![]() To learn more about Delaro® 325 SC Fungicide, please visit and contact your retailer. Infection usually occurs very late therefore, management is generally not necessary.Īpply Delaro® 325 SC Fungicide. Usually a secondary disease after mechanical or insect injury, or another disease. Infected seeds are smaller, shriveled, and dark-brown to black.įavored by warm, moist conditions late in the growing season. Leaves eventually die and fall from the plant. ![]() Leaf lesions enlarge and merge together to produce large dead areas. Leaves may become reddish or yellowish in color.ĭark-brown lesions, usually with concentric rings, ¼ to 1 inch in diameter usually appear on leaves and pods near soybean maturity throughout the canopy (Figure 9). Seeds can also have no symptoms.Ĭrop rotation and tillage to encourage residue decomposition can help reduce pathogen levels.Īpply Delaro® 325 SC Fungicide. To learn more about Delaro® 325 SC Fungicide, please visit and contact your retailer.Ĭaused by fungal species of Alternaria, a seedborne pathogen. Lesions can grow through pods and may cause seeds to be dark, shriveled, and have cracked seed coats. On leaf undersides, the center of the lesions may have a dark-black area where spores are being produced.įavored by warm (77 to 86☏) temperatures and prolonged periods of dew or light rain. Later, the lesions become circular to angular with a purple to dark-brown margin around the tan to gray center (Figure 8). Symptoms initially appear during reproductive growth stages as dark, water-soaked lesions on younger leaves with centers that become ash-gray to light-brown in color. Harvest in a timely manner to reduce the risk of extended exposure of the mature crop to wet weather.Īpply Delaro® 325 SC Fungicide. To learn more about Delaro® 325 SC Fungicide, please visit and contact your retailer. Utilize tillage to promote decay of infected residue. Rotate crops to help reduce the amount of infected residue. Seeds may appear healthy, shriveled, cracked, or chalky because of coverage by white mycelium.įavored by wet weather during maturation growth stages and delayed harvest. Injury to pods by insects favors pod infection. Pod infection can occur at flowering however, most are infected around the R7 growth stage (beginning pod maturity). The upper plant canopy turns yellow and dies. Linear rows of dark specks (fungal fruiting bodies) develop on stem nodes, pods, and petioles (Figure 5). Pathogens overwinter on infected seed and soybean residue. Diaporthe sojae is the preferred scientific name. Identification, Characteristics, and Diagnosis:Ĭaused by various species of the fungi Diaporthe and Phomopsis. Additionally, diseases caused by Alternaria, Fusarium, Cladosporium, and Penicillium are known as secondary diseases responsible for quality reduction because they have the potential to infect plants after injuries from insects, hail, or mechanical means. Frogeye leaf spot, Anthracnose, and downy mildew can also reduce seed quality but generally less so than purple seed stain and the Diaporthe complex of diseases. Purple seed stain, caused by Cercospora, and the complex of Diaporthe fungal diseases (Phomopsis seed decay and pod and stem blight) are the diseases most mentioned for causing reductions in germination, and oil and flour quality. In general, the most probable conditions and time for quality deterioration of soybean seed by bacterial and fungal diseases occurs when the environment is warm and wet near or after seed maturation (Figure 1). A timely harvest after maturation is the best management practice for reducing the potential impact of these types of diseases on seed quality. Reductions in seed quality from viral diseases are not as dependent on temperature and moisture conditions. In any one year, yield potential can be reduced by several soybean diseases that can infect the crop depending on product susceptibility, available source of infection (fungus, bacterium, virus), timing of infection, and environmental conditions. However, only a few diseases have the potential to affect soybean seed quality and germination.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |