INTRODUCTION

The Symposium "'Insect Control of Tomorrow" has been organized to mark the occasion of the 65th birthday (15 September, 1981) and the subsequent retirement (September 1982) of Professor Dr. J. de Wilde, Head of the Department of Entomology, Agricultural University, Wageningen. Jan de Wilde unveiled in 1954 his foresight on future trends in applied entomology with his inaugural address: "'Insect control of tomorrow". From then on he showed himself to be very actively in favour of measures in insect control which could be ecologically just# fled; he propagated this ethos both in teaching and research, as well as in organizational activities at national and international levels. First of all, De Wilde is known as a stimulating teacher and gifted speaker. His reputation in combining and exhibiting scientific results became proverbial, and resulted in many lectures by invitation at home and abroad. The considerable number of students who achieved a Ph. D. degree in a wide variety of entomological subjects (about 55, the highest score in Wageningen) is another proof of this flourishing period of Dutch entomology. De Wilde's research activities cover different fields, such as photoperiodicity, diapause, reproduction and mechanisms of hormonal regulation. More recently, he developed a student programme on the ecophysiological adaptations of the colorado beetle in Europe. In recognition of his scientific merits he has received many distinctions. Moreover, De Wilde was a talented organizer. Of his manv initiatives and organizing activities, one national and one international enterprise in particular may be mentioned here. In 1956 he established a committee to coordinate and stimulate research on nonchemical methods of pest control. The achievements of this, known since 1958 as the "Working Party of Integrated Control", are laid down in the book: "Integrated control of insect pests in the Netherlands" (ed. Minks & Gruys), Pudoc, Wageningen, 1980. On the other hand, it was due to De Wilde's great interest in applied problems in developing countries that he also became involved in tropical affairs. The founding of the International Centre of Insect Physiology and Ecology (ICIPE, Nairobi, Kenya) in 1970 had his great interest, and he acted for several years as chairman of the governing board. The present issue of Entomologia experimentalis et applicata is a mark of honour to the dynamic personality of De Wilde. It comprises the text of the Symposium lectures, for which 4 of his pupils and 5 other experts and friends were invited. The last paper fits together thoughts and experiences which could not be presented in this original way other than by the recipient of the honour himself. The Organizing Committee is indebted to the editorial board of Entomologia experirnentalis et applicata for publishing the contents of the Symposium lectures, and to the Uyttenboogaart Etiasen Foundation for making a contribution towards the expense.