Migratory and red locusts update for the first dekad of February, 2012 and a forecast for the next dekad

Situation Report
Originally published
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I. Meteorological and ecological conditions

During the 1st and 3rd dekads of January, tropical cyclones Chanda and Funso brought above average rainfall to the gregarization areas of the Malagasy locust (LMC). Average to above average rainfall was recorded in Central Horombe (Ianabinda, Analamary, Ankomanga, Ianakafy, etc.), the initial multiplication area (AMI), in the foothills of Isalo, North Horombe (Andohan Ilakaka, Ranohira, Satrokala, etc.) as well as the Manja basin in the northern AMI. Good rain was also reported in December and January, 2012 in the transitional multiplication (ATM) and densation areas (AD).

II. Locust situation

Migratory (Malagasy) Locust

Hatching was observed during the third dekad of January and small groups of hoppers were formed in Manja in the Northwest part of the AMI. Large groups of hoppers were detected in the central part of the AMI, between Analamary and Ianakafy and they could leave these areas before intervention is launched. No report was received from the southern part of the AMI during this period. The second generation hoppers formed small and large groups in the ATM where mating and egg laying continued. In the Nort-West area of the ATM, small and large groups of 1st to 4th instar hoppers at densities ranging from 40-300 insects/sq. m were observed in Heteropogon contortus and Stereospermum variabilae in the savannah areas on 60 to 500 sq m in over 50 meters to 5 km stretch. Relatively heavy hopper infestations were observed in the Soahazo, Befandriana-Sud, and Basibasy triangle. However, hatching contiues and will likely exacerbate the situation.

Low to medium density 1st and 2 nd instar hoppers and mating adult LMC were obsered in the Central ATM areas in Vineta and Balomotra. Adult and hoppers of red locust (NSE) mixed with LMC were observed. Low density immature adult solitario-transient and larval populations were observed in the pereplain of Fontandrevo and the Mahafaly Arc. Vey low density adults were observed in the Northwest zone of the AD, in Morombe and Mangoky delta (perhaps due to heavy moisture). In the lowlands of Tuliara, low density 1 st to 3 rd instar transient and solitary-transient hoppers and mature adults were observed. Adults were preparing for 1 st or 2 nd generation egg laying. Mature adults were also detcted in green grasses between Beheloka and Itampolo on the coastal lowlands in Mahafaly, but no hoppers were observed during this time. Low density adult populations were observed where hatching was just commencing in the Mahafaly plateau between Ankazomanga et Beomby (see map, courtesy FAO-CNA).