Disease Note.

Blotch Miner Associated with Mango Leaf Anthracnose in Micronesia. I. H. Schreiner, College of Agriculture and Life Sciences, University of Guam, Mangilao, Guam 96923. G. C. Wall, College of Agriculture and Life Sciences, University of Guam, Mangilao, Guam 96923. Plant Dis. 74:253. Accepted for publication 16 October 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0253B.

Anthracnose of mango (Mangifera indica L. ), caused by Colletotrichum gloeosporioiodes Penz., is a serious problem in the Mariana Islands. For many years, shot holes observed on leaves were attributed to this disease. but recent studies on Guam have shown that the primary cause of Shot-hole damage on young leaves is feeding by an insect and that C. gloeosporioiodes is a secondary invader. Infected leaves serve as a source of inoculum from which infection can spread to flowers, fruits. and new buds. Procontarinia sp.n. is a cecidomyid fly that develops in mango foliage. The flies attack mango when leaves are recently emerged and only 5- 10 cm long. The larvae develop as miners within the leaf, creating a circular mine 1.5-3 mm in diameter. Larvae complete their fceding period in 5 days and emerge from the leaf to pupate in the soil. Once damaged. the leaf tissue is quickly colonized by the anthracnose fungus. Because the miners abandon Ihe leaves at an early stage, it is easy to overlook their presence and attribute all of the damage to anthracnose. Although the flies have been reared only on Guam. the same symptoms have been observed on Saipan, Mariana Islands, and on Palau and Yap, Caroline Islands.