Archer, T.L., Onken, A.B., Bynum, E.D., Jr., Peterson, G.C., 1990.
Banks grass mites (Oligonychus pratensis) abundance on sorghum cultivars with different levels of nitrogen use and metabolism efficiency. Experimental and Applied Acarology, 9: 3-4.
Abstract
The abundance of Oligonychus pratensis was recorded in Texas for 3 years (1985-87) on sorghum cultivars with different levels of nitrogen (N) use, metabolism efficiency. The cultivars tested were 77CS1, SC630-11E, R6956 and SC325-12. Nitrogen fertilizer was applied to plots containing each cultivar at 0, 45 and 180 kg N/ha. Significantly more mites were found on plants treated with 180 kg N/ha than on those treated with 0 or 45 kg N/ha. The lowest mite densities were recorded on SC325-12, the N-use-inefficient and N-metabolism-efficient cultivar. In July, O. pratensis abundance was statistically equivalent on SC325-12 and R6956, the other N-metabolism-efficient cultivar. In August, mite densities on R6956 were as high as on 77SC1 and SC630-11E, which are N-metabolism-inefficient cultivars. Mite densities were lower on N-use-inefficient and N-metabolism-efficient sorghum cultivars than on their respective efficiency counterparts. Physiological differences in N-use and metabolism-inefficient cultivars may influence the amount of leaf N plus the amount and form of amino acids and other N-based chemicals in sorghum leaves. These plant chemicals have been shown to influence mite abundance on several hosts, and it is suggested that they may have been key to influencing the results of these experiments.
