Kentucky Pest News Newsletter

HIGHLIGHTS IN THIS ISSUE

Number 1032__________August 2, 2004

DIAGNOSTIC LAB HIGHLIGHTS


Ky Blue Mold

TOBACCO



CURRENT BLUE MOLD STATUS
By William Nesmith

Even though blue mold activity has slowed some with the drier weather of the past month, don't be deceived, as the region continues to experience very strong disease levels. Moreover, the stage is set for potentially even stronger activity unless there is a change to hotter or drier weather, especially hot nights. The cool, cloudy, and moist weather experienced recently has provided conditions favorable for blue mold to flash again. This is similar to the cool weather pattern experienced in 1979 when blue mold caused much damage to the crop in early August. This time, the high levels of inoculum are already present within the field.

I urge growers not to under estimate the potential threat, especially those that have been attempting to control the disease. Be careful of dropping the guard too soon, thinking the plant is too old to be damaged by blue mold, or you have it under control with fungicides. Appreciate that under the type weather being experienced this year and the level of spores available, the blue mold pathogen can destroy tissue at all leaf positions at about all stages of growth. Even crops already topped are maturing very slowly, and thus remaining in the zone of high blue mold susceptibility for much longer than normal. Most communities in the Bluegrass and eastern Kentucky have sufficiently high inoculum that missing a single fungicide spray can result in >20% leaf surface damage a week later. Fungicides must be applied at close intervals to keep up with all the new growth and wash-off, as much of that tissue is inside the canopy, shaded, wet for longer periods of time, and difficult to cover with fungicides.

To illustrate the inoculum potential, I present the following: On July 22, a plant of burley tobacco grown in our campus greenhouses was exposed over-night to the foggy air in western Clark County; a companion plant was not exposed. The foliage of the two plants has been keep dry since, with water added in the pot only. On the morning of July 28, about 30% of the leaf surface of the exposed plant was showing very faint yellowing. On the night of July 28, both plants were exposed to the cool, moist air of western Clark County. Nearly 50% of the leaf surface (bottom side) of the plant with symptoms was covered with blue spores on the morning of July 29, plus the top side was covered in a grayish down.

Abundant sporulation occurred each morning between July 26 and August 2 in many areas of the Commonwealth that have established blue mold. Several experienced agents have called inquiring about the possibility of this being a new strain of blue mold because the sporulation was so massive. What we have been seeing is consistent with how the common strains of blue mold perform in laboratory tests when day temperatures remain in the 70's and the nights temperatures in the 50's to low 60's. New infections and those developing from late last week will likely result in the pathogen going systemic in the leaves, resulting in death of major veins and general blighting at many stalk positions on the plant. Instead of the classic discernable spots, expect nearly the whole leaf to sporulate blue and scald in large panels.

I checked isolates from 18 farms where growers claim less than desirable control from using Acrobat MZ for their sensitivity to dimethomorph, the active ingredient in Acrobat 50 W and the systemic material in Acrobat MZ. All isolates were sensitive at 1 ppm. We see no evidence of current blue mold strains in the area showing resistance to dimethomorph. Poor control on each of those farms is related to poor fungicide timing, poor coverage, or wash-off rather than resistance, in my opinion.

Many crops escaping serious blue mold earlier because of poor plant growth have recovered somewhat and are now producing considerable succulent growth - which will be very susceptible to blue mold. This is especially true on farms using supplemental or layby nitrogen applications. Crops protected earlier by fungicides remain susceptible unless fungicide programs are maintained. When fungicide applications are stopped, expect to see serious blue mold development about 10 days later unless the plant has been topped and is approaching maturity. Many growers are not spraying at close enough intervals or using sufficient fungicide rates.

EMERGENCY EXEMPTION OBTAINED FOR USING QUADRIS FUNGICIDE IN KENTUCKY'S TOBACCO By William Nesmith

The US EPA and the Kentucky Department of Agriculture granted approval on July 29, 2004 to use Quadris Flowable Fungicide in Kentucky burley and dark tobacco fields under a Section 18 Crisis Emergency Exemption. Foliar fungicide sprays are approved from July 29, 2004 to October 15, 2004, unless EPA orders them stopped earlier, for management of frogeye and target spot. A copy of the emergency label and use guidelines is available at the local office of the UK Cooperative Extension Service, or it can be found by following the link to the Blue Mold web page at the end of the Tobacco section.

The use rate is 8 fl.oz./Acre, with a maximum of 4 applications per field. Quadris must be used in rotation with either Acrobat MZ or the tank-mixture of Acrobat 50W + Dithane DF Rainshield. Back-to-back applications of Quadris are prohibited. Even though Quadris has only a 1 day pre-harvest interval, due to the lack of a rotational partner between topping and harvest, only one of the Quadris applications can be made within 30 days of harvest. Tank mixing Quadris with Thiodan and/or sucker control chemicals is prohibited by the label. It is important that growers note the advisory of the flecking potential of Quadris and that the using grower accept all liabilities associated with this use. Also, growers need to note and follow all cautions and prohibitions present on both the product label and the emergency label.

Used in this manner, Quadris should greatly assist in the management of the leaf spotting complex currently present, which involves blue mold, frogeye, and target spot. Failure to use in this manner can result in poor control of one or more of these diseases and lead to more rapid development of fungicide resistant strains of these pathogens.

In addition to the epidemic of blue mold, our region is also experiencing epidemic levels of other leaf spotting diseases, although they are causing much less damage overall than is blue mold. Tissues damaged by the blue mold fungus have been colonized by the frogeye pathogen, Cercospora nicotianae, which is now producing an abundance of inoculum. These spores will continue to build, attacking the physiologically imbalanced leaves and potentially trashing the crop, or reducing the grade and market value, if green spotting develops. Moreover, where labeled fungicides are used for blue mold control, the leaves will remain vulnerable to frogeye and target spot (caused by Thanatephorus cucumeris/Rhizoctonia solani) infections, due to lack of adequate efficacy in current fungicides against these diseases. Fungicides containing mancozeb (Acrobat MZ and Dithane DF) have significant efficacy against frogeye, but not target spot.

Data on the performance of Quadris against this complex of leaf blighting diseases from a 1999 study can be found on the Kentucky Blue Mold Warning System website under the disease information section at http://www.uky.edu/Agriculture/kpn/kyblue/kyblu 04/related/related.htm. Look for the article entitled: "Evaluation of Experimental Fungicides for Controlling a Leaf Blighting Complex of Blue Mold, Target Spot, and Frogeye in Burley Tobacco, 1999" by William Nesmith.

For the latest blue mold status, Quadris emergency label, and other tobacco disease information, check the KY Blue Mold Warning System online.
Blue Moldhttp://www.uky.edu/Agriculture/kpn/kyblue/kyblue.htm


Corn






CORN



FACTORS THAT COULD ENHANCE STALK ROTS OF CORN
By Paul Vincelli

The corn crop is generally over a week ahead of normal, so as the crop approaches maturity, it is a good time to consider stalk rots. Stalk rots of corn are caused by a variety of fungi, including Gibberella zeae (also known as Fusarium graminearum), Diplodia maydis, and Colletotrichum graminicola. They attack the stalk and rot the pith, causing the stalk to become weakened and susceptible to lodging from a strong wind. This results in a crop that is much more difficult to harvest, usually leading to some loss of corn that cannot be picked up by the combine.

Some areas of the state recently have received periods of several days of cloudy, somewhat cool weather. Under these conditions, the corn continues filling the grain, pulling reserves from the stalk. This can reduce the stalk's resistance to infection, resulting in higher stalk rot potential as the corn matures.

Also, on a recent trip to southern Kentucky, I saw a fair amount of common rust on corn up and down the canopy. The levels of common rust were not sufficient to cause direct yield loss, but it could create a stress on the crop that permits increased invasion of stalks by stalk rot fungi. Common rust can be recognized as pustules which are circular to oval, golden-brown to cinnamon brown, up to 1/8 long.

While widespread and serious problems with stalk rots are not expected, it is always advisable to scout corn for lodging potential as it approaches maturity. This practice helps identify fields that should be harvested early and dried down. A simple way to scout for lodging potential is to walk the field and push plants 12-18 inches from vertical at about chest height. Stalks that don't spring back have the potential to lodge. If 10- 15% of the field shows such lodging potential, plan on harvesting the field soon after the grain is physiologically mature (development of black layer, about 30% grain moisture).


Alfalfa

ALFALFA



PESTS OF FALL-SEEDED ALFALFA
By Lee Townsend

Several insects feed on fall-seeded alfalfa. If enough are present, they can cause significant stand loss. The most common culprits include fall armyworms, grasshoppers and crickets but Mexican bean beetles and spotted cucumber beetles (southern corn rootworm beetles) can be there, too. Regular inspection of new seedings will allow early detection of pest problems, assessment of damage, and treatment, if necessary.

Some pests are clumped in a field so large numbers can be found in localized areas. Fall armyworm infestations will tend to be clumped and intense because females lay masses of several hundred eggs. The small larvae will move out from this focus as they grow and eat all of the nearby plants. Look for roughly circular bare areas. Look under surface debris and in soil cracks for the striped larvae. Spot treatments with an insecticide can be used to deal with the problem.

Grasshoppers and crickets can chew off small seedlings. Damage may appear at the edge of the field and progress across it. These insects will move readily so feeding should be less concentrated. Mexican bean beetles and spotted cucumber beetles also may move in and feed. These insects move frequently as they feed, this dilutes their impact on a stand.

Evaluate injury and patterns carefully. Low rates and spot treatments with an insecticide labeled for alfalfa may be all that is needed to deal with pest activity. See ENT-17 for control recommendations.


Wheat

WHEAT


 


WHEAT SEED QUALITY
By Don Hershman

The following is an article written by Cindy Finneseth, Seed Testing Coordinator in the University of Kentucky, Division of Regulatory Services, on the impact of Fusarium head blight on wheat seed quality in 2004.

HEAD SCAB ON WHEAT SEED
by Cindy Finneseth

Fusarium head blight (FHB), also known as head scab, is caused by different species of Fusarium. In Kentucky and neighboring states, the disease is caused primarily by Fusarium graminearum. The disease is present every year, but the effect on seed crops varies, primarily due to inconsistent environmental conditions and, thus disease pressure, from year to year. The fungi that cause FHB infect seed of wheat, as well as barley, rye and triticale. Infection occurs during flowering, but as the seed crop matured growers may have noticed bleached heads, all or portions of heads, in their fields. Infected seeds are often recognized by a shriveled, chalky appearance and seed coats may have a pink discoloration. Infections can cause lower grain yields and reduced test weights. Poor quality seed lots may require significant cleanout and seed treatment with a fungicide to obtain an acceptable germination percentage. An additional problem with infected grain is the production of mycotoxins, especially deoxynivalenol or DON, which can restrict use of diseased grain as a feed source.

FHB was at epidemic levels in many wheat fields during 2004. As a result, more than 75% of the wheat samples submitted to our lab have been infected with Fusarium species to varying degrees. Seed counts per pound have ranged between 12,000 to 19,000, with an average of nearly 13,900 seed/lb. Average germination of untreated seed lots submitted to our lab this summer is 65%, with lots ranging from 34% to 97%.

Fungicide seed treatments can have a substantial effect on limiting the impact of seed-borne Fusarium on seed germination. Thus, as a courtesy this season, we have been treating lots and reporting both untreated and treated test results to producers. In some lots, seed treatment increased germination dramatically (10-20%). In other lots, however, a marginal effect (1-5%) or no effect was seen. On average, germination after seed treatment has been 84%. In the lab we use a Raxil- Thiram product, but there are other fungicides labeled for use on wheat. Prior to applying any seed treatment consult the product label and follow all label directions. Note, dead seed or healthy seed not infected by Fusarium will not respond to fungicide seed treatments. Either or both of these situations may account for the differential response we have seen when treating wheat seed lots this summer.

A less expensive alternative to seed treatment can be to re-condition the seed lot to remove light, "scabby" seed. Growers may be tempted to use infected seed and adjust planting rates to achieve a better stand. This is a very risky thing to do unless you are certain that untreated seed germination is near the 84% germination standard. Increasing seeding rates of low germination seed is unlikely to result in acceptable wheat stands. When possible, seed lots with germination below 80% should be avoided.

To gain the most information about a seed lot, have the lot treated and test for both treated and non-treated germination at the same time. This allows comparison of the results to make management decisions based on effect and cost of treatment. If requesting this paired test, please submit enough seed for two tests (2-3 lbs.) and clearly mark the sample for treated and untreated germination tests. Cost of the two tests is $14.00. Samples can be mailed to the Seed Testing Laboratory, Division of Regulatory Services, 103 Regulatory Services Bldg., Lexington, KY 40546-0275 or can be hand delivered. We are located on campus across from Commonwealth Stadium on the corner of University and Alumni Drives. For more information about submitting seed and available tests, please visit our website at http://www.rs.uky.edu or call (859) 257-2785.

For additional information about FHB and control methods, refer to the Extension publication Head Scab of Small Grains in Kentucky, PPA 38, available online at: http://www.ca.uky.edu/agc/pubs/ppa/ppa38/ppa38. pdf and at county Extension Offices.

For an overview of the most recent FHB management strategies, consult: http://www.ca.uky.edu/ukrec/newsltrs/News03-5.pdf.

For a discussion on the impact of crop rotation and tillage effects on FHB, see: http://www.ca.uky.edu/agcollege/plantpathology/PPAExten/PPFShtml/ppfagsg9.htm

For information on the 2004 Folicur section 18, see issue 1017 of the Kentucky pest news, see: http://www.uky.edu/Agriculture/kpn/kpn_04/pi040419.htm.


Apples

FRUIT



BLACKBERRY ROSETTE (DOUBLE BLOSSOM) DISEASE APPEARING
By John Hartman and Terry Jones *

Rosette disease, also called double blossom, is caused by the fungus Cercosporella rubi. This disease is being observed frequently on blackberries in the field this summer and is the subject of many recent diagnoses in the plant disease diagnostic laboratory. Disease symptoms appear the year after infection occurs, so it is possible that wet weather last year provided conditions for increased disease incidence this year. Blackberry rosette is a very serious disease which can destroy a blackberry planting by reducing fruit yield and quality and causing death of canes. Rosette occurs in all regions of Kentucky.

Symptoms. Blackberry growers will notice flowers with distorted petals, giving the appearance of a double flower (hence double blossom). The mycelium of the fungus grows over the flower pistils and stamens producing a whitish spore mass. Unopened flowers are usually elongated and larger, coarser, and redder than normal. Sepals on infected flowers enlarge and occasionally become leaf-like. On some varieties, shoots may appear abnormal with leafy proliferation (rosette) or witches broom while on other varieties the rosette may fail to develop but infected blossoms are sterile. Berries do not develop from infected branches and other parts of the cane may produce only small, poor quality fruit. Thus, this loss of yield should concern growers.

How the disease is spread. The disease begins when the buds of new canes become infected from fungal spores produced on infected distorted flowers of old canes. Symptoms from these infections do not appear until the next year. Blackberries can become infected from spores produced on wild blackberries nearby. Blackberry nursery stock can harbor the causal fungus in rooted plants, but not in root pieces, which are commonly sold for blackberry propagation. We have observed that one can obtain successful growth of disease-free blackberries from root pieces taken from infected plants while rooted plants from the same source become diseased.

Disease management. Select a site isolated from wild blackberries or other brambles. In many parts of Kentucky, this may be difficult. Use disease-free nursery stock, roots only. If the disease is not already severe, infected rosettes and blossom clusters should be picked off and destroyed before they produce spores. Old canes should be removed and destroyed immediately after harvest. Remove and destroy wild blackberries and other brambles near the planting.

If the disease is serious, application of Bordeaux mixture or Benlate at just the right times may be needed. Bordeaux mixture can partially reduce disease incidence if applied weekly from bloom through harvest. The fungicide Benlate can be used up to 5 times in a season at two week intervals beginning at first bloom and extending through harvest. However, this fungicide is no longer being manufactured and when stocks of Benlate run out, it will no longer be available. Fungicides such as Abound and Pristine, now available for use on blackberries, may be effective against rosette disease. However, fungicides are not totally effective when disease pressure is high and/or spray coverage and timings are deficient.

Some growers control this disease by harvesting blackberries in alternate years and destroying the above ground parts of both the new and old canes in spring every other year. Splitting the planting into two fields allows harvest every year with biennial cropping on each half. There are no blackberries resistant to rosette (double blossom) disease. Rosette rarely occurs on red and black raspberries.

* Dr. Terry Jones is U.K. Extension Horticulturist


Tick

HUMAN/PUBLIC HEALTH PESTS


RAINS CONTINUE TO MAKE MOSQUITO BREEDING GROUNDS
By Lee Townsend

Frequent rains across the state leave standing water in drainage ditches and other low areas. These sites can produce large numbers of "floodwater mosquitoes" in about two weeks. Several species of floodwater mosquitoes are vicious biters that routinely move several miles from their breeding sites to feed. Eggs of these mosquitoes are laid singly in flood prone areas so they are there waiting for the water. Draining or filling these areas, when practical, is the long term solution to mosquito management. Treatment with "mosquito dunks or doughnuts" is another option. These products contain Bti an insecticide that is specific to mosquito larvae.

Rainwater also accumulates in discarded cans, tire, and in low spots on tarps covering equipment or stored materials such as silage. This water is ideal for container breeding mosquitoes, such as the house mosquito, treehole mosquito and Asian tiger mosquito. Their eggs are laid on or just above the surface of the water and hatch in a day or two. These mosquitoes do not move far from their breeding sites and are important potential disease vectors. Regular checks around your property will help to identify these small accumulations of water so that they can be drained.


Lawn and Turf

LAWN & TURF



CICADA KILLERS ACTIVE
By Mike Potter

Cicada killers have been flying about and burrowing into lawns, prompting calls from homeowners. Despite their menacing appearance (up to 2 inches long with rusty red head/thorax, amber-yellow wings, and black and yellow striped abdomen), the wasps seldom sting unless provoked.

Biology - Cicada killers do not live in communal nests like hornets or yellowjackets. They overwinter as larvae within cocoons deep in the soil, emerging as adults during July. The females feed, mate, and excavate burrows in the ground about " inch in diameter, ending in a series of brood chambers. Bare ground or sand are especially prone to infestation. Excess soil is pushed out of the burrow, leaving a mound of dirt at the entrance. Each female excavates numerous burrows and provisions them with adult cicadas which she ambushes, paralyzes with her venom, and stuffs into individual brood chambers. She then lays an egg on top, backs out, and seals the cell behind her. The egg hatches within a few days and the hungry larva devours the offering, eventually transforming into an adult the following summer.

Management - Cicada killers seldom sting and the females normally do not defend their burrows. The males, while incapable of stinging, sometimes dive- bomb passers-by, or hover menacingly nearby. Insecticide treatment may be warranted where the soil burrows become unsightly, or the wasps are digging in a high-traffic area such as along a sidewalk, playground, or sand trap on a golf course. Individual burrows can be effectively sprayed or dusted with most lawn & garden insecticides (Sevin, Bayer Advanced Lawn & Garden Multi-Insect Killer, Spectracide Triazicide Soil & Turf Insect Killer, etc.), or a wasp & hornet aerosol. Multiple nests may need to be treated with a broadcast application to the ground surface, using a pump up or hose-end sprayer.

As a deterrent to future nesting, clients should be advised to eliminate bare-ground areas. Cicada killers generally do not prefer burrowing into well-managed turf, gravel, pebbles or mulch. In situations such as playgrounds, camping areas, or commercial landscapes, these materials may be substituted for sand or bare soil. Another option is to wait and do nothing in a few more weeks the adults will die off and there's a chance the problem will not reoccur next year.


Maple

SHADE TREES AND ORNAMENTALS



LACE BUGS CAN WHITEN SHADE TREES AND LANDSCAPE PLANTS
By Lee Townsend

Lace bugs use their sucking mouthparts to remove plant sap. Feeding signs resemble spider mite damage, ranging from scattered tiny white spots on the foliage to complete bleaching of the leaves. Some lacebug species feed on many different types of plants while others choose a single species. Injury builds slowly but can become very intense late in the summer. Adult lacebugs have ornate or lacy wings that are held flat over their backs while the spiny nymphs are wingless. They can be found on the underside of infested leaves along with varnish-like spots of their tarry waste.

Azalea lace bugs, about 1/8" long with light brown bodies, are one of the common offenders. They prefer evergreen azalea varieties but attack deciduous varieties and mountain laurel. In heavy infestations, leaves may turn white and drop prematurely. The lacy wings of the adults have dark brown to black markings, nymphs are black. Populations are greatest in mid- to late summer as the second generation bugs appear. Insecticidal soap (Safer), Orthene, or malathion can be used to reduce lace bug numbers. The spray must be directed to the underside of the leaves to contact the insects directly. The treatment may need to be repeated to bring populations under control. Sycamore lace bugs can be abundant on trees from late summer to early fall. These insects rarely affect tree health. They can fall on people and may probe the skin, giving a bite "sensation" and there may be a temporary, slight skin reaction.


BRIGHTLY COLORED OR "HAIRY" CATERPILLARS OFTEN FOUND NOW
By Lee Townsend

Several distinctly marked caterpillars can be found now of landscape, woodlot, and forest trees. Often feeding begins at the tops of the trees and remains unnoticed for the first week or so that the insects are present. Most of the leaf consumption of caterpillars occurs over the last few days of their life so defoliation appears virtually overnight.

Orange-striped oakworms are black caterpillars with eight narrow yellow stripes that run the length of the body. There is a pair of long, curved "horns" behind the head. Small larvae feed in groups and skeletonize the leaves, older larvae eat all of the leaf except the main veins. They usually destroy all of the leaves on a branch before moving to a new feeding site. They can be found from August through October. Infestations usually start in the top of the tree and the larvae move down as they feed and destroy foliage.

Yellow-necked caterpillars have black heads and dark bodies with four yellow stripes running the length of the body. A yellow band around the segment behind the head gives these larvae their common name. They feed on oaks, apple and a variety of trees and shrubs.

The hickory tussock moth is a hairy white and black caterpillar that prefers hickory and walnut but will feed on many other shrubs and trees. It is common from July through September.

Pruning or sprays of Bt (Bacillus thuringiensis - Dipel, etc.) may be used to protect small trees that are being heavily attacked. Bt works as a stomach poison so treated leaves must be eaten.

Both giant and stinging caterpillars are reaching stages where they are easier to spot. The following links provide pictures and information on some of our more common species. Stinging caterpillars and giant moths and caterpillars.


House

HOUSEHOLD



FOREIGN GRAIN BEETLE ALERT
By Mike Potter

"I keep seeing tiny, brown beetles crawling along windows, walls, and floors of my new home. I spray the ones I see, but they keep coming back. What kind of bugs are these and how do I get rid of them?" These are the questions typically asked by clients who have foreign grain beetles, especially when the calls come in late summer (August- September).

Foreign grain beetles are very small (about 1/16-inch long), brownish, and are often mistaken for flour beetles or other stored product insects. The key characteristic to look for in identifying this beetle is the presence of a slight projection or knob on each front corner of the shield-like segment directly behind the head. A microscope or good quality hand lens is necessary to see this character (See Entomology Entfact-610, Foreign Grain Beetle).

Foreign grain beetles are frequently a problem in new construction (less than 5 years old). They are one of a group of beetles called "fungus beetles" that feed on molds and fungi growing on poorly seasoned lumber or wet plaster and wall board. If they are found infesting flour, grain, or other stored products, the products are generally moldy or in poor condition. When new homes are built, damp wood is often covered with molds or mildew which attracts the beetles. The beetles are also attracted to accumulations of sawdust trapped behind walls during construction. Eggs are laid on this food material and the larvae develop on the surface fungi. The adult beetles usually become a problem in late summer when they move out of wall voids and are attracted to windows and lights. In older homes, foreign grain beetles can also be associated with plumbing leaks, condensation problems, or poor ventilation.

There is no fast or easy way to get rid of foreign grain beetles. Control is difficult because the breeding source of the beetles is concealed within the walls. The ultimate solution is time and patience. Most new homes dry out naturally within the first few years and the fungi and molds disappear along with the beetles. Drying time can be enhanced by increasing ventilation, e.g., by use of fans and air conditioning. A vacuum cleaner can be used to remove beetles emerging from hidden locations. Pest control companies may be able to provide limited relief by locating the infested wall areas or source of dampness (usually in the rooms where the beetles are most abundant), and injecting residual aerosols or dusts into cracks and crevices beneath baseboards and into the wall voids.

If the homeowner can tolerate the emergence of the adult beetles during August-September, the problem will usually resolve itself. Most newly-built houses cease to have problems after a few summers, and the beetles usually will not be evident during the rest of the year. Some comfort can be taken in the fact that foreign grain beetles are only a nuisance by their presence. They do not bite or damage wood, fabric or stored foods in a sound condition.


Microscope

DIAGNOSTIC LAB HIGHLIGHTS


DIAGNOSTIC LAB - HIGHLIGHTS
By Julie Beale and Paul Bachi

Recent samples in the Diagnostic lab have included frogeye, downy mildew, sudden death syndrome, and Rhizoctonia canker and root rot on soybean; black shank, blue mold, frogeye leaf spot, target spot, angular leaf spot, potyvirus, manganese toxicity, leaf distortion from calcium deficiency and Fusarium wilt on tobacco.

On fruits and vegetables, we have diagnosed double blossom on blackberry; powdery mildew and phylloxera leaf galls on grape; brown rot on peach; scab and cedar-apple rust on apple; gummy stem blight and Phytophthora blight (P. capsici) on watermelon and other cucurbits; bacterial wilt and Phytophthora blight on pumpkin; Fusarium dry rot on potato; Phytophthora blight on pepper; and bacterial speck, Septoria leaf spot, Cladosporium leaf mold, early blight and yellow shoulders on tomato.

On ornamentals and turf, we have seen Phytophthora root rot on rose; genetic anomalies on chrysanthemum ("'Lisa' problem" see note below); Cercospora leaf spot on maple; Actinopelte leaf spot and iron deficiency on oak; Phyllosticta leaf spot on maple; powdery mildew on crepe myrtle; and brown patch and Rhizoctonia root rot on fescue.

Note: A chrysanthemum sample (cultivar 'Lisa') was received recently with white tissue in areas on the leaf margins and areas of white flecking located symmetrically on the leaves. We consulted with a number of floriculture experts and obtained information from a representative from Yoder Bros. on what they call the "Lisa problem". Yoder has done extensive virus/viroid testing over time and has never been able to associate a virus or viroid with the problem. Likewise, they have done foliar and soil analyses and have not consistently been able to associate nutritional problems or spray injury, etc. with the symptoms. Yoder usually sees this problem on the cultivar 'Lisa' in the heat of the summer. The sunken white flecks are not apparent in cooler temperatures. The crop grows typically outgrows the symptoms, and the flecking symptom has not been considered a major problem for the chrysanthemum crop.


Scout Cat

IPM TRAP COUNTS:


By Patty Lucas, University of Kentucky Research Center

UKREC-Princeton, KY, April 16 - 23, 2004
Black Cutworm 4
True Armyworm 2
Corn Earworm 11
European Corn Borer 1
Southwestern Corn Borer 31
Fall Armyworm 0


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

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