Weed Update

Weeds don't take holidays.

While we are thinking about a holiday trip to the mountains or the coast -- weeds are going to keep doing what they do best -- reproducing. Summer annual weeds are going to seed with wild abandon. Although you cannot stop seed production you can sure reduce the amount of seeds produced by controlling summer annuals now. While herbicides like glyphosate work on mature weeds, the time it takes to die from glyphosate treatments will allow a lot of seeds to mature before plants succumb to the inevitable.

Fall applications work better you say?
I had a salesman once try to explain to me how bentazon (Basagran TO) worked really well on Yellow Nutsedge in early Fall. My response was -- "well, so does frost". Seriously, nutsedge has been making tubers for months but it is still a good idea to kill what you still have to prevent even more tubers from forming. Nutsedge can be controlled by glyphosate or glufosinate or bentazon But please, next year resolve to get serious about nutsedge earlier in the season.

Fall applications of glyphosate do work better on many perennial weeds. In particular, deciduous woody weeds are generally well controlled with late summer or early fall applications of glyphosate. But, you often don't see the results until next spring when plants begin to grow -- ahh, then the fun begins. New growth, if it occurs, will be stunted, malformed, and yellowed. Plants usually die back but often will start new growth after a time. When this occurs, treat again with an appropriate herbicide such as glyphosate or triclopyr for the one--two punch that knocks your weeds flat.

But don't forget to plan ahead --
Winter weeds have already started to emerge in some areas, so get your preemergence herbicide applications out soon to prevent winter annuals like henbit, chickweed and annual bluegrass from turning your Thanksgiving celebration into another gardening labor day.


Joseph C. Neal
Professor and Extension Specialist -- Weed Science
Department of Horticultural Science

Fall Webworms

Fall webworm tents are prominent features of many landscapes this time of year. They set up shop in pecan, walnut, American elm, hickory, fruit, some maples, persimmon and sweetgum trees. They are well protected from contact insecticides within their water proof tent. In addition, fall webworms expand their tent as they feed rather than foray out to feed and return the way eastern tent caterpillars do. Look for large silken tents at the ends of branches. All the caterpillars are in the tent, so if tents are pruned from a tree the problem is solved. For larger infestations, use a systemic insecticide that will move into the plant tissue. This will ensure that caterpillars die when they consume leaves. Some systemic products are acephate, TriStar, and Acelepryn, which can be applied as foliar or drench applications. For recommendations, see http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note07/note07.html.

Euonymus Scale

From: Steve Frank, Extension Entomologist

Euonymus scale crawlers have emerged on containerized research plants on the North Carolina State University campus. It seems that landscape plants, particularly shaded ones, are still a week or so behind. Therefore if you haven’t dealt with this scale yet this year you have a third and final chance to deal it and prevent problems in the spring. Crawlers are very susceptible to insecticides so scout to determine when they are active in your region. There are several newer products available that may be more effective and softer on beneficials than pyrethroid and organophosphate insecticides. More information can be found at http://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note15/note15.html.