Advocacy: IPM Alerts

Special IPM Alert

Tuesday, February 28, 2017  

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Ambrosia Beetle Activity Update

By: Stanton Gill

It is one very strange winter with the mildest temperatures since 2004. We are putting out a special IPM Alert this week on early insect, weed, and animal activity, due to the warmer than normal temperatures.

Last week, I received over 20 emails and phone calls asking with the spring-like weather if ambrosia beetle adults, specifically Xylosandrus species, were active yet in Maryland. The temperatures were in the low 70 °F range for a couple of days. We rushed alcohol dispenser to a monitoring site in Darnestown (Marie Rojas) and put up a trap at CMREC. I also put an alcoholbaited sytrax bolt in Westminster. From February 21-25, I saw absolutely no activity in the traps.

On Sunday afternoon, my wife and I went with friends to visit National Harbor in Oxon Hill, Prince George’s County. While my friends were busy trying to find a suitable restaurant, I was over scouting around trees in the relatively new landscapes surrounding the high rise buildings. What caught my attention was a couple of Zelkova serrata covered in sooty mold and a large population of lecanium scale. This made the trip worthwhile. While I was looking at the scale, I noticed three of the trees had small, almost micropiles of sawdust that is commonly seen when the female Xylosandrus starts to bore into the tree. I did not find any actual beetles since my patient friends were getting a little anxious. The small tell-tale sawdust pile found with early activity was there.

Now, this location wasa very warm site, and I saw Prunus subhirtella ‘Autumnalis’ cherries in full bloom there, deciduous magnolias with color showing in the blooms and Kwanzan cherries with very swollen flower buds close to opening. This landscape was ahead (temperature wise) of most of central Maryland. I checked the traps at CMREC in Ellicott City on Monday morning, but there was absolutely no activity in the traps. If you are on the Eastern Shore or in Deleware you should put out an ethyl alcohol trap this week and if you find activity send me the beetles for identification at CMREC, 11975 Homewood Road, Ellicott City, Maryland.

Meanwhile, keep your powder dry but don’t start spraying yet. I don’t see activity in most parts of the state so far, but it is likely not far off if the temperature stay in the 70 °F plus range.


Weeds and Unusually Mild Temperatures

By: Chuck Schuster, UME

With the extremely mild temperatures of the last several weeks, soil temperatures have reached the mid 50 °F range. It is very important to monitor soil temperatures as several days at 55 can be the start of the season. The temperature monitored needs to be the low for the day, which is usually the first part of the morning. Pre-emergent products need to be placed and watered in (at least a quarter inch of rain is necessary to activate) prior to the first seeds germinating. Japanese stiltgrass will germinate slightly below those soil temperatures needed for crabgrass. The soils did drop almost 10 °F from Saturday to Monday, but some locations where many buildings still are radiating energy will have warmer temperatures. Remember that pre-emergent products bond to nitrogen-based fertilizer and cannot be applied until Wednesday at the earliest. This will be an excellent year to split your treatment into two separate applications to spread out the efficacy. Crabgrass can germinate anywhere from the mid 50s to the low 70 °F range. Products containing dithiopyr (Dimension) prodiamine (Barricade) and pendimethalin (Pre-M) are shoot and root development inhibitors. Dithiopyr (Dimension) is also an early post emergent product that inhibits certain steps in plant cell division. All of these products can be used on established turf, but not sites that will be seeded with new seed. Siduron (Tupersan) is the only product that can be used in a turf setting when overseeding after application is considered. Monitor the soil temperature at your sites to help stay ahead of weed germination. If temperatures cool down and stay low as they did the last two years, having your second application in early to mid-April is very useful.

In landscape settings, it is very important to place your pre-emergent herbicides properly as you are working. Remember not to use the same class of product year after year as resistance has been noted.


Sap Sucker Damage

By: Stanton Gill

Jessica Ahrweller showed me a picture at the MNLGA Chessie Green Conference on Thursday (Feb 23). It was a dogwood with a series of wounds on the trunk. The sapsucker is a migratory bird and usually head south in winter and does not show up until spring in Maryland. I spoke with Donna Davis, DNR, and she commented she saw the sapsuckers feeding at bird feeders in Carroll County all winter. It may be that either the sapsucker did not migrate south this winter because of the mild weather or the ones that did have returned early with the mild February. Karen Rane noted that sapsuckers were damging maples in a landscape in Silver Spring. there is nothing much you can do about it, and it is just one of the side effects of a mild winter.

Here are a few facts about sapsucker:

From: USDA Forest Service
The yellow-bellied sapsucker (Sphyrapicus varius), a member of the woodpecker family, is a migratory bird whose summer breeding range includes Maryland. The identifying field markings of adult birds are a black crescent on the breast, pale yellow belly, white wing stripe, and a crimson crown. The male also has a crimson chin and throat, distinguishing him from the female whose chin and throat are white.

Although insects make up part of its diet, the sapsucker is better known for its boring of numerous holes in the bark of live trees to obtain sap, the activity from which it derives its name. The yellowbellied sapsucker is the only member of the woodpecker family to cause this type of injury. More than 250 species of woody plants are known to be attacked. Birch, maple, dogwood and hemlock are the preferred species.

Download the Special IPM Alert PDF for more information.


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