General Conditions: Cooler weather over the first week of July, gave way to hot, humid weather and very little rain. Hanson received 0.92 inches of rain over the past two weeks and soils are very dry. Plants in unirrigated soils are becoming drought-stressed and most of MA is under a drought watch except Cape Cod and the westernmost part of the state. Continue to remind clients to water trees and shrubs planted this season and trees defoliated by caterpillars. Drought stressed trees are prone to increased problems, especially defoliated, drought-stressed oaks that might become a target for the two-lined chestnut borer. The following plans are in full bloom: Oxydendrum arboreum (Sourwood Tree), Stewartia pseudocamellia (Japanese Stewartia), Stewartia ‘Scarlet Sentinel’, Catalpa bignonioides (Southern Catalpa), Catalpa ovata (Chinese catalpa) Rhododendron maximum, Campsis radicans, Weston hybrid azaleas, Amorpha canescens (Leadplant), Indigofera sp., Clematis, Roses, Spiraea sp., Hydrangea arborescens (Smooth Hydrangea), Hydrangea quercifolia (Oakleaf hydrangea), Hydrangea macrophylla, Hydrangea paniculata ‘Praecox’ and other early cultivars, Rubus odoratus, Campanula sp., Persicaria polymorpha, Astrantia major, Achillea, Alchemilla mollis, Lamium, Asiatic lilies, Heliopsis sp., Platycodon grandiflorus, Asclepias tuberosa, Asclepias syriaca (common milkweed), Actaea (formerly Cimicifuga) racemosa, Shasta daisies, Deinanthe caerulea, Perovskia atriplicifolia, Yucca filamentosa, Astilbe, Liatris spicata, Hollyhocks, Corydalis lutea, daylilies, Hosta, Coreopsis sp., Kniphofia sp., Lysimachia clethroides, Filipendula venusta, Lysimachia ciliata, Monarda didyma (Beebalm) and Spigelia marilandica (Indian Pink). Cotinus obovatus (American Smoketree) and Cotinus coggygria (European Smokebush) continue to enhance the landscape with their colorful “smoke”. Staghorn sumac fruit is red. There are a few Kousa dogwoods remaining in bloom.
Pests/Problems: Gypsy moth caterpillars began pupating in late June – early July and a few stray caterpillars were observed actively feeding on July 8th. Male gypsy moths began to emerge around July 4th and continue to emerge now, by the thousands! The landscape is littered with them flying around! Females began to emerge after the males and egg-laying has begun. Without sufficient moisture, the insect-attacking fungus, Entomophaga maimaiga, while killing some late stage caterpillars, was not present enough to do significant damage to this season’s gypsy moth caterpillar population. There are now thousands and thousands of eggs being laid, and unless next spring brings rain to activate the fungus, there is the potential for an epic amount of gypsy moth caterpillars next year. (See Tawny Simisky’s Insect section of the Landscape Message). Defoliated trees are slowly leafing out and, as noted above, need water to alleviate drought stress and to help ‘push out’ new growth. A curious observation in Hanson, MA: staff from Dr. Elkinton’s UMass lab, observed the rare black-billed cuckoo in a forested area. This bird is known to eat “hairy caterpillars” and the thinking is, that this was a very good year for “hairy caterpillars”, hence the rare sighting: http://www.audubon.org/field-guide/bird/black-billed-cuckoo.
Japanese beetles were observed around July 11th, a bit later than usual and were found feeding on roses, and other usual hosts, along with Oriental beetles and Asiatic garden beetles.
Asian longhorned beetle look-alikes, like the White-spotted Pine Sawyer and Graphisurus fasciatus (Longhorned Beetle) are active. However, start scouting and monitor host trees for Asian longhorned beetles which may begin to emerge in July: https://ag.umass.edu/fact-sheets/asian-longhorned-beetle.
The caterpillar-like larvae of various sawflies can cause significant damage to plants, if not managed. Monitor white pine, Mugo pines etc. for the Introduced Pine Sawfly (black head, black body with white and yellow spots).
Monitor new foliage of Rhododendron maximum and R. catawbiense, as well as the foliage of roses and raspberries for the Sharpshooter leafhopper or red-banded leafhopper. Continue to monitor for Hibiscus sawfly larvae which are almost done. Four-lined plant bug damage is very noticeable now as brown circular lesions, coalescing together, sometimes mistaken for a disease. Monitor Azaleas for Azalea bark scale, eggs and crawlers.
The following insects remain active: Spider mites, lily leaf beetle, Cottony Camellia/Taxus scale; sunflower moth caterpillars (Homoeosoma electellum); Taxus mealybug; earwigs; azalea, rhododendron and Andromeda (Pieris) lacebugs; aphids; slugs; snails;leafhoppers; wasps; hornets; mosquitoes; deer flies; horse flies, deer tick nymphs and dog ticks.
The dry weather seemingly has helped slow down plant disease. Powdery mildew is starting to show up on Cornus florida and various Lonicera and there is some black spot on roses.