Blue Mold Advisory Statewide! Blue mold is established widely along three main fronts and increasing slowly. Watches and warnings are in effect for selected areas. The overall level of activity is low, but isolated outbreaks of very strong activity are also occurring. Laboratory tests indicate Kentucky is dealing mainly with metalaxyl- resistant strains of blue mold, tolerating 100 ppm, while sensitive strains are controlled at 0.06 ppm.
Do not underestimate the potential for blue mold to develop rapidly and widely in Kentucky with short periods of blue mold favorable weather as improved growing conditions will increase plant susceptibility, increase canopy cover, and thus, increase the potential for damaging levels of blue mold where cool, wet nights persist.
Blue Mold Watches are in effect for southern and central Kentucky, including the following Extension Areas: Pennyrile, Mammoth Cave, Lake Cumberland, Lincoln Trail, Bluegrass and Wilderness Trail. Viable spores should be impacting these areas from sources established within the area or nearby.
Blue Mold Warnings are in effect for the following Kentucky counties within the watch areas because active, sporulating blue mold has been confirmed in the past week: CHRISTIAN AND TODD of the Pennyrile Area; WARREN AND MONROE of the Mammoth Cave Area; TAYLOR of the Lake Cumberland Area; BOURBON of the Bluegrass; and, CLAY, JACKSON, LAUREL, and WHITLEY of the Wilderness Trail Area. Some additional counties outside the watch areas remain under blue mold watches/warnings, depending on the local county agents discretion, because blue mold was confirmed in these counties sometime during the past three weeks, but new sporulation was not reported during the past week. These counties include: SHELBY, MENIFEE, FAYETTE, CLARK, HARRISON, POWELL, BREATHITT, AND BRECKINRIDGE.
CONTROL ACTIONS: Preventive fungicide spray programs should be maintained in all transplant production systems statewide until the transplants are set or destroyed. Blue mold- infected plants should not be set. Under no circumstances should infected transplants be moved out-of- state, or from one region to another within Kentucky. If infected plants must be used, they should be utilized within the local community where the outbreak has occurred. Do not abandoned plant beds, but destroy them by deep disking or plowing.
In field plantings, preventive sprays should be deployed in communities under blue mold watches or warnings. In areas under an advisory, however, growers have less need to spray fungicides in the field but should remain alert for changing status reports, scout fields frequently, and be prepared to make timely fungicide applications, should the status be upgraded or the disease appear. All tobacco should be scouted frequently for early detection of blue mold, concentrating observations on the plants growing best and in shady areas of the field.
COOL TEMPERATURES FAVOR DISEASE: Temperature greatly impacts blue mold development. Although the weather conditions in general have not favored new infections over a wide area, blue mold activity will intensify greatly where infections have already occurred following the cooler temperatures experienced over the July 4th weekend. Cooler temperatures will greatly favor lesion expansion. Newly developing lesion will expand rapidly without much necrosis of the lesion with night temperatures in the 50 - 70 F and day temperatures in the 70's. Such lesions are excellent spore producers, so a lot of infection potential will be developed should a wet period follow this cool period. Areas of the state that experience cloud cover and moisture events, with the cooler temperatures experienced over the July 4th weekend, could see a rapid change in blue mold activity.
In contrast, the hot temperatures of a week ago caused rapid necrosis to develop in newly expanding lesions. As a result, the lesions appear to be much older than they are. Also, lesions developing under hot temperatures (especially night temperatures in the high 70's with day temperatures in the high 80's to low 90's) are poor spore producers.
Temperature is a very important driving force in blue mold epidemics because it has great impact on spore production and how long a lesion can produce spores. Once necrosis develops in a lesion, the lesions does not produce many new spores, unless the lesion expands into surrounding tissues.
Budworms can cause serious damage to tobacco at this time of the season. Their eggs are laid singly on the underside of the leaves. The larvae feed for 3 to 4 weeks and are about 1.5" long when full grown. Feeding is generally confined to the bud area and the small larvae and early signs of feeding damage are often undetected. Feeding holes enlarge and become obvious as the leaf continues to expand. The larvae are usually very large by this time and most of the feeding damage has been done.
Examine the bud area of tobacco plants at weekly intervals for small feeding holes on the bud leaves and the small black insect droppings that collect on the leaves. Budworm control can be accomplished by properly timed sprays. (See ENT-15 for recommendations)
Field infestations begin when winged adults land on plants and begin to produce colonies on leaves in the tender bud area. Arrival of these adults cannot be predicted, so weekly field checks are needed to catch the onset of the problem. Earlier detection and treatment are needed to keep aphid populations at acceptable levels.
The presence of small black insects on tobacco plants should not be used as the "trigger" to begin spraying. A multitude of small gnats, about the size and shape of aphids, can be found on tobacco leaves. Delay any treatment until you see small colonies of aphids. This removes the chances for cases of mistaken identity. Unneeded insecticide applications kill beneficial insects that can keep pests at The aphids can move upward to reinfest even when good initial control was achieved. acceptable levels.
Most cases of unsatisfactory aphid control on tobacco are the result of several factors:
Treat for tobacco aphids when 20% or more of the plants in the field have small colonies of aphids on the 3" to 6" long leaf out of the bud. Do not make a decision on the success of the application for at least 3 to 5 days after treatment. The goal is to protect new leaves coming out of the bud, not just to kill a lot of aphids. If these new leaves are "clean" they will have a good chance of expanding to their full size to produce a good yield.
Tobacco aphids can reduce yields by 300 to 500 pounds per acre. This yield reduction results from 6 to 8 weeks of sap removal as aphids increase in numbers during the mid-portion of the growing season. Late control applications generally produce unsatisfactory results and the yield losses have already occurred.
Effective aphid control must begin as small colonies or clusters of aphids are seen on the upper leaves of about 20% of the plants in the field. This level of infestation generally occurs about 4 to 5 weeks after transplant. Infestation levels can be determined by examining 5 groups of 10 plants at scattered, randomly selected locations in the field. Examination of the first 4" to 6" leaf from the bud on each plant will allow calculation of the percentage of infested plants. Weekly field checks can also detect hornworm and budworm activity.
Use of this treatment guideline will allow application of an insecticide when aphids are present but a low numbers. They are generally limited to the upright leaves in the tops of the plants so spray coverage is good. Also, the developing bud leaves are treated and the natural tendency of aphids to move up the plant puts them in contact with these treated surfaces. Additional insecticide applications can be made based on weekly followup evaluations.
Anthracnose has been confirmed on corn where the lower leaves are spotting in western Kentucky, and indications are that it may be found widely. Thus far, we have not yet seen cases of gray leaf spot on lower leaves, although symptoms of that disease may be appearing, as well.
Both diseases can cause spot symptoms on lower leaves. A fair amount of experience and the aid of a hand lense can help in distinguishing these diseases in the field, butpositive identification requires microscopic analysis. The following are guidelines that may help provide a preliminary diagnosis. Note that corn has three types of venation in the leaves:
Anthracnose produces oval, tan spots that sometimes are surrounded by a yellowish zone and are not bounded by the secondary veins; in fact, the lesions sometimes run up the secondary veins for very short distances (1/16" or so). The lesions often are most common towards the leaf tip. The fruiting structures (acervuli) are sometimes randomly scattered over the surface of the lesion, although they can occur in rows, as well. Dark brown spines are evident in the fruiting structures.
Gray leaf spot produces lesions that are often surrounded by a "watersoaked" (olive-green) margin when they are young, (1/8" to 1/4" in size). As these lesions mature, they tend to become bounded by the secondary veins. In many susceptible hybrids , the lesions take on a very rectangular appearance, looking like long match sticks. These lesions may or may not be surrounded by a yellow border, depending on the hybrid. The spore-bearing structures are small clusters of tiny dark brown stalks emerging from the dead tissues. These fruiting structures typically occur in straight rows running in the direction of the long axis of the leaf. These spore-bearing structures cannot really be readily distinguished from the spines of the acervuli of anthracnose with a hand lense.
Once again, positive identification of these diseases requires microscopic analysis. This can be important for corn producers considering whether to apply Tilt fungicide for gray leaf spot control on susceptible hybrids. They may wish to consider the possibility that what they are seeing is anthracnose. Tilt is labeled and somewhat effective against gray leaf spot; it is not labeled and ineffective against the anthracnose disease of concern (stalk rot, top dieback).
Distinguishing these diseases in the field is not a sure thing. Where fungicide spray considerations are at stake, a very quick turnaround is possible for samples submitted to the UK Plant Diagnostic Labs by Extension Agriculture Agents. Overall, use of Tilt fungicide on field corn is not considered to be an important tool for management of gray leaf spot (see the 20 May 96 issue of Kentucky Pest News for more on this subject). However, for producers considering this option, it is important to know if the leaf spotting they are observing in their fields is gray leaf spot.
Corn and peppers growers should be advised that the second generation of European corn borer will become active shortly. Peppers are particularly vulnerable to this generation and growers will need to manage for corn borers carefully over the next few weeks. Corn growers are encouraged to monitor fields carefully during the next two to three weeks for corn borer activity. While last year was a peak year for corn borer, this year we are finding more infested corn than we would expect following a peak year.
The table below summarizes the degree day totals for selected locations throughout Kentucky for 7/7/97. Some of the important degree day values to watch for include 1660 (initial moth flight), 2190 (peak flight), 1740 (start of egg laying), and 1860 (beginning of egg hatch). If a field exceeds the economic threshold for the second generation, treatments for corn borers should be applied before corn borers tunnel into the stalk. If treatment for corn borers is impractical, heavily infested fields should be identified and harvested as early as practical. See EntFact 106.) for a complete listing of the degree day values corresponding to the various corn borer life stages.
| LOCATION | DD Total | 1660 | 1740 | 1860 |
|---|---|---|---|---|
| Bardstown | 1489 | 7/13 | 7/17 | 7/21 |
| Berea | 1511 | 7/12 | 7/16 | 7/20 |
| Bowling Green | 1600 | 7/9 | 7/12 | 7/17 |
| Buckhorn Lake | 1423 | 7/16 | 7/19 | 7/24 |
| Campbellsville | 1562 | 7/10 | 7/14 | 7/18 |
| Covington | 1200 | 7/25 | 7/28 | 8/2 |
| Cumberland Gap | 1605 | 7/9 | 7/12 | 7/17 |
| Dix Dam | 1393 | 7/17 | 7/20 | 7/25 |
| Glasgow | 1858 | 6/28 | 7/1 | 7/7 |
| Grayson | 1318 | 7/20 | 7/23 | 7/28 |
| Hardinsburg | 1420 | 7/16 | 7/19 | 7/24 |
| Henderson | 1580 | 7/10 | 7/13 | 7/17 |
| Jackson | 1454 | 7/15 | 7/18 | 7/23 |
| Lexington | 1291 | 7/21 | 7/24 | 7/29 |
| London | 1465 | 7/14 | 7/18 | 7/22 |
| Louisville | 1564 | 7/10 | 7/14 | 7/18 |
| Mayfield | 1742 | 7/2 | 7/6 | 7/11 |
| Nolin Lake | 1541 | 7/11 | 7/15 | 7/19 |
| Paducah | 1633 | 7/8 | 7/11 | 7/15 |
| Princeton | 1825 | 6/30 | 7/2 | 7/8 |
| Quicksand | 1572 | 7/10 | 7/13 | 7/18 |
| Somerset | 1495 | 7/13 | 7/16 | 7/21 |
| Spindletop | 1292 | 7/21 | 7/24 | 7/29 |
Cucurbits (cucumber, cantaloupe, squash, gourds, watermelon, and pumpkins) can suddenly sustain serious loss from several foliar diseases that are currently active. Rain is not required for many of these diseases to develop, just a wet leaf surface (e.g., from dew) or very high humidity depending on the particular disease. Preventive fungicide programs need to be in place and maintained. Consult, ID-36, Commercial Vegetable Crops Recommendations, for details.
Anthracnose, downy mildew, gummy stem blight, and powdery mildew are active. I was very surprised recently to find powdery mildew active on July 2 in the Bluegrass area. This is the earliest I have experience the disease, except where infected, greenhouse-produced plants were set. So the powdery mildew spray program needs to be deployed earlier than normal.
If you are growing downy mildew susceptible varieties, watch closely for early development of this disease. This disease can destroy susceptible cucurbits within a few days. If blue mold is active in tobacco (which is downy mildew of tobacco) in your community, expect downy mildew to be active in susceptible cultivars of cucurbits. I recently observed very strong downy mildew in a planting of butternut squash while visiting a farm I was inspecting because of active blue mold.
With the onset of hot weather several weeks ago, a number of new creeping bentgrass putting greens have suffered sudden deterioration of roots. Without a good root system, these greens quickly suffered extensive turf loss.
At this time, we cannot say for certain which factors are directly responsible. We strongly suspect two factors, which perhaps interact. During hot weather, photosynthetic efficiency of cool-season grasses declines, yet cellular respiration increases. Bentgrass must "go to the bank" and withdraw food reserves from stolons and crowns. These closely mowed new greens probably suffer from a rapid energy deficit during the hot weather. Bent tillers on new greens are very upright and have few stolons, especially when seeded at a heavy rate of 1-2lbs/1000 sq. ft. And initial establishment is very rapid. Because they are young in age, individual tillers may not have enough leaf surface to maintain adequate photosynthesis, and they may have insufficient stolon and crown development to provide an energy bank for cellular respiration during hot weather. Although we observed that some of the largest tillers died, those tillers that were still alive were among the larger ones with robust pseudostems and sometimes attached to a significant stolon, which is consistent with this hypothesis.
Another factor that may be involved is the observation of some layering in these greens. Frequent topdressing and irrigation can create a surface layer about 3/8" to 1/2" that holds water readily, compared to the root zone mix below. Test it for yourself: Remove a core from a new green with a cup cutter, pour water through it, wait five minutes, gently tear open the core, then tear out some of this top layer with thumb and forefinger and squeeze. Plenty of water is there! Try this again with some of the root-zone mix, and it is already at field capacity. This tendency to "pond" water in the top half-inch may create an oxygen-poor environment during hot weather, by sealing the root zone from the air above. Microbial activity in the root zone and root respiration may deplete the roots of oxygen during weather in which their oxygen demand is quite high.
Many new greens are constructed with sand that does not completely stabilize for a year or two. When these new greens become very wet from frequent watering and when much of the root system is lost during hot weather, the lack of structural stability is very obvious as one walks on the green The physical injury that occurs to the root system from soil abrasion probably places additional stress.
It is very possible that these factors interact. A low energy reserve, reduced oxygen in the root zone, and high respiratory demand caused by hot weather may cause roots (a "sink" for photosynthate) to lose out to leaves, which didn't have enough to share.
What to Do?
While we don't fully understand this condition at this
time, we feel that the following recommendations will
provide the best chance of recovery for creeping bentgrass
greens in which roots have suffered loss of the cortex and
associated tissues. It may also be possible to prevent
this conditions.
Curative
Don't go crazy with fungicides, since infectious fungi
don't appear to be involved. These greens must be allowed
to grow new roots at a time of year when roots don't really
grow well. Aerify the greens (solid tines, 1/4" hollow
tines, a Hydroject with the platform raised, whatever will
punch holes with as little damage as possible). Raise the
mowing height and reduce the mowing frequency, to allow for
as much photosynthesis as possible. A 3/16" to 1/4" height
is recommended until the turf recovers and cooler weather
returns. Re-seed bentgrass. This is not a good time to
try to get it established, but the general management of
plants without roots will tend to favor the new seedlings.
Provide light/frequent irrigation, preferably hand-
watering. "Spoon-feed" the green with soluble fertilizer
(1/8 to 1/10 lb nitrogen every 10-14 days). Use preventive
Pythium control to protect the new seedlings during
sustained periods with nighttime temperatures above 70 F.
Preventive
When establishing new greens, make sure they are well-
aerified by Memorial Day, and do not lower the mowing
height quickly during the first summer. Depending on
surface smoothness, 3/16" to 1/4" may be advisable during
the first summer.
Ridding a home of fleas can be a frustrating and costly endeavor. Unlike most pests encountered around the home, fleas cause discomfort and irritation to both pets and people. Fleas account for more than half of all dermatological conditions requiring veterinary assistance, and even a single flea bite to a hypersensitive animal or human may cause intense itching and irritation.
For successful flea control, the home, pet and oftentimes, the yard must be treated. Yet the manner in which these treatments are performed will greatly influence the results. The following information will help frustrated pet owners effectively rid their homes and pets of fleas.
Essential Facts About Fleas
Treatment of Premises
If you neglect to treat the pet's environment (the
premises), you will miss more than 90% of the developing
flea population -- the eggs, larvae and pupae. If the pet
spends time indoors, the interior of the home should also
be treated.
Before treatment, the pet owner should:
Insecticide Application - Once fleas become established in a home, insecticides are almost always needed to control them. Always read and follow label directions on the insecticide container. Other than the person performing the application, people and pets should be out of the house during treatment. People and pets should also remain off treated surfaces until the spray has dried. This may take several hours, depending on carpet type, ventilation and method of application. Aerosol-type products normally dry faster than those dispensed as liquids. Opening windows and running the fan or air conditioner after treatment will enhance drying and minimize odor.
Many different products are available for home treatment. The most effective formulations contain both an adulticide (e.g., permethrin), effective against the biting adult stage -- and an insect growth regulator (methoprene or pyriproxyfen), necessary to provide long-term suppression of the eggs, larvae and pupae. Pet owners will need to carefully read the "active ingredients" panel on the product label to determine if these ingredients are present. Examples include Raid Flea Killer Plus(R), Siphotrol Plus(R), , Bio Flea Halt(TM), and Fleatrol(R). Most homeowners will find aerosol formulations easier to apply than liquids. Moreover, aerosol products which can be dispensed by hand -- and thus directed under and behind beds, furniture, etc. -- tend to be more effective than "foggers" or "bug bombs" which are indiscriminately set off in the center of a room. It is essential that the application be thorough and include all likely areas of flea development. Carpets, throw rugs, under and behind beds and furniture, and (beneath) cushions on which pets sleep should all be treated. Pay particular attention to areas where pets spend time or sleep, as these will be the areas where most flea eggs, larvae and pupae will be concentrated. For example, if the family cat sleeps within a closet, or hides under the bed, these areas must be treated or the problem will continue. Hardwood and tile floors generally do not require treatment, but should be thoroughly vacuumed.
Expect to see some fleas for 2 weeks or longer following treatment. Provided all infested areas were initially treated, these "survivors" are probably newly emerged adults which have not yet succumbed to the insecticide. Instead of retreating the premises immediately, continue to vacuum. As noted earlier, vacuuming stimulates the insecticide-resistant pupae to hatch, bringing the newly emerged adults into contact with the insecticide sooner. Flea traps, such as those utilizing a light and glue board to attract and capture adult fleas, can be helpful but will not eliminate a flea infestation unless used in combination with other methods. If adult fleas continue to be seen beyond 2-4 weeks, retreatment of the premises (and pet) may be necessary.
Treatment of Pet
It is important that the pet be treated in conjunction with
the premises, preferably on the same day. Adult fleas
spend virtually their entire life on the animal -- not in
the carpet. Untreated pets will continue to be bothered by
fleas. They may also transport fleas in from outdoors,
eventually overcoming the effectiveness of the insecticide
applied inside the home.
Pets can be treated either by a veterinarian or the pet owner. A variety of on-animal formulations are available. Many provide only short-term relief against biting adults (a few hours to a few weeks); however, two new veterinarian-supplied products, Advantage and Frontline, control adult fleas on pets for 1 and 3 months, respectively. Some products also contain an insect growth regulator (IGR) to prevent eggs from hatching as they are laid on the animal (e.g., Raid Flea Killer Plus, Ovitrol Plus(R), Bio Spot(TM)). Convenient, long-term prevention of egg hatch can be accomplished either with the Ovitrol(R) Flea Egg Collar, or Program(R), administered orally to pets as a tablet. See EntFact 628;) A Smarter Approach To Flea Control). Both of these products are available through veterinarians.
Pet owners should always read the product label. Certain products can be used only on dogs, and some list specific treatment procedures for puppies and kittens. Do not treat pets with the same products used to treat carpeting or the yard. As previously mentioned, it is important that pets be kept off treated carpets and surfaces until the spray has completely dried.
To recap, "de-fleaing" the pet is an essential step in ridding a home of fleas. However, pet owners must also treat the pet's environment, the home. Having your pet dipped will not, in itself, eliminate fleas in an infested home.
Treatment of Yard
Most flea problems in Kentucky can be eliminated by
treating the pet and the interior of the home. In cases
where pets spend most of their time outdoors, it may also
be necessary to treat the yard. One way to determine if
the yard is infested is to walk around the property
wearing white athletic socks, pulled to the knee. If large
numbers of fleas are present, they will be seen against the
white background of the socks.
Outdoor flea treatment should focus on areas where pets rest, sleep, and run, such as doghouse and kennel areas, under decks, along fences and next to the foundation. It is seldom necessary to treat the entire yard or open areas exposed to full sun. Insecticide formulations containing chlorpyrifos (Dursban) or permethrin are somewhat effective for outdoor flea treatment. These can be applied with a hose-end or pump-up sprayer. Long term suppression of fleas infesting kennels or outdoor areas can be enhanced with formulations containing an IGR such as methoprene or pyriproxyfen.
Fleas can be successfully controlled by diligently following the steps outlined above. Homeowners who lack the time to control fleas themselves, or who are uncomfortable applying pesticides may wish to enlist the services of a professional pest control firm.
| Princeton | |
| Black Cutworm | 1 |
| True Armyworm | 17 |
| European Corn Borer | 0 |
| Corn Earworm | 3 |
| Southwestern Corn Borer | 0 |
| Allen Co. | |
| European Corn Borer | 0 |