UMASS Landscape Update

Pioneer Valley (Amherst)

General Conditions: 

As we round the corner into the last days of July, it’s been a very hot and humid month in the Pioneer Valley. A 13-day stretch of mugginess spanned from July 6 to July 18 with dew points firmly in the 70s to near 80°F on the worst days. A cool front that generated strong thunderstorms (and a microburst in Belchertown) on July 20 produced some peak summer days (July 21 – July 23) with low temperatures dipping into the lower 50s. But the long-term forecast at the time of writing shows the heat will be ramping up once again.

Many trees and shrubs seemed to handle the hot and humid conditions quite well, but the rigors of the growing season are showing themselves. Leaf blotches, thinning canopies, scattered branch dieback are just a few of the symptoms on display right now.

Rainfall was highly scattered over the past two weeks, with some areas receiving an overabundance (5” in Northampton) while others received only scraps (~0.5” in New Salem). Precipitation totals over this reporting period (July 9 to July 23) ranged from 0.5–2.5” in Franklin County, 1.0–5.0” in Hampshire County, and 1.75–4.0” in Hampden County. Upper surface soils are dry in many locations, and supplemental irrigation is necessary for woody plants.

An enormous array of pollinators are visible in the landscape on plants such as joe pye weed (Eutrochium purpureum), Astilbe, Russian sage (Salvia yangii), ironweed (Vernonia fasciculata), mountain mint (Pycnanthemum muticum), and cup plant (Silphium perfoliatum), among many others.

Pests/Problems:

Continue to carefully scout the landscape and take note of any health issues that may require immediate intervention or treatment early next season. Invasive scarab beetle feeding is present on scattered woody and non-woody plants. If beetle damage is suspected but none are found, then Asiatic garden beetle (Maladera formosae) may be responsible. Gently excavate the soil around the roots at the base of the plant to determine if these dull brown beetles are present. Hand watering around the base can also flood them out for capturing.

Mushrooms and conks of common wood-rotting fungi are starting to appear, like chicken of the wood (Laetiporus spp.) and the black-staining polypore (Meripilus sumstinei; pictured here).

Various woody plant issues seen across the UMass campus include Marssonina leaf blotch on apple (Marssonina coronaria), downy leaf spot of hickory (Pseudomicrostroma juglandis), dogwood powdery mildew (Erysiphe pulchra), azalea bark scale (Eriococcus azaleae), a wide variety of eriophyid mites on deciduous hardwoods like Japanese elm (Ulmus davidiana var. japonica) and hackberry (Celtis occidentalis), and quince rust (Gymnosporangium clavipes) on serviceberry (Amelanchier canadensis) and hawthorn (Crataegus sp.).

There are large areas of brown turfgrass on the UMass campus with dry soils.

Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from Amherst.