Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Estimation of mortality of Dacus xanthodes (Broun) maggots in fumigated and non-fumigated watermelons, a fruitfly (Dipt.: Tephritidae) of plant quarantine importance in the Pacific Region.

Abstract

Exports of watermelons from Tonga to New Zealand were banned in November 1985 becaused of infestation with larvae of Dacus xanthodes. [Bactrocera xanthodes]. Testing standard quarantine fumigation with methyl bromide is rendered difficult because of low levels of infestation in the field and unsuitability of watermelons for larval survival. Two testing methods that were studied are described. In the 1st, 300 larvae were artificially introduced into the fruit, the rind was replaced and sealed with tape, 5 holes were punched and methyl bromide was applied at 32 g/m3 for 4 h. In the 2nd, there were 200 larvae/fruit and 1 hole. Initial mortality averaged 98 and 44% for the 2 methods, resp., as compared with 17-35% for infestation at the lower rate and no fumigation.