Occurrence and abundance of watermelon (Citrullus lanatus) arthropod pests in Oklahoma

Populations of the squash bug, Anasa tristis (DeGeer) (Hemiptera: Coreidae), and the cucumber beetle species complex, Acalymma vitattum (Fab.) and Diabrotica undecimpunctata howardii Barber (Coleoptera: Chrysomelidae), were more abundant in time and space on watermelon, Citrullus lanatus (Thunberg) Matsumura and Nakai (Cucurbitaceae), than the melon aphid, Aphis gossypii Glover (Hemiptera: Aphidae), or the spider mite species complex, Tetranychus spp. (Acariformes: Actinedida: Tetranychidae). Abundance of the squash bug and the cucumber beetles varied among geographic districts, among locations within a district, among peripheral and interior positions within a field, and among years. Squash bugs and cucumber beetles occurred about a week earlier in the southeast and southwest districts than the northeast district in the spring 1998. Populations of both insects were more frequent in time (sampling interval) or in space (number of fields) in the southeast district than the northeast or southwest districts in 1998, 1999, and 2001. Seasonal patterns of occurrence of both insects may be related to planting date and initial abundance early in a growing season.