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PestNet is a network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests. It started in 1999. Anyone with an interest in plant protection is welcome to join. PestNet is free and is moderated, ensuring that messages are confined to plant protection.
Crops > Trees, palms & pandanus > Palms & cycads > Cycads > Thrips & anthracnose, cycads, Australia & Malaysia
November 2003 & February 2006. Pests of Cycas revoluta were of interest to members in Australia as well as Malaysia. Two common problems in Darwin (Northern Territory of Australia) have been attributed to thrips (thought to be Labiothrips tenor) and Colletotrichum gleosporioides, the causal agent of anthracnose in many crops/plants. Although the photos (lower right) do not show it, fronds of cycads affected by thrips regularly emerge completely dessicated due to their feeding activity within the furled frond. Although the photos of anthracnose (top & bottom, left) are not C revoluta, the symptoms are very similar (just on a smaller scale).
Aulacaspis yasumatsui (Hemiptera: Sternorrhyncha: Diaspididae) was mentioned as being recorded only on members of the Cycadaceae (not Arecaceae).
The Cycad Aulacaspis Scale (CAS, Asian scale) is listed in the Global Invasive Species Database as present in New Zealand. This scale, Aulacaspis yasumatsui, is not present in New Zealand. It was detected on cycad plants in post-entry quarantine. All plants associated with CAS were destroyed. The detection of CAS in New Zealand is outlined in:
KL Paice, JE Richmond, SJ Bennett, HG Pearson and GSC Gill (2005) Detection of scale insects (Hemiptera: Diaspididae) in 2004. New Zealand Plant Protection 58.
Descriptons of symptoms of A yasumatsui, as well as Fusarium ovale and Cyas necrotic stunt virus were provided.
Aulacaspis yasumatsui – infests all above-ground plant parts and roots to a depth of 60 cm (in Florida). Highly infested cycads are almost completely coated with a white crust (appearing like snow) of live and dead scales. Insects on roots cause chlorotic or necrotic leaves which later turn brown and desiccate within a year. Crusts composed of several layers of male scales are especially common on the rachides.
Fusarium ovulerot – two Fusarium isolates, namely F moniliforme Sheldon and F moniliforme var intermedium Neish & Legget have been identified and confirmed by the International Mycology Institute, Surrey, England, as causal agents for this disease. Infected ovule are light to dark brown and show a necrotic dry rot.
Cycas necrotic stunt virus – Infected cycads show twisting on young leaves and chlorotic or necrotic spots on mature leaves.