UMASS Landscaping Update

Pioneer Valley (Amherst)

General Conditions:

This tremendously colorful spring continues to dazzle in the Pioneer Valley. An array of rhododendrons, azaleas, and herbaceous perennials are now in peak flower. Conifers are draped in new growth. As we make our way into the home stretch of May, high temperatures and humidity have really started to climb. The mercury peaked at 90ºF on 5/22 with dew points in the upper 60s, causing a burn on some tender new growth in full sun. But we continue to experience a heavy dose of cloud cover intermixed with periods of sun and clear skies. Scattered showers across the tri-counties occurred on 5/15–5/16, with accumulations ranging from 0.25” to >1”. Strong, isolated bands of thunderstorms (with hail) on 5/21 dumped >1.5” in the Greenfield area. Overall, soil moisture is good across the landscape with supplemental irrigation only necessary for new transplants. The distinctive trills of the gray treefrog (Hyla versicolor) have been regularly heard in the late afternoon and early evening hours. Red maple samaras are spent and oak catkins are falling.

Pests/Problems:

Symptoms and reports of beech leaf disease (BLD) continue to develop in the area. Canopy dieback typically begins in the lower canopy and spreads upwards. The interveinal banding appears dark green on American beech (Fagus grandifolia) but may appear a purplish red on European beech (F. sylvatica). Additional symptoms include undersized, distorted leaves and a blight of the buds, meaning no leaves were produced this season. Woolly beech aphid (Phyllaphis fagi) appears to be common once again this season on European beech. Infestations can result in curled and distorted foliage that is covered in honeydew (aphid waste product). While unsightly, this pest often does not warrant management. Eastern tent caterpillar (Malacosoma americanum) is abundant this spring on black cherry (Prunus serotina) and crabapple (Malus sp.). Scattered leaf chewing and defoliation of tender new growth has been observed on oak and maple from unknown green caterpillars. Mosquitoes have emerged in a big way over the past two weeks and bee and wasp activity is very high overall. Be mindful not to overhead irrigate on sunny days from late morning into early afternoon. Water droplets on deciduous leaves can result in a foliar burn. Fruiting bodies of Cerioporus squamosus (Dryad’s Saddle) and Kretzschmaria deusta (Burnt Crust Fungus) can be found right now. The latter is most common on large European beech and sugar maple.