Control of aphids on barley • economic treatment levels • analysis of yield increases
AuthorsVernon M. Stern
William R. Bowen
Authors AffiliationsVernon M. Stern is Associate Professor of Entomology, Department of Entomology, University of California, Riverside; William R. Bowen is Laboratory Technician, Agricultural Extension Service, Riverside.
Hilgardia 21(3):14-15. DOI:10.3733/ca.v021n03p14. March 1967.
Very good control of aphids in barley was obtained with commercial-scale airplane applications as low as 5 Ibs of 10% Thimet granules (1/2 Ib actual toxicant) per acre. However, problems with hopper calibration, and the extreme accuracy in flying necessary to apply this low rate of the systemic insecticide, make a 71/2- to 10-lb rate of application more realistic. Chemical control of aphids on barley was found economical only when populations averaged significantly higher than 25 to 30 aphids per tiller. In seven southern California barley fields treated with Thimet granules (at 1 Ib of actual material per acre) the mean yield increase was 434 ± 128 Ibs per acre. Even at the lowest increase (306 Ibs per acre) the value of the extra yield was well above the cost of aphid control. The average aphid population in the check plots rose to 39 per tiller.
Also in this issue:Rapida… a new oat crop for California
Whitewash found harmless in applications on walnut leaves
Strains of the Verticillium wilt fungus in California cotton
Precision planting for cannery tomatoes
A progress report… olive yield decline study in Tehama County
Herbicides for control of annual weeds in California apples and pears
Control of powdery mildew on cantaloupe
Lumber grade recovery in a circular-saw mill in California