included scab (Venturia) on apple and crabapple, frogeye (Botryosphaeria) on apple, anthracnose on blackberry, powdery mildew and rose mosaic virus on rose, leaf/flower gall on azalea, and black root rot and Cercospora leaf spot on holly.