Chemical Control of Heterodera schachtii on Sugarbeet in California.

Received for publication 21 February 1978. 1Broom's Barn Experimental Station, Higham, Bury St. Edmunds, Suffolk, England. 2 Department of Nematology, University of California, Riverside, California 92521. 3Farm Advisor, Cooperative Extension, Santa Maria, California 93456. 4 Farm Advisor, Cooperative Extension, El Centro, California 92243. Much of this work was done while the senior author was on a one-year secondment to the Nematology Department, University of California, Riverside. We thank J. Fukuto for assistance. tonnes /ha were obtained in 1974-75 following fumigation with Te lone (1,3-dichloropropene) or D-D in combination with an "at-planting" treatment with Tem ik 15 G (2-methyl-2-(methylthio)propionaldehyde O(methylcarbamoyl)oxime) in a silty clay soil (Brinkman, Imperial Valley, southern California) (4). Yield increases were greater with fumigant nematicides (D-D or Telone), alone or in combination with the granular Tem ik 15 G or Furadan 10 G (2-dihydro-2,2dimethyl-7-benzofuranyl methyl carbamate), than with the granular compounds used alone (3). T h e five tests reported here were conducted to test effects of chemical control in fields infested with low populations of H. schachtii. Four of the five experiments (Chew, Lerno, Doel I, Doel II) were on clay