Rutgers Cooperative Extension
Seasonal updates on ornamental, nursery, and turf pests.
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… summertime gonna come and go by and by. As the weather changes from the dog days of summer to a more “fall-like” pattern, I am feeling pretty good; but so is the fungus that causes dollar spot.
Dollar spot on bluegrass surround. Photo: Matt Roderick, Oakley Country Club
During the weeks of summer, the symptoms caused by Oak Lace Bugs (Corythucha arcuata) can be a concern to some landscapers & nurserymen. Often times, the infestations are most pronounced on white oaks. From a distance, the stippling of leaves from this piecing-sucking insect can produce symptoms that are similar to those from oak spider mites or classic leaf scorch. Closer inspection determines the identity of the pest.
Oak Lace Bug Severe Symptoms in Late August. Photo by Steven Rettke of RCE
Bacterial leaf scorch (BLS) season is officially upon us. Over the last 7 to- 10 days, I have been seeing increasing numbers of red oaks in central New Jersey exhibit the tell-tale symptoms of the disease.
Irregular leaf scorch due to Xylella infection. Photo: Richard Buckley, Rutgers PDL
Everybody keeps asking me “any gray leaf spot yet?” And I answer, “why yes, but not where you think.” Gray leaf spot was diagnosed last week on samples of Hakonechloa that were submitted from a central New Jersey nursery grower.
Gray leaf spot on Japanese Hakone grass. Photo: Sabrina Tirpak, Rutgers PDL
By Jim Murphy
We are seeing and hearing about increasing problems with green and false kyllinga; both are very troublesome invasive weed species that have moved northward into New Jersey. Green kyllinga and false green kyllinga are very similar in appearance, and both are referred to as green kyllinga. Green kyllinga is very difficult to control once large mats form.
These weeds thrive under mowing and are prolific in areas that are poorly drained or frequently wet. If you do not have control over irrigation, encourage property owners to reduce irrigation when you find that the turf is frequently wet during dry weather; excess irrigation makes the problem worse.
Unfortunately for us, there are fewer herbicide options in the cool-season turfgrass market than in warm-season turfgrass market to our south. [Read more…]
In most areas of NJ, the application timing of imidacloprid to nursery containers to achieve best efficacy against Oriental beetle grubs (Anomala orientalis) has now expired. The majority of eggs are laid during late June through early July and by the time August arrives, many of the grubs will have begun to molt into the 2nd instar stage. If imidacloprid is not applied until August, then some root feeding damage may have already occurred & furthermore, the larger instars will be more difficult to control. Generally, the preventative applications should be applied from early June to mid-July to achieve best results.
Next year, some nurseries may want to attempt the new Oriental beetle mating disruption pheromone that is discussed in the second half of this article.
Imidacloprid has good efficacy against Oriental beetle 1st instar grubs, but is significantly less effective against the 2nd & especially 3rd instar grubs
