Strawberry Guava (Psidium cattleianum) – Prospects for Biological Control

Strawberry guava Psidium cattleianum Sabine (Myrtales, Myrtaceae) was introduced to Hawaii about 1825 and quickly escaped from cultivation. It is now found on all inhabited islands where it is one of the most important forest weeds. The small trees form extremely dense monotypic stands up to 10 m in height. Four insect species were found that have significant deleterious effects and, therefore, considerable potential. A leaf gall produced by Tectococcl~s ovefus Hempel (Homoptera, Eriococcidae) is the most promising due to the damage caused and the ease of handling. Bud galls, precocious developments of the bud that terminate shoot growth, are formed in response to Dasineura gigantea (Diptera, Cecidomyiidae). A seed gall induced by Eurytoma psidii Thurdczy and Wikler, in ed. (Hymenoptera, Eurytomidae) cements groups of seeds together and prevents germination of all seeds in the fruit. These latter two species have a significant impact but are more difficult to manipulate in quarantine. A shoot gall produced by Eurytoma cattleianii or Eurytoma desantisi (Hymenoptera, Eurytomidae) terminates further growth of the shoot. The species are difficult to handle in the laboratory. The biological control potential of three additional species is discussed: a leaf gall formed in response to Neotrioza tavaresi (Hemiptera, Psyllidae) which, though species specific, has little impact on the plants; a sawfly, Haplostegus epimelas Konow (Hymenoptera, Pergidae) is unsuitable because it attacks commercial guava occasionally; and, a chrysomelid Lamprosoma azureurn Germar (coleoptera, Chrysomelldae) IS not recommended because it attaCKS a number OT myrtaceous species.