Pests and diseases of vegetable crops in New Caledonia
The main and almost unique resource of New Caledonia is nickel. However, agriculture is an important activity, and vegetable crops are important for the local economy. The main crops are potatoes (1128 t), 'squash' (Cucurbita maxima x C. moschata; 2610 t), salads (715 t), tomatoes (670 t), cabbages (452 t), onions (250 t), cucumbers (516 t), carrots (380 t), courgettes (172 t), capsicums (71 t). The EPPO Secretariat has extracted the following details on pests and diseases of quarantine importance from an article presenting the phytosanitary problems in New Caledonia.
Bactrocera tryoni (EPPO A1 quarantine pest)
This fruit fly has been introduced from Australia several years ago. B. tryoni and other indigenous species like B. curvipennis and B. psidii are particularly damaging during the hot season on aubergine, capsicum and tomato crops.
Bemisia tabaci (EPPO A2 quarantine pest)
This pest has recently been found in New Caledonia. It is reported that geminiviruses causing leaf curl diseases have been observed although no particular damage occurred so far.
Helicoverpa armigera (EPPO A2 quarantine pest)
This pest is present all year round. Programmes of integrated control are being developed (use of traps, research on more selective active ingredients with shorter pre-harvest intervals).
Liriomyza sativae (EPPO A1 quarantine pest)
Larvae of L. sativae are no longer considered as a problem in crops where farmers can use selective compounds (e.g. cyromazine, abamectine) and where a threshold of 3-5 mines per leaf is used to trigger applications.
Ralstonia solanacearum (EPPO A2 quarantine pest)
The bacterium causes losses mainly on tomatoes during summer on the north-east coast. Potatoes are grown during the cool season (June to October) and are rarely infected. Some infections are locally and occasionally reported in years where particularly hot summers had taken place before the potato growing season.
Thrips palmi (EPPO A1 quarantine pest)
T. palmi outbreaks can lead to total losses in commercial crops, particularly on aubergine and capsicum. Serious losses can also be observed on beans and cucumber. Chemical control is applied and there is an attempt to use products which are compatible with integrated management programmes.
Xanthomonas vesicatoria (EPPO A2 quarantine pest)
This is frequently found on capsicum and tomato crops in the south of New Caledonia. Prophylactic measures are taken to limit infections. The EPPO Secretariat had previously no data on the occurrence of X. vesicatoria in New Caledonia.
Sources
Daly, P. (1999) Les cultures légumières en Nouvelle-Calédonie. Situation des maladies et des ravageurs.
Phytoma - La Défense des Végétaux, no. 519, 28-30.