Archer, T.L., Losada, J.C.v., Bynum, E.D., Jr., 1990.
Influence of planting date on abundance of foliage-feeding insects and mites associated with sorghum. Journal of Agricultural Entomology, 7: 221-232.
Abstract
At 2 sites in Texas, aphids were the dominant foliar-feeding insects on sorghum. Rhopalosiphum maidis was first recovered on seedling plants, densities declined during panicle exsertion in most planting date treatments. The highest densities of the aphid (about 200 aphids per plant) occurred on sorghum planted on 1 May or in June. Densities of Schizaphis graminum were increasing rapidly by mid- to late July and peaked in early to mid-August. The highest densities of this aphid were recorded on sorghum planted on 21 May, although abundance was high on both May- and June-planted sorghum. Although predators were present in association with both aphids, their numbers oscillated during the season and predators did not suppress increase in numbers of S. graminum in late July and August. Parasitoid abundance was dependent on density of S. graminum and the parasitoid failed to reduce its numbers before plant damage exceeded the economic injury level on sorghum in some of the May planting dates during 2 of the 4 years. Several minor arthropod species were present, including thrips in June, Heliothis zea [Helicoverpa zea] and Spodoptera frugiperda in the whorl in July and August, and mites (Oligonychus pratensis and Tetranychus urticae) after the density decline of Schizaphis graminum.
