Pest News for Week of May 28

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

New App for Landscape and Nursery Pests

The Southern Nursery IPM Working Group (SNIPM), of which several faculty at North Carolina State University are members, has just released and exciting new App available for iPhones and Android phones. The App predicts the emergence of arthropod, disease, and weed pests based on degree day estimates, provides diagnosis help, and even pesticide recommendations. This is a very comprehensive tool that should prove valuable to industry and extension personnel. A complete description can be found on the website  http://www.ipmproapp.com/.

  

Crape Myrtle Aphids

Crape myrtle aphids are one of the most common pests of crape myrtle but rarely require treatment. Small populations are present in Raleigh and have been building over the past couple weeks. Feeding by these aphids results in leaf yellowing and distortion, leaf drop, and honeydew deposits which of course lead to sooty mold. Crape myrtle aphids are generally kept in check by natural enemies. When scouting for them I often find almost as many lacewing eggs, lady bug larvae, and other predators as aphids. Interestingly, there are no known parasitoids of this exotic aphid. A variety of chemicals are available should these aphids reach unacceptable levels in nurseries or landscapes. Some of the same chemicals recommended for aphids such as imidacloprid can be applied as a drench to protect against Japanese beetles later in the year. For more information on this pest including control options, visit http://ecoipm.com/ and Ornamentals and Turf Insect Note ENT/ort-31 at http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note31/note31.html.

Indian Wax Scale Eggs Hatching

Indian wax scale, Ceroplastes ceriferus, is a common scale on landscape plants. In particular we find it on hollies, cherry laurel, spirea, boxwood, and barberry. Indian wax scale is a soft scale that, as the name suggests, looks like white, gray, or pinkish wax on the branches of infested plants. Indian wax scale secretes a lot of honey dew as do most soft scales. This can create sooty mold and reduce the aesthetic appeal of landscape plants. Heavy infestations will reduce plant vitality. Indian wax scale has one generation per year. They overwinter as mostly as adults but we have found younger stages in the fall and spring that apparently overwintered. In spring crawlers emerge and crawl around to find a new feeding site. Crawlers are the best stage to target for control of any scale and for wax scale the time is now. Crawlers are emerging from eggs under the heavy wax covers on campus right now. At this stage crawlers can be killed very easily as they are small and unprotected. Thus horticultural oil is a very viable option. Systemic products such as neonicotinoids make the plant toxic so crawlers and later stages will be killed as they feed. More information can be found at http://ecoipm.com/ or  http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note156/note156.html.

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.

Pest News for Week of May 21st

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Thrips are Early and Abundant in Greenhouses

Western flower thrips have several life history traits that make them notoriously difficult to manage. In particular of the four primary life stages (egg, larvae, pupae, adult) only larvae and adults are susceptible to insecticide applications. Eggs are inserted into leaves and pupae are in the soil. Thus, right after you make an application eggs start hatching and adults start emerging from pupae and you feel as though you are right back where you started. This is why we recommend that growers make 3 applications 5 to 7 days apart to help break the lifecycle of the population present in their greenhouses. This initial round of applications could be done with a single chemical but rotate to a new chemical with new mode of action for subsequent applications. Since many plants are starting to bloom we have several chemicals that are generally not phytotoxic to foliage or flowers though mixing chemicals (insecticides, fungicides, etc.) or addition of adjuvants can have unexpected phototoxic results. Consider a rotation that includes Conserve (spinosad; label indicates potential spotting on African violets), Avid (abamectin; label indicates potential phytotoxicity on Adiantum ferns and Shasta daisy), Flagship (thiamethoxam), and/or bifenthrin. Complete list of chemicals can be found at:

http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/ort072e/ort072e.htmor

http://dpm.ifas.ufl.edu/plant_pest_risk_assessment/ALS6921%20Presentations/ThripsManagementProgram_09_12_09.pdf.

Lilac/Ash Borer Adult Flight

The lilac/ash borer, Podosesia syringae, has been captured in phermone traps this week in the Piedmont and foothills. This particular clearwing borer is not a major pest. Others such as the banded ash clearwing typically cause more damage. However, this critter will cause lilac canes to wilt suddenly as larvae bore within. So, it is good to be aware of this even though we do not recommend preventative insecticide treatments. The lilac/ash borer overwinters as larvae in twigs then adults emerge over several weeks to mate and lay eggs. Later in the summer dogwood borers, lilac borers and other will be emerging.

Second Generation Euonymus Scale Crawlers

Euonymus scale has three generations per year in North Carolina the first of which we reported on in the spring.  It is best to treat euonymus (or any) scale in the crawler stage. So if you forgot in the spring or didn’t get sufficient control, now is your second chance. Crawlers are active at research sites on campus and in Raleigh neighborhoods. In the first generation crawlers come out all at once but become less synchronized in second and third generations. Thus you may find all developmental stages present at this time. There are many predators that feed on scale insects such as the lacewing larva in this video (http://youtu.be/cnzlMrxv0tA). However, euonymus scale still tends to reach damaging levels once established. There are a number of products that can be used to treat armored scale. We have found neonicotinoids Safari, Flagship, and TriStar to be very effective also plant growth regulators Distance and Talus. Note that imidacloprid is not labeled for or effective against armored scale. Please check our blog http://ecoipm.com/ and the updated insect note for recommendations and up-to-date informationhttp://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note15/note15.html.

From: Mike Munster, Plant Disease and Insect Clinic, and Kelly Ivors, Extension Plant Pathologist

Controlling Botrytis in the Greenhouse

Due to weather conditions, Botrytis epidemics are currently occurring in greenhouses across the state. A wide range of floriculture crops can be affected. Symptoms of Botrytis infection range from flecking of blossoms, blossom blight, and even leaf and stem rot. On rose canes it can cause a tan-colored canker. The characteristic gray mold may be visible under high humidity conditions. The two keys to Botrytis management are keeping the relative humidity below 85% and maintaining the greenhouse free of dead or injured plant material (spent flowers, fallen leaves, pruned branches, culls, etc.) on which the fungus can produce new spores. Irrigate at times of day when foliage will dry quickly, and if possible ventilate greenhouses in the evening to bring down the humidity. Avoid wounding plants, which allows Botrytis to invade healthy tissue. Keep fertilization at optimal levels to avoid premature leaf senescence. Plants with bloom infection or crown rot should be discarded along with the potting mix. NEVER REUSE POTTING MIX WITH THIS PATHOGEN. Clean up all plant debris from the block and discard it. Do not compost any of this material, as the sclerotia of the fungus are capable of surviving adverse conditions. Spores of this fungus can be windborne, so be sure there are no cull piles nearby on which the fungus could produce them.

If re-using pots, first clean thoroughly and then sanitize with either steam (150 to 160 F for at least an hour at the center of the pile) or one of many chemical disinfectants available.

Fungicides may help prevent new infections, but won't cure plants that already have symptoms like those submitted. Effective products for Botrytis control include Chipco 26019/26 GT (Iprodione), Decree, Medallion and Pageant. Chlorothalonil (e.g., Daconil) can also be used; however chlorothalonil can cause phytotoxicity on blooms so this product should not be used on flowering plants. Decree is probably the most effective product for Botrytis control; however, it is only labeled for controlling Botrytis and should be used in a rotational program. In addition, there is a new Syngenta product named Palladium that just got registered for use in greenhouses and it is very effective against Botrytis. Be sure to rotate fungicides of different modes of action (FRAC groups) so as not to pressure the fungus into becoming insensitive (resistant) to any particular chemical. Note that one of the active ingredients in Palladium (fludioxonil) is the same as that found in Medallion. Get good coverage of the stems/crowns. Test any new treatments on a small number of plants first, to ensure that there are no adverse effects.

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Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina State University, North Carolina A&T State University or North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact an agent of North Carolina Cooperative Extension.

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.

Pest News for week of May 14th

ORNAMENTALS AND TURF

From: Steve Frank, Extension Entomologist

Cottony Maple Scale Egg Hatch

Cottony maple scale eggs are hatching. For some reason cottony maple scale is the least common cottony scale I find on campus. I seem to find cottony maple leaf scale and cottony camellia scale far more frequently. It also seems to be a little later as I reported on the other cottony scales and sent Twitter alerts (@OrnaPests) a couple weeks ago. However, I did find some cottony maple scale the other day and was able to get a picture. The main diagnostic difference between cottony maple and cottony maple leaf scale is where the ovisacs are produced. Cottony maple scale produces ovisacs on branches, whereas cottony maple leaf scale ovisacs are on leaves. Insecticide recommendations are similar as other soft scale listed at:http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note156/note156.html.

Be on the Lookout for Emerald Ash Borer 

Emerald ash borer has not yet been found in North Carolina. However, it is found in Tennessee and Virginia so it is just a matter of time before it arrives here (or is detected). The reason I bring it up now is that it is peak adult activity (based on degree day estimates) so they may be more noticeable now than other times of year. Adults will be emerging from D-shaped holes in ash trees. If you notice ash trees that seem to be in decline look for these exit holes and frass around the base of the tree. Early detection of emerald ash borer in North Carolina will be critical in trying to reduce the economic impact and protect trees. The most comprehensive and up-to-date information on emerald ash borer can be found at http://www.emeraldashborer.info/.

Japanese Maple Scale Crawlers

We are approaching peak activity of Japanese maple scale crawlers. Japanese maple scale is an armored scale that has many hosts including maple and many other woody ornamentals. Scales are extremely tiny and are often concealed in bark crevices and branch crotches. However, at high densities entire trunks may be covered. Information provided by University of Maryland indicates there are two generations per year (http://ipmnet.umd.edu/nursery/docs/JapaneseMapleScale-UMD2011.pdf). Japanese maple scale has not been studied in depth in North Carolina but we assume there are two generations here also. Japanese maple scale has been an increasingly important pest in the past decade or so and made its way throughout eastern North America. The most effective pesticides tested have been insect growth regulators such as Distance and Talus. The neonicotinoid including Safari has also been effective. More information is availablehttps://utextension.tennessee.edu/publications/Documents/W277.pdf or complete biology and management information was presented in a recent webinar (http://ecoipm.com/ ipm-webinar/ipm-webinar-archive/).

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.

Installing a Rain Garden

Interested in learning about rain garden installation?  Here is a video taken last summer at the 4-H camp in Swannanoa:

The video is a small sample of what you learn in the Residential Rain Garden  Installation classes we offer from time to time.  Diane Silver, our Natural Resources Agent, is narrating this video for us on site.  Thank to the Public Information folk from Buncombe County for filming, editing, and posting the YouTube for our use!

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.