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Jim Murphy

Dormancy vs Death

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The question of the day is… How do I know whether the grass that is losing its green color is going dormant or going to die? It isn’t always easy to tell but here are some clues that can help.

First, asses the uniformity of the grass. Is all of the grass turning brown or straw colored? Or… is the grass turning brown in spots or small patches? If the browning is occurring in spots or small patches, there is a good chance the grass plants in those spots are dying, especially if this occurs in a matter of hours to a couple days. [Read more…] about Dormancy vs Death

Crabgrass Emerging

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I have been observing the emergence of crabgrass since late April (see image above). Some crabgrass has now entered the tillering stage of growth.

As a general rule, most people begin to notice crabgrass in turf around the 4th of July (Independence Day). At that time, the crabgrass plants are large enough that the leaves stick-up above the desired grasses and the lighter (yellow) green color is highly noticeable from a distance. However, the crabgrass plants will be relatively large (tillered) by that date.

For those that want to control crabgrass postemergence, the next few weeks is the time for action because, regardless of the control tactic, crabgrass becomes more difficult to remove as it matures (get larger).

For those interested in non-chemical options, hand-picking the crabgrass is easiest when the plant are relatively small seedlings. As the plants grow, the enlarged root system makes it more difficult to pull these plants without snapping off the leaves and leaving the crown attached to roots. If this happens, the plants will re-grows its leaves. Hand-picking crabgrass plants is only practical for small turf/lawn areas.

There is limited detailed information the application and efficacy of “organic” herbicides to control crabgrass postemergence. So specific recommendations, other than make treatments to small plants, are not available.

For those interested in conventional postemergence herbicides, these are most effective when applied to seedling crabgrass plants. Two, sometimes more, treatments are often needed, especially when crabgrass plants are relatively large. Apply at 7-to 10-day intervals. Do not apply to drought stressed plants. Discoloration may occur on the desired turfgrass after the treatment is applied. Discoloration is generally more noticeable if the grass is under stress from heat or drought. Spraying the herbicides will be more effective than applying as a granular product. Do not irrigate for 24 hours after the appliation and do not apply if rain is forecast within 24 hours after the application.

Herbicides with postemergence activity on crabgrass that is less than the 4-tiller growth stage include: quinclorac (Drive, SquareOne ), mesotrione (Tenacity), and fenoxaprop (Acclaim Extra). Dithiopyr (Dimension) is primarily used as a preemergence herbicide but it does have postemergence activity on crabgrass plants in the 1- to 4-leaf growth stage.

The use rates and tolerance of desired turfgrasses varies among these herbicides, so consult the label for specific use information. You can also read more at: Crabgras and Goosegrass Control in Cool Season Turfgrass.

 

Red Thread Sightings

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Red Thread in North Brunswick June 1

I have observed a fair amount of red thread disease this spring. This disease has been most active on perennial ryegrass (see attached image). It has also been seen this spring on tall fescue and fine fescues but to a lesser extent than perennial ryegrass.

Red thread disease tends to be more aggressive in full sun than shade and it often appears where soil fertility and organic matter are low. The recent warm weather will probably make this disease less active but it could resume if cooler wet weather returns. See Fact Sheet FS798 for more details.

Looking forward, turf disease activity is shifting towards brown patch disease as the weather warms. So you could see an influx of inquiries about brown patch if you haven’t already; there was a large increase in this disease at the research farm this weekend. N fertilizer can stimulate brown patch disease, so applicators needs to use moderate to low rates and/or slow N fertilizer.