Study on biology of alfalfa weevil (Hypera postica Gyll.) in Sistan region.
2014
Golmohammadi, Gholamreza | Golamiyan, Golam Hossein
Alfalfa weevil is an important pest of alfalfa in Iran, particularly Sistan region. Studies on biology this pest conducted during the years 2001-2003. In this period, 3 fields in different region Sistan were chosen and by weekly sampling whit sweeping net (100 net per field) and cutting of stem; different stages and their density were determined.Results revealed that there were three generations of the pest per year in Sistan region. The alfalfa weevil overwinters in both the adult in protected areas outside of fields, such as windbreaks, wooded areas, or other protected habitats and egg stages in stems. Eggs are laid in the alfalfa stems and hatches after 5-6 days. This weevil passes through four larval stages (with head capsule width ./18, ./26, ./4 and ./56 respectively) in approximately 23days. When fully grown, the larvae spin a cocoon on the leaves of alfalfa plants or on the ground, after 6 days adults emerge. The second and Third generations of adult weevils emerge around late Ordibehesht and the first Tir. The adult has a resting period (Aestivation) in summer. But they are beginning activities from midle-Mehr The highest density of larval observed from late Esfand to first Farvardin; thus that times is most suitable for control. Key Words: biology, Hypera postica and Sistan
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