Studies on the Use of DBCP in Vineyards. I. Two Years of Efficacy Data

Abstract

Fluctuations in nematode population, vine vigor and yield were assessed in five commercial vineyards following implementation of 18 different nematicide treatment programs. Data from 11 treated sites indicated a 79 to 179% change in fruit yield as a result of DBCP with a two year average of 132% improvement over untreated. We calculate an average gross return of six dollars for every one dollar of DBCP input. Including application costs the average gross return was 4.7 dollars to one. Data obtained were highly variable depending upon vine and vineyard condition, and method of DBCP application. Vines with limited root systems were damaged by use of repeated DBCP applications in one vineyard. Greatest yield improvements were obtained in two treatment sites where water applications were made; however, certain of the chisel applications provided an equivalent vine response. Nematode samples indicated that chisel and water applications made to relatively large treatment sites were effective at lowering plant parasitic nematode populations to half of the initial. Populations of certain nematodes were not lowered due to several biotic and abiotic factors.