Biology of Acanthiophilus helianthi Rossi (Diptera: Tephritidae): A Safflower Pest of Southern Iran

ABSTRACT: The safflower fly is one of the most important pests of safflower in Iran. Losses caused by larval feeding leads to disrupted plant activities, reduction in flower buds, and, ultimately, to decreased quality and quantity of crop. This study was conducted on Acanthiophilus helianthi Rossi (Diptera: Tephritidae) at the Gachsaran Agricultural Research Station in Iran from November 2008 to July 2009. Sampling was performed weekly using a two-stage cluster sampling method. For the life cycle studies, the infected flower heads were collected from an experimental field plot and were developed in cages (160×160×100 cm) from egg to adult under laboratory conditions(27±2°C; relative humidity, 60%; and 16/8 L:D).The results showed that the first adults emerged gradually in mid April 2009. Female A.helianthi had a pre-oviposition period of 5.8 ± 1.0 days and the average fecundity was 27 ± 3.2 eggs. The Eggs were laid in the bracts of flower heads singly or in clusters of 3-18. The Incubation period was 3.8 ± 0.6 days under field conditions and 3.4 ± 0.6 days under cage conditions. The egg dimensions were 1.19 × 0.19 mm. Three larval instars occurred, and the larval phase was 7-10 days. The mean body dimensions (L × W) of larvae were 4.79 × 1.71mm. Pupa were coarctate and become sluggish before last molt. The pupal period was 7.5 days (range,6-9 days). The mean pupal dimensions of male and female cocoons were 3.95 × 1.42 and 4.55 × 2.27 mm, respectively. The flies spent their entire lifespan from egg to adult inside the flower heads of safflower plants. Males emerged earlier than females, but the longevity of the adult females (12 ± 3.0) was significantly greater than that of males (8 ± 1.0). Analysis of aggregated male and female sampling data showed that the sex ratio was 1:1.28.

Acanthiophilus helianthi, Safflower fly, Biology, Safflower, Iran