Distribution of fruitfly, Euphranta signatifacies Hardy (Diptera: Tephritidae) and effect of growth of black mangrove seedlings, Avicennia officinalis Linn. (Avicenniaceae) when fruits infested

Abstract

The study focused on the distribution of the fruit fly, Euphranta signatifacies, and the effects on the growth of black mangrove seedlings, Avicennia officinalis. Samples were collected from 6 mangrove forests in Songkhla, Surat Thani, Nakhon Si Thammarat, Satun, Trang and Phang Nga provinces. A total of 540 mangrove fruits were graded to groups by the number of oviposition scars (0-5) per fruit and observed in the laboratory. It was found that mangrove fruit flies emerged from the collected fruits from all provinces.The fruits with 5 scars had the highest average number of fruit fly larvae (4.13±1.17). These were significantly different from those with no oviposition scar (0 scars) which had no fly larva in the fruits. The planting of seedlings in the mangrove forest and the observation took 6 months. Three parameters were applied to assess the growth of seedlings, as follows: height of the seedling, circumference at the root base, and number of leaves per seedling. The seedlings developed from fruits with no oviposition scar had the highest values in all parameters: 44.44±5.93 centimeters, 2.56±0.20 centimeters, and 7.20±0.69 leaves per seedling, respectively. The lowest values in all parameters were noted in the seedlings which grew from fruits with 5 oviposition scars per fruit, with values of 28.65±8.53 centimeters, 2.23±0.15 centimeters, and 5.57±1.09 leaves per seedling, respectively.