IDENTIFICATION OF DAMAGE SYMPTOMS AND PATTERNS OF FEEDING OF PLANT BUGS (HETEROPTERA, MIRIDAE) IN COTTON

The top 4 expanded nodes (terminals) of cotton plants, G. hirsutum L. [''DeHapine 61''], were exposed in plastic enclosures to Lygus hesperus Knight, Orius insidiosus (Say), Empoasca abrupta DeLong, Spanogonicus albofasciatus (Reuter) and Pseudatomoscelis seriatus (Reuter). Feeding damage was observed only on terminals exposed to L. hesperus, S. albofasciatus and P. seriatus. Symptoms of feeding on floral buds (squares) were necrosis and subsequent browning of the staminal column and occasionally of the ovary and pedicel. Insect damage was readily distinguished from the desiccation of all tissues of squares that abscised because of physiological stress. The preferred feeding sites for L. hesperus females and P. seriatus adults were the squares at the 1st nodes of fruiting branches at the base of the 1st and 2nd expanded leaf below the apical bud. These squares were 2-4 mm in width. At an average temperature of 30.degree. C, L. hesperus damaged 3.69 squares/insect per day.