ELECTRICAL PENETRATION GRAPHS FROM PEREGRINUS-MAIDIS ON A SUSCEPTIBLEMAIZE HYBRID

The feeding behavior of Peregrinus maidis (Ashmead) (Homoptera: Delpha cidae), vector of maize mosaic virus (MMV) and maize stripe virus (MSt pV) in maize (Zea mays L.), has been studied by Electrical Penetration Graph (EPG). The different recordings collected have allowed the temp oral distinction of three EPG signal classes. These class 1, class 2 a nd class 3 signals are correlated through histological sections to the feeding activities of probing, xylem ingestion and phloem ingestion, respectively. Although these signals are described by various statisti cal parameters, only the median allows significant differentiation bet ween class 2 and class 3 signals, the others varying from one insect t o the next. On the other hand, spectral analysis is used to describe t he signal classes by associating a characteristic frequency spectrum t o each. This study treats the importance of such analysis in character izing and comparing the signals of various piercing and sucking insect s.