Rhopalomyia chrysanthemi (Ahlberg), A NEW PEST FOR CHRYSANTHEMUM IN COLOMBIA

Abstract

The first record of the presence of the chrysanthemum gallnut fly, Rhopalomyia chrysanthemi (Ahlberg) (Diptera: Cecidomyiidae), in Colombia and in South America is presented in this work. Given its economical importance in the flower industry, a general distribution survey and preliminary studies on some aspects of its biology and feeding and re­production habits were conducted. The survey indicated that once the post was introduced into the country, it did not reach population levels of eco­nomical importance in exportation flower plantations;^-however, it was increasing in other plantations handled without any technology, becoming them a focus of infestation. The results obtained under laboratory conditions (T16± 2°C and R.H. 70 ± 5°/o) on the life cycle and feeding and reproduction habits are as follows: the mean duration of the egg, larvae, and pupae were, 7, 19 and 5 days, respecti­vely. Adults emerge early in the morning. They feed on the natural plant exudates (honeydew) and the mate dies after the copula, and the female dies after finishing the oviposition period. The female seeks for the terminals as oviposition sites. The sex ratio found was 1:1.