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United States Department of Agriculture

Agricultural Research Service

Title: Fumigation and Fallowing Effects on Replant Problems in California Peach.

Authors
item Trout, Thomas
item Ajwa, Husein - UNIV OF CALIF SALINAS
item Schneider, Sally

Submitted to: Methyl Bromide Alternatives and Emissions Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 1, 2001
Publication Date: January 10, 2002
Citation: Trout, T.J., Ajwa, H.A., Schneider, S.M. 2002. Fumigation and fallowing effects on replant problems in california peach.. Methyl Bromide Alternatives and Emissions Research Conference Proceedings, pp. 77-1,2.

Interpretive Summary: When peach and several other types of fruit and nut trees are replanted after a previous orchard is removed, the trees often grow slowly. Growers have learned that fumigation with methyl bromide (MeBr) reduces this "replant disorder" and the new trees are more vigorous and uniform. The causes of replant disorder have not been identified but are believed to result from a complex of major and minor soil- borne plant pests whose populations evolved with the previous orchard. We tested, in field trials, chemical and non-chemical strategies that reduce the replant problem in peach and plum. Increasing fallow periods reduce the replant disorder. One year gives some benefits, but even three years may not be sufficient to control the problem as well as methyl bromide. Herbicide treatment to stumps of removed trees did not enhance the fallowing effect. Fallowing is an expensive option for orchard crop growers, especially for peaches that are replanted an average of every 7 years in California. Drip irrigation- applied Telone C35 (InLine) is effective against the replant problem. Drip fumigation with chlorpicrin gave the best tree growth and merits further study. Work is needed to determine the etiology of the replant problem.

Technical Abstract: When peach and several other types of fruit and nut trees are replanted after a previous orchard is removed, the trees often grow slowly. Growers have learned that fumigation with methyl bromide (MeBr) reduces this "replant disorder" and the new trees are more vigorous and uniform. The causes of replant disorder have not been identified but are believed to result from a complex of major and minor soil- borne plant pests whose populations evolved with the previous orchard. We tested, in field trials, chemical and non-chemical strategies that reduce the replant problem in peach and plum. Increasing fallow periods reduce the replant disorder. One year gives some benefits, but even three years may not be sufficient to control the problem as well as methyl bromide. Herbicide treatment to stumps of removed trees did not enhance the fallowing effect. Fallowing is an expensive option for orchard crop growers, especially for peaches that are replanted an average of every 7 years in California. Drip irrigation- applied Telone C35 (InLine) is effective against the replant problem. Drip fumigation with chlorpicrin gave the best tree growth and merits further study. Work is needed to determine the etiology of the replant problem.

Last Modified: 8/27/2014