General Conditions: Warm weather finally arrived with temperatures in the mid 80’s on Wed. May 25th. The warm weather and lack of rain over the past few weeks is beginning to stress plants. Soils are powder-dry, and rain is needed, Hanson received only 0.25 inches of rain this past week and only 4.55 inches over the past 8 weeks. Remind clients to water newly planted plants and lawns. The following plants are in full bloom: Rutgers hybrid dogwoods (Stellar series), Aesculus hippocastanum (Common Horsechestnut), Halesia sp. (Silverbell), Magnolia fraseri, late blooming magnolia hybrids, Viburnum opulus, Viburnum plicatum var. tomentosum (doublefile viburnum), Cornus florida, Calycanthus floridus (Carolina allspice), Syringa sp., Loniceratatarica (invasive), Wisteria floribunda (Japanese Wisteria), Kerria, Daphne x burkwoodii 'Carol Mackie', Weigela florida, Aristolochia durior (Dutchman's pipe), Trillium, Convallaria majalis (Lily-of-the-valley), Euphorbia polychroma, Lamium sp., Primula sp., Brunnera macrophylla, Ajuga, Saruma henryi, Phlox subulata, Phlox divaricata, Phlox stolonifera, Myosotis sylvatica (Forget-me-not), Lunaria annua (honesty or money plant), Violets, Dicentra spectabilis (Bleeding heart), Tiarella cordifolia (Foam Flower), Vinca minor, Galium odoratum (Sweet Woodruff), Hyacinthoides hispanica, Arisaema sp., (Jack-in-the-pulpit), Polygonatum sp. (Solomon's Seal), Epimedium sp., Asarum canadense, Stylophorum diphyllum (Wood Poppy), Lamiastrum galeobdolon, bearded iris, early peonies, poppies, oxeye daisy, Buglossoides purpurocaerulea, Geranium sp., Corydalis lutea, Mazus reptans, Doronicum sp., Cypripedium parviflorum (Yellow Lady’s Slipper) and Persicaria bistorta ‘Superbum’. The flowering bracts of Kousa dogwood are beginning to open and show color. Ilex opaca, American holly, continues to shed its’ older yellow leaves. Three Massachusetts invasive plants barberry, autumn olive and burning bush, are in bloom. Now is a good time to remove and destroy the plants, and/or prune and shear them to remove flowers to prevent further seed production and dispersal.
Pests/Problems: Winter moth caterpillars remain active and while third instars may be found, many of the caterpillars are in 4th and mostly 5th instars (Growing Degrees Days 707, base 40). At this stage, the caterpillars produce large amount of frass (insect poop) and it sounds like rain as it drops to the ground covering whatever is beneath. In many areas, winter moth caterpillars have started to pupate and, according to staff at Dr. Joe Elkinton’s lab, winter moth season will probably be over by next week in areas in southeastern MA. Damage to plants is varied throughout; some crabapples, oaks, maples (Norway, sugar, red), etc. show significant damage, while others nearby show very little. Overall, so far, damage to trees, including the ‘test trees’ in Hanson, by winter moth caterpillars doesn’t appear to be as bad as in previous years. However, there are still late instar winter moth caterpillars feeding and they can do significant damage at this stage. Gypsy moth caterpillars are numerous and were found feeding alongside the late instar winter moth caterpillars in oak. Unless it rains heavily and Entomophaga maimaiga kicks in, we could see significant damage from gypsy moth caterpillars this year. Azalea sawfly is now active on deciduous azaleas like Exbury and Weston hybrid summer flowering azaleas. This small, bright glossy green caterpillar can be found feeding on the outer leaf margin and will devour the leaf, leaving only the midvein; manage early to avoid defoliation.(see Tawny Simisky’s Insect section of the Landscape message.) Euonymus caterpillar is active. Look for webbing at the tips of branches, as the caterpillars feed and web the leaf tips together. The webs are small now, but will grow in size as the caterpillars feed and develop. Roseslug sawfly remains active on roses. Continue to monitor rose foliage for the small, slug-like larvae, if left untreated, the sawfly larvae will skeletonize the rose foliage. Bt (Bacillus thuringiensis) is not effective on sawflies. Continue to monitor spruce, hemlocks, arborvitae and firs for spruce spider mite. Monitor hemlocks for hemlock woolly adelgid. Also, monitor hemlocks and firs for elongate hemlock (Fiorina scale) and manage as needed. Eastern tent caterpillar webs, although not numerous, are large at this time and can easily be seen on Malus and Prunus species. Continue to monitor for boxwood psyllid, cottony Taxus scale (aka: cottony camellia scale)andEuropean pine sawfly.The following insects remain active: aphids, spittlebugs, woolly beech aphid on beech, azalea whitefly, slugs, snails, ants, wasps, hornets, mosquitoes,lily leaf beetle, carpenter bees, dog ticks and deer tick nymphs; remember, the deer tick nymph stage is often thought to be most responsible for transmitting Lyme disease. A fungal disease, Exobasidium vaccinii, (Azalea leaf gall) is showing up on azaleas. Look for small-medium size, glossy green galls and hand pick remove and destroy, before they turn white. Garlic mustard, ground ivy, buttercups and veronica continue in full bloom. Wild turkeys, chipmunks, squirrels and rabbits are active.