Knowledge for a sustainable world

Horticultural entomology in the 21st century Jerry Cross, Visiting Professor of Horticultural Entomology

Jerry Cross, Visiting Professor of Horticultural Entomology, gave his inaugural lecture to an audience of more than 120 in the Pilkington Lecture Theatre on the Medway Campus on Thursday 11 February 2010. Professor Cross is Science Team Leader for Entomology and Plant Pathology at East Malling Research and entitled his lecture "To spray or not to spray: that is the question" (2.8Mb).

Professor Cross described how sprays of chemical pesticides are essential to control pests and diseases on horticultural crops in order to ensure the quantity of produce required to feed an increasing population and the quality we have come to expect, all at an affordable cost. Nevertheless, there is justified concern among the public at the effects of pesticides on the environment and the possibilities of residues remaining in food.

Professor Cross described the many aspects of his research aimed at resolving these dilemmas by developing alternatives to pesticides, by making sure pesticides are applied only when necessary and at the most effective time and by improving the efficiency of the spraying process. These included reducing the need for pesticides by conservation and manipulation of natural enemies to control aphids and pear sucker. Detailed studies of the biology and life cycles of insect pests have lead to much better timing of the application of pesticides for control of mussel scale on apple, gall mite on blackcurrant and aphids on apples. Traps baited with attractive pheromones have been developed for growers to monitor gall midges, capsids and strawberry blossom weevils, and the pheromones may provide alternatives to control of the pests. Laser technology has been used to provide maps of the tree canopy in orchards which are used with web-based dose calculators to minimise the amount of pesticide required. Integration of a variety of approaches is vital to overcome the dependence upon pesticide sprays which Professor Cross described as one of the greatest challenges for horticulture in the 21st century.

Professor Cross generously acknowledged the many collaborators he has worked with, particularly scientists at the Natural Resources Institute of the University with whom he has worked for more than 15 years on development of pheromones and other natural products for monitoring and control of insect pests.