Anthracnose diseases are generally described as stress diseases and management practices that can damage the plant have often been implicated in disease development
rotted base to the plant, and the leaf tissues change from green, through yellow to red/orange as the severity of the infection increases. Eventually, the plants can be easily pulled from the rotted crown tissue. In this situation, the disease is referred to as Anthracnose Basal Rot and this has historically been the most widely known and discussed Anthracnose disease in amenity turf. However, infection can also develop
throughout the plant and, as the fungus develops its spore - producing structures (acervuli) on the leaf, the accumulation of the dark spore-bearing masses turn the leaf darker in colour, a symptom that is more noticeable as the leaf itself becomes tan following the development of the infection. In this situation, the disease is called Anthracnose Foliar Blight. Spores are again released from these acervuli and the life cycle is repeated.
Anthracnose Basal Rot has historically
been referred to as a disease that only affects Poa annua, and it remains correct to say that this grass, under close-mown conditions, is the most likely to show Basal Rot infection. However, I have definitely seen Basal Rot in Agrostis in the UK but the incidence of this appears to be relatively low. The Foliar Blight disease, however, can be found in all turfgrasses and is becoming an increasing problem on close-mown fine turf areas. Basal Rot Anthracnose has typically been documented as a disease that develops on Poa annua from late autumn through to spring on areas of turf that
may be subjected to compaction and that are maintained under low fertility. Certainly, the development of this disease occurs under cool, wet conditions but the disease can establish at any time of the year. With regard to Anthracnose Foliar Blight, the disease tends to develop through the warmer summer months but, as with the Basal Rot, this Anthracnose disease also needs free water for infection by the fungus. Anthracnose Foliar Blight is not uncommon on the turf above rootzones that are prone to water-repellence. If the rootzone is repelling water, applied irrigation or rainfall may sit around the base of the sward rather than moving through the rootzone, and this will allow ideal conditions for disease development. It is possible to identify the presence of
C. cereale on the older leaves of many turfgrass swards, and it is important to be able to determine if the fungus is actually causing disease or if its presence is merely that of a saprophyte on the decaying leaf tissues. As with all fungal diseases, the presence of the fungus does not automatically guarantee that it is causing damage to the plant, but analysis of the plant tissues can confirm if the fungus has entered the plant tissues and is causing disease. One interesting fact that has emerged
from research completed in the USA is that there appears to be a certain amount of host specificity within fungal isolates of C. cereale that cause Anthracnose diseases. What this means is that in a mixed Poa/Agrostis sward, C.
cereale may preferentially infect either the Poa or the Agrostis but not necessarily both. Although the most damaging symptoms of infection are seen on close- mown fine turfgrasses, this fungus may develop on all cool-season turfgrasses, causing a Foliar Blight infection on most. The Basal Rot infection is still most frequently seen on P. annua in the UK. Once the symptoms of Anthracnose Basal Rot are seen on the sward, the infected plants will die because of the extensive crown and root infection. Turf affected by Anthracnose Foliar Blight may recover if the infection is detected before it becomes established, but the high rate of spore development is a major factor in affecting disease severity. It is imperative that the turf is maintained under adequate nutrition to prevent a reduction in turf strength as this would likely encourage disease. Research has shown that weekly, low
nitrogen applications can result in reduced turf damage by Anthracnose diseases compared to applications made at twenty eight day intervals and, at advanced stages of infection, a combination of seven day low nitrogen application plus plant growth regulators have shown the greatest reduction in disease severity (Inguagiato et al, 2008). A recent article in Golf Course Management (Murphy, et al, 2008) discusses the best practices for Anthracnose management based on the research available to date. The effects of cultural management practices are discussed with regard to disease severity, and the following is a summary of their
Raising the height of cut can have a significant effect of reducing many fungal diseases as it reduces the overall stress on the plant
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