One standard technique for distinguishing strains is microscopy. Diagnosis Ĭertain techniques can be used to determine which pathogen is causing disease. pisi rarely attacks the base of the plant or causes foot rot in comparison to M. Oftentimes, small black pycnidia are present. Lesions on leaves and pods are circular in shape, while lesions are elongated on stems. pisi can be identified by slightly sunken, tan-colored lesions that are defined by dark-brown margins. In contrast, the foot rot is usually more severe, oftentimes infecting the stem at the soil line and extending below ground, causing the lateral roots to die. pinodella tends to cause less damage to the leaves, stems, and pods. pinodella are very similar to those caused by M. Severe infection may kill or stunt young plants and in mature plants, it is likely to cause senescence of all lower leaves and blackening of the stems at the base of the plants. Planting of infected seeds may result in seedlings with foot rot. pinodes infected seeds might not show symptoms, but if symptoms are present, the seeds may appear shrunken and have a dark-brown discoloration. This greatly affects the number of surviving pods and limits seed production. pinodes infects the blossoms, small, pinpoint lesions appear on the flowers causing the blossom or small pod to drop. This gives the lower half of the plant a blue-black appearance. Over time, these lesions become increasingly longer and oftentimes coalesce with to completely girdle the stems of the plant. These lesions extend upward and downward from the point of attachment. From the attachment point of infected leaves, purplish-brown stem lesions are produced. The infected leaf will die but will still remain attached to the plant. Sometimes these lesions will enlarge and coalesce together forming a completely blighted leaf. However, under moist conditions, the purple spots enlarge, turning into well-defined, brown- black lesions. Under dry conditions, these spots remain small and have no well-defined margin. pinodes produce leaf infections that can be identified by many small purple spots on the undersides of leaves. However, there are some small differences between the fungal pathogens. Although three different pathogens cause ascochyta diseases of pea, the symptoms are relatively similar to one another, thus making diagnosis difficult. The ascochyta blight disease complex affects field peas ( Pisum sativum), as well as many other legumes such as chick peas, lentils, and faba beans. Other methods-chemical control, biological control, and development of resistant varieties-may also be used to effectively control ascochyta diseases. The best method to control ascochyta blights of pea is to reduce the amount of primary inoculum through sanitation, crop-rotation, and altering the sowing date. These diseases are conducive under wet and humid conditions and can cause a yield loss of up to fifty percent if left uncontrolled. Of the three fungi, Ascochyta pinodes is of the most importance. pinodella) causes Ascochyta foot rot, and Ascochyta pisi causes Ascochyta blight and pod spot. Ascochyta pinodella (synonym: Phoma medicaginis var. Ascochyta pinodes (sexual stage: Mycosphaerella pinodes) causes Mycosphaerella blight. Three fungi contribute to the ascochyta blight disease complex of pea ( Pisum sativum). Sanitation, crop-rotation, altering the sowing date, chemical control, biological control, and development of resistant varietiesĪscochyta blights occur throughout the world and can be of significant economic importance. Necrotic lesions caused by Ascochyta pinodes on field pea leavesĪscochyta diseases of pea, ascochyta blights, Mycosphaerella blight, Ascochyta foot rot, Ascochyta blight and pod spotĪscochyta pinodes, Ascochyta pinodella, and Ascochyta pisi
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