Relationship of Predatory and Injurious Insects in Cotton Fields In the Salt River Valley Area of Arizona

A study of the importance of easily seen predators was conducted on cotton during 1958-1960 in the Salt River Valley of Arizona. The abundance of such predators as Geocoris, Orius, Collops, lacewings, plant spiders, damsel bugs, assassin bugs, and lady beetles was determined during the cotton-growing season. At the same time population records were taken of lygus bugs and such destructive lepidopterous larvae as salt-marsh caterpillars ( Estigmene acrea (Drury)) and cotton leaf perforators (Bucculatrix thurberiella Busck). The predator complex did not bring severe lygus bug infestations below nondestructive levels. In the presence of high predatory insect populations present on August 1, severe infestations of either salt-marsh caterpillars or cotton leaf perforators developed in 10 of the 16 cotton fields studied.