It is essential to use a purified single-species inoculum for resistant resource screenings to identify the host resistance to each single species. Pathogen inoculation must be completed within 1.5 h post-detachment to avoid false positives of resistance for detach-leaf assays. A whole-plant inoculation assay is necessary for identifying resistance to stem/node infection. Our findings suggest that AB screening can be done with any of the three protocols. pinodes or the mixture of the two species. After screening nine pea cultivars, we discovered that cultivar Fallon was immune to A. We found that different plant development stages do not affect AB infection type on peas, but the timing of inoculation affects the infection type of detached leaves due to wound-induced host defense response. We tested and optimized three protocols to determine the optimum type of pathogen inoculum, the optimal development stage for host inoculation, and the timing of inoculation for detached-leaf assays. To identify resistant individuals to assist AB resistance breeding, low-cost, high throughput, and reliable protocols for AB screening are needed. This disease is managed in the same way as Ascochyta Leaf Blight.Ascochyta blight (AB) is a destructive disease of the field pea ( Pisum sativum L.) caused by necrotrophic fungal pathogens known as the AB-disease complex. Septoria produces a large number of speck-sized fruiting bodies near the tips of the diseased blades. Ascochyta leaf blight may continue throughout the summer under high humidity or otherwise moist conditions. Also, while cool (60-75☏) wet weather is favorable for both diseases, Septoria leaf spot will not continue to afflict the grass during the heat of summer, but may return with cool wet conditions in autumn. Septoria leaf spot has symptoms similar to Ascochyta leaf blight, but begins as gray-green lesions, and the grass does not appear pinched above the green lower blade of a diseased tiller. See below for photos of affected lawns as they appeared on June 11 and how they looked on June 21.Īscochyta symptoms on June 11th on front lawnĪscochyta symptoms on June 11th on back lawn Lawns with this disease often quickly recover. Ascochyta blight disease development is sporadic and rapid, so fungicide spray is not recommended. Turf may look dead from a distance, but the blight does not affect bluegrass crowns and roots. Therefore, grass will recover in 2 to 3 weeks or longer depending on weather conditions. Collecting clippings to reduce fungal inoculum has not reduced disease severity. Also, it is recommended to avoid excessive nitrogen fertilization, especially in the spring, and try to maintain uniform soil moisture and good drainage. Avoid mowing during wet weather as it will harm the turf and provide more infection points for the pathogen. When disease is present reduce mowing frequency and increase mowing height. To manage the disease, reduce thatch by core aeration at least once a year to allow better water penetration. Maintain grass height between 2.5 and 3 inches. Note lower blades and crown remain healthyĪscochyta damaged turf where spores might have been spread by the mower Ascochyta blight is known to occur on drought-stressed turf and also during periods of hot weather preceded by wet conditions.Īscochyta leaf blight on turf grass showing typical symptoms of pinched-looking, bleached out grass tipsĪscochyta leaf blight symptoms of Kentucky bluegrass leaf blades. The fungus generally enters plants soon after the grass is mowed and begins to grow from the freshly cut end toward the leaf base. Hundreds of fungal spores emerge from pycnidium during wet weather and are dispersed by water, mowing, or other activities. The fungus survives as mycelium and fungal structures called pycnidia on dead leaves or clippings in the thatch. Other factors, such as thick thatch, poor soil, over or under-fertilization, and dull mower blades can contribute to disease severity. There are approximately 80 species of fungi in the genus Ascochyta that can cause Ascochyta leaf blight. Infected leaves present a bleached tip dieback and the margin between healthy and diseased shows a slightly pinched appearance. Some leaves may have uniform lesions that affect the entire leaf blade. From a distance, the symptoms resemble drought stress. The difference is that the symptoms of Ascochyta may appear quickly or overnight. Ascochyta leaf blight cause large irregular patches of turf to quickly turn straw-brown in color and appear dead.
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