A heavy drift of Botrytis spores from a nearby planting may endanger spikes that are to be shipped, even though the planting was sprayed every other day. Some control is obtained by dipping the cut spikes for 2 seconds in a solution of 1 pint Puratized Agricultural Spray in 100 gallons of water with enough wetting agent, such as Glim or Joy, to cause the solution to film over the hard-to-wet petals. Some growers prefer dipping the spikes in a spray mixture of nabam and zinc sulfate. The dip is not a substitute for spraying or dusting.

Sanitation may be helpful in controlling the disease, but has not made spraying unnecessary. Diseased material should be buried deeply or burned. Bloomed-out spikes should not be left standing in the field but should be removed from the field by hand if possible; otherwise they may be cut off and dragged out of the rows with cultivators. Covering them with soil promotes rotting.

CURVULARIA LEAF SPOT, a new disease, swept over the gladiolus fields of Alabama and Florida in 1947. We had no previous record of it on gladiolus, but a few growers believe they saw it in 1946 on gladiolus in Tennessee and Alabama. Its rapid spread through Florida and from Southern to Northern States indicated travel through the air and on the corms. The disease has been identified on corms or flowers received up to 1951 from New Hampshire, Vermont, Connecticut, New Jersey, New York, Indiana, and most of the Southeastern States. It has been reported to occur also in Illinois and Michigan.

Caused by a soil fungus, Curvularia lunata, the disease is favored by high temperatures and moisture and is a serious threat to gladiolus culture in areas having long periods of summer temperatures of 65 to 90 and frequent rainfall or heavy dews.

Leaves from cormels and seed are much more susceptible than leaves from large corms. Young leaves are more susceptible than old leaves. The rapidly growing flower spikes of some varieties are very susceptible. Infection of above-ground parts of the plant is serious in Southern States, although corm infection is slight or rare. In some Northern States, infection of corms has been severe, compared to flower infection. In all areas having warm, moist weather, the disease would be expected to be severe on seedlings and on plants grown from cormels.

Curvularia spots on large leaves are oval and tan, with a dark-brown margin. They may be as large as 2 inches long by one-half inch wide. There is a sprinkling of black spore specks near the center of the older spots. Typical spots seldom are seen on small leaves. Infection of cormel and seedling plants frequently appears as a damping-off and as a severe yellowing and browning of leaf tips. Large, oval, brown or black spots develop on stems and floret buds. Petal spots are large, brown, and nearly round. Infection of the flower bud often prevents its opening.

Corms and the leafy stalk below ground may be partly or completely rotted by the Curvularia fungus held over in ground where the disease occurred the previous year. Stalk infection may be very damaging to small plants but is generally outgrown and seldom noticed on larger plants. Diseased spots on corms are sunken, dark brown or black, and irregular in size and shape. They are hard, shallow, and usually separate easily and cleanly from the healthy tissue, although corms of some varieties have been rotted completely.

THE CURVULARIA FUNGUS lives in the soil 3 years and probably longer. Gladiolus should not be replanted for 3 years in a soil where a severe attack of the disease occurred. Crop rotation will help to control infection of underground parts but will not prevent reappearance of the disease on leaves when the weather is favorable.

Infection of leaves and flowers is controlled by spraying or dusting the plants with nabam or zineb. Applications of the fungicide are made once, twice, or three times a week, depending on the weather, the presence of infection, and stage of growth. Young or newly exposed growth is most susceptible and requires frequent applications for protection during moist weather. The spray is more effective if a spreader is added and if applied as a fine mist.

Many varieties are resistant to the disease and need no fungicidal protection. The leaves of some varieties are susceptible only when grown from cormels. Some varieties need protection also at the time of flowering. A few varieties, such as Picardy, Picardy sports, Corona, Purple Supreme, and Vredenburg, may be attacked severely at almost any stage of growth, except on mature, weathered leaves. Some varieties with good resistance to above-ground infection have shown little resistance to below-ground infection.

Growers no longer fear this disease as they did in 1947 and 1948, when losses were severe in the South. They have learned that timely, preventive spraying of the plants will control the disease, even on the most susceptible varieties.

R. O. MAGIE, pathologist in the Florida Agricultural Experiment Station, was born in Madison, N. Y., and was educated at Rutgers University and the University of Wisconsin. Dr. Magie conducted research at the New York State Agricultural Experiment Station before taking up research on gladiolus in 1945 at the Gulf Coast Experiment Station, Bradenton, Fla.

a, Group of asci; b, single spore at apexof ascus.