UMASS Landscape update

Pioneer Valley (Amherst)

General Conditions: 

Cloudy and wet conditions dominated yet again over this past reporting period in the Pioneer Valley. The last week had a bit of everything, with high heat and humidity (June 5 and June 6) broken up by a band of powerful thunderstorms that caused scattered tree damage and power outages. This was followed by yet another Saturday (June 7) with locally heavy rainfall. The pounding rain has toppled irises, peonies, and deciduous tree branches thick with new growth. With the long-term forecast calling for more rain over the upcoming weekend, it feels like there is little hope of a dry Saturday at this point.

Smoke from Canadian wildfires then settled over New England, pushing air quality index levels into unsafe levels for sensitive groups (June 7 - June 9). Finally, we got a few sunny, dry days (June 11 and June 12). On the positive side, it appears that many plants are enjoying the wet conditions, a welcome reprieve from the historical drought that wrapped up the 2024 season.

In some parts of the valley, the mosquitoes are as bad as they’ve been in recent memory. Spending even brief periods in the garden requires anti-mosquito efforts to avoid the biting hordes. Weeds continue to come in hard with the wet weather, but there has been little need to water. Rainfall totals over the past week (June 4 - June 11) in the valley spanned 0.6” in eastern Hampden County to 2.3” in western Franklin County.

Pests/Problems:

White pine needle damage (WPND) is visible on scattered trees throughout southern New England. While eastern white pine (Pinus strobus) is the primary host, numerous two-, three-, and five-needle pines also serve as hosts. Severe WPND was reported from northern New England in 2024, but the disease remains patchy across southern New England. Abundant June precipitation is often a driver of the disease.

Some common diseases of landscape trees seem to be appearing a bit early this season. Shothole of cherry (Prunus), which can be the result of fungal or bacterial infection, is present on several trees. Tubakia leaf blotch (Tubakia spp.) has been observed on oak (Quercus), a disease that typically appears later in the summer. Also, quince rust (Gymnosporangium clavipes) was observed on the fruit of serviceberry (Amelanchier canadensis). It could be a long season for the latter, as G. clavipes is capable of sporulating on rosaceous hosts into September.

Aphids can be detected almost anywhere with some close scouting. Cottony camellia scale (Pulvinaria floccifera) is abundant on yews (Taxus spp.). 

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