Powdery Mildew Update

Powdery mildew is now present in many gardens, especially those with dense plantings and tree cover. Powdery mildew develops best on warm to hot days, cool nights and under conditions that cause dew to form on leaves. The disease has been found on lilacs, zinnias, crabapples, dogwoods, sycamores, turf and many other hosts.

New Publications

The Good Guys! Natural Enemies of Insects is a set of 31 laminated cards that provide full- color photos and life history information on beneficial natural enemies of insects. The cards were developed and produced by Mike Jeffords, Sue Post and Rob Wiedenmann from the Illinois Natural History Survey and Cliff Sadof from Purdue University. The cards are available for $8 from the Distribution Office, Illinois Natural History Survey, 607 East Peabody Drive, Champaign, IL 61820, (217) 333-6880.

Tomato Problems

Maturing tomato fruit sometimes develop large dead areas on the surface. The two most common causes of these lesions are blossom-end rot and sunscald.

Pepper, summer squash and other cucurbit crops may also show this problem.

Blossom-end rot

Blossom-end rot develops as necrotic areas at the blossom end of the fruit. Tomato fruit tips turn brown to black, while the ends on peppers usually become light brown or tan. Blossom-end rot results from a calcium deficiency in the plant caused by large fluctuations in soil moisture. When soil moisture is limited, plant growth slows and nutrient uptake by the roots is reduced. If water becomes available again, from rain or irrigation, the plant begins to grow rapidly, but the uptake of calcium lags behind. Thus, the rapidly expanding fruit tip does not have enough calcium available to develop properly, even though there is plenty of calcium in the soil.

The best method for controlling blossom-end rot is to maintain even and adequate levels of soil moisture. With soil that becomes neither too dry nor too wet, the plants grow at an even rate and the nutrients stay in balance. Of course, this goal is not easy to accomplish.

Sunscald

Sunscald also causes large necrotic areas on tomato and pepper fruit. Sunscald develops when an area on the fruit surface becomes too hot from sun exposure. On tomatoes and some pepper, therefore, sunscald often develops on the sides or "shoulders" of the fruit, near the stem end. Sunscald often develops on fruit that forms in the shade of the plant canopy but which is suddenly exposed to direct sunlight. Sunscald often occurs when plants lose leaves from foliar diseases. On tomatoes, early blight and Septoria leaf blight can cause premature defoliation, which leads to sunscald. On peppers, the defoliation occurs when plants infected with bacterial spot drop their leaves. Vascular wilt diseases and bacterial canker can also cause defoliation and, thus, lead to sunscald.

Avoid sunscald by controlling diseases that cause premature defoliation. Grow tomato varieties that are resistant to Verticillium and Fusarium wilts. Plant pepper varieties producing fruit that hang down and are covered by foliage. Minimize plant breakage during harvesting to avoid suddenly exposing the fruit to sunlight.

Japanese Beetle Update

Japanese beetles continue to be present and feeding on rose, crabapple, linden, birch and many other trees and shrubs. Numbers appear to be lower this year throughout the state, reducing the need for frequent insecticide applications. These beetles will be present until the third week of August.

Clean Houseplant Foliage

Removing dust from the foliage of your houseplants keeps them attractive and allows them to receive the maximum amount of light. Cleaning also can go a long way toward controlling some insect pests.

Leaves of houseplants should be cleaned once or twice a month with a soft brush, damp cloth, sponge, feather duster or simply by rinsing them with a gentle shower of water. Plants with hairy leaves, such as African violets, can be syringed occasionally with clear, room-temperature water. When using a cloth, sponge or towel, put one in each hand and clean the upper and lower leaf surfaces at the same time. If using a feather duster to clean your houseplants, upon finishing, spraying the duster with insecticidal soap or rubbing alcohol will kill any mites or insects that may cling to the feathers.

A high shine can be developed on many foliage plants by merely rubbing the leaves gently with soft cheesecloth or a camel's hair or sable brush. But beware of commercial leaf polishes. They are usually not necessary and can be toxic to the plant. They can inhibit transpiration. Just warm water and a soft cloth will do the trick. If you really want to use a leaf polish, test it first. Apply it to a couple of leaves, rinse off the excess and wait a couple of days to see if the plant tolerates it. Make sure to cover the soil with plastic to prevent contamination. Do not allow your plant cleaner to accumulate in the leaf bases and avoid using leaf cleaners on flowers and buds.

Source: Oregon State University

Houseplant Safety

Most of our homes are graced with houseplants. As adults, we realize these plants are to be looked at and not eaten, but children may have other ideas. Be sure children understand about houseplant safety and if necessary, place houseplants so little hands cannot reach them. Following are some plants that require caution.

Members of the Aracea family

These plants contain needle-like crystals of calcium oxalate that penetrate and irritate tissues of the mouth and throat. Chemicals in their sap, such as asparagine (a protein), also can cause inflammation of mucous membranes. Plants in this family include dieffenbachia, philodendron, caladium and elephant's ear. Symptoms of poisoning from dieffenbachia are intense burning and irritation of the mouth, tongue and lips. Although rare, if the reaction is severe enough, the swelling can seal off the breathing passages. Philodendron, caladium and elephant's ear produce the same types of symptoms when ingested. If a piece of the corm (underground stem) is eaten, symptoms are a fiery burning of the mouth and throat.

Euphorbiaceae (spurge) family

Most members of the spurge family have a milky sap that is acrid and toxic. This sap can cause dermatitis in some people and poisoning if eaten by someone who is allergic to the chemicals in the sap. Members of this family include the crown-of-thorns, the pencil tree (milk bush), poinsettia and snow-on-the-mountain. Snow-on-the-mountain can cause blisters and skin burns.

It is appropriate to note here the debate about the poinsettia. The original warnings on this plat were from a report in 1919 on a child who died in Hawaii where poinsettia is used as an outdoor ornamental. However, laboratory tests have NOT confirmed the toxicity of the plant when ingested. Poison control centers receive many reports each year of ingestion of poinsettia, but only occasional abdominal pain and nausea have been documented.

Solanaceae family

These plants contain solanine, a poisonous glycoalkaloid, that is extremely toxic even in small amounts. Jerusalem cherry is an ornamental in this family. Eating its berries cause symptoms ranging from headaches and stomach pains to shock and paralysis of the circulatory and respiratory systems. However, not all members of the Solanaceae family are toxic; for example, tomatoes and peppers.

Now that you are aware of possible dangers with certain houseplants, you can take steps to ensure the safety of others around these lovely plants. Try using hanging baskets, high shelves or window boxes to keep plants away from children. You don't need to stop displaying the plants mentioned above, just do so carefully.

Source: Virginia CES

Manual Sod Cutter

This tool cuts one-foot-wide strips; basically, it consists of cultivator-style handles attached to a horizontal roller down in the front, with a U-shaped blade mounted a few inches behind the roller. Suggested uses include removing sod for flower bed installation and patching established lawns. Fore more information, contact Quail Manufacturing Co., 6250 Industry Ave., N.W., #222, Ramsey, MN 55303, phone 800-786-9523 or 612-422-1991.

Late Summer 1997
It's Harvest Time! | Fences in the Landscape | Hort Shorts | Hort Tips | Using Electrical Garden Tools Safely | Bug Bites | Cybergarden Sites | Food Safety: September is National Food Safety Month | Locally Grown: Farmers' Market | Food Handling: How to Ripen Fruit | Health & Household Tips | Did You Know?

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