Pecan anthracnose

Pecan anthracnose is a fungal disease of Pecan trees caused by the ascomycete Glomerella cingulata (Stoneman) Spauld. & H. It is a widespread disease found wherever pecan trees are grown. Pecan Anthracnose has been reported as far back in time as 1914 (Rand 1914),^[1] and as far away as Argentina (Mantz, Minhot et al. 2010).^[2] Glomerella cingulata has two anamorphs which cause disease on pecan trees, Colletotrichum gloeosporioides and Colletotrichum acutatum (Latham 1995).^[3] The occurrence of Colletotrichum on pecans has contributed to a significant decline in pecan production in various years. An increase in the incidence of Pecan Anthracnose is highly correlated with heavy rainfall, especially heavy rainfall occurring in early spring. The severity of symptoms increases as the season progresses, often culminating in leaf drop in the late autumn. This defoliation is linked to lower yield and poorer quality of nuts(Brenneman 2010).^[4]

Economic consequences

The financial loss due to Pecan Anthracnose in 2009 in Georgia was estimated at 3.4 million USD (Brock 2010).^[5] However, the actual loss due to the disease is difficult to quantify. Due to the nature of carbohydrate storage in perennials, the damage to pecan production is also likely to present itself in a lower yield in the year directly following a disease outbreak (Worley 1979).^[6]

Progression of Disease

Pecan Anthracnose is reported to have an unusually long latent period; it can take weeks to months from the time of initial infection to symptom development. Both ascospores and conidia can be found in the field and in culture, and both of these spore types can cause infection(Rand 1914).^[7]

Symptoms

Pink conidial oozes can be observed emerging from acervuli with setae on leaves and shucks.

References

See Also