Kentucky Pest News April 2, 2013

7/28/2019 Kentucky Pest News April 2, 2013

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Online at:www.uky.edu/KPN

Number 1333 April 2, 2013

FORAGE CROPS-Late Alfalfa Weevil Season for 2013

TOBACCO- Fungicide Spray Schedule for Tobacco

Transplant Production

SHADE TREES AND ORNAMENTALS-EAB Development and Timing of Preventive

Drench Treatments

WEEDS-Be Aware of Poison Hemlock

HOUSEHOLD PESTS-Varied Carpet Beetles

DIAGNOSTIC LAB HIGHLIGHTS

INSECT TRAP COUNTS

FORAGE CROPS

Late alfalfa weevil season for 2013By Lee Townsend, Entomologist

Degreeday (dd) accumulations provide the bestway to determine when to check fields for tipfeeding by alfalfa weevil larvae. The first chanceto see damage occurs when 190 dd (base 48 F)have accumulated starting on Jan 1.

The table below shows the differences indegreeday accumulations at 4 Kentucky weatherstations through 31 March for 2011 through 2013.Alfalfa weevil egg hatch had begun at all locationsby this time in 2011 and larval feeding was wellalong by now in 2012. We have yet to reach the190 dd total this season at any of the locations.

Alfalfa weevil degreeday totals (1/1 3/31)

Location 2011 2012 2013Lexington 197 437 146Princeton 271 550 157Somerset 264 508 159Williamstown 182 415 101

So far, low temperatures have delayed the start ofthe alfalfa weevil season. However, the pace canpick up rapidly if there is a sudden warming trend

that stimulates egg hatch and rapid development ofthe insects.

While we are coming off a cold winter, weevileggs are hardy so there is no reason to think therewill be a substantial winter kill to reducepopulations. The cold spring should cause egghatch to be pretty synchronized rather than beingspread out over a longer time frame. If weevils areat damaging levels in fields, feeding should

become apparent pretty quickly. The longer fieldshave been in production, the greater the chance forsignificant weevils populations.

TOBACCO

Fungicide Spray Schedule for TobaccoTransplant Production

By Clint Hardy, Daviess County ANR Agent andKenny Seebold, Extension Plant Pathologist

Production of tobacco seedlings is well under wayin Kentucky and up to this point in the seasondiseases havent been much of an issue. However,the time to make decisions about using chemicalsto protect against diseases is drawing close. Forthe most part, the fungicides that are labeled for

Lexington, KY 40546
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use in the float system are protectants. This meansthat preventive use of these products, beforesymptoms of disease are seen, is the best way toensure good control of diseases on tobaccoseedlings. The following is an example of acalendar-based spray program that targets key

diseases encountered in tobacco float beds. Actualgrowth stages of plants and timing of clipping willvary depending on temperatures during the season.

2-4 Weeks after SeedingWhen roots of plants emerge from trays and enterfloat water, apply Terramaster EC at 0.7 to 1 floz/100 gal of float water for control of Pythiumroot rot. Make a follow-up application of

Terramaster at 1 fl oz/100 gal of float water noearlier than 3 weeks later (see below).

3-4 Weeks after SeedingWhen plants have reached the size of a dime,apply a mancozeb fungicide (Dithane DF,Manzate ProStick, or Penncozeb 75DF) forsuppression of Rhizoctonia damping-off. The rateis 0.5 lb/100 gal of water, which is the equivalentof 1 tsp/gal. Use 3 gal of spray solution per 1000sq. ft of bed (~400 trays) and apply as a fine mistto ensure good foliar coverage.

5 Weeks after SeedingContinue foliar sprays with mancozeb-based

fungicides, increasing spray volume to 4-5 gal per1,000 sq. ft as plant size increases.

6 Weeks after Seeding

The first time plants are clipped:- If target spot is not present, continue with

mancozeb based fungicide products andincrease spray volume to 6 (or more ifneeded) gal/1,000 sq. ft. Dont exceed 12gallons of spray volume per 1,000 sq. feet(even on the largest plants).

- If target spot is active, treat with Quadrisat 0.14 fl oz/1000 sq. ft of bed. This is theequivalent of 4 cc (~1 tsp), and should bediluted in 4-5 gallons of water beforedispersing as a fine spray. Oneapplication of Quadris is permitted ontobacco seedlings in float beds

6-7 Weeks after Seeding

- Make follow-up application ofTerramaster EC at 1 fl oz/100 gal of floatwater.

- After the second clipping, and if Quadrishas not been used earlier, apply Quadrisfungicide (see 6 Weeks after Seeding forrate).

7 Weeks after Seeding.Continue with mancozeb based fungicideproducts, slightly increasing spray volume per1,000 sq. ft as plant size increases, not to exceed12 gallons of spray volume per 1,000 sq. feet

(even on the largest plants).

8 Weeks after Seeding (and beyond)Continue with mancozeb based fungicideproducts, slightly increasing spray volume per1,000 sq. feet as plant size increases, not to exceed12 gallons of spray volume per 1,000 sq. feet(even on the largest plants). A final application of

Terramaster EC can be made at 0.7 to 1 fl oz/100gal of float water if needed; do not apply morethan 5 days before transplanting.

Additional Information

- The amount of float water in a bed (ingallons) is calculated by the followingformula: (the number of trays in the bed)X (the water depth in inches) X 1.64

- 5 cc =approximately one teaspoon (tsp)- 1,000 sq. ft =400 trays- Banrot, Rovral, Iprodione 50W or Ridomil

Gold are not approved fungicides for usein tobacco greenhouses


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SHADE TREES AND ORNAMENTALS

EAB Development and Timing of PreventiveDrench TreatmentsBy Lee Townsend, Entomologist

Peak emerald ash borer emergence occurs when450 to 500 degree days (base 50 F) haveaccumulated starting on January 1. Thisinformation is readily available at this UK AgWeather site:http://wwwagwx.ca.uky.edu/cgi-bin/generic_dd_www.pl.

Select the station nearest you from the drop downmenu, select 50 from the Base menu, and have theinformation returned to the screen. Accumulateddegree days will appear in a table using

temperature data up to the current date. An Fwill indicate that degree day totals beyond thecurrent day will be calculated using historicaldaily high and low temperatures. A run of themodel on 2 April indicates peak EAB flight shouldoccur around Lexington on May 17; however,degree days should accumulate rapidlyconsidering the predicted high temperatures forthis week. The 450 dd sum for Lexington wasreached on 20 April 2012. Peak flight date fornorthern Kentucky should be about 26 April.

An imidacloprid drench is the preventive treatmentavailable for homeowners. Applications to protectash trees should be made 4 to 6 weeks before EABbecomes active so we in the time frame to do that.Follow the instructions on the label.

Detailed information on control alternatives forEAB are available in Insecticide Options forprotecting ash trees from emerald ash borer available on line at:http://emeraldashborer.info/files/Multistate_EAB_Insecticide_Fact_Sheet.pdf

WEEDS

Be Aware of Poison HemlockBy J. D. Green, Extension Weed Scientist

During the past few weeks the evidence of poisonhemlock (Coniummaculatum) is widespread.Although this plant is often seen along roadways,abandoned lots, fencerows, and other non-cropland sites, in more recent years, it hasexpanded out into grazed pasture lands and hayfields. The concern not only stems from itsinvasive nature, but the fact that it is one of themost toxic plants in the world. Throughouthistory, the toxicity of poison hemlock is wellknown for accidental deaths of humans and otheranimals.

Description Poison hemlock is classified as abiennial that reproduces only by seed. It iscapable, however, of completing its lifecycle as awinter annual in Kentucky if it germinates duringthe fall months. Flowers and new seed aretypically produced in late May and June. Plantsemerge as a cluster of leaves that form a rosette.Poison hemlock is most noticeable at this stage ofgrowth in late fall through early spring with itsparsley-like leaves which are highly dissected orfern-like (Figure 1). The individual leaves areshiny green and triangular in appearance.

Figure 1. Poison hemlock rosette.

As the plant begins to send up flower stalks, theleaves are alternately arranged on the main stem.Each individual leaf is pinnately compound withseveral pairs of leaflets that appear along opposite
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sides of the main petiole. As the plant matures,poison hemlock can grow upwards to about 6 to 8feet tall (Figure 2). At maturity the plant is erect,often with multi-branched stems, and forming adeep taproot. Poison hemlock has hollow stemswhich are smooth with purple spots randomly seen

along the lower stem that help distinguish it fromother plants similar in appearance. The flowers,when mature, are white and form a series ofcompound umbels (an umbrella-shaped cluster ofsmall flowers) at the end of each terminal stalk.Although poison hemlock is often associated withareas that have moist soil conditions, it can alsosurvive in dry sites.

Figure 2. Mature poison hemlock plants growing in hayfield.

Toxicity-All classes of livestock are known to beaffected by poison hemlock. Cattle, horses, andgoats are considered to be the most susceptibledomestic animals although other animals can beaffected as well. Symptoms of poisoning canoccur rapidly anywhere within 30 minutes to 2hours depending on the animal, quantity

consumed, and other factors. Initial symptoms caninclude nervousness, trembling, muscularweakness and loss of coordination, dilation ofpupils, coma, and eventually death fromrespiratory paralysis. Lethal doses for cattle areconsidered to be in the range of 0.2 to 0.5% of theanimals body weight. Poison hemlock is alsoknown to cause fetal deformation when pregnantanimals consume the plant.

Fortunately most animals tend to avoid grazingpoison hemlock if other forage is readily available.However, animals may be more prone to consumegreen plants during the late winter and early springwhen other forage species are more limited. All

parts of the plant, including the seeds, areconsidered to contain the toxic principles (coniineand coniceine). Toxicity may be somewhatreduced in dried plants, but the potential fortoxicity still exists, particularly when a sufficientquantity is consumed in dried hay. Therefore,extreme caution should be considered beforefeeding animals hay known to contain poisonhemlock.

Control-The principle strategy for poisonhemlock control is to prevent seed production

which can be a challenge since a fully matureplant is capable of producing 35,000 40,000 newseeds. It is too late to utilize herbicide controlmethods after plants have produced flowers.

Therefore, mechanical control efforts (if feasible)such as mowing or cutting down individual plantsshould be initiated just before peak flowerproduction to avoid or reduce the amount of newseed being produced.

Make note of areas heavily infested with poisonhemlock this spring and begin to look for

emergence of new plants in the fall. During thelate fall (November) or early spring (March) is thebest time of year for herbicide treatment. In grasspastures and hayfields herbicide productscontaining 2,4-D can be effective when applied toyoung, actively growing plants that are in therosette stage of growth. Spot treatments withproducts containing 2,4-D, triclopyr, or glyphosatecan also be used depending on the location.

HOUSEHOLD PESTS

Varied Carpet BeetlesBy Lee Townsend, Entomologist

The varied carpet beetle is one of the firsthousehold insects to show up in the spring. Thistiny, 1/10-inch long beetle has irregular patches of


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white, brown, and yellow on its back.

Figure 3.

Adults are attracted to sunlight so they accumulate

at windows or in ceiling light fixtures. It is timefor these scavenger beetles to visit flowers to feedon nectar and pollen.

Figure 4.

The hairy, worm-like larva stages prefer dark,protected places so they are more likely to befound in drawers or along baseboards. Deadinsects seem to be the preferred food of this carpetbeetle species. This means the source can beaccumulations of dead insects in wall voids, attics,

or behind external siding. Once present in a home,they also can feed on woolens, carpets, furs, hides,feathers, horns, bones, hair, silk, fish meal, rye orcorn meal, red pepper, and cereals.

Carpet beetle control is challenging because theycan develop on small amounts of food in obscureplaces. The best weapon to use against them is thevacuum cleaner. Rooms where many beetles are

found should be cleaned thoroughly to removehair, lint, dead insects and other carpet beetle food.

This is especially important in households thathave pets indoors. Close attention should be givento carpets (especially under furniture), rugs,draperies, upholstered furniture, closets (especially

where woolens and furs are stored), heat vents andregisters and associated duct work, corners,cracks, baseboards and moldings, light fixtures,and other hard-to-reach areas. Open containers ofdried foodstuff and pet food should be regularlyinspected for signs of carpet beetles and discardedif contaminated.

Cleaning is always the best strategy long-term;however, areas that cannot be cleaned can besprayed with an insecticide labeled for indoor use.Use a product that lists carpet beetles on its label

and closely follow the directions. Applyinsecticides as spot, and crack and crevicetreatments. Limit sprays to edges of floorcoverings, under rugs and furniture, floors andwalls of closets, shelving where susceptible fabricsare stored, cracks and crevices, and in other lint-accumulating areas.

DIAGNOSTIC LAB HIGHLIGHTS

By Julie Beale and Brenda Kennedy

The following samples have been diagnosed in thePDDL in recent weeks: wheat spindle streakmosaic virus and cold injury on wheat;Phytophthora root rot on blueberry; black root roton petunia; fertilizer burn on zinnia and pepper;scurf and Fusarium dry rot on stored sweet potato;high soluble salts, Pythium root rot and tomatospotted wilt virus on tomato seedlings.


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2013 INSECT TRAP COUNTS

March 22-29

Graphs of insect trap counts for the 2013 seasonwill available soon on the IPM web site at -http://www.uky.edu/Ag/IPM/ipm.htm.

Note: Trade names are used to simplify the informationpresented in this newsletter. No endorsement by theCooperative Extension Service is intended, nor iscriticismimplied of similar products that are notnamed.

Location Princeton,KY

Lexington,KY

Black cutworm 0 0Armyworm 0 1European CornBorer

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Kentucky Pest News April 2, 2013

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