A new species of gall midge (Diptera: Cecidomyiidae) attacking mango foliage in Guam, with observations on its pest status and biology

Abstract

AbstractA new species of gall midge,Procontarinia schreineriHarris, which attacks mango foliage in Guam, is described and the results of field observations on its pest status, biology and population fluctuations are reported. Eggs are laid on young mango leaves and larvae, which develop rapidly over about 5 days, induce blister galls before leaving to pupate. Secondary damage to infested foliage is caused by the fungusColletotrichum gloeosporioides, which invades damaged leaf tissue and causes mango anthracnose disease.P. schreineripopulation fluctuations on mangoes were assessed at four localities on Guam over three years by counting the numbers of galls. It was concluded that the main factors affecting populations were rainfall and location. More galls were present during rainy periods, possibly because high humidity improves larval and pupal survival. Gall populations were generally low and unlikely to have direct effects on fruit yields but the introduction of new improved varieties of mango might increase susceptibility to damage. In addition, old galls on damaged leaves may provide reservoirs of anthracnose inoculum.