Landscape Message - Landscape Nursey and Urban Forestry

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The LANDSCAPE MESSAGE is an educational newsletter intended to guide landscape, nursery and urban forestry professionals in identifying pests in the landscape, monitoring their development, planning management strategies and creating site-specific records for future management reference.

UMass Extension has updated this issue to provide timely pest management information and the latest regional news and environmental data throughout Massachusetts. During the months of April through June, this newsletter will be published weekly. The next update will be available on or about April 17, 2009.

Missed a previous message? Visit the Landscape Message Archive.

Interested in additional turf-oriented content? UMass Extension Turf Program Management Updates

2009 GROWING DEGREE DAYS

Soil Temp
(°F at 4" depth)

Precipitation
(1-Week Gain)

Total accumulation for 2009

n/a = information not available

* = no activity to report/information not available

As the snow melts and exposes bare ground, we await the first activity of the White Pine Weevil. These small (approximately 1/4”) weevils overwinter in the adult stage in protected areas in such places as leaf litter, rock walls, and elsewhere. The adult female seeks the terminal growth of white pines and many different spruces where they will chew pits and lay eggs. The larvae soon hatch and tunnel downward in this apical shoot eventually killing 2-3 years of growth. The top whirl of lateral branches will then start to compete to become a new leader thus creating a multi-trunk form. This attack does not kill the host tree but merely changes its normal habit of growth. Eventually, attacked trees will become bushier; and if the trees are utilized as a privacy screen or windbreak, this may be desirable. Infested shoots can be pruned away before June and destroyed. Then, a new leader can be chosen from the best lateral branch on the remaining top whirl. Pyrethroid spray(s) applied early can help to deter attack from this pest. In many parts of the state now, this insect has been active for 1-2 weeks and infestation, in some cases, has already occurred.

Winter Moth flight last November/December was substantially more prevalent than it has been in Massachusetts for several years. This is a strong indicator that the numbers of caterpillars this spring will be up considerably for the first time in 3 years, and serious damage to trees, apple crops, and blueberries may occur. Winter moth caterpillars hatch early (approximately 20–50 GDD or about mid-April) and wriggle into swelling buds where they feed and harm leaf and flower buds. Dormant oil sprays for fruit tree crops (apple, blueberry) may be prudent. Once the foliage is open, these caterpillars then feed freely and can be managed with Bacillus thuringiensis Kurstaki (B.t.K.) while they are still small, or with a product that contains spinosad, or with a registered pyrethroid product. Winter moth egg hatch should occur any day now.

Hemlock Woolly Adelgid (HWA) is rebounding from the significant winter mortality it experienced in 2005 in Massachusetts. Monitor for the new egg masses that are appearing now. Once the weather is conducive to apply dormant oils, take advantage of this option where the numbers of HWA are increasing. Later, HWA can be managed with oil sprays at the summer rate or with systemic applications of imidacloprid.

Viburnum Leaf Beetle was found in MA during the 2008 growing season in several different counties. It was known to be established in Berkshire county for the past 3 years but has now been identified in Franklin, Bristol, and northern Worcester County. Many of the finds suggest strongly that this serious pest is being moved on nursery plants throughout the Northeast. Inspect now for the eggs, which were deposited on the terminal twigs last season. When found, such twigs should be removed and destroyed prior to the eggs hatching in late April–early May. Larvae will appear soon after the leaves emerge and feed until approximately mid June whereupon they will pupate. Adult beetles appear about 2-3 weeks later and feed until the first frost. Much damage can occur, especially from the larvae. For more details and preferred viburnum host species, visit: http://www.hort.cornell.edu/vlb Spinosad products work well for the larvae. Inspect viburnum twigs now for any signs of eggs; prune out and destroy if found.

Asian Longhorned Beetle (ALB) was found in Worcester, MA last August. The Regulated Area is now at 64 square miles. Approximately 19,000 trees have been removed and rendered into wood chips since January 2009. It is estimated that this population may have been in Worcester for at least 15 years. Survey work has renewed within the Regulated Area, and it is already known that many more trees are infested. Everyone must be on the lookout for this pest and report any potential finds immediately if eradication efforts are to be successful. Also, take great care when moving firewood to avoid moving this very serious killer of forest and landscape hardwood trees.

To report a potential ALB find: http://massnrc.org/pests/alb
To see “How to Recognize ALB” slide presentation: recognize_alb_ppt.pdf

Balsam Twig Aphid will be active soon. The ‘stem mothers’ can be seen with a hand lens. These pale green aphids will feed on true firs, in particular, and then produce many offspring that will feed on the new needles as they emerge from the buds causing them to twist and curl. This insect also produces much honeydew, which causes new (twisted) needles to stick together. This pest is of most concern in Christmas tree plantations but can be problematic in the landscape. If found in significant number, treat with a registered pyrethroid or with a horticultural oil if weather and plant phenology allows.

Mining Bees and Ground Bees: Many reports have been received within the past week concerning the activity in large numbers where the soil is suitable for them to build tunnels for offspring. Dozens or more at a time can be seen flying above the ground and entering into anthill-like holes in the ground. There are numerous species, but virtually all are quite docile and rarely, if ever, sting. However, their presence usually creates alarm for some people. Their busiest time is now and will continue for the next several weeks. After that, they usually become unnoticeable. Treatments are generally not applied given that these insects are important pollinators.

Reported by Robert Childs, Entomologist, Plant, Soil and Insect Sciences Department, UMass Extension, Amherst.

See our disease fact sheets section for many helpful fact sheets on disease problems of trees and shrubs.

Rhabdocline needle cast fruiting structures are becoming more visible on infected Douglasfir needles. Symptoms of Rhabdocline infection appear as elongated tan-brown spots and bands on infected needles. Spots often coalesce, and most of the needle turns color except for the base, which remains green. Infection tends to occur on the bottom of the tree first. Infected needles drop prematurely from now into the summer. Spores released from these fruiting bodies during wet spring weather infect new needles that will soon start developing. Avoid overhead watering of Douglasfir at this time of the year. Provide adequate spacing and limit weed growth around young trees. Consider fungicide applications to protect susceptible, high-value trees if this spring is wet. Maintain protection during the vulnerable period from when the buds swell/needles are first emerging from buds until they expand to full size.

Diplodia (Sphaeropsis) blight on pine can cause significant damage to stressed red, pitch, Japanese black, and, especially, Austrian pine in our area. If wet weather continues, new shoots developing on these trees are vulnerable to infection. Consider applying fungicides to protect susceptible trees beginning as soon as buds swell significantly (before buds break open). If wet conditions persist, reapply sprays at labeled intervals until the new growth fully expands. The Diplodia pinea fungus produces significant amount of inoculum on the outer scales of second-year cones, as well as infected shoots and needles. Remove affected shoots when plants are dry to improve appearance; however, this will make little difference in reducing inoculum for new infections without cone removal, too. If replacement of severely affected pines is an option, plant trees resistant to Diplodia blight as well as better adapted to grow on the site.

Ramorum blight, also known as sudden oak death (SOD) and ramorum dieback: The Phytophthora ramorum detection, quarantine, and eradication survey completed its seventh year as a United States Department of Agriculture-Animal and Plant Health Inspection Service-Plant Protection and Quarantine (USDA-APHIS-PPQ) regulatory program in 2008. The program began by monitoring nine counties in California along with part of Curry County in Oregon. It focused on regulating movement of risk articles such as wood, soil, foliage, and nursery stock. Infested areas grew to 14 California counties and the larger part of Curry County in Oregon, which Oregon aggressively surveyed and treated since 2001. Discovery of a shipment of P. ramorum-infected Camellia plants from a large production nursery to many garden centers and retail nurseries nationwide resulted in the USDA-APHIS-PPQ regulatory program receiving a great deal of scrutiny and policy revision in 2004. As a result, in January 2005 USDA-APHIS-PPQ extended the regulation of nursery stock to the entire states of California, Oregon, and Washington. Through ongoing surveys of nurseries, USDA-APHIS-PPQ continues to define the extent of the pathogen’s distribution in the U. S. and limit its artificial spread beyond infected areas through quarantine and a public education program.

Summary of Phytophthora ramorum in 2009:

Note:There were no updates for 2009 reported by USDA-APHIS-PPQ at this time. See earlier 2009 editions of the Landscape Message for a summary of the 2008 program.

Federal Regulation, State Inspection, Nursery Survey, and Other Finds: There was no report this month.
Forest Detection Survey: There was no report this month.

Reported by Dan Gillman, Plant Pathologist, UMass Extension Plant Diagnostic Lab, Amherst

IMPORTANT INFORMATIONAL RESOURCES

For a complete listing of upcoming events, see our Conferences and Workshops page.

Don't forget to visit the UMass Extension Online Weed Herbarium!

2008-2009 Professional Management Guide for Insects, Diseases and Weeds of Trees and Shrubs in New England - Pesticide label registration changes every year in all states and you can only legally apply pesticides according to the current year's label. This updated 2008-09 guide tells you what is current and legal for use in all the New England states and is the way for you to stay current with pesticide information. If you already have the 2003 version, this is the updated supplement for pesticide information. Remember, if you're a pesticide applicator, it's the law! Created by UMass Extension professionals, this manual offers the latest on virtually all the insects, diseases, and weeds of woody plants in New England; current and legal listings of chemical compounds labeled for the management of these pests; Integrated Pest Management (IPM) considerations for most of these pests; environmentally friendly alternatives in pest management such as horticultural oils, soaps, biologicals, etc.; and Growing Degree Day (GDD) information for most of the insect pests of woody plants. Click here to order online from the UMass Extension Bookstore or contact (413) 545-0895; eweeks@umext.umass.edu for information.

Planting and Maintaining Sustainable Landscapes: A Guide for Public Officials and the Green Industry - An updated and reprinted collection of fact sheets, including Trees and Shrubs for Low Maintenance Landscapes; Recommendations for Planting and Maintaining Trees and Shrubs; Integrated Pest Management and Plant Health Care; Streetscape Design and Planting; Selecting Turfgrasses for Low Maintenance Sites; Turf Pesticides and the Environment; Children's Protection Act and School IPM Plans; and Guidelines for Planting within the 100 Foot Wetland Buffer. Click here to order online from the UMass Extension Bookstore or contact (413) 545-0895; eweeks@umext.umass.edu for information.

UMass Extension Landscape Message #6
April 10, 2009

DIAGNOSTIC SERVICES

UMass Extension Landscape Message #6 April 10, 2009

DIAGNOSTIC SERVICES

UMass Extension Landscape Message #6
April 10, 2009