Best Lawns News. Late Spring 2014 Edition Virginia Cooperative Extension Prince William Unit. Featured in This Issue

Transcription

1 Best Lawns News Late Spring 2014 Edition Virginia Cooperative Extension Prince William Unit Featured in This Issue Stilt Grass 2 National Arboretum s Grass Roots Exhibit 4 Grub Control 5 All content was written by Thomas Bolles, except where noted, and is based on university research at Virginia Tech, Virginia State and other partner universities in the Land Grant system. Staff contact information Paige Thacker, Extension Agent, Horticulture Phone: pthacker@pwcgov.org Nancy Berlin, Natural Resource Specialist/Master Gardener Coordinator Phone: nberlin@pwcgov.org Thomas Bolles, Environmental Education Specialist/BEST Lawns Coordinator Phone: tbolles@pwcgov.org Jennifer Graham, Administrative Assistant Phone: jgraham@pwcgov.org VIRGINIA COOPERATIVE EXTENSION 8033 Ashton Avenue, Suite 105 Manassas, VA Phone: Fax: Disclaimer Commercial products are named in this publication for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.

2 Stilt Grass Japanese Stilt Grass (Microstegium vimineum) is an invasive weed in our area. It is a warm season annual capable of producing a large amount of seed every fall. It is tolerant of shade and prefers moist areas. Left alone it will generally grow upright to about 3. When mowed, it will sprawl across the lawn. Stem Flower Growing Seedlings

3 Stilt Grass Blanketing Forest Understory (Photo by Chris Brown, University of Georgia) Because proper weed control requires the proper weed identification, if you are unsure a weed is stilt grass, bring in a sample to our office and we will identify it for you. Stilt grass can produce up to 50,000 seeds per square feet, making it easy to spread and difficult to control. The following options exist for treating this weed: Chemical Controls: Crabgrass Pre-Emergents that contain pendimethalin or prodiamine control Japanese stiltgrass. Timing will be slightly earlier than for crabgrass. They can be applied beginning in late-february weather permitting. Reapplication may be necessary. Fenoxaprop applied as a post emergent. This is most effective when applied to young plants. Repeated applications may be necessary for larger plants. Glyphosate maybe applied, but will harm turf and other desirable plants as well. Some of these products can not be used near waterways, including small streams and wetlands. It is important that you read and carefully follow the directions of any pesticide you choose to use. Cultural/Mechanical Control: Hand Pulling beginning early in the season. Repeated efforts may be needed. Mowing after allowing it to grow about 3+ feet when the seed heads are starting to form. This method depends on having a killing frost before the plants can regrow and set seed again. Any stilt grass control program may require multiple attempts and/or strategies. Because of the amount of seed they produce, removal of stilt grass infestations may take a few years to fully remove the problem. Thinking about growing vegetables this year? Check out Master Gardener Paul Gibson s Sustainable Vegetable Blog at:

4 Grass Roots Turfgrass Exhibit The National Arboretum in Washington, DC is operated by the USDA s Agriculture Research Service. It hosts exhibits on a variety of trees, shrubs and other plants. This year, however, the arboretum is installing the first of it s kind turfgrass exhibit. The exhibit features a variety of elements related to turf and turf care. Displays include a small scale golf green, a small green roof and a rain garden. Over 40 different ornamental grass species will be display as well. Included in the exhibit are sections on both live and artificial sports turf. Other educational displays will cover the basics of irrigation, fertilization, mowing and power equipment. You ll also find information on warm and cool season turfgrasses as well as information on common turf pests and diseases. Bad weather in the early part of the year pushed back the opening date. Parts of the exhibit should be finished for viewing by July, with the grand opening of the entire exhibit expected in late July or early August.

5 White Grubs White grubs are the immature stage of scarab beetles (Japanese beetles, masked chafers, oriental beetles, and others). Many white grubs are pests because they feed on the roots of turfgrass. This stresses the turf and can kill turf if the stress becomes severe enough. White grub numbers are expected to be high this year. The appropriate time to monitor for grubs is usually during the month of August, starting in early August. You want to estimate your white grub infestations before they cause significant damage. Be aware that in addition to monitoring for the white grubs themselves, you should also be monitoring for signs of natural enemies. There are numerous vertebrates, insects, fungi, nematodes and other organisms that attack and kill white grubs. Look for signs of changes in color, size, and/or shape of the body of grubs as these can indicate natural predators at work. Monitoring for white grubs involves peeling back 1 x 1 sections of turf, 2-3 inches deep, at various spots in the lawn and counting grubs. If the average number of grubs per square foot is 6 or more, treatment should be considered. Regardless of the product you choose for grub control, timing is key. There are a number of granular chemical products that can be effective in controlling white grubs. These should be applied in August. Be careful not to over apply. After application, water in with ½ inch of water for best results. Always read and follow label instructions. Many products have labels available online so you can look at them beforehand. This will help you make a more informed choice about the product you wish to buy. This is especially important with biologicals as few homeowners have experience using them. There are biologicals available for grub control but there are some things you need to know before starting a biological control program. Biologicals take time to work and you need to be patient. Fungicide use will interfere with some biological controls. Biologics need to be purchased from reputable suppliers to ensure that products contain viable organisms. As with chemical controls, it s very important to follow the directions for use, storage and handling of biologics. Milky Spore (Bacillus popilliae) was the first commercially available biological control for grubs. Milky spore only treats Japanese beetle grubs and is ineffective other species. There is some evidence that some of the milky spore on the market does not contain viable cultures. Moreover, based on surveys in recent years, Japanese beetle grubs are not the main grub pest in Virginia home lawns. Beauveria bassiana is an insect pathogenic fungus that attacks a broader spectrum of white grub species. It is a better choice for grub control in lawns than milky spore. There are a few other biological options. Products with the nematodes Steinernema riobrave or Heterohabditis can be used on white grubs as well. These parasitize grubs and are relatively rapid grub killers. They have effect on non-pest species. They are sensitive to UV light and should be applied in evening. They also often need to be refrigerated until use. Chemical pesticide use, low soil moisture, high salinity and ph extremes can all reduce the effectiveness of nematodes. A new biological being tested for use in Virginia is Metarhizium anisopliae (Met). Met grows naturally in soils and affects a range of insects. In turf, it is currently only registered for use on ticks. Testing is ongoing at a number of universities, including Virginia Tech, to study it s potential use on white grubs in turf. Typically grubs aren t a major pest in Prince William home lawns. Always scout for grubs first. Then apply a control only if needed and apply it at the right time to maximize effectiveness.

6 VCE Schedule of Classes Master Gardener Saturdays in The Garden The Teaching Garden at St. Benedict Monastery 9:00 am to Noon June 7 th, July 12 th, August 2 nd, September 6 th, October 4th July 12 - Simple ways to use water wisely in your landscape. Learn how plants use water, tips on rain barrels, proper irrigation & best practices for utilizing water more effectively. The Fall Vegetable Garden The Cooks Garden team will share tips for planting the Fall vegetable garden & extending the seasons. August 2 - The Frugal Gardener How to garden on a shoestring budget, get the most from your dollar by dividing plants, saving seeds and other smart ideas from Master Gardener Volunteers. Seasonal Solutions Join the Cooks Garden Volunteers for some seasonal tips for the organic vegetable garden September 6 - Weeds, Soil Health and Cover Crops Learn from VCE Staff & Master Gardener Volunteers how to improve your soil, identify weeds and use cover crops effectively. October 4 - Tree identification Join Arborist, Julie Flanagan, for a class on tree identification from 9 11:30 am. Storing homegrown produce The Cooks Garden Volunteers will give you tips for storing your homegrown produce from 11:30-12 noon. Master Gardener Clinics at Manassas City and Dale City Farmers Markets Saturdays (Manassas) and Sunday (Dale City) PLEASE NOTE: All Classes are of these programs are free. Registration is requested by calling or ing master_gardener@pwcgov.org June 14 is National Get Outdoors Day. Checkout the many local, state and federal parks and recreation areas across the region. Some federal facilities have free or discounted admission on the 14 th in celebration of this event.