General Conditions: Warm, windy, sunny days, and some cool nights, has been the norm for the past week. Hanson received 0.12 inches of rain. Soils are very dry and plants in unirrigated landscapes are starting to wilt and flowers are prematurely going-by, due to the warm, dry weather. If Dicentra spectabilis goes without water for too long, it often dies back and goes dormant for the remainder of the season. Remind clients to water their plants, especially trees defoliated by caterpillars. The following plants are in full bloom: Liriodendron tulipifera (Tuliptree), Magnolia virginiana (Sweetbay magnolia), Styrax japonicus, Sinocalycanthus chinensis, Cornus kousa, Weston hybrid azaleas, Hydrangea anomala petiolaris, Itea virginica, Spiraea sp., Rhododendron sp., Calycanthus floridus (Common Sweetshrub), Indigofera sp., Beautybush, Weigela florida, landscape roses, Lonicera sempervirens, Rosa rugosa, Clematis sp., Viburnum dilatatum (Linden Viburnum), Viburnum dentatum (Arrowwood Viburnum),Clematis, Alchemilla mollis, Salvia sp., Geranium sp., Thalictrum aquilegifolium, Anemone canadensis, Persicaria polymorpha, Doronicum sp., Lamium, Foxgloves, Allium, Nepeta sp., Baptisia australis and Baptisia hybrids, Dianthus sp., Tradescantia, Lupines, Corydalis lutea, and Valeriana officinalis. Chionanthus virginicus, Physocarpus opulifolius (Eastern Ninebark) and Amsonia sp. are ending bloom. Cotinus obovatus (American Smoketree) and Cotinus coggygria (European Smokebush) are now past bloom and are producing plume-like hairs (that form on the sterile flowers) which provide the landscape with their colorful “smoke”. It is a banner year for Kousa dogwoods!
Pests/Problems: The “big story in town” this week is about Gypsy moth caterpillars, which are in 4th and mostly 5th instars. These late instar caterpillars are feeding heavily and the resulting frass or “insect poop” can be heard falling in those areas where caterpillar populations are high. In some areas the caterpillars have done a good job defoliating oak and apple trees that were spared by winter moth caterpillars. There are reports of heavy feeding in areas of Carver, Plymouth, Kingston, Middleboro, etc. There are also reports of a very few “sick” and dying caterpillars but not enough to make a difference. We really need rain for soil moisture for plants and also to activate the fungus, Entomophaga maimaiga. (See Tawny Simisky’s report in the Insect Section of the Landscape message).
Asiatic garden beetles have started to emerge. These small copper-colored beetles feed at night on a wide range of plant material and are often attracted to lights. Caterpillars of the sunflower moth, (Homoeosoma electellum), were found in flowers and flower buds of Bidens ferulifolia. Sunflower moths lay eggs on the developing flower buds of plants in the Compositae (Asteraceae) family. The eggs hatch into small, brownish-dark grey caterpillars which destroy the buds and flowers, making them appear ‘rain-damaged’ and messy. Besides Bidens, monitor other composite plants like Echinacea, Helianthus,Rudbeckia, Heliopsis and marigolds. Earwigs are now active, as are slugs and snails, all of which are often found feeding on plant material at night. Feeding by the roseslug sawfly larvae has ended.
Continue to monitor dogwoods for dogwood sawfly which is active and manage if needed.
Continue to monitor for Andromeda lacebug on Japanese andromeda (Pieris japonica) and managed as needed. This can be a serious pest of Pieris, especially when planted in sunny locations. Euonymus caterpillars have started to pupate. The following insects remain active: White pine sawyer beetle (Asian longhorned beetle lookalike), Hemlock woolly adelgid, woolly beech aphid, cottony camellia scale on Meserve hollies and Taxus, Taxus mealybug, mosquitoes, aphids, stink bugs, four-lined plant bugs, leafhoppers, lily leaf beetle, wasps, pine spittlebugs, azalea whitefly, hornets, deer flies, horse flies, dog ticks and deer tick nymphs. Sod webworm moths remain active on turf. With all the dry weather here in southeast, MA, not too much has shown up plant disease-wise: a few leaf spots on dogwood; some tip dieback on Kwanzan cherry, most likely caused by brown rot (Monilinia sp.) and leaf spot showing up on a Hydrangea quercifolia ‘Little Honey’, which is probably receiving too much sun and stressing the plant. Continue to remove Azalea leaf galls (Exobasidium vaccinii) from deciduous azaleas and place them in the trash. White pine pollen is done for the year, having left behind a ‘blanket’ of yellow ‘dust’ covering the landscape. A good rain is also needed to wash that away! It is a banner year for chipmunks and rabbits, with many people commenting about the damage they do.