Lawn and Landscape Problem Solving — Help is Available From the MU College of Agriculture, Food and Natural Resources

April is here and with the arrival of spring, the grass is greening up, trees and shrubs are flowering, and many people are looking forward once again to creating that perfect landscape. Unfortunately, the rigors of winter, notably freezing and thawing, can result in plant damage. And late spring frosts are not out of the picture until mid-May in most areas of Missouri. Add to that the various insects that infest turfgrass and ornamentals in the landscape and the plant disease organisms that can infect them. One sometimes wonders how plants survive at all.

There are several resources available in the MU College of Agriculture, Food and Natural Resources to help you grow the healthiest plants possible. The Soil Testing and Plant Analysis Laboratory conducts tests to measure soil fertility levels and soil pH. Knowing the soil fertility status and soil pH gives you a chance to provide adequate nutrition to promote plant vigor. Fertilizing your lawn or landscape to soil test recommendations also avoids the overuse of fertilizer, preventing runoff that can have a negative impact on your watershed.

The easiest way to collect soil samples is to use a soil probe or auger, but a shovel will also work. Collect 8-10 cores per sample into a plastic bucket. Mix thoroughly, then reserve one pint of soil for testing. Flower beds, gardens, and lawns should be sampled individually, because soil conditions are often very different in these areas. Cores should be taken from the 0-6 inch profile for gardens and beds and from the 3-6 inch profile for most lawns. The preferred method of submission is through your University Extension Center. Those offices can supply you with soil test boxes for sample submission, and the regional extension specialists on staff can help to interpret the results. For more information visit the Web site at: http://www.soiltest.psu.missouri.edu/.

Diseases, insects, or weeds can sometimes become problems in spite of our best efforts to promote healthy plants. The Plant Diagnostic Clinic provides a fee-based service to identify such problems and make appropriate management recommendations. The key to managing plant health problems in the landscape is to have an accurate identification of what is causing the problem. Accurate diagnosis avoids application of the wrong product, which can be costly and ineffective.

Sample plants or plant parts showing a range of symptoms from mild to severe. Include a healthy example for comparison when possible. Include enough of the plant to clearly indicate whether the symptoms are occurring on old or new growth. Above ground symptoms often result from a problem occurring in the lower stem or roots, so it’s best to send entire plants when feasible. Dig plants to leave roots intact in a soil ball and prevent drying. With larger specimens, try to sample from the transition zone between healthy and affected tissue.

Digital images submitted through our Web site or photos accompanying the sample are also very helpful in diagnosis. Occasionally, we can identify the problem on the basis of the digital image, but images are best used as an additional piece of information along with the physical sample. For more information on submitting plant or insect samples, visit our Web site at: http://www.agebb.missouri.edu/pdc/

Special instructions for Disease Identification

Turfgrass samples:
Take plugs at least 4 inches across with a cup cutter or knife to a depth to include the roots. Always include a diseased plug, a healthy plug, and one plug from the transition zone between healthy and affected turf.

Dutch elm disease, oak wilt, and other vascular wilts:
Submit live branches 1-2 inches in diameter, cut from areas of the tree that are just beginning to show symptoms. Include leaves. For oak wilt detection, submit branches exhibiting streaking in the sapwood. Keep samples cool during shipment by packing with ice packs.

Pine wilt nematode assay:
Submit branch pieces at least 1/2 inch in diameter and 3 to 4 inches long, taken from a branch expressing symptoms or segments of the trunk from trees that have recently died.

Special instructions for plant identification

Herbaceous plants (plants with green and/or soft tissue stems that die back each year) or grasses:

Whenever feasible the entire plant should be dug, not pulled, from the soil so that the roots or a representative portion remain relatively intact to a depth of approximately 4-5 inches. If rhizomes, bulbs or tubers are present, be sure to include these with the basal portion of the plant. If the plant is flowering or fruiting (seeding), send a portion of this part of the plant. Tall plants can be folded once or twice or cut into shorter lengths (for shipping purposes).

Woody plants — trees, shrubs, woody vines:
It is necessary to have a terminal or end portion of a leafy branch with at least five leaves or buds if collected in fall or winter. If flowers or fruit are present, these should be included. Fresh or dried leaves or fruit found beneath the tree, shrub, or vine and known to come from the same plant, are also valuable. If thorns are present, be sure they are represented in the samples. If the plant is a woody vine, a portion of the vine bearing representative leaves, tendrils (if present) that wrap around other plants or other supports enabling the plant to climb, and flowers or fruits (seeds), if present, should be included.

Note - Leaves of dicots or so-called broad-leafed plants may be of two types, i.e., simple or compound. Because of this, it is inadvisable to send for identification what appears to be a single leaf. Unless it is unusually distinctive and/or from a very common plant, it does not, as a rule, provide enough information to permit accurate identification.

Packaging Plant Materials for Shipping
Fresh samples should be wrapped in dry paper to absorb moisture and placed in a plastic bag. If roots are included, insert the root-soil ball in a plastic bag and tie around stem to avoid soil contact with leaves while in transit. Then wrap the entire sample in paper and place in a plastic bag. Do not add moisture to packing materials. Pack samples firmly in the shipping container.

Packaging insects for shipment
Submit only dead insects for identification, and pack them so they arrive unbroken. Badly damaged specimens are often unidentifiable, and a request for additional specimens could cause a great time delay. Insects differ greatly in body form and require two different preservation techniques.

Sending soft-bodied insects:
Aphids, thrips, mites, cutworms, caterpillars, fleas, ants, ticks, spiders, grubs and tiny or otherwise soft-bodied insects are best submitted in 70 percent alcohol (rubbing (isopropyl) alcohol is suitable). Place the specimen in alcohol in a leak-proof container. Do not send specimens in water, formaldehyde or without fluid.

Sending hard-bodied insects:
To submit beetles, flies, grasshoppers, cockroaches, wasps, moths, butterflies and other hard-boded insects, kill them by freezing them or by exposing them to alcohol fumes. Submit them dry in a crush proof container. Place dead specimens between layers of tissue or cotton in a small pill box or other small container. Identify the box with the client’s name, if possible.

Other Tips

• Don’t tape specimens to paper.
• Don’t ship live insects or mites.
• Don’t send only one specimen if more are available.
• Don’t place loose insects in envelopes
• Don’t use water or formaldehyde as a preservative.

Submitting Samples
As with soil testing, the preferred method for submission is through your Regional Extension Center. Most offices have forms available, so you can provide us with background information that will help our diagnosis. Mail early in the week. Always use at least first class mail. A next day service is the best way to assure that the sample arrives in good order.

Contact: Barb Corwin, State Extension Specialist for Turfgrass and Ornamental Diseases, 573-882-1335 corwinb@missouri.edu or Manjula Nathan, Director of Soil Testing and Plant Analysis, 573-882-3250, nathanm@missouri.edu.

Barb Corwin, Extension Specialist for Turfgrass and Ornamental Diseases, UMC (573) 882-1335