Just like clockwork and in time to thrill your mother for Mothers Day, the telia of the fungus Gymnosporangium juniperi-virginianae appeared on area junipers.
Landscape, Ornamentals, Nursery, and Turf Edition
Seasonal updates on ornamental, nursery, and turf pests.
Subscriptions are available via EMAIL and RSS.
Companion Website Links:
Rutgers Turf Blog - Articles on turfgrass diseases and cultural practices for the commercial turfgrass industry. Subscription available via RSS.
Rutgers Weather Forecasting - Meteorological Information important to commercial agriculture.
Slow Green-up of Kentucky Bluegrass
By Jim Murphy
There are numerous elite varieties of Kentucky bluegrass (Compact Types) that have excellent tolerance of leaf spot, summer patch, and stripe smut diseases. Many varieties produce a very attractive, dense, compact (low growing) turf with dark green color during the summer.
Some elite varieties of Kentucky bluegrass exhibit slow spring green-up (plot in center foreground).
However, many of these Kentucky bluegrass varieties that are grown and sold as sod have the growth characteristic of long winter dormancy and slow spring green-up. The cool dry weather of this spring has certainly exacerbated this growth response. Full green-up of these varieties typically occurs by mid- to late-May.
Practices that hasten spring green-up of turf include fertilization with moderate amounts (0.4 to 0.7 pounds per 1,000 square feet) of water soluble nitrogen (WSN) and covering the turf with a growth blanket early in the spring (March and April).
Perennial ryegrass and tall fescue will often green-up several weeks earlier than these Compact Type Kentucky bluegrasses. Perennial ryegrass typically will have the earliest green-up.
Of the fine fescues used for turf, creeping red fescue will green-up earlier than Chewings fescue and hard fescue will have the slowest spring green-up. Green-up of creeping red fescue is relatively early and not too different from perennial ryegrass.
Slow Growth This Spring
By Jim Murphy
Slow growth of grasses has been a common complaint this spring. There are many factors that can cause this but cool dry weather has been a major factor this year.
Slow growth of turf can be due to many factors but cool dry weather has been important this spring.
But this is changing as I type. The abundant rains of this week will stimulate a lot of shoot growth. Be on the watch for large surges of growth from turfs that have been fertilized with relatively large amounts of nitrogen fertilizer. Water, warmer weather, and nitrogen can stimulate plenty of shoot growth.
Moreover, rains could interrupt mowing schedules. Sharp blades and bedknives will be very helpful in cutting fast growing, dense turfs. Overgrown turf will present the greatest challenge to mulching mowers. Raise the cutting height if rains significantly delays mowing and turf becomes severely overgrown. Double cutting may be another useful practice to reduce clipping debris.
Avoid mowing turf areas that are squishy wet. Operating equipment under these conditions can cause significant traffic damage to the turf and soil.
Downy Mildew in Ornamental Crops
Although the disease “downy mildew” sounds similar to the more familiar disease called “powdery mildew,” the downy mildews are caused by fungal relatives called Oomycetes. These fungal-like organisms, troublesome in during cool, moist weather, attack tender, above-ground plant parts, dispersing rapidly in films of water. In susceptible ornamental plants, downy mildews are most often caused by species of Peronospora, although species of Plasmopara, Pseudoperonospora, Sclerospora, and Bremia also cause this disease. [Read more…]
Leaf Spot Diseases in Landscape Turf
An unexpected sample walked into the laboratory at the end of last week. Net blotch, which is caused by the fungus Drechslera dictyoides, was subsequently diagnosed on a sample of turf-type tall fescue.
Take Off Your Rose Colored Glasses
Downy mildew was identified in Knock Out® rose samples submitted to the Plant Diagnostic Lab from a south-Jersey nursery this week. Knock Outs®, which have few problems, have been a favorite in New Jersey landscapes in recent years. Unfortunately, it seems this plant has met its Achilles’ heel.