June 30, 1993

Benlate and Conifer Diseases


You probably know that Benlate has been the subject of many claims from greenhouse growers about phytotoxicity on various crops. The fallout from this controversy included DuPont's virtually eliminating ornamental uses from the Benlate label. Contrary to what you may have heard, however, certain conifer diseases remain on the Benlate label. These include Diplodia tip blight (on Austrian, red, and Scots pine) and Swiss needlecast (on Douglas fir). The fungicide is labeled for brown spot needle blight, but ONLY on longleaf pine, which doesn't occur in Iowa.

Plant Disease Clinic--Highlights


Brown Rot

Cherry samples showing signs of brown rot have been arriving at the Plant Disease Clinic. Brown rot is caused by the fungus Monilinia fructicola and affects stone fruits such as peach, nectarine, apricot, plum, and cherry. The fungus may infect blossoms, fruit spurs, twigs, small branches, and fruit. Disease development is favored by warm, wet, humid weather.

Summer Gardening Hints


This spring and early summer have certainly been seasons for the record books. Abundant rains and cool temperatures have everyone wondering if this is the midwest or the pacific northwest. Listed below are some hints to help plants look and produce to their fullest potential.

Fruit IPM update


APPLES

Dividing Irises


While bearded irises are easy-to-grow, long- lived perennials, they need to be divided every 3 to 5 years. If not divided, the plants become overcrowded and flower production decreases. Crowded plants are also more prone to disease problems. The best time to dig, divide, and transplant irises is in July and August.

Strawberry Renovation


June-bearing strawberries are most productive when grown in 2-foot-wide matted rows. If the strawberry bed is a solid mat of plants, renovate the planting by creating 8 inch-wide plant strips with a rototiller or hoe. These 8-inch-wide strips should be about 3 to 4 feet apart. Runners will form and the new plants will create a 2-foot-wide matted row by the end of the summer. June-bearing strawberries grown in rows should also be renovated. Simply narrow the rows to 8-inch wide strips by removing the older plants and keeping the younger ones.

Consumer Reports Rates the Repellents


Insect repellents were researched and reviewed by Consumers Union and the results published in the July, 1993, issue of Consumer Reports magazine. Twenty-one different commercial products were tested, including aerosol and pump sprays, squeeze bottles or tubes, and wipe-on sticks and towelettes. Repellents were tested against two species of mosquitoes and against stable flies. Only mosquito repellency is summarized here.

Slugs in the Landscape


Slugs are usually not a problem in Iowa vegetable gardens and flower beds, although prolonged periods of wet weather like we have had for the past year may change our luck. Slugs are familiar pests because of the frequent write-ups they get in gardening publications from eastern U.S. where conditions for slugs are more favorable.