Method of insect introduction onto inoculated plants
Second stage larvae of P. xylostella were introduced onto inoculated and control plants by releasing one larva per leaf per plant. After introduction, each larva was confined to the leaf using a small cage ( Fig. 1). The cage consisted of two identical parts (transparent fiberglass) that fitted exactly to each other with the help of spongy margins. Each part had a dish-like shape with a circular base of 3.5 cm diameter and 1.5 cm height. A circular, small mesh muslin sheet was tightly fixed to the bottom of each part for ventilation. The cage could be fixed to the plant leaf with the support of a clipe so that the larva and circular part of the leaf were confined inside.