I read with interest your opening statements regarding the current and future status of the Mediterranean fruit fly in California in the most recent issue of California Agriculture (49[4]: 4–6). Generally, you have provided an accurate assessment of the current situation. If you will permit me, I have just one or two points to clarify.

The area of origin of the Medfly has long been a controversial issue, and has only recently been resolved with some degree of certainty. The inability of earlier scientists to locate and confirm the Medfly's area of evolutionary origin has had unusual and far-reaching consequences relating to Medfly control. I will not expound upon them here, but I have done so in a recent article for Biological Control. Our current understanding of the zoogeography of Ceratitis leads us to believe that the group originated in east central Africa, more specifically in the higher elevations of Kenya, Tanzania, Mozambique and Zimbabwe.

The Medfly was first recognized as a pest in fruit sent from the Azores to England in 1829, and as a pest on Malta as early as, perhaps, 1820. By the turn of the century the Medfly had managed to invade nearly every major continent and island, except for North America. The first invasion into North America took place in 1929 in the Orlando area of Florida. The current distribution in Asia is of some concern and deserves further investigation. There are anecdotal records that indicate Medfly may occur in the tropical and subtropical areas of China. Many Asian export markets claim to be free of Medfly, I should think that this claim warrants verification.

David Headrick

UC Riverside

I am writing to express my appreciation for California Agriculture. This publication has proven to be a valuable information resource. I teach a course called Pesticides in the Environment and use information from the publication on a regular basis to enhance technical presentations of the fate of pesticides in terrestrial ecosystems. Students will often comment on the quality of the publication and on the usefulness of the information when they return a loaned copy. I must say that I agree wholeheartedly.

Larry Zibilske

University of Maine